[chrisdrop]

Hi CAJ,
I think I remember somebody trying the 6P5GT and mentioning the edgy quality.
Re the hum with 6C5 tubes, Glenn advised that it may be helped by connecting pins 1&8 in the adapter. These are the pins on each side of the center notch in the adapter - I also think that the Chinese adapters have the pins designated by number.
It is easily done by taking a little piece of very thin wire and and stripping off the insulation at each end long enough to go inside the pin socket. Leave the insulation on in the middle and make a little U and stick it in.

Even better, @Deyan can make you 2x adapters

 

[CAJames]

Thanks for the suggestions. The hum is (at least mostly) from the 6BX7 power tubes I've been using instead of 6080s. It has always been there, but the adapters have made it noticeably worse, but still listenable. Today I went back to the 6BL7s that have been dead quiet in the past with the National Union 6C5s. There is a tiny bit of hum, compared to dead quite with any dual triodes, but the 6C5s are new and I'm letting them cook a little before any serious listening. The picture doesn't look much different from the Tung-Sols, except you can see some of the labels.

I guess if I had to pick my favorite brand, or Team Tube, (sorry Chris, Side Valve sounds like plumbing to an American ear) it would NU. My phono stage uses a 12SN7, and you can get the 12V versions of many of the "famous" 6SN7s for literally pennies on the dollar if you shop around. And, long story short, I've tried a lot of 12SN7s and my favorite is a NU gray glass. My rectifier is also a NU VT-145 JAN 5Z3 which itself if the 4 pin version of a 5U4. It got mine for $10, I would imagine a similar 5U4 would go for 10x that at least.

How about we get jerseys made with our favorite tube company logos? And under served market for sure, but perhaps deservedly so.

 

[leftside]

Thanks for the suggestions. The hum is (at least mostly) from the 6BX7 power tubes I've been using instead of 6080s. It has always been there, but the adapters have made it noticeably worse, but still listenable. Today I went back to the 6BL7s that have been dead quiet in the past with the National Union 6C5s. There is a tiny bit of hum, compared to dead quite with any dual triodes, but the 6C5s are new and I'm letting them cook a little before any serious listening. The picture doesn't look much different from the Tung-Sols, except you can see some of the labels.



I guess if I had to pick my favorite brand, or Team Tube, (sorry Chris, Side Valve sounds like plumbing to an American ear) it would NU. My phono stage uses a 12SN7, and you can get the 12V versions of many of the "famous" 6SN7s for literally pennies on the dollar if you shop around. And, long story short, I've tried a lot of 12SN7s and my favorite is a NU gray glass. My rectifier is also a NU VT-145 JAN 5Z3 which itself if the 4 pin version of a 5U4. It got mine for $10, I would imagine a similar 5U4 would go for 10x that at least.

How about we get jerseys made with our favorite tube company logos? And under served market for sure, but perhaps deservedly so.

Yep - a lot of those 12V tubes are great. I especially like the TS BGRP 12SN7. Sounds just like the expensive 6SN7.

They already exist
https://www.aliexpress.com/item/32903907465.html

 

[mordy]

https://www.redbubble.com/shop/mullard+t-shirts

 

[Monsterzero]

Thanks for the suggestions. The hum is (at least mostly) from the 6BX7 power tubes I've been using instead of 6080s. It has always been there, but the adapters have made it noticeably worse, but still listenable. Today I went back to the 6BL7s that have been dead quiet in the past with the National Union 6C5s. There is a tiny bit of hum, compared to dead quite with any dual triodes, but the 6C5s are new and I'm letting them cook a little before any serious listening. The picture doesn't look much different from the Tung-Sols, except you can see some of the labels.



I guess if I had to pick my favorite brand, or Team Tube, (sorry Chris, Side Valve sounds like plumbing to an American ear) it would NU. My phono stage uses a 12SN7, and you can get the 12V versions of many of the "famous" 6SN7s for literally pennies on the dollar if you shop around. And, long story short, I've tried a lot of 12SN7s and my favorite is a NU gray glass. My rectifier is also a NU VT-145 JAN 5Z3 which itself if the 4 pin version of a 5U4. It got mine for $10, I would imagine a similar 5U4 would go for 10x that at least.

How about we get jerseys made with our favorite tube company logos? And under served market for sure, but perhaps deservedly so.

Its been my experience that if you have noisy 6BX7s(or any other tube) that a good sandpaper cleaning will fix the issue. If that doesnt work simply try re-seating the tubes.
This has worked 100% of the time for me,though im sure there are some tubes that are beyond help.

 

[bcowen]

Its been my experience that if you have noisy 6BX7s(or any other tube) that a good sandpaper cleaning will fix the issue. If that doesnt work simply try re-seating the tubes.
This has worked 100% of the time for me,though im sure there are some tubes that are beyond help.

Could be as well that the solder has separated inside one or more of the pins. This is a known issue with '50's Russian 6N8S's (Fotons especially and some Melz). I've had a couple Tung Sols though with the same issue. Best way is to suck out the old solder and replace it entirely, but almost as good is just reheating the pins until the solder melts and adding a little fresh solder. Most times this problem manifests itself as a rustling, static-ey, or even squealing sound, but I've had a couple that had one triode testing totally dead -- until I resoldered the pins at which point it jumped up to NOS GM levels.

Edit: a good cleaning of the pins as you suggest should always be the first course of action. Easy to do and can solve a lot of problems. And don't forget the sockets too -- not with sandpaper, but a pipe cleaner dipped in isopropyl alcohol works quite well. If you've swapped a bunch of tubes in and out, it's surprising the amount of black gunk that ends up on the end of that pipe cleaner. Just please (for the uninitiated) be sure the unit is turned off (and preferably unplugged from the wall socket) before sticking wet things in tube sockets.

 

[CAJames]

https://www.redbubble.com/shop/mullard+t-shirts

Those are awesome! However, I'm going to hold off on the National Union jersey for a while. Turns out at least one of the tubes was bad. Tried them with the known quite power tubes and they were still noisy, and then one of them went all mircophonic and the noise got much worse. Went back to the Tung-Sols with some old reliable 6080s and they were dead quite, and sounded really good. Not as good as with the 6BX7s modulo the noise, but as good or better then I ever remember the system sounding with the 6080s. This has been kinda exhausting, so now that it is sounding good again I'm just gong to listen for a little while. Plenty of time for more tube rolling later.

I appreciate everyone's suggestions for what to do with the noisy tubes, but I'm pretty sure the problem is a more fundamental than "noisy tubes." I've tried 3 different pairs from two different manufactures and all them have the same hum. The 6BX7 is very different from the 6080/6AS7 that my amp is supposed to use, and there is really no reason to think it should work even as well as it does.

 

[leftside]

Those are awesome! However, I'm going to hold off on the National Union jersey for a while. Turns out at least one of the tubes was bad. Tried them with the known quite power tubes and they were still noisy, and then one of them went all mircophonic and the noise got much worse. Went back to the Tung-Sols with some old reliable 6080s and they were dead quite, and sounded really good. Not as good as with the 6BX7s modulo the noise, but as good or better then I ever remember the system sounding with the 6080s. This has been kinda exhausting, so now that it is sounding good again I'm just gong to listen for a little while. Plenty of time for more tube rolling later.

I appreciate everyone's suggestions for what to do with the noisy tubes, but I'm pretty sure the problem is a more fundamental than "noisy tubes." I've tried 3 different pairs from two different manufactures and all them have the same hum. The 6BX7 is very different from the 6080/6AS7 that my amp is supposed to use, and there is really no reason to think it should work even as well as it does.

I had no hum with 6BL7 or 6BX7 when I had the WA22. Used those tubes all the time.

 

[CAJames]

Yes, and others too. But I have the "new improved" WA22, so who knows if that is really an apples to apples comparison. I don't have any hum with the 6BL7s.

 

[mordy]

Yes, and others too. But I have the "new improved" WA22, so who knows if that is really an apples to apples comparison. I don't have any hum with the 6BL7s.

I found it very tricky to get a quiet set of 6BX7 tubes. By listening to only one channel at a time I could determine which three tubes to check (instead of six) and by way of elimination identify the culprit.
Sometimes it even helped to switch the positions of the tubes.

 

[mordy]

Could be as well that the solder has separated inside one or more of the pins. This is a known issue with '50's Russian 6N8S's (Fotons especially and some Melz). I've had a couple Tung Sols though with the same issue. Best way is to suck out the old solder and replace it entirely, but almost as good is just reheating the pins until the solder melts and adding a little fresh solder. Most times this problem manifests itself as a rustling, static-ey, or even squealing sound, but I've had a couple that had one triode testing totally dead -- until I resoldered the pins at which point it jumped up to NOS GM levels.

Edit: a good cleaning of the pins as you suggest should always be the first course of action. Easy to do and can solve a lot of problems. And don't forget the sockets too -- not with sandpaper, but a pipe cleaner dipped in isopropyl alcohol works quite well. If you've swapped a bunch of tubes in and out, it's surprising the amount of black gunk that ends up on the end of that pipe cleaner. Just please (for the uninitiated) be sure the unit is turned off (and preferably unplugged from the wall socket) before sticking wet things in tube sockets.

Could you describe how you add a little solder? I am always afraid that by heating up the solder it will flow inside the tube and create problems.

 

[bcowen]

Could you describe how you add a little solder? I am always afraid that by heating up the solder it will flow inside the tube and create problems.

Sure, just position the tube horizontally before you start heating the pin.. Capillary action will help draw the new solder inside the pin. Don't need to add a lot...just a little. Sometimes just reheating (re-melting) the old solder will do the trick too. When the tube was manufactured, the wire in each pin stuck out from the end of the pin and the excess wire was snipped off after soldering. So the wire itself should be right at the end tip of the pin -- just need to make sure the very tip has a good solder connection. @Paladin79 has provided some very nice instructions in another thread and gave me a lot of great advice, just can't remember which thread that's in right now. probably the Lyr 3 tube rollers thread or the main Lyr 3 thread...I'll see if I can find it tomorrow.

 

[CAJames]

I found it very tricky to get a quiet set of 6BX7 tubes. By listening to only one channel at a time I could determine which three tubes to check (instead of six) and by way of elimination identify the culprit.
Sometimes it even helped to switch the positions of the tubes.

So when you had noisy 6BX7s what was the noise like? I've been listening to tubes for a long time and I'm pretty sure I know the difference between "hiss" and constant 60 cycle hum that is equal in both channels. I've dealt with the former with all the techniques already mentioned (I'm a fanatic about DeoxIT) and including tube dampers which no one has mentioned (yet). But the noise I hear with 3 different pairs of 6BX7s (2 GE, one Sylvania), all with shiny new pins, is constant 60 cycle hum that is equal in both channels. Swapping left to right doesn't change it. It is certainly possible I've got 3 pairs of similarly bad tubes, and I've got one or two more pairs I can try, but this really seems like the tube is operating under conditions it doesn't like. The base of the tube also gets really hot, although the amp itself stays very cool.

 

[Paladin79]

Sure, just position the tube horizontally before you start heating the pin.. Capillary action will help draw the new solder inside the pin. Don't need to add a lot...just a little. Sometimes just reheating (re-melting) the old solder will do the trick too. When the tube was manufactured, the wire in each pin stuck out from the end of the pin and the excess wire was snipped off after soldering. So the wire itself should be right at the end tip of the pin -- just need to make sure the very tip has a good solder connection. @Paladin79 has provided some very nice instructions in another thread and gave me a lot of great advice, just can't remember which thread that's in right now. probably the Lyr 3 tube rollers thread or the main Lyr 3 thread...I'll see if I can find it tomorrow.

You can always PM me and I will share photos. Personally I prefer to remove all the old solder, add liquid flux inside the pins and then re-solder using 3% silver solder. Here I am adding liquid rosin flux to the inside of each pin using a straight pick, I also use very tiny diameter solder, I want to say it is .021 but I will have to check that out later. You will see the wire @bcowen mentioned on the inside of many pins. Flux cleans the metal you are about to solder, I use rosin core solder but when dealing with tubes that can be 60 years old or more, I prefer a more thorough cleaning since you cannot see how well the wire and inside of the pin are being cleaned.



Here are a couple ST Sylvania 6j5's in a headphone amp I designed, I also use quite a few 7A4"s which is the Loctal version of the 6j5.

 

[bcowen]

You can always PM me and I will share photos. Personally I prefer to remove all the old solder, add liquid flux inside the pins and then re-solder using 3% silver solder. Here I am adding liquid rosin flux to the inside of each pin using a straight pick, I also use very tiny diameter solder, I want to say it is .021 but I will have to check that out later. You will see the wire @bcowen mentioned on the inside of many pins. Flux cleans the metal you are about to solder, I use rosin core solder but when dealing with tubes that can be 60 years old or more, I prefer a more thorough cleaning since you cannot see how well the wire and inside of the pin are being cleaned.

Thanks for responding!

I will note that even after resoldering umpteen bazillion pins on my tubes, @Paladin79 's still look better. I'm pretty sure the doctor had to cut a soldering iron cord rather than an umbilical cord when he was born.

It's no issue to get a good solder connection that is electrically sound. It's keeping the solder off the outside of the pin that proves challenging for me. Then you have to file it down to get it smooth again. Not a big issue either, just kind of a PITA. I've found that wiping any excess flux off the outside of the pin before hitting it with the soldering iron helps a lot, as does using a very thin gauge solder as Paladin already mentioned. Mine look better and better as I get more experience, but I'd highly recommend practicing on a useless or worn out tube first before globbing up a prized treasure if this is your first attempt.

Some of us have plenty to practice on.