Dear Friends,
I have recently bought the KT88 genalex gold lion and 6sn7 Tung Sol for my Dynaco inspired project. I have a question regarding the sockets used for the lamps.
I have seen some ceramic China made sockets or old Soviet ones for 3 USD. The manager from the shop from where I got the tubes told me that they were crap and I should buy more expensive ones from him (14,4 USD each: Керамические ламповые панельки CMC8G Ceramic Gold, купить-гнездо под лампы)
Since I need 7 of them, the difference in costs is significant.
Can you share your experience? What sockets would you recommend?
Anatoly
I have recently bought the KT88 genalex gold lion and 6sn7 Tung Sol for my Dynaco inspired project. I have a question regarding the sockets used for the lamps.
I have seen some ceramic China made sockets or old Soviet ones for 3 USD. The manager from the shop from where I got the tubes told me that they were crap and I should buy more expensive ones from him (14,4 USD each: Керамические ламповые панельки CMC8G Ceramic Gold, купить-гнездо под лампы)
Since I need 7 of them, the difference in costs is significant.
Can you share your experience? What sockets would you recommend?
Anatoly
Try to find mica loaded phenolic sockets. Ceramic conducts vibration, while the composite exhibits some vibration damping.
Lots of Chinese parts are, indeed, говно. However, he was also looking out for his own interests. Soviet era military surplus parts frequently are excellent. If you can source Red Army surplus mica loaded phenolic Octal sockets, buy them.
Lots of Chinese parts are, indeed, говно. However, he was also looking out for his own interests. Soviet era military surplus parts frequently are excellent. If you can source Red Army surplus mica loaded phenolic Octal sockets, buy them.
i'd get the china sockets. When they arrive, inspect and if ok use them.
Put the money where it makes difference such as output transformers.
I'd also go for military surplus parts from whatever source. No need for gold plated and overpriced parts. As the base pins themselves are just tinned, this literally calls for corrosion under certain circumstances (humid air etc.)
Best regards!
Best regards!
Eli Duttman
Do you mean something like this?
8 Pin "Octal" Wafer Phenolic Socket (Item: NOS-SKT-67) - Radio Daze LLC
I have managed to find on AliExpress exactly the same sockets he is offering in his shop 2 times cheaper.
petertub
Yes, I have the llundahl PP transformers. Looked like good ones for their price.
Thank you! I will look into all advises.
Do you mean something like this?
8 Pin "Octal" Wafer Phenolic Socket (Item: NOS-SKT-67) - Radio Daze LLC
I have managed to find on AliExpress exactly the same sockets he is offering in his shop 2 times cheaper.
petertub
Yes, I have the llundahl PP transformers. Looked like good ones for their price.
Thank you! I will look into all advises.
Those old Soviet ceramic octal sockets are actually quite decent. They're made from some rough and dense material remotely similar to the cases of the modern "cement" wirewound resistors.
Even the bakelite black (not brown) ones aren't that bad, though I'd avoid using them for power tubes.
Just make sure the contacts are clean - they're often not after the decades of improper storing.
Even the bakelite black (not brown) ones aren't that bad, though I'd avoid using them for power tubes.
Just make sure the contacts are clean - they're often not after the decades of improper storing.
+1 on Belton.
They have nice, tight pin-sockets that lasts. Get them at Partsconnexion at the moment for $2.28 each.
Belton Socket 8 Pin Octal Chassis Mount Solder Lug
They have nice, tight pin-sockets that lasts. Get them at Partsconnexion at the moment for $2.28 each.
Belton Socket 8 Pin Octal Chassis Mount Solder Lug
FYI --
Morgan Jones looked into tube sockets and wrote about them in his book "Valve Amplifiers". What I see in there is...
- Teflon (PTFE) and ceramic sockets have the highest insulation resistance (lowest leakage currents) so are the best as far as rejecing leakage currents between tube pins.
- Regarding ceramic sockets, I never thought about transmission of vibration, but that might be a concern in phono preamps or similar.
- Brown phenolic and white plastic are good insulators too, but not as good as PTFE or ceramic. You can find vintage brown micalex sockets NOS pretty easily, so this may be a good compromise between best performance and lower cost. I don't know if those Chinese-made white PC-mount tube sockets are durable enough to be recommended, but the material should be a decent insulator.
- Black phenolic sockets have carbon in their composition (to make them black, I suppose) which gives them worse leakage resistance than the previously mentioned materials.
- Phenolic wafer sockets are the worst. They can absorb moisture, which makes them more susceptible to leakage currents. Don't bother, except maybe for quick 'n dirty experimenting.
See Morgan Jones "Valve Amplifiers" 4th Edition, pp. 236-7.
--
Morgan Jones looked into tube sockets and wrote about them in his book "Valve Amplifiers". What I see in there is...
- Teflon (PTFE) and ceramic sockets have the highest insulation resistance (lowest leakage currents) so are the best as far as rejecing leakage currents between tube pins.
- Regarding ceramic sockets, I never thought about transmission of vibration, but that might be a concern in phono preamps or similar.
- Brown phenolic and white plastic are good insulators too, but not as good as PTFE or ceramic. You can find vintage brown micalex sockets NOS pretty easily, so this may be a good compromise between best performance and lower cost. I don't know if those Chinese-made white PC-mount tube sockets are durable enough to be recommended, but the material should be a decent insulator.
- Black phenolic sockets have carbon in their composition (to make them black, I suppose) which gives them worse leakage resistance than the previously mentioned materials.
- Phenolic wafer sockets are the worst. They can absorb moisture, which makes them more susceptible to leakage currents. Don't bother, except maybe for quick 'n dirty experimenting.
See Morgan Jones "Valve Amplifiers" 4th Edition, pp. 236-7.
--
Regarding vibrations, everything vibrates, all materials vibrate either by themselves or by influence.
I use Russian sockets of ceramics everywhere they are better than most I have tried, maybe not so much bling and no cool name but they work for little money.
There is still plenty of good quality electronic equipment from the 50's performing perfectly OK with phenolic wafer type sockets, and there are plenty of tubes being broken when being jammed into modern ceramic style sockets, so I will aways plump for NOS, if is serviceable. I bought some NOS B8G wafer style sockets to build loktal to octal adaptors, and they work fine.
If I had to buy modern ones, those Belton ones look to be the closest to a modern equivalent.
I would have thought the biggest hassle faced by diy enthusiasts is poor quality pins (too tight or losing grip), as opposed to the ability of the tube substrate to withstand high voltages.
If I had to buy modern ones, those Belton ones look to be the closest to a modern equivalent.
I would have thought the biggest hassle faced by diy enthusiasts is poor quality pins (too tight or losing grip), as opposed to the ability of the tube substrate to withstand high voltages.
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I absolutely concur. What should be better with a socket that has a mica layer sandwiched between two moisture absorbing phenolic discs compared to one consisting of phenolic discs only? Absorbing vibrations surely isn't an issue that holds for line or output level stages, and for input stages mounting the sockets with the help of rubber grommets surely would be more effective.
Yes, indeed I've seen carbonized tracks between pins 2 and 3 of EL34 bakelite sockets. So I prefer ceramic ones at least for output tubes without plate top caps.
Best regards!
