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Vintage threads from the first ten years

Sound amps

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12/23/1999 3:37 AM
Robert	Sound amps Can anybody tell me about these? thanks.

1/3/2000 2:58 PM

I have had a couple of these "Sound" amps. They were made in NY I believe. One bass amp 2-7868s was okay once the Jensen Speaker was replaced. I have a guitar amp that uses one of those strange german output tubes, but I have not been able to figure out which one. The tube is a double triode that allows push pull with only one tube. An older radio tech told be that the german radios were taxed based on the number of tubes in the radio, so the engineers designed lots of multi-section tubes to reduce the number of tubes. SOUND apparently used these double power tubes in their outputs. The ones I have been able to identify all squeal and oscillate when placed in the circuit. If anybody knows the right power output tube number for this amp (X-305) I would love to hear about it. Until then, it sits in the basement unused and unloved. Both these amps came out of Cleveland Ohio. Also, please correct if my interpretation of this amp is wrong.

1/3/2000 4:52 PM
Graywater	Rob, You don't know the output tube number(s)? OK, how many total tubes does the amp have? Some low power european amps used a pair of 6GW8s (ECL86), triode/output pentode, usually with another voltage amp stage or two for a 3 tube, 3 or 4 stage, P-P 15w amp. So, could it be that instead of a dual triode output you have two triode/pentodes (more common) with pentode outputs. GW

1/3/2000 6:41 PM
Farrow	Hmmm... I had thought the 7868 was the magnoval version of the 7591. I've seen many more Euro amps with ECL86 and Japanese amps with 6BM8. I'm inclined to go with Graywater on this one. Farrow http://surf.to/pharaohamps

1/3/2000 11:37 PM
Marc	Rob: There's also the ECLL800 that has a triode and a dual pentode in one envelope that drives a P-P output to 8-10 watts. That's alot to pack into one tube. They weren't all that common. I've found them twice in old german HIFI's. Marc

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