It is 1 Ohm, actually. Drawing software puts 1k by default for all resistors, I forgot to change it.
I bought that 2.2 Ohm trimpots on epay long time ago. I'll check if they have some part numbers on them, but I am going to measure what is needed to get filaments warmed up then put some resistors instead of the trimpot there.
Today I tried one experiment: +12V on the 3'rd grid. As the result, linear output from the tube is even higher!
Now I need to make that +12V stabilizer, and increase voltage of the negative stabilizer.
Now I need to make that +12V stabilizer, and increase voltage of the negative stabilizer.
6J5P is as I described already, is a small 7 pin repackage of an octal tube 6AC7, in triode mode with 5-10 mA of idle current and high dynamic load is quite a good voltage amplifier for this amp.
Speaking of 6N16B, it is a tiny replacement for 6SN7. Actually, it is more close to 6N1P than to 6SN7. I put it inside because when experimented did not want to punch an extra hole for a tube socket: I was searching for a decent interstage transformer. But as the result discovered that what I made is even better than an interstage transformer, and punched more holes: for 4P1L in parallel, and for 6J9P to replace 6N16B as a cathode follower.
It is not the first time when trying to "cheat" simplifying something I found better solution than intended initially.
Now I have very clean stereo amp, with amazing stereo image, single ended, no feedback, 5W per channel, using extremely cheap tubes, that sounds better than amps that use very expensive tubes and interstage transformers.
A little bit of a bodywork...
An externally hosted image should be here but it was not working when we last tested it.
Cool, looks nice!
My 4P1L arrived safely from Mockba today. I got these from rutubes along with a bunch of other interesting tubes & stuff. Well packed and not a very long wait really.
Thank you!
I can't figure out how to fix better the plastic mirror between hot toobs and transformers. Also, how to fix a top lid for transformer apartment...
Congratulations Kevin!
I buy my stuff from e-pay sellers from Ukraine and Lithuania. They sell from military warehouses, cheap!
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Hi Anatoliy,
Usually I get mine from those ePay sellers but rutubes had some pretty compelling deals, so I grabbed them directly from them. Their site is very nice and they have lots of interesting items - of course there was a run on their stock of 4P1L once I mentioned them. Shipping was very quick.. Russian and Eastern block sellers in general seem to be amongst the most honest/ethical in their customer dealings I have ever dealt with - never a problem. Hope it stays that way.
I wonder, how good is adhesion of mirror finish to Lexan: I think about gluing the plastic mirror between hot toobs and transformers, so no bolts would be visible...
Any experience?
Any experience?
Some glues don't like heat. They get brittle and dry and don't hold.
Got my 4p1l's today. Ordered 10 and received an extra one at no cost! They are all Svetlana "winged C".
Got my 4p1l's today. Ordered 10 and received an extra one at no cost! They are all Svetlana "winged C".
After WW-II Germans redesigned Telefunken military tubes, and they were produced by Svetlana only. And all of them have "Diamond" stamp, that means military QA accepted, as well as OTK that means Svetlana's own QA accepted them before military QA.
They have these marks. What is in the diamond varies quite a lot. Years are:- 6 of 66, 2 of 78, 1 each of 72,73 and 74. Now I must wait for the sockets and hope they will be O.K.
I have used Clear silicone glue for such applications. Very good adhesion, heat proof and hardly visible, especially if applied on the inner surface only.
A little bit more of bodywork (click the image to expand it):
An externally hosted image should be here but it was not working when we last tested it.
