Howdy;
Thought I would try tube rolling in my Nuera 340SE class A 7 watt amp so ordered some new tubes and the 5AR4 and EL34 tubes work fine.... But the first pair of EH 6SN7 tubes I put in made ugly noises on one channel and then the replacement pair I got from the (reputable) dealer hummed loudly on one channel and quietly on the other channel . The Stock OEM Chinese tubes have worked flawlessly and quietly since I bought the amp several years ago although they aren't the greatest in resolution. Bad tubes or mismatch ?
I think the Nuera company is long gone, doesn't have a working e-mail any longer, and the manual has no schematic.
Since the top panel has the tube numbers printed next to each socket there are also another designation behind a slash mark next to each of the 5 tubes.
It says 6SN7/6H8C for the 2 front tubes.
My question is should I stick with a particular 6SN7 tube type ?
Would it be the 6SN7GT or another variant ?
I thought the 6H8C was different than some 6SN7 tubes
Any info appreciated.
Thought I would try tube rolling in my Nuera 340SE class A 7 watt amp so ordered some new tubes and the 5AR4 and EL34 tubes work fine.... But the first pair of EH 6SN7 tubes I put in made ugly noises on one channel and then the replacement pair I got from the (reputable) dealer hummed loudly on one channel and quietly on the other channel . The Stock OEM Chinese tubes have worked flawlessly and quietly since I bought the amp several years ago although they aren't the greatest in resolution. Bad tubes or mismatch ?
I think the Nuera company is long gone, doesn't have a working e-mail any longer, and the manual has no schematic.
Since the top panel has the tube numbers printed next to each socket there are also another designation behind a slash mark next to each of the 5 tubes.
It says 6SN7/6H8C for the 2 front tubes.
My question is should I stick with a particular 6SN7 tube type ?
Would it be the 6SN7GT or another variant ?
I thought the 6H8C was different than some 6SN7 tubes
Any info appreciated.
The 6SN7 was one of the cleanest valves to be produced in the 1950/60's and very sought after.
The data on the 6H8C is similar but had a metal clad base.
There are a number of clones built to a similar specification in Russian factories that are exceptional and some made in China, and other places, that are sh 1 t.
The data on the 6H8C is similar but had a metal clad base.
There are a number of clones built to a similar specification in Russian factories that are exceptional and some made in China, and other places, that are sh 1 t.
I'm surprised you had trouble with the EH 6SN7, as it's 1 of the 2 decent current production varieties. The better current production 6SN7 is the "reissue" TungSol. If you've yet to do business with Jim McShane, it's time to start.
Desirable NOS 6SN7s are VERY costly. However, there is a way to experience good NOS, without surrendering some body parts. The Loctal based 7N7 is electrically equivalent to the Octal based 6SN7. Construct adapters from Loctal sockets and Octal plugs.
Desirable NOS 6SN7s are VERY costly. However, there is a way to experience good NOS, without surrendering some body parts. The Loctal based 7N7 is electrically equivalent to the Octal based 6SN7. Construct adapters from Loctal sockets and Octal plugs.
Thanks for chiming in with your posts , and thanks for the link Eli, actually I'm also surprised I had trouble with the EH 6SN7's as several people recommended them so I bought matched and tested pairs from a longtime reputable dealer . The only dodgy thing was the tubes slide around loosely in their cardboard sleeves so they might have suffered some trauma in transit? Don't know .
I've got a pair of the new Tung-Sol 12AX7's I bought for my Bellari phono preamp several years ago but they have almost too much clarity , I wound up going back to my Phillips JAN12AX7
I've got a pair of the new Tung-Sol 12AX7's I bought for my Bellari phono preamp several years ago but they have almost too much clarity , I wound up going back to my Phillips JAN12AX7
Also worth contemplating 6CG7's, the 9 pin version of same tube.
I'm running a Radiotron branded pair which I beleive are Australian manufacture.
A recent review I saw of tube amps under 2000 pounds in hifi choice in the UK was not terribly charitable about an amp that was using a very bulbous globe style variant of the 6SN7 available today. They thought they were pretty microphonic.
I'm running a Radiotron branded pair which I beleive are Australian manufacture.
A recent review I saw of tube amps under 2000 pounds in hifi choice in the UK was not terribly charitable about an amp that was using a very bulbous globe style variant of the 6SN7 available today. They thought they were pretty microphonic.
I've been pretty happy with vintage Sylvania 6SN7GTB. (GTA as well where ratings are not exceeded) I've found late 1960s vintage and up in the past to be a good trade off between performance and cost. They were made into the early 1980s finally under the Philips ECG label.
yes, one i am using now is a 6cg7/6gu7 combo aikido...
i have replaced the 6cg7 with the russian 6n23 and the japanese 6r-rh8, results are consistently good, using the japanese 6r-rh2 however resulted in more gains..but sound is okey...
some snapshots of my 6H8c aikido using tube rectification...
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