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-   -   Attenuating input gain on X amp? (http://www.diyaudio.com/forums/pass-labs/103149-attenuating-input-gain-x-amp.html)

jeffjazz 7th June 2007 05:21 AM

Attenuating input gain on X amp?
 
I have a Modwright SWL 9.0 preamp which gain is too hot for my Pass Labs X-150 amp. I only have usable volume range to 9o clock. Is there any way to reduce the gain on the inputs of my X150 without affecting sonics? Dan at Modwright suggested I could increase the plate resistor value from 100K to 200K to reduce gain by 3db in the preamp (but this may affect bandwidth at higher frequencies). I don't know if that would be enough. I am using the single-ended inputs on the amp since the preamp is not balanced.
Any solutions from the experts? Thanks

Zen Mod 7th June 2007 07:21 AM

Re: Attenuating input gain on X amp?
 
Quote:

Originally posted by jeffjazz
I have a Modwright SWL 9.0 preamp which gain is too hot for my Pass Labs X-150 amp. I only have usable volume range to 9o clock. Is there any way to reduce the gain on the inputs of my X150 without affecting sonics? Dan at Modwright suggested I could increase the plate resistor value from 100K to 200K to reduce gain by 3db in the preamp (but this may affect bandwidth at higher frequencies). I don't know if that would be enough. I am using the single-ended inputs on the amp since the preamp is not balanced.
Any solutions from the experts? Thanks


try using 4K7 to 22K resistor instead shorting plug on XLR pins.....
I just presume that's way to unbal connection on your amp

Babowana 7th June 2007 07:34 AM

2 Attachment(s)
I use this method for my SRPP tube pre to attenuate the gain at the output. R1=4.7K/R2=22K, or R1=22K/R2=4.7K or you could use different values for your purpose.



:darkside:

Babowana 7th June 2007 02:39 PM

2 Attachment(s)
Hmm . . .
This one shows better.



:darkside:


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