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6SN7 tubes

Hello!

Come looking for a little help. I have a Mastersound Compact 845 amplifier, and I'd like to put some NOS tubes in it to replace the stock Electro Harmonix. Not the power tubes, just the driver and pre-driver tubes. Kinda stuck with Shuguang for the power tubes...

Anyways, the pre-driver tubes are 12AU7/ECC82's, and the driver tubes are 6SN7's. Problem is, the pre-driver stock tubes are labelled 12AU7A...the driver tubes are labelled 6SN7GTB.

I have a matched pair of NOS Telefunken ECC82/12AU7's- minus the "A" designation at the end. Can I drop these in, or is it a question for the maufacturer? Also, I'm hunting for some NOS 6SN7's- does it matter if they're straight 6SN7's, 6SN7GTA or GTB?

What's the difference with these minute designations at the end of the tube name? Am I overcomplicating things here?

Thanks in advance for any advice!
afc
goldeneraguy
439 posts
 
When in doubt you should check with the Manufacturer before making any changes.That said.
If your driver tubes are 6SN7GTB you can NOT use the 6SN7 or substitutes other then 6SN7GTA
The GTB and GTA tubes have higher voltages that your amp requires.
Your Telefunken's can be used.
You also may want to look into some Shuguang 845B tubes
Much better then the Shuguang standard 845.
rodman99999
3,557 posts
 
Some further 6sn7 family info: (http://home.att.net/~chimeraone/6sn7sound.html) That your equipment has those higher voltage tubes installed, does not necessarily indicate that the piece is operating at higher voltages. DO contact the builder, and inquire. There are a number of NOS tubes that WILL increase your listening enjoyment, IF they can be utilized.
tpreaves's avatar
tpreaves
2,515 posts
 
Here is an interesting piece on the 6sn7..... http://www.6sn7.com/
afc OP
141 posts
 
Thanks, everyone. Much appreciated. Goldeneraguy, a pair of 845B tubes is in the works already.
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