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Old 7th June 2007, 05:21 AM   #1
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Default 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
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Old 7th June 2007, 07:21 AM   #2
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Default 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
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Old 7th June 2007, 07:34 AM   #3
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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.



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Old 7th June 2007, 02:39 PM   #4
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Hmm . . .
This one shows better.



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