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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
mofimadness's avatar
mofimadness
4,972 posts
 
Depending on how the gain stage is setup, you could replace the 12AX7 with a 5751. The 5751 usually has 30% less gain, depending on how the tube is used in the circuit.
vandermeulen
191 posts
 
12AY7 reduce further to 50%. 12AU7 reduce to 80%. Though personally I have never substituted any of these for my AX7's.
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
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