2. amps-preamps
  3. 1141077063

can changing 6sn7 tubes affect the output voltage

I recently changed my input tubes, 6sn7, and eventualy, (about a 100 hours) fried a pair of eml 45 mesh plate tubes. I have a pair of eml non mesh coming and am a little nervous about cooking these as well. My preamp is a Supratek Cabernet, with a voltage selector switch that accepts the low voltage 45's as well as the 4 volt px and the 5 volt 300's. Should I go back to the stock russian tubes or am I "safe" with the rayethon 6sn7's I rolled out. Someone help! I gulping $400 a pair!! Until the went, the 45 mesh plates were fantastic. What am I missing? Supratek folks and tube lovers, please lend me you expertise.
larryrosen
larryrosen OP
83 posts
 
I can help, but my thread hasnn't been posted
dogpile
118 posts
 
I don't know if this will help with your query but here goes.

6SN7 tubes have different voltages as you know. I would ask Supratek to recommend a "specific" 6SN7 tube that matches the design of your pre-amp or check the specs.

A 6SN7GT / 6SN7WGT is 300 volts max & 3.5 watts max per section.
A 6SN7GTA / 6SN7GTB is 450 volts max & 5.0 watts max per section with this tube being more efficient than the later.

You didn't specify the Raytheon 6SN7 tube type, ie. GT / GTA / GTB, etc...

Hope this helps.
larryrosen OP
83 posts
 
Thank you D'pile. I will put back in the stock tubes, and check with Mick Maloney.
larryi
3,718 posts
 
Your EML 45 failure was probably a coincidence. By the way, a friend of mine had two pairs of EML mesh 45s fail within ten hours (total for both pairs), so you got a lot more mileage. The replacement pair of solid plate 45s have been going strong for more than a year. If you are concerned about reliability, you could change the bias to run a lower current through the tube; that increases life dramatically (though at some sacrifice in sound quality).

I run EML meshplate 2a3s. I like the sound very much. So far, they have been holding up fine.
larryrosen OP
83 posts
 
Larryi, The Supratek I have is a Cabernet. It has a 3 position switch to change bias. 45, 300 or PX4. I was running at the 45 position which I assume is the lowest current. Is their another way that I am not aware of?
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