[Bard Rich]

lawshredpower, please what are those double power tubes in your WA22 that you’re using? I’m using Tung Sol 5998 power tubes, with Sophia Electric 6SN7 drivers, and a USAF 596 rectifier, which I’ve really enjoyed. Thnx

how sophia electric 6SN7 sound?

 

[bpcans]

how sophia electric 6SN7 sound?

They are very nice sounding indeed. They’re the best matched pair Sophia Electric made back when I bought them almost ten years ago.

 

[CAJames]

Nice! I’ve searched for a USAF 596 for myself but those are hard to come by it seems. Friend of mine gave me a nice deal on his U52 so I could not pass that. I’ll try the USAF when I can.

I’m using a quad matched GE 6BL7GTA. Did wonders to my setup! Lowered the hum compared to the stock power tubes and the sound... wow! Wider, faster, tighter, more analytical. Right on my alley. I’m starting to agree with the former owner: the stock tubes are merely to see the amp functions correctly lol

I’m still on the quest to achieve a dead silent background if I can. Some hum I don’t mind at all but total silent would be ideal.

That's interesting. For me the stock tubes were dead silent but kinda uninteresting. I went through a 6BX/L7 phase myself, I only used 1 per side and always had hum. Some worse than others but it was always there. I guess I should get the adapter and try 2 per side. I also recall someone using 1 6BX/L7 and 1 6SN7 per side and liking it. That seems just weird enough to work.

 

[cddc]

That's interesting. For me the stock tubes were dead silent but kinda uninteresting. I went through a 6BX/L7 phase myself, I only used 1 per side and always had hum. Some worse than others but it was always there. I guess I should get the adapter and try 2 per side. I also recall someone using 1 6BX/L7 and 1 6SN7 per side and liking it. That seems just weird enough to work.

IIRC, 6BL7/6BX7 were mainly used in vintage TVs, and they definitely had a tough life there, stayed on 24/7 often. So few of the 6BL7/6BX7 tubes on the market come with satisfying conditions, lots of them have hum or other issues.

I'd personally stay away from those tubes.

 

[lawshredpower]

That's interesting. For me the stock tubes were dead silent but kinda uninteresting. I went through a 6BX/L7 phase myself, I only used 1 per side and always had hum. Some worse than others but it was always there. I guess I should get the adapter and try 2 per side. I also recall someone using 1 6BX/L7 and 1 6SN7 per side and liking it. That seems just weird enough to work.

Maybe that goes to show how much of a lottery tubes are, especially those stock ones. Not sure atm, merely speculation on my part. Let's see if rolling the stock recto tube will make a difference. My goal is pitch black background. Good to know it's achievable!

 

[HiFiGuy528]

keep in mind that changing the stock power tubes will change the specifications and the noise floor of the amplifier. Additionally, tubes sourced from online marketplaces may not be the highest quality or lowest noise. The tubes we offer on our website are carefully chosen and tested by us, backed by a min. of 30 days guarantee.

 

[CAJames]

IIRC, 6BL7/6BX7 were mainly used in vintage TVs, and they definitely had a tough life there, stayed on 24/7 often. So few of the 6BL7/6BX7 tubes on the market come with satisfying conditions, lots of them have hum or other issues.

I'd personally stay away from those tubes.

The thing is, modulo the hum, they are fantastic sounding tubes. And practically free compared to the "heritage" 5998s and the like. They do have a lot more gain than the "approved" power tubes, which may be good or bad depending on you headphones, and probably explains the hum to some degree. I didn't have any trouble finding plenty that looked and tested like new.

 

[cddc]

I read mixed reviews on the duo. When they were initially unearthed couple of years ago, lots of people went for it, even here in the wa22 thread, then some people liked them and some didn't, but eventually the fever after new discovery cooled down, and few people discuss them today, I think that tells something about the duo. If they were indeed good, they would have become some hot candidates by now. But they are not. The most I read about these tubes are that they are very noisy, hum often, and it's extremely challenging to find a quiet pair/quad.

 

[cddc]

2 possible reasons to explain why 6BX/L7 tubes are so noisy, that I can think of:

1) they were mainly used as vertical deflection tubes in old TV's, and definitely had a tough life there.
2) their gain of 10-14 is too high for the power tube job, for comparison, 6080/6AS7G have a gain of only 2, and 5998 is slightly higher at 5.5. A gain of 14 from 6BL7 is more suitable for the driver tube seat, like 6SN7 (gain=20).

 

[cddc]

If people like the idea, I think they can even try 2 x 6SN7 or 3 x 6SN7 as a single power tube, why not...I'd like to hear how they sound

At least 6SN7 was designed for audio use, and we don't have to worry about their being abused in TV's.

 

[CAJames]

I don't think it is fair to say the 6SN7 (and its predecessors, I'm currently using the Type 37 in my WA22) was designed "for audio use." It was general purpose amplifier tube and used in almost everything, esp. radios but also telco and test equipment. And millions were used (and abused) in TVs and early computers as well. They were popular in "hifi" in the 50's and early 60's but that was a tiny fraction of the market, and they were replaced with noval tubes like the 6DJ8 and 12AU7, not because the they were better but because the smaller tubes were cheaper to make and use.

As for using them as power tubes, you can try but they don't put out much power. That was one of the intriguing things about the 6B_7s, for little tubes they put a bunch of watts, like 11 IIRC.

 

[MIKELAP]

I don't think it is fair to say the 6SN7 (and its predecessors, I'm currently using the Type 37 in my WA22) was designed "for audio use." It was general purpose amplifier tube and used in almost everything, esp. radios but also telco and test equipment. And millions were used (and abused) in TVs and early computers as well. They were popular in "hifi" in the 50's and early 60's but that was a tiny fraction of the market, and they were replaced with noval tubes like the 6DJ8 and 12AU7, not because the they were better but because the smaller tubes were cheaper to make and use.

As for using them as power tubes, you can try but they don't put out much power. That was one of the intriguing things about the 6B_7s, for little tubes they put a bunch of watts, like 11 IIRC.

A picture of your type 37 tube would be nice .Need an adapter for this tube ?Thanks

 

[cddc]

Here you go, @MIKELAP (pic from the bay)

It's a single triode, so you will need two. And, it's an old 5 pin style tube, so you'll need two 5-pin to octal adapters or one dual 5-pin to octal adapter.

There are just too many 6SN7 predecessors, you are going to get lost if you go down the predecessor road

 

[cddc]

I don't think it is fair to say the 6SN7 (and its predecessors, I'm currently using the Type 37 in my WA22) was designed "for audio use." It was general purpose amplifier tube and used in almost everything, esp. radios but also telco and test equipment. And millions were used (and abused) in TVs and early computers as well. They were popular in "hifi" in the 50's and early 60's but that was a tiny fraction of the market, and they were replaced with noval tubes like the 6DJ8 and 12AU7, not because the they were better but because the smaller tubes were cheaper to make and use.

As for using them as power tubes, you can try but they don't put out much power. That was one of the intriguing things about the 6B_7s, for little tubes they put a bunch of watts, like 11 IIRC.

Yes, it's a little bit unfair to say 6SN7 was designed for audio use solely. It's a general purpose tube, but because of its linearity it was widely used as an audio tube from early on. I think tube manufacturers in 50s/60s knew that, and possibly made some modifications for better use in audio equipments. 6080/6AS7G on the other hand were not designed for audio use, they were mainly used as voltage regulators before tube-philes found them.

The shift to 12A_7 tubes is an ugly move, just for the sake of cost cutting.

 

[MIKELAP]

Here you go, @MIKELAP (pic from the bay)

It's a single triode, so you will need two. And, it's an old 5 pin style tube, so you'll need two 5-pin to octal adapters or one dual 5-pin to octal adapter.

There are just too many 6SN7 predecessors, you are going to get lost if you go down the predecessor road

First of all was it worth the trouble soundwise ? Would you have a link or did you make your own adapters ?.Thanks again