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Old 30th Nov 2021, 8:54 am   #27
stevehertz
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Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
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Default Re: Quad 34 preamp volume knob clicks

Quote:
Originally Posted by Craig Sawyers View Post
Quote:
Originally Posted by stevehertz View Post
Quote:
Originally Posted by Craig Sawyers View Post
Yes - the 44 (1979) was introduced before the 34 (1982). The 44 used the more conventional +/-15V rails. But sometime between those two dates, Quad figured out that the 071/072 clipped asymmetrically and skewed the (lower) voltage rails to +8.6V -9.4V.

But the 44 was very flexible with input modules, all of which were pluggable in any combination. The 34 had a single selectable module for disc - either moving magnet or moving coil being the choices.

Amazingly the 34 only consumes 2.5W, which is pretty impressive.

Craig
Thanks. I upgraded my 44 with OPA134 op amps and I could definitely hear an improvement in detail.
Although the OPA134/2134 have higher performance (particularly in lower distortion and noise) as compared with the 071/072, they are much higher current draw, 4 to 5 mA per opamp as compared with 1.5 to 2.5mA. So the power supply needs some careful consideration.

Craig
Oh... Have you any experience of what needs to done in practical terms?
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