Manual

PHANTOM

48V Off

-20 Off

VU CAL
Clip 48 V Limit AD OVL -10 0

LIMITER

18 Off 12
Dual Channel Microphone, Line & Instrument Preamplifier

PHASE Rev.

HI PASS

50 Off

Performance

High Off Med

TUBE AMP

Gold Mike

Mark 2
Discrete Class A Preamplifier Stage

INSERT

On Off

SOURCE

Instr. Line Mic

INSTR.

-10 -9 -8 -6 -12 -5 -14 -2.5 ---20 3.5 -22 -5.5 -25 -dB

Output

Model 2485

GoldMikeMk2

Dual-channel microphone and instrument preamplifier

Manual GoldMike MK2

Version 1.2 12/2005 Designer: Ruben Tilgner
This user's guide contains a description of the product. It in no way represents a guarantee of particular characteristics or results of use. The information in this document has been carefully compiled and verified and, unless otherwise stated or agreed upon, correctly describes the product at the time of packaging with this document. Sound Performance Lab (SPL) continuously strives to improve its products and reserves the right to modify the product described in this manual at any time without prior notice. This document is the property of SPL and may not be copied or reproduced in any manner, in part or fully, without prior authorization by SPL.
SPL electronics GmbH Sohlweg 55, 41372 Niederkruechten Germany Tel. +49 (0)40 Fax +49 (0)420 Email: info@soundperformancelab.com Website: www.soundperformancelab.com SPL USA EMail: www.spl-usa.com Website: info@spl-usa.com
2005 SPL electronics GmbH. All rights reserved. Names of other companies and their products are trademarks of their respective owners.

GoldMike MK2

Contents
Introduction.. 4 Before You Begin.. 5
Rear Panel/Connections.. 6 Wiring... 6 General advices... 7 Mic Input 1/2, Line In 1/2, Inserts 1/2.. 8 Outputs 1/2, GND Lift.. 9 Front Panel/Connections.. 9 Instr. Input 1/2... 9 Control Elements.. Power, Gain, About Gain Adjustments. Output, Phantom... Phase, Pad, Hi Pass.. Flair, Tube Amp, About Tube Amping.. Limiter.. VU-Cal, Source, Display, VU-Meter. 48V LED, Clip LED, Limit LED, AD OVL LED.. 16 17
Technology... 18 Solid State and Tube Stages, Output Stage. 18 Instrument Input, Relays, Foil Condensers. 19 Power Supply... 20 Options (A/D Converter and Lundahl Transformers). 21 Specifications/Dimensions & Weight.. 23 Guarantee... 24 Notes.... 25

Introduction

The GoldMikeMK2 is the result of all our experience and knowledge from its successful predecessor and represents an improved, more flexible and more modern version. We have added technologies that have already proven to provide superior tonal results in other SPL products. For example, the instrument input is designed around a class A impedance converter which premiered in the SPL GainStation preamp. A significant contribution to the success of the predecessor was the hybrid preamplifier concept. It combines transistor and tube preamplifier stages and specifically utilizes their technological and sonic advantages: the efficiency and low noise of a discrete transistor stage is enriched with musical coloration of a tube stage. The transistor stage is composed of single transistors in a class A design. The circuitry is fully discrete, and each transistor is completely optimized for its specific task. You will not find any integrated circuits in this preamplifier stage because they cannot be optimized for this specific application to the degree we aimed for. This all new discrete class A transistor stage is a genuine innovation in the entire preamplifier market at this price level. The degree of tube pre-amplification is no longer the fixed +6 dB value of its predecessor. The GoldMikeMK2 sports the selection of three different tube pre-amplifications: +6 dB remains the standard complemented by +12 dB and +18 dB. This allows creative variety with the tube saturation and limiting effects. We have also added an extra setting to the popular Flair circuitry to give more flexibility to the presence improvement. Because the GoldMikeMK2 is a dual channel preamplifier, its channel separation is of fundamental importance for the stereo image. Therefore the print-board layout is symmetrically mirrored around the power supply in the center from channel 1 to channel 2. This results in an identical signal flow to supporting a naturally balanced stereo image. Additionally the print-board provides extra-large ground areas maximizing the shielding against crosstalk and interference.

Before You Begin

IMPORTANT: Before you operate your GoldMikeMK2, first check carefully whether the local voltage setting corresponds to the switch setting on the rear panel!

VOLTAGE

V~50 Hz V~60 Hz
If not, and the voltage is in one way or another, incorrect, you will either experience an immediate fuse burn through (if the setting is lower than the supplied power) or, if the power is 110-120V at a 220-240V input switch setting, the GoldMikeMK2 will simply not function correctly. Moreover, make sure you remove the power plug from your GoldMikeMK2 before changing this switch setting! Always turn volume down or mute your speakers when connecting or repatching audio cables to avoid damage to your speakers and ears. It makes good sense to think about where you place the unit before connecting it. It should be positioned so that you can easily reach it, but there are other considerations. Try not to place it near heat sources or in direct sunlight, and avoid exposure to excessive vibrations, dust, heat, cold or moisture. It should also be kept away from transformers, motors, power amplifiers and digital processors. In addition, please: Do not open the case. You may risk very dangerous electric shock and damage to your equipment. Leave repairs and maintenance to a qualified service technician. Should foreign objects fall inside the case, contact your authorized dealer or support person. To avoid electric shock or fire hazards, do not expose your unit to rain or moisture. In case of lightning, unplug the unit. Always unplug the cable by pulling on the plug only; never pull on the cable. Never force a switch or knob. Use a soft, lint-free cloth to clean the case, if necessary together with an acid-free cleaning oil. Avoid any cleaning agents as they may damage the surfaces of the unit.
Optional A/D converter, model 2376 S/P-DIF signal for external synchronization S/P-DIF signal to DAW, HD recorder, etc.

Mono Jack: Unbal. 0 dB

Use Mono Jacks for Unbal. Operation Use Mono Jacks for Unbal. Operation

Use Mono Jacks for Unbal. Operation
TRS Jacks: Balanced +4 dB V~50 Hz V~60 Hz TO REDUCE RISK OF FIRE OR ELECTRIC SHOCK DO NOT EXPOSE THIS UNIT TO RAIN OR MOISTURE. DISCONNECT MAINS BEFORE REMOVING COVER. THIS EQUIPMENT MUST BE EARTHED.
XLR &TRS Jack: Balanced +4dB

WARNING

XLR &TRS Jack: Balanced +4dB TRS Jacks: Balanced +4 dB

RETURN

C AU T I O N
RISK OF ELECTRIC SHOCK DO NOT OPEN

Rear Panel/Connections

MIC INPUT 2
AVIS: RISQUE DE CHOC LECTRIQUE - NE PAS OUVRIR

LINE IN 2

INSERT 2

OUTPUTS 2

GND LIFT

OUTPUTS 1

INSERT 1

LINE IN 1

Effects (EQs etc.)
Converter, recorder, console

Line signals*

Microphone
Pin wiring of XLR mic inputs
Pin wiring of XLR outputs 1=Ground, 2=hot(+), 3=cold(-)
Pin wiring of TRS connectors Tip=hot(+), Ring=cold(-), Sleeve=Ground
1=Ground, 2=hot(+), 3=cold(-)

Wiring

* For signals with impedances lower than 1kOhms, i. e. D/A converters, synths, samplers. Instruments with impedances above 1kOhms are to be connected to the instrument input on the front (see input descriptions on pages 8 and 9).

MIC INPUT 1

24/96 AD SAMPLE RATE Converter
SPL electronics GmbH Niederkrchten, Germany
SYNC INPUT DIGITAL OUTPUTS

SYNC LOCK

XLR Wiring:
Pin 1 = GND, Pin 2 = (+), Pin3 = ()
www.soundperformancelab.com

G o l dM i k e 0 0

V~50 Hz: 315 mA slow V~60 Hz: 630 mA slow

Model 2376

TRS Jack Wiring:
Tip = (+), Ring = (), Sleeve = GND SPDIF OUTPUT OPTICAL OUTPUT

Made in Taiwan

MADE IN GERMANY SERIAL NUMBER FUSE RATING

Sound Performance Lab

44,x2 SPDIF INPUT

Mono Jack Wiring:

Tip = (+), Sleeve = GND

General Advices

Again, while the GoldMikeMK2s housing is EMV-proof and protects against HF-interference, placement of the unit is very important since it amplifies microphone signals as well as other unwanted signals. Before connecting the GoldMikeMK2 or any other equipment turn off all power.
IMPORTANT: Adjust the voltage setting on the back so that it corresponds with your local power conditions. The following graph shows the correct wiring for connecting unbalanced signals to the balanced XLR connectors:

The Line Input connector is designed for unbalanced signals only. The TRS output connectors (see Outputs on page 9) can be operated both with balanced and unbalanced wiring. Simply use a mono 1/4" plug for unbalanced operation.

Mic Input 1/2

Dynamic, condenser or tube microphones can be connected to the Mic inputs. The 48V switch provides the phantom power necessary for some microphones (see also Control Elements/ Phantom on page 11). Alternatively the GoldMikeMK2 can be equipped with optionally available input transformers from Lundahl (see Lundahl Transformers on page 22).

MIC INPUT 1 MIC INPUT 1

Mono Jack: Unbal. 0dB

Line In 1/2

The unbalanced Line Inputs are dedicated to high-impedance, high-level signals such as A/D converters, synthesizers or samplers with an impedance of less than 1kOhm. Signals with an impedance of above 1kOhm, e. g. instruments like E bass, acoustic guitars with pickups or Fender Rhodes must be connected to the Instrument Input on the front panel. The max. input level of the Line Inputs is +23dB. IMPORTANT: The Line Input is deactivated as long as an instrument is plugged into Instrument Input jack on the front. We recommend connecting the Line Input to a patchbay if sources need to be changed regularly.
TRS Jacks: Balanced +4 dB

LINE IN 1 LINE IN 1

Inserts 1/2
The balanced TRS Insert connectors (Send and Return) are used to integrate further units (EQs, compressors, limiters, effects.) into the signal path of the GoldMikeMK2. The Send connector is placed behind the tube stage and can also be used as direct out (without output level control). The Return connector is located in front of Limiter and Output control which allows to control the output level, e. g. for precise drive level of following A/D converters.

Use Mono Jacks for

XLR &TRS Jack: Balanced +4 dB
The preamplifier signals are fed to these electronically balanced outputs. Alternatively the GoldMikeMK2 can be equipped with optionally available transformer outputs from Lundahl (see Lundahl Transformers on page 22). Since the XLR and 1/4 inch TRS connectors are wired in parallel, an unbalanced connection at one connector will cause unbalanced operation in its parallel connector, e.g. if a mono 1/4 inch plug is inserted into the 1/4 inch jack, the corresponding XLR socket will also operate unbalanced.

The GND Lift switch separates internal ground from chassis ground. The switch can be activated to eliminate ground loop humming which may occur if the GoldMike MK2 is connected to units with a different ground potential. The switch should normally be in the GND position to maintain the shielding effect of the metal housing for internal GoldMikeMK2 electronics.

Front Panel/Connections

Instr. Input 1/2
The Instrument input jack is placed on the front panel for easy access. It should be used to connect instruments like E-bass, electric guitars, acoustic guitars with pick-ups, etc. The Instrument input features a 1MOhm (one Mega Ohm) input impedance. IMPORTANT: As long as an instrument is plugged into front Instrument input, the rear panel Line Input is deactivated.

GND Lift

Unbal. Operation

Outputs 1/2

Control Elements
You guessed that: with the Power switch the GoldMikeMK2 is activated, verified by the illuminating switch. Please read Before You Begin on page 5 before throwing in for the first time.
The Gain control determines the level of pre-amplification. The pre-amplification values cover a range from +14dB up to + 67dB. IMPORTANT: If Lundahl input transformers are fitted the scale values are to be increased by up to +14dB (depending upon microphone in use).

About Gain Adjustments

Amplifying a signal to line level should principally be done solely with the Gain control. The Output level control is used to adjust the proper drive level for subsequent equipment. The VU Cal switch should be set to 0dB (Note: The VU displays the pre-amplification, not the output level). Now turn up the Gain control until the VU shows values between 0dB and +3dB. There is still enough headroom to prevent clipping at varying input levels. Note that the VUs show average levels instead of peak levels (which can be up to 10dB higher). Thus, in recording high-level signals such as snare and kick, etc. it may be necessary to engage the Pad switch. You can drive the Gain harder if you know that unexpected input level changes are unlikely to occur. Watch if the Clip-LED indicates clipping in the preamplifier stages and set the VU Cal to -10dB to adjust the VU meter range accordingly. IMPORTANT: The Clip-LED should never illuminate during a recording session to avoid distorted results.
This potentiometer adjusts the output level for devices following in the chain or to the converter. The Output Level control allows an additional +6dB of amplification or -26dB of reduction. Output level values set with the output level control are not indicated by the VU meters, which indicate pre-amplification levels before this final stage.

Phantom

The GoldMikeMK2 provides 48 Volt phantom power for microphones requiring external current (generally condenser microphones). Such microphones are dependent upon a clean, consistent and noise-free power supply for optimal operation and audio quality. The GoldMike MK2 continuously delivers precisely 48V and a maximum of 14mA, which will power all microphones.

48 V Off

VERY IMPORTANT: All microphones with balanced, groundfree outputs, including tube microphones, can be used with the phantom power activated. Phantom power should only be activated when using microphones that require it. Please be sure to deactivate phantom power with all other microphones. Unbalanced microphones may only be used with phantom power deactivated. PLEASE ALWAYS FOLLOW THESE INSTRUCTIONS TO ACTIVATE AND DEACTIVATE PHANTOM POWER: First connect the microphone to the GoldMikeMK2, then activate phantom power. When finished, first deactivate phantom power and wait at least until the 48V LED has gone out completely before disconnecting the microphone! This ensures residual current will be discharged. Furthermore, when changing microphones, you should wait until the 48V LED is completely dark before re-patching. THE GOLDMIKE MK2S INPUT STAGES CAN BE DAMAGED IF YOU IGNORE THESE PROCEDURES!
The phase reverse function reverses the polarity of the microphone signal, inverting the phase (by 180) to correct phaseinverted signals caused by multiple signal sources. A voiceover artist, for example, hears himself during recording through the headphones and simultaneously through the bones in his head. Phase inversion will cause an unnatural sound, and even minimal variations in distance to the microphone will cause drastic variations in the sound. Phase inversion is also commonly encountered when using multiple microphones on a single sound source. We recommend checking for correct polarity before each recording.
The Pad switch attenuates the input by -20dB. High-level input signals can be attenuated in order to prevent overdriving the preamplifier. The GoldMikeMK2 has a minimum pre-amplification of +14dB. But with miked signals such as drums and brass or high level line input signals, this may already be too much. Engaging Pad attenuates the minimum pre-amplification (Gain control fully counter clockwise) to -6dB, thus providing a useful Gain control range for loud input signals.

Hi Pass

This switch activates the integrated high-pass filter, which operates from 50Hz downwards with 12dB/octave (often called a rumble filter). The filter is entirely passive, avoiding additional active circuitry that could potentially degrade the signal, and cuts 6dB pre- and 6dB post-solid-state stage pre-amplification to prevent the amplification of unwanted low-frequency signal components.

As with its predecessor, the model 9844 GoldMike, the GoldMikeMK2 features our sound-optimizing Flair circuitry. This circuitry takes advantage of a combined coil and tube filtering to enhance signal presence.In comparison to simple EQ manipulation, this intensified presence sounds very natural and unobtrusive, and is particularly suited for optimizing the overtones in voice and acoustic instruments. With Flair processing, a signal gains richness in detail, presence, intelligibility (for vocals), and in an increased ability to cut through in a mix. In such mixes, a Flair-processed signal stands out without resort to conventional processing often unsuited to the task, saving both time and a need for artificial processing. Flair works through an emphasis in the 1.5-20kHz range centered around 6kHz. The GoldMikeMK2 provides for two different settings, with a High setting of +2.5dB and a Med. with +1.5dB emphasis. An Off setting allows you to deactivate the Flair circuit entirely.

Tube Amp

The Tube Amp switch varies the degree of tube pre-amplification added to the discrete class A pre-amplification, which itself is set with the Gain control. The switch allows for three settings: +6dB (standard) +12dB and +18dB. In each setting the output level of the tube is automatically accomodated so that output levels do not have to be recalibrated when the tube is driven hotter. This allows for instant comparison between varying Tube Amp values and their sonic effects (also refer to About Gain Adjustments on page 10).
Using the Tube Amp switch
Engaging the Tube Amp switch tends to have a significant impact on the overall sound, as it directly changes the sonic character of the tube. The higher the Tube Amp value, the more you will have tube saturation and harmonic distortion, in addition to limiting effects. These effects can be used creatively to shape a sound. Subtle overdrive of the tube creates moderate saturation effects and relatively little harmonic distortionthe limiting effects are already present. If this behavior is desired, try a +12dB setting with the Gain control also set to moderate pre-amplification. For a more dramatic tube sound the Tube Amp switch should be set to +18dB. This results in a very audible saturation and harmonic distortion. The intensity can then be fine-tuned with the Gain control: the more gain, the more phatt. Tube limiting controls peaks in a musically advantageous fashion and can be used to co mplement the Limiter. The tube limiting is not as accurate and sonically neutral as the PeakLimiter because harmonic tube distortion is added to the signal. To fully protect connected converters you should keep the PeakLimiter active and monitor the action of the VU meter, the Clipand Limiter-LED.

Limiter

The GoldMikeMK2 offers a peak limiter that operates before the output level control. This ensures that the limited signal can be controlled as perfectly as possible for the internalor an externalconverter. The peak limiter operates with special diodes that convert signal peaks into a pleasant-sounding saturation. Depending on the signal, this allows for an effective and subtle level limiting. Diode-based limiting works very quickly (much faster than common VCA- or FET-based limiters), reliably limits even microsecond-long transients, and is very effective for drums and percussion. The peak limiter also enables maximum loudness. Its degree of activity is displayed via the Limit LED. The peak limiter is ideally suited to limit signals with a high degree of transients such as snare, kick, brass and other percussion instruments. Sine-wave like signals such as vocals, flute and layer sounds can also be protected, but the degree of increased loudness is limited. Overdriving the peak limiter will be audible as distortion, an effect quite similar to overdriving the preamplifier. In order to avoid irritations please monitor the Clip-LED. If the Clip-LED is not illuminating, the distortion is coming from the peak limiter. In that case increase the Threshold value. There are two threshold values to choose from: +12dB and +18dB. Limiting is less when selecting the +18dB threshold and intensified when choosing +12dB. If the Limit LED illuminates constantly, you should select the +18dB setting or reduce the Gain control setting (also see Limit-LED on page 17). After setting the Limiter you can adjust the output level signal for equipment coming next in your chain. If you have opted for the internal A/D converter, you should keep an eye on the A/D Ovl LED. When this LED illuminates, the internal A/D converter is clipping. Reduce the output level until the A/D Ovl LED goes out. If external converters are used, check their clipping LEDs when setting the output level. This placement of the limiter before the output level control helps exploit the headroom of A/D converters to the maximum while at the same time offering a signal peak safety margin.

VU-Cal

The display range of the VU meter can be shifted using the -10dB VU Cal switch position. If the VU Cal switch is set to its 0dB position and the output level control is also set to 0dB with the limiter switched off, the output level will effectively be 0dBu. With the VU Cal set to -10dB the 0dB mark on the VU meter will represent a +10dBu output level. This way you can display audio level higher than +6dB (up to +16dB) on the VU meter.

Source

This switch allows you to select between the Mic and Line/ Instrument inputs. All inputs can remain connected at all times, regardless of which input is selected. You can choose the Line input as source as long as the Instrument input is not being used. If you engage this switch first after powering up the unit, there can be a noticeable pop due to the discharge of residual current. This is normal and no cause for concern.

Clip 48 V

Limit AD OVL

Central Display

The display consists of all status LEDs and the VU meter so that all important information can be viewed without distraction.

Display/VU Meter

The VU meter shows the internal gain level (not the output level). Its scale ranges from -20dB to +6dB. If needed, the sensitivity can be reduced by 10dB, which extends the scale to +16dB (see VU Cal above). Please refer as well to the information About Gain Adjustments on page 10.

Display/48 V LED

The 48V-LED indicates that the phantom power supply is activated. The 48V-LED will slowly dim before going out to indicate that it takes some time for residual current to discharge. VERY IMPORTANT: The connection between microphone and GoldMikeMK2 should not be disengaged before the LED is completely dark! To avoid damages, please note also the phantom power supply usage information on page 11.

Display/Clip LED

The Clip LED shows internal clipping of the GoldMikeMK2. To avoid distorted results the Clip-LED should never illuminate during a recording session (also refer to About Gain Adjustments on page 10).

Display/Limit LED

The Limit LED shows the activity of the Peak Limiter. The Limiter threshold can be set to 12 or 18dBu, and for optimal operation, should only illuminate in very short intervals. If the LED is illuminating too often even at the 18dB position, you must reduce the Gain value (and possibly afterwards, further adjust the output level) to achieve unobtrusive resultsunless, of course, you really want this effect (also see the chapter Limiter on page 15).

Display/AD OVL LED

This LED is only active when the optional AD converter module is installed. It displays clipping in the internal AD converter and illuminates at approximately 0.5dB before 0dBfs. This LED should never illuminate when using the internal converter. If it does, the output level must be reduced accordingly. For further information on the converter module see page 21, Optional Digital Output: 24/96 AD converter, model 2376. With external converters in use, please always check their internal clipping displays.

Technology

Solid state and tube stages
The solid stage preamp section is based on a fully discrete, balanced instrument amplifier and operates 12 single transistors in class A mode. A sophisticated circuitry ensures a nearly constant frequency response at any gain level. With an impressive slew rate of more than 200V/s the solid stage is capable to amplify highest frequencies and fastest transients with almost no distortion, which is crucially important to achieve a realistic sound experience. Coupling condensers were used as sparingly as possible to avoid their inherent disadvantages such as diffuse sound, slurring and loss of dynamics. To eliminate DC artifacts, these are replaced by servo circuits operating outside of the audio signal paths. An op-amp subsequently converts the instrument amplifiers output signal into an unbalanced one, which is then fed to the tube. Here an additional +6dB tube amplification is added, switchable to +12 and +18dB with the Tube Amp function. The tube typea Sovtek 12 AX7 LPSwas also selected after extensive measurements and listening tests. This tube type outclasses the standard 12 AX 7 by far and delivers an open, transparent sound, excellent noise values and is especially reliable. An impedance converter adapts the tubes high-impedance signal to the following stages.

Output Stage

The output stage can drive very long connections (depending on cable capacities, up to several hundred yards). The maximum output level is at +26dBu, allowing plenty of headroom to drive subsequent converters.

Class A Instrument Input

The Instrument Input is a fully discrete impedance converter that also operates in class A mode. It is based on a low-noise field effect transistor that, due to its extremely high input impedance, is especially well suited to this task.

Relay switching

In order to ensure the shortest possible signal paths, nearly all switching functions are handled by optimally positioned, encapsulated relays with gold-plated contacts (the switches themselves only trigger the relays). Since resistors also greatly affect audio quality, the entire audio signal path utilizes painstakingly selected resistors with 0.1% tolerance.

Foil condensers

The op-amp circuits use premium FKP foil condensers, which sound much more open than ceramic types and provide more natural dynamic response.

Power Supply

In the case of the power supply, no expense was spared. After all, the power supply is one of the primary factors in the audio quality and overall sound of any device. Just like the best coffee beans in the world will not produce a good cup of coffee with poor water, the best circuits cant produce a great sound with unreliable, inconsistent voltages. The transformer delivers three different voltages, each of which is separately screened and regulated: 250V anode current for the tube, 48V for phantom power and 2 x 15V for the audio signal path. Critical currents are stabilized via a 100-nF MKP foil condenser, to ensure sufficient current for even the shortest impulses. The transformer is encompassed by double shielding to keep magnetic stray fields to an absolute minimum. An AC power cord is included for connection to the standard 3-prong IEC connector. The transformer, power cord and IEC connector are VDE, UL and CSA approved. The AC fuse is rated at 315mA for 220/240V and 630mA for 110/120V.

Options

24-Bit/96kHz A/D converter (after sale upgrades can be done by clients). Lundahl input and output transformers (after sale upgrades by authorized service personnel or SPL only).

24/96 A/D Converter

44,1 48

SPDIF INPUT

SPDIF OUTPUT

OPTICAL OUTPUT

The optional 24/96 Converter module (model 2376) provides a digital output for the GoldMikeMK2 in the form of an S/P-DIF output with RCA and optical connectors (in parallel). The converter transmits 24-bit signals. The module is based on a 24-bit converter by AKM with a variable sample rate of up to 96kHz. All common sample rates can be selected (see below). Highly accurate quartz oscillators ensure a clean, low-jitter master clock.

Sample Rate

The 24/96 AD converter module allows you to select among the four most common sample rates of 44.1, 48, 88.2 and 96 kHz. Using the 44.1/48 button, select one of the two basic sample rates (out: 44.1 kHz; in: 48 kHz). The x2 button doubles these sample rates to select 88.2 or 96 kHz respectively.

Dig. Out

The converted S/P-DIF signal is routed in parallel to the RCA and optical outputs. The signal is in professional format with no sample rate data in the status block.

Sync Input

The SYNC input allows you to feed an external signal into the converter to control the sample rate (since this is an AD converter, the SYNC Input is no audio signal input). Connect an S/P-DIF output from your master source (e.g. sound card) to the SYNC input. The AD converter will automatically switch to the same sample rate that is received. The 2376 is not equipped to accept Word Clock synchronization. The yellow Sync Lock LED illuminates when a valid sync signal is present at the Sync input and the converter is automatically synchronized to the external sample rate. To prevent interference, the internal oscillators are automatically disabled when an external clock signal is present. If the sync signal is no longer present (e.g. in the case of a dropout), the converter automatically reverts to the sample rate selected via the converters control switches.

Lundahl-Transformers

Transformers have characteristics usually associated with other analog components like tubes or coilsthey sound warmer, and punchier especially in the bass and mid area and deliver improved presence without boosting the top end. One reason for this is that transformers cancel out a large amount of odd harmonics (those portions of an audio signal that sound harsh to human ears). Equipping the GoldMikeMK2 with transformer-based inputs and outputs means you benefit from their unique characteristics. IMPORTANT: The GoldMike MK2s input transformer delivers up to +14dB of additional passive gain, which must be added to the printed values.

Specifications

Frequency response Input impedances Microphone, XLR Line In, TRS Instr. In TRS Output impedances XLR and TRS connectors THD+N Input level -30dBu -40dBu -50dBu -60dBu Noise, A weighted, R=40Ohm Gain 30dB 40dB 50dB 60dB Dynamic range, 30dB Gain E.I.N Max. Input level Mikrophone, XLR Mikrophone, XLR +PAD Line In, TRS connector Instr. In TRS connector Instr. In TRS connector +PAD Max. output level Balanced, XLR+TRS Unbalanced, XLR+TRS CMRR 1KHz, Gain 30dB 10KHz, Gain 30dB Power consumption Dimensions B x H x T Weight Gain 30dBu 40dBu 50dBu 60dBu 10Hz to 90kHz (-3dB) 2,8kOhm 10kOhm 1MOhm 50Ohm
0,016% 0,017% 0,022% 0,048%
-91,2dBu -86,6dBu -78,7dBu -69,3dBu 110dB 128dBu +7dBu +28dBu +23dBu +7dBu +14dBu +26,8dBu +21,5dBu 75dB 75dB
25W 482 x 88 x 210mm/19.28 x 3.52 x 8.4 in 4,1Kg/9.02 lbs
Specifications subject to change without notice.

Guarantee

All SPL products come with a two-year manufacturers guarantee against defects in material or assembly from the date of purchase. End users are supported in the two-year guarantee through their distributor or dealer. In such cases, please contact your dealer for full guarantee conditions and service. Direct SPL product support requires product registration. Please fill out the guarantee card enclosed in the package legibly in printed letters and send it directly to SPL. Or use the online registration form that may be reached at www.soundperformancelab.com (international clients) or www.spl-usa.com (US clients).
....................................
Rediscover Analog at soundperformancelab.com

Manual

Model 9844 Vacuum Tube Microphone Preamplifier

GoldMike Manual

Model 9844
By Hermann Gier and Wolfgang Aichholz Version 1.4 - 5/2000
The information in this document has been carefully verified and is assumed to be correct. However Sound Performance Lab (SPL) reserves the right to modify the product described in this manual at any time. Changes without notice. This document is the property of SPL and may not be copied or reproduced in any manner, in part or full without the authorisation of SPL.
Limitations of Liability: In no event will SPL be liable for any damages, including loss of data, lost profits, cost of cover or other special, incidental, consequential or indirect damages arising from the use of the unit, however caused and on any theory of liability. This limitation will apply even if SPL or an authorised dealer has been advised of the possibility of such damage.
SPL electronics GmbH P.O. Box D- 41368 Niederkruechten, Germany Phone + 49 - / 98 34-0 Fax + 49 - / 98 34-20 eMail: info@ soundperformancelab.com
2000 SPL electronics GmbH. All rights reserved.
Foreword... 3 Introduction.... 4 Hookup.... 5 Installation & Connections... 5 Power Supply.... 6 Tech Talk... 7 Control elements... 9 MIC GAIN... V... 9 REVERSE....10 PAD...10 HIGHPASS...11 FLAIR....11 Displays....11 Specifications....12 Warranty....13

Contents

Dear customer, Thank you for the confidence you have shown towards SPL electronics GmbH by purchasing the SPL GoldMike. You have decided to use an innovative microphone preamp which provides excellent sound quality by combining exemplary specifications with highest manufacturing standards. Please read this manual carefully to ensure you have all the information you need to use the Gold Mike. We wish you every success with it. Your Sound Performance Lab-Team

Foreword

I would like to start with my thanks to all our staff, who created what is to be described here. The importance of their exceptional qualification and talents cannot be overestimated. Special thanks to Ruben Tilgner for his creativity. Our products are often tested and compared in many publications and by our customers themselfs and constantly valued with best results. I would like to pass on this broad appreciation to those, who deserve it my excellent colleagues. Hermann Gier

Thanks

Introduction
The GoldMike is another jewel in the SPL Tube series. Like all SPL tube processors, the GoldMike combines the unique sonic qualities of tube technology with state-of-the-art manufacturing, meticulous component selection and high-tech conception. This latest product, a dual-channel tube microphone preamplifier with superb sonic qualities, is particularly suited for recording vocals and acoustic instruments. You will be surprised by not only its precision but also the natural impact of different vocal timbres the silky warmth of a pristine tube sound is needed by more than just acoustic guitars! You don't have to listen to those dead and sterile HD recordings. GoldMike's whisper quiet performance makes it ideal for digital recording. Even the most demanding recording subjects, such as a choir, are easily handled. The Class A tube amp, designed as two independent mono blocks, guarantees absolute channel separation. Your stereo recordings in particular will benefit from a wider stereo depth. GoldMike's technical standards are predicated on an uncompromising effort to combine the sonic advantages of tubes with the experience of more than 12 years of research in semi-conductor amplification design. The GoldMike allows for up to 72 dB of gain a value tube-only designed preamps can't match. The SPL tube/IC construction, on the other hand, superbly combines today's standards with such trademark tube characteristics: improved spatial depth, rich detailed imaging, warm and smooth sonics. Moreover, the GoldMike delivers high common-mode-rejection and ultra linear amplification in addition to the high gain capabilities.

Features

Unique "FLAIR" circuitry enhances the presence and intelligibility of any signal. Vocals, for example, seem to move closer. Pristine, non-colored "softening" of very harsh and aggressive sounds 50 Hz high-pass filter Phase reverse switch 30 dB pad Switchable 48-volt phantom power with independently filtered power supply High-quality ALPS potentiometers Click-free switches Five LEDs per channel Two backlit VU meters Warm-up LED indicates tube status during warm up Star ground wiring scheme for best sound performance; extra wide PCB ground connections guarantee stable voltage distribution Power supply with state-of-the-art filtering schemes and solid power reserves (6000 F in the main supply and 400 F in the tube supply) XLR inputs XLR and 1/4" outputs (can be used individually or simultaneously)
Carefully select a place for setting up the GoldMike. The unit should be situated away from heat sources and direct sunlight. Avoid installing your GoldMike in environments exposed to vibrations, dust, heat, cold or moisture. Keep the unit away from transformers or motors or any other unit that could generate large variations in power supply or cause electrical interferences. Do not install the unit in close proximity to power amplifiers or digital processors. You may consider placing it in a rack containing other analog gear. Such placement can prevent interference from Word Clock, Smpte, MIDI, etc. Do not open the case. You may risk electric shock and may damage your equipment. Leave repairs and maintenance to a qualified service technician. Should foreign objects fall inside the case, contact your authorised dealer or support person. To avoid electric shock or fire hazards do not expose your unit to rain or dampness. In case of lightning unplug the unit. Please unplug the cable by pulling on the plug only; never pull on the cable. Never force a switch or knob. To clean the case use a lint-free cloth. Avoid cleaning agents as they may damage the chassis. Manufactured in standard 19" EIA format, it utilises two rack units. Please support the back of the unit whenever it is being mounted into a 19" rack (especially important when touring).

Hookup

Important safety instructions-please read carefully!
Again, while GoldMike's housing is EMV-proof and protects against HF-interference, placement of the unit is very important since it is capable of amplifying microphone signals as well as other unwanted signals up to 2200 times. Before connecting the GoldMike, or any other equipment, turn off all power. Adjust the voltage setting on the back so that it corresponds with the power conditions.The GoldMike's XLR inputs, which are used for connecting microphone and line level signals, are electronically balanced, while the outputs allow for simultaneous feed to the balanced XLR connectors as well as to the unbalanced 1/4" outputs.The unit can even be used as a microphone splitter.
Installation & Connections
The following graph shows the correct wiring for connecting unbalanced signals to the balanced XLR connectors. VERY IMPORTANT Phantom power must be switched off before unbalanced signals are connected! Otherwise short circuits cause damages!

Power Supply

A stable, low ripple torroidal power supply is the foundation for any high-fidelity sound shaping.
Built around a torroidal transformer, the power supply allows for a minimal electromagnetic field with no hum or mechanical noise. The supply voltage can be set to 230 V/50 Hz or 115 V/60 Hz. Check your country's power requirements for the appropriate setting. An AC power cord is included to feed the IEC-spec, 3prong connector. Transformer, AC cord and IEC-receptacle are VDE, UL and CSA approved. The main fuses are rated at 315mA (230 V) and 500 mA (115 V). Chassis ground and AC ground can be physically disconnected by the Ground Lift switch (GND LIFT). This helps to eliminate hums.The power supply's output side is filtered by an RC circuit to extract noise and hums caused by your power service. 6000f capacitors smooth out the positive and negative half waves. The phantom power is derived from a separate winding in the transformer. Filtered and rectified by a series of zener diodes and transistors, a clean 48 volts leaves the circuitry.This supply voltage reaches the phantom power switch through the PCB where another RC circuit stabilises the supply again. Our high quality 0.1% / 6,81 kOhm resistors ensure the pristine quality of the phantom power supply.
The GND-LIFT switch helps eliminate hums caused by ground loops.
Phantom Power with a complex filtering scheme and highly selected components.
Advantages of the SPL dual-stage preamplifier

The GoldMike's engine is the newly designed SPL dual-stage preamplifier. During the first stage of amplification the signal is amplified by a semi-conductor circuit while the second stage applies tube electronics. We achieve a high common-mode-rejection by using laser trimmed components. Likewise, minimal noise and distortion figures distinguish our high-quality preamp. Analog Device's semi-conductor (SSM2017) is very unreceptive to HF and hum interference, and is perfectly integrated by the PCB layout; wide PCB conductors guarantee a stable power supply even when extreme level changes demand an immediate current supply. The star ground wiring scheme ensures a quiet electronic performance. The dimensions of the PCB conductors, and their respective layout (wide or narrow), were especially designed for the integration of tubes and ICs in the preamplification circuitry. The MIC GAIN potentiometer adjusts the semi-conductor stage, allowing amplification up to 2200 times the original signal. The following secondary tube stage adds a constant 6 dB of gain; therefore, the same amount of tube character is added regardless of amplification. The MIC GAIN should be adjusted for a "0" VU meter reading. At this level the best signal-to-noise performance is achieved and the tube will perform in its ideal sonic range. (Please note that the VU readings are not peak PPM but average levels. In other words, watch out for the meter hitting the red.)

Tech Talk

The GoldMike combines superb signal-to-noise specs with not only the amplification power of semiconductors but also the warmth and liveliness of tubes.
In summary, our dual-stage design maximises the amplification power and signal-to-noise performance of the SPL semiconductor at the first stage and then maximises the warmth and liveliness of a meticulously selected and tested ECC 83 tube at the second stage. This makes the GoldMike an ideal partner for highend HD recording. The unit's dynamic range of 111 dBu even outperforms some 24-bit recording gear.
An outstanding dynamic range of 111 dBu outperforms even the average 24-bit recording system.
Advantages of the dual mono design
GoldMike's two mono amplifier blocks are designed with a central power supply that utilises a star ground wiring scheme. Chief advantages of this particular layout are the excellent channel separation and, respectively, the low crosstalk figures. In your daily work you will find many practical applications for these advantages. You may use the GoldMike's channels for a snare and a vocal (arguably the most important elements in a mix) simultaneously. Stereo recordings, benefiting in particular from the low crosstalk figures, will have wider stereo depth and precise spatial definition. Another advantage of the central power supply with a star ground wiring scheme is that the two individual circuitries, operating discretely, can deliver identical sonic performances per channel. The current demands of one channel (i.e., snare) are not compromised by the current demands of the other channel (i.e., vocal). All power supplying conductors, layed out identically and symmetrically, provide both channels with the necessary current. Dual-Mono-Layout, with central power supply and star grounding, delivers excellent channel separation two discrete signals (snare, vocal) may be recorded simultaneously without crosstalk precise spatial definition identical sonic performance per channel

Sound optimization already during recording: FLAIR circuitry
The FLAIR circuitry enhances the presence of vocals and acoustic instruments, FLAIR makes these elements cut better through a mix. It has proved to be superior in double-blind tests. Once a signal completes the semi-conductor amplification stage, it is then split and fed into the tube stage and the FLAIR electronics.
The FLAIR circuitry enhances a signal's presence and cutting ability.
The correlation between frequency- and amplitude-timebase to the dynamics of the input signal remains intact. Ideally suited for HD recording.
The FLAIR circuit is built from a unique valve/inductor/capacitor hybrid. It operates in a bandpassed frequency range from 1.5 kHz to 20 kHz. The center frequency is set at 6 kHz with a boost of 2.5 dB. Frequency response, harmonic contents and time of impact are manipulated as well. The FLAIR circuit's output is mixed directly in the tube with the source signal. The circuit's character can be best described as a "closed shelving bandpass"; nevertheless, a shifted timebase (phase) is responsible for boosting the harmonic content. The close correlation, however, between frequency- and amplitude-timebase to the dynamics of the input signal remains intact. When working on a hard disc recording system, you will greatly appreciate the appeal of the Flair circuitry and the topnotch sounding signal it delivers. It can spare you hours of twiddling with a compromised recording.

WARM UP circuit

The WARM UP circuit measures the tube's anode plate and heater voltages. After approximately eight seconds the anode voltage of 250 Volts is reached; the heater voltage takes only four seconds. Once the ideal working status is achieved, the output signal is enabled. As the WARM UP LED is lit, no output is present.

Control elements

The MIC GAIN knob controls the input signal's amplification. The range extends to 72 dB of gain.The levels should be adjusted for a meter reading around 0 VU to get the best signal-to-noise performance. Please note that the meters show only an rms/average level, so keep your GoldMike from pegging the meters' needles. When adjusting the MIC GAIN, consider the type of microphone (dynamic, condenser or ribbon) and the microphone's sensitivity; likewise, check sound pressure levels at the sound source, the microphone placement and room acoustics. The sensitivity of a dynamic microphone is approximately 2 mV/Pa, whereas a condenser microphone may reach 20 mV/Pa, an increase of 20 dB.

MIC GAIN

The VU meters show a rms/average signal
Check the transducer type and sensitivity
Condenser Mics require a 48-volt power supply, which is sent through the balanced audio cable on pins 2 and 3. When turning on the supply voltage, a phantom circuit is generated by splitting the 48-volt supply signal equally between the + and - conductors of the audio cabling; the voltage is returned through the cable's shield. No potential difference is present between the two conductors (+/-); dynamic microphones may be used while phantom power is switched on without damage. Phantom power in effect reduces the interference from ground loops as well as other unwanted signals picked up by the shielding. It also proves to be a very HF resilient connection.
Phantom power specs in accordance with DIN 45 596/ IEC 268-15
WARNING: All balanced microphones with isolated grounds, even tube-equipped microphones, may be used while phantom power is switched on. All other microphones require the phantom power to be switched off. Connect line-level signals and unbalanced microphones only while phantom power is off.

REVERSE

By pressing the REVERSE button, you invert the microphone's polarity.When the REVERSE button is released (status LED off ) the signal is in phase. Pressing it switches the signal out-of-phase (LED on). Reasons for reversing the phase: 1. You are recording a vocal or voice-over and the vocalist cannot hear him or herself very well in the headphones. Reversing the phase effectively reverses the polarity between microphone and monitor signal, thus enabling the vocalist to hear him or herself better without any volume increase in the headphones. 2. The REVERSE button is engaged to adjust the GoldMike to the polarity of a microphone or microphone wiring scheme. GoldMike's XLR connectors are configured as follows: pin 2 = high (+), pin 3 = low (-). 3. Experimenting with the phase reverse option may reward you with better results.
Tips on how to use the phase reverse

30 dB pad

The PAD switch attenuates the input signal by 30 dB, allowing even high-level signals to be processed by the GoldMike.This may apply to loud drum or brass recordings.

HIGHPASS

Filters problematic frequencies (rumble, etc.)
The HIGHPASS filter will pass only frequencies above a certain threshold, thereby eliminating unwanted portions of a signal. The GoldMike's roll-off point is set to 50 Hz. We use a 2nd order Butterworth filter for its low ripple. The roll-off slope is 12 dB per octave. Applications for the HIGHPASS filter: 1. Voice-over recordings suffering from the "proximity effect", a boost in low frequencies due to the short distance between sound source and microphone. 2. "Pop" sounds that extend into the lower frequency range. 3. Any unwanted signal, such as steps, rumble and other low-frequency sounds.
True to SPL's philosophy, the GoldMike features the sound enhancing FLAIR circuitry. More than simply a frequency-range manipulating tool, the FLAIR circuitry is also a timebase shifting (phase) device that enhances a sound's harmonic content. The close relation between frequency- and amplitude-timebase and the source signal's dynamics remains intact. FLAIR boosts the frequency range from 1.5 kHz to 20 kHz. The center frequency, set at 6 kHz, is boosted 2.5 dB and applied mainly to the harmonic content and format frequencies of voices and acoustic instruments. And finally, the FLAIR's output is mixed right along with the original source signal by the tube during the tube amplification stage. The resulting recorded signal resounds with more detail, intelligibility, presence and cut- through. The FLAIR circuitry is especially valuable when working in an HD recording environment because of the great sounding signal it delivers at the outset, thereby sparing you hours of fixing a compromised recording.
Circuitry enhances presence and boosts cut-through
Manipulates frequency range, time impact and harmonic content simultaneously
Each of the GoldMike's channels is equipped with a backlit VU meter (calibrated to 0 dBu) that displays the unit's output level. Five LEDs per channel display the current operating status. The WARM UP LED, located next to the power switch, remains lit until the unit's tubes reach their optimum operating condition. As long as the WARM UP LED is lit, no output is available.

DISPLAYS

Specifications
Frequency Response:.. 10 Hz - 100 kHz, +/- 0.5 dB Common-Mode-Rejection at -20 dBu:. 1 kHz: -80 dBu. 10 kHz: -73 dBu Harmonic Distortion Input level Gain THD -30 dB.. 30 dB. 0.175 % -60 dB.. 60 dB. 0.2 % Signal-To-Noise Ratio Signal-to -Noise ratio: Gain 72 dBu 60 dBu 30 dBu A-weighted -62.4 dBu -71.8 dBu -85.6 dBu

Dynamic Range:.. 111 dBu Noise Figure:.. 3.8 E.I.N. (Equivalent Input Noise). 135.4 dBu

Inputs

Microphone/Instrument Preamplifier, electronically balanced (differential), transformerless Input Impedance.. 1.8 kOhm Max. Input Level.. +25.72 dBu

Outputs

XLR-Output: Microphone/Instrument Preamplifier, electronically balanced (differential), transformerless Nominal Output Level XLR. + 6 dB Max. Output Level XLR.. +25.4 dB Nominal Output Level 1/4". 0 dB Max. Output Level 1/4".. +19.4 dB Output Impedance (XLR/Klinke). < 600 Ohm

Dimensions

GoldMike Rear Panel, Model 9844 Standard EIA 19"/1HE chassis.. 19" x 3.47" x 6.18" (482 x 88 x 157mm) Weight... 6.7 lbs. (3.05 kg)
Rear Panel Controls and Connectors
Balanced Inputs and Outputs (XLR/+6 dB) Unbalanced Outputs (1/4" / 0 dB) Voltage Selector 115 V/60 Hz or 220 V/50 3-Prong Standard-IEC-AC Receptacle GND-LIFT-Switch
SPL electronics GmbH (hereafter called SPL) products are warranted only in the country where purchased, through the authorized SPL distributor in that country, against defects in material or workmanship. The specific period of this limited warranty shall be that which is described to the original retail purchaser by the authorized SPL dealer or distributor at the time of purchase.

Warranty

SPL does not, however, warrant its products against any and all defects: 1) arising out of materials or workmanship not provided or furnished by SPL, or 2) resulting from abnormal use of the product or use in violation of instructions, or 3) in products repaired or serviced by other than authorized SPL repair facilities, or 4) in products with removed or defaced serial numbers, or 5) in components or parts or products expressly warranted by another manufacturer. SPL agrees, through the applicable authorized distributor, to repair or replace defects covered by this limited warranty with parts or products of original or improved design, at its option in each respect, if the defective product is shipped prior to the end of the warranty period to the designated authorized SPL warranty repair facility in the country where purchased, or to the SPL factory in Germany, in the original packaging or a replacement supplied by SPL, with all transportation costs and full insurance paid each way by the purchaser or owner. All remedies and the measure of damages are limited to the above services. It is possible that economic loss or injury to person or property may result from the failure of the product; however, even if SPL has been advised of this possibility, this limited warranty does not cover any such consequential or incidental damages. Some states or countries do not allow the limitations or exclusion of incidental or consequential damages, so the above limitation may not apply to you. Any and all warranties, express or implied, arising by law, course of dealing, course of performance, usage of trade, or otherwise, including but not limited to implied warranties of merchantability and fitness for particular, are limited to a period of 1 (one) year from either the date of manufacture. Some states or countries do not allow limitations on how long an implied warranty lasts, so the above limitations may not apply to you. This limited warranty gives you specific legal rights, and you may also have other rights which vary from state to state, country to country. SPL electronics GmbH, 41372 Niederkruechten, Germany