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"Matisse" preamp - 12AX7 12AT7

I'm using a Xindak XA3250, which is basically a clone of the Matisse circuit, with two 12AX7 tubes and two 12AT7 tubes. Problem is, the gain is so high that I can hardly turn the volume pot without the system being too loud for some late night listening.

Anyone know the best way to reduce the gain? I figure changing the 12AX7 tubes for another set of 12AT7 tubes would be a possibility....
bleoberis
bleoberis OP
33 posts
 
okay - ace. presumably I could run it with 4 matched 12AT7 instead, too. is there any danger to the circuit/power supply by running a non-specified tube? so many forums say yes, and and equal amount say no!
mofimadness's avatar
mofimadness
4,972 posts
 
I have always been told and/or read, that you should never sub an AU for an AT, or an AX for an AU, or AX for an AT, or any of the above combinations. Some preamps, like the Lector ZOE, let you use whatever tube you want, but this is usually not the case.

The 5751 is a DIRECT replacement for the 12AX7, just less gain, again, depending on the circuit.

Maybe ask your question over here also:

http://www.audioasylum.com/cgi/etv.mpl?forum=tubes
elevick
2,636 posts
 
Are you sure it's the pre and not your source? I've seen this when someone has a high gain piece plugged into a low gain input (ie mixing up mc & mm or cd into phono)?
bleoberis OP
33 posts
 
hmm could be the source, but how do I test? I have only one source, one pre and one power amp...
newbee
4,767 posts
 
An easy and inexpensive way is to put in a fixed value attenuator at the amp input. You can buy them or have a techie do it for you. Cheap commercial ones are made by Rothwell. I believe you can get different values. Cost about $60. They are fairly transparent. Worked for me when I needed to do that. BTW, you may also be able to use them between your source and pre-amp if you underlying problem is too much gain from your source.
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