"Matisse" preamp - 12AX7 12AT7

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.

There is absolutely NO danger in swopping the tubes you have mentioned. You will not damage anything, and 9 times out of 10 it will run OK, and give you the gain lowereing you desire.

But it may not sound as good as it would if the stage had been designed to take the tube you use - but it won't harm anything - and may work perfectly!

Of the tubes that you can sustitute, the 12AU7 has by far the lowest gain.

Just don't try fitting something that uses different pin connections - or uses far more heater current than the ones it was designed for.

Regards, Allen (Vacuum State)

wow... ...Allen just completed the thread. Hell, I'm ordering some replacements for my gear now. LOL. Thank you Master Wright. Heck, I'm going to go listen to my JLTI right now. :)~

Okay that is good news, thanks guys. I will try it with a spare set of 12AT7 tubes (ie 4 12AT7 tubes) and let you know how it goes.

Okay well, to report back, I tried it and it did not really change much at all!!
I rolled in a few other sets of tubes to see if any differences could be noticed, and slightly less gain was apparent on the following combination;
Brimar CV4004, GE JAN 12AT7WC
This also sounds great (except for the first time I turned it on there was good deal of buzzing whilst turning the volume dial on low levels - although it went away after a while, any idea what could cause this?).

I will now head down the in-line attenuator path I think....