Better search it, the Audioportal is the place of beliefs and fashions, and they don't like when somebody asks questions that they already discussed. I started topics several times, they closed them, "This topic had been already discussed", so I don't participate there any more.
Translation:
Listening longer than 1 week current owner preferred 6P21S. Couuld not compare yet to SE on 6S4S, but IMHO 6P21S is not so bad for SE. I have a question: did anybody analyze data from an article of E. Karpov, "Spectrums of harmonic distortions in vacuum tubes", Radio #11, 2003?
Translation:
I myself listen at home 6S4S, my comrade had SE on 6P3S that had been modified for 6P21S. Still can't compare side by side, even though subjectively 6S4S sounds better, and variant with 6P21S is not bad. By advise of gurus I am searching for PP transformers (don't want to wind them for an experiment only). I have a couple of Zu-470 amps that use 6P3S output, will try on them.
Translation:
Very good valve. I used it some time as a driver for 300B. Light fast sound, natural and relaxed. Slightly bloated bass. Sounds better with fixed bias: stricter, more precise. I did not have feeling as if 6S4S is better.
Hi Lars!
What's up with a bifilar??
I use the Koren models as being closer to the real tubes than others - and they work with the native tetrode & pentode symbols in LTspice. The SVEL509 is in there (gm too high, but will work with lower VG2). Attached...
Yes, 250V screen is possible. But only use as much screen voltage as you need for your load line.... they are only 18W bottles! I would start LOW and only increase screen voltage if it needs more power. The screens are probably fragile on this Beam Tube.
I will be more than happy to trace pentode or schade curves but unfortunately will have to fix tracer after the fireworks caused by 814 in triode
Ale
The tracer would be ideal for developing a Schade 6P21S. Run it for a family of different feedback resistors, starting with just a little feedback, until the curves look right.
How high will the voltage go, when you have the fix for it
Hi Rod,
This is a discussion between me and Dave Slagle about the same:
:: View topic - Bifilar IT with signal on both ends of secondary
This is a discussion between me and Dave Slagle about the same:
:: View topic - Bifilar IT with signal on both ends of secondary
Hi Lars,
The bifilar has problems with LF resonances?
***
In the FET-driver schematics, the FET is injecting current into the output stage? To match the open-loop nonlinearity of the tetrode? If so, I will have some fun with that.
If anyone has time to transcribe the curves from Charm's linked post into an LTSPICE model, we will be roundly grateful!
The bifilar has problems with LF resonances?
***
In the FET-driver schematics, the FET is injecting current into the output stage? To match the open-loop nonlinearity of the tetrode? If so, I will have some fun with that.
If anyone has time to transcribe the curves from Charm's linked post into an LTSPICE model, we will be roundly grateful!
Work will be bad, you can see without spaysmodel: when the DN2540 drain voltage increases, the plate voltage is reduced. A plate voltage is the supply voltage for DN2540.
So you can do in PP if you take the plate voltage on the opposite shoulder.
Hey SVStube, you just exposed your ignorance
.Before you post, I suggest you use "search" at diyaudio. In this case you would have found out this topology works great. Michael Koster have designed and built a few.You should also had spiced it to find it also sims great.
It actually works at least as good as a D3a pentode as Schade-driver.
This is the prototype from MJK:
http://www.diyaudio.com/forums/tubes-valves/165221-most-linear-triode-strapped-pentode-7.html#post2204502
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The tracer would be ideal for developing a Schade 6P21S. Run it for a family of different feedback resistors, starting with just a little feedback, until the curves look right.
How high will the voltage go, when you have the fix for it
Rod,
It can go up to 335-350V
As per Lars' request I will trace at Vs=250V
I think I can add a simple pot divider between anode and G1 to trace the curves in Schade?
Ale
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