18 GoldMike MK2
Solid state and tube stages
The solid stage preamp section i s based on a fully discrete,
balanced instrument amplifie r and operates 12 single transis-
tors in class A mode. A sophisticated c ircuitry ensures a nearly
constant frequency response at any gain level. With an impres-
sive slew rate of more than 200V/µs the solid stage is cap able to
amplify highest frequen cies and fastest tran sients with almost
no distortion, which is crucially impo rtant to achieve a realistic
sound experience. Coupling condensers wer e used as spar-
ingly as possible to avoid their inherent disadvantages such as
diffuse sound, slurring and los s of dynamics. To eliminate DC
artifacts, these are r eplaced by servo circ uits operating outsi de
of the audio signal paths.
An op-amp subsequently converts the instrument amplifier’s
output signal into an unbalanced one, which is t hen fed to the
tube. Here an additional +6 dB tube amplification is added,
switchable to +12 and +18 dB with the Tube Amp funct ion.
The tube type—a Sovtek® 12 A X7 LPS—was also sel ected after
extensive measurements and lis tening tests. This tube type
outclasses the standard 12 A X 7 by far and delivers an open,
transparent sound, excellent noise v alues and is especially reli-
able. An impedance converter adapt s the tube’s high-imped-
ance signal to the following stages.
Output Stage
The output stage can drive ver y long connections ( depending on
cable capacities, up to several hun dred yards). The max . output
level is at +26 dBu, all owing plent y of headro om to drive s ubse-
quent converters.
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