Lowering gain of a UCD400 module

[brain1970]

Hi, I'm using a home build UCD400 amplifier. Recently I replaced my speakers with Klipsch Lascala II's. Gain is way to high (20x?) for these sensitive speakers.
Is there an easy way to change the gain on the UCD400 (replacing a resistor?)

I'm using a vintage Luxman C-1000 preamp (no vintage sound though, very detailed and refined, a Tim de Paravicini design). Maybe the gain of this preamp is also higher than a contemporary preamp.


I also have a LM3875 Gainclone, that is a better match in terms of gain for these speakers. But somehow the weight of instruments sounds more realistic with the UCD400 amp, although with less apparent detail compared to the gainclone...

Henk

 

[mashm]

hi,

you can change the gain of the ucd400 by changing one resitor R3:

http://www.hypex.nl/docs/appnotes/gain_appnote.pdf


markus

 

[brain1970]

thanks for the link!

 

[lucpes]

From what I read on the pdf and if I got Ucd400 HG this year (2015) a good value for R3 would be 2k or 2.2k? I have a dac/pre that goes as high as 10V pp.

 

[JonSnell Electronic]

Attenuate the input. At least then the balanced amplifier will not be off set.

 

[lucpes]

This is the resistor to change/remove if you want 1x gain on the buffer.