Just got a chance to try out some JJ 6V6 tubes. They sound much better than the NOS Russian 6P6C . Especially the hum that the 6P6C had has disappeared. The 6P6C used to hum and it used to drop a lot when you placed a hand over it ! Now it's not there at all.
HF appears clearer. Need to check this after several hours of run in. The tube is bigger too and looks better made !
No time to try any experiments now.
HF appears clearer. Need to check this after several hours of run in. The tube is bigger too and looks better made !
No time to try any experiments now.
6P6S is a copy of 1930'Th RCA. JJ 6V6 is modern re-design. 6P15P, or even 6J52P (frame grid, the last one designed in USSR) can be better.
In my amp they give 150V swing before clipping working on 4mA (only!) idle current (400V B+, 100V on LTP tail).
Thank you. I knew you had lots of experience with with the tube as it was your recommendation that caused me to purchase them in the first place🙂 sorry for OT
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Basicly an EL84 without g3 interconnected to cathode, isnt it? Means that you can do as many newer HF transmitters. Connect it with a film cap instead.
No, basically it is like EL84 with denser G2.
www.wavebourn.com • View topic - 6p15p data ?????? 6?15?
Any new test results ?
What about reviews on the 6v6 basic circuit after so many weeks of burn in !🙂
What about reviews on the 6v6 basic circuit after so many weeks of burn in !🙂
So is it worth getting a 6j52p or 6p15p for experimentation ?
I'm fascinated by the report that the G3 connected via a film capacitor to the cathode sounds very good. Can anyone comment on that ?
I'm fascinated by the report that the G3 connected via a film capacitor to the cathode sounds very good. Can anyone comment on that ?
Got a chance to compare a 6v6 Electro Harmonix and a 6v6 Mullard. The Mullard sounds better to me. The EH seems to be lighter in the bass and not as good in the midrange as the Mullard. Maybe they just need different operating points and one shouldn't just plug in different valves without changing the resistors. They may belong to a generic number but are not exactly identical.
But then again the Mullard was run in for a few days. Would that make a difference ? I'll know after a few weeks of using them I guess.
But then again the Mullard was run in for a few days. Would that make a difference ? I'll know after a few weeks of using them I guess.
Mainly check that the heater voltage remains the same. Also try some NOS USSR 6П6С pair. They are usually more "melodious" than the recent crop. Preference is a matter of full system synergy for the most part though. Given the opportunity that a GZ34 rectifier died with a bang after some yrs of service and I opened up my preamp to fix it I also substituted my old Alps Black Beauty pot with a Tocos 50K. Sounds more open and tonally accurate to me. Recommended.
I have the 6П6С and it has quite a bit of hum. With an ac heater the Mullard 6V6 has very low hum and sounds very nice. The Electro Harmonix 6V6 has a lot of hum when put in place. With the 6П6С it seems to pick up hum even if my hand gets close to the tube. A problem not there with the other tubes. Even the JJ 6V6 sounds good.
Might have to use a dc heater to cut down on hum. Current board is open. There is no metal casing around it. It sits on an aluminum sheet with brass standoff's .The aluminum sheet is earthed.
No time to do much tinkering now and for the next few weeks. But will try things if time permits.
Might have to use a dc heater to cut down on hum. Current board is open. There is no metal casing around it. It sits on an aluminum sheet with brass standoff's .The aluminum sheet is earthed.
No time to do much tinkering now and for the next few weeks. But will try things if time permits.
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I have no more hum with a 6П6С vs new Tungsol (glorified EH production, smoother) or Sylvania etc. My pre has the original dc current source heater circuit that I have shown. Its easy to make as it uses the ubiquitous LM317. Try it. Then again you should check with a scope in case its not just hum but oscillation with some tubes. Maybe you need a higher value grid-stopper for those or better wiring etc.
You are right I should scope it and see what's happening. Unfortunately my stuff is all packed and ready to move home to a new place. So it will take a few weeks to get going again !
I don't remember seeing your current source heater. Did you put up the circuit ? or is it just like the application sheet shows. However since the sound is nice it's worth following up. Zero hum would be great !
Wonder if it will sound any better in an Aikido configuration....with some form of noise cancellation. But that cuts supply borne noise and may not do anything else here . Here maybe a CC dc heater is the answer. About my Russian tubes being sensitive to hum sources, possibly in a shielded chassis that will not be a problem.
I'll get a few more Russian 6П6С's later and see if they also have the same problem. I've bought the Tungsol 6V6. Will take a while before I get to use them.
Cheers.
I don't remember seeing your current source heater. Did you put up the circuit ? or is it just like the application sheet shows. However since the sound is nice it's worth following up. Zero hum would be great !
Wonder if it will sound any better in an Aikido configuration....with some form of noise cancellation. But that cuts supply borne noise and may not do anything else here . Here maybe a CC dc heater is the answer. About my Russian tubes being sensitive to hum sources, possibly in a shielded chassis that will not be a problem.
I'll get a few more Russian 6П6С's later and see if they also have the same problem. I've bought the Tungsol 6V6. Will take a while before I get to use them.
Cheers.
It might come down to the layout of your wiring, as the hum is always there, in more or lesser degree. Give us some graphic information if you can.
Bit too late for pictures now. All the tubes are packed up for transport. It isn't exactly a great setup and I'll redo everything when it is set up again after a couple of weeks. The problem could be just because of the the way it's laid out now.
Salas, yes, now I remember the psu circuit. I didn't look at it too closely earlier. Will see what I can do. Thanks.
Cheers.
Salas, yes, now I remember the psu circuit. I didn't look at it too closely earlier. Will see what I can do. Thanks.
Cheers.
I was thinking about the 6P15P with g3 connected to cathode with a capacitor. Usually this grid has a low dc voltage on it due to the cathode connection. In this method there is no dc on it and it's floating as far as dc is concerned.
The question was if this is a problem.
I feel that at dc the lack of dc connection of g3 will make the tube behave like a tetrode and it should not be a problem . With ac signals it behaves like a pentode .
How this affects the sound is something that will have to be studied I guess.
I will put this on my next tube project list. Maybe try the 6P15P and the 6J52P. Someone didn't like the 6J52P but didn't describe what was wrong. Can anyone who has used the tube give their opinion ?
The question was if this is a problem.
I feel that at dc the lack of dc connection of g3 will make the tube behave like a tetrode and it should not be a problem . With ac signals it behaves like a pentode .
How this affects the sound is something that will have to be studied I guess.
I will put this on my next tube project list. Maybe try the 6P15P and the 6J52P. Someone didn't like the 6J52P but didn't describe what was wrong. Can anyone who has used the tube give their opinion ?
I've only used 6J52P as a triode, as the first stage in an RIAA phono preamp. I think the plate current was about 13mA, plate voltage about 120V. I tried a few different ones. They were all microphonic. Tapping on the tube or on the chassis produced a nice 'piiiiiiiiiiiiinnnnnnggggg' sound. Also, finding two that had similar characteristics was a challenge. They aren't very consistent. This is all probably due to their very high transconductance (electrodes made of tiny wires extremely close to each other).
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