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Tube Substitute question

R

Rocky1313

Active Member
I have a Nobsound EL 34 Single ended 8 watts per channel Amp
My question is...
I am thinking of upgrading tubes ... from EL34's tubes to...Tung-Sol 6550 tubes
Opinions appreciated....Is this a sideway move or an advantage ?
Thank you
 
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The amp is biased for EL34's. You should contact the seller first. You wouldn't get any more power out of the amp using 6550's. You should be able to use 6CA7's, they are interchangeable. The EH 6CA7 fat bottles sound nice. You might be able to use KT-77's also?
 
6550 are KT88, you cannot run those on that amplifier. I have one myself so I know what I'm talking about. You would need to re bias it by replacing parts, besides, transformers are small, not sure if it could handle them.
You can run 6CA7, or KT77's in this amp, like it's already been said, although I didn't like how KT77's sounded in my EL34b Nobsound amp, 6CA7's sounded better than the stock tubes, with a little more punch and bass.
 
Stonegarden said:
6550 are KT88, you cannot run those on that amplifier. I have one myself so I know what I'm talking about. You would need to re bias it by replacing parts, besides, transformers are small, not sure if it could handle them.
You can run 6CA7, or KT77's in this amp, like it's already been said, although I didn't like how KT77's sounded in my EL34b Nobsound amp, 6CA7's sounded better than the stock tubes, with a little more punch and bass.
Click to expand...
Thats why I suggested the 6CA7's. I was using KT-77's in an amp I have for several years. They did sound good, but the 6CA7's added a bit better bass and an added sparkle to the high end.
 
6550 draws more filament current that the EL34 does. EL34 bias is a much less negative voltage than that required for 6550, so the 6550 could draw too much plate current. Stick with EL34 or KT-77.
 
Stonegarden said:
6550 are KT88, you cannot run those on that amplifier. I have one myself so I know what I'm talking about. You would need to re bias it by replacing parts, besides, transformers are small, not sure if it could handle them.
You can run 6CA7, or KT77's in this amp, like it's already been said, although I didn't like how KT77's sounded in my EL34b Nobsound amp, 6CA7's sounded better than the stock tubes, with a little more punch and bass.
Click to expand...
 
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