hello all ,
Possible is it to exploit(run) in good condition , the tube 6P21S with an OPT of 3 K / 8 ohms under 250 V = ? this tube countered relatively nice to make a small single end .
😉
thank
Possible is it to exploit(run) in good condition , the tube 6P21S with an OPT of 3 K / 8 ohms under 250 V = ? this tube countered relatively nice to make a small single end .
😉
thank
Triode Curves: 6P21S tube | Bartola Valves
LTspice model: http://www.bartola.co.uk/valves/wp-content/uploads/2012/07/6P21S-spice-model.txt
I have some of these and am building an amplifier that will be switchable between 4p1l and 6p21s both filiment biased. 250 seems about right so we are talking flee power
I also have 6 of this DHT tetrode and plan to use for PP amp in pentode....the two remaining will end on SET....
Does anybody know what OPT impedance is needed for Pentode mode PP? Ht=400-500v...
Does anybody know what OPT impedance is needed for Pentode mode PP? Ht=400-500v...
hello ,
not use PP , only SE to OPT 3 K and driver 6N2P-ev for news build to comparate EL 502 mode " Triode " 😉
not use PP , only SE to OPT 3 K and driver 6N2P-ev for news build to comparate EL 502 mode " Triode " 😉
Hello ,
I build this 6P21S SE amp for the ETF 2014 , driver is a russian 6J9P ( E180F ) , the circuit is a MTA ( Multiplied Transconductane Amplifier ) as described from Frank Bloehbaum in Linear Audio Vol 6 and 8 .
The picture is made from Holger Barske at the ETF and it is the amp in the middle of the picture , between the 811 mono amps from a friend .
Kind regards and happy christmas ,
Alexander .
P.S.: The four 0D3 ( two per cannel ) stabilize the lower voltage for the driver stage .
I build this 6P21S SE amp for the ETF 2014 , driver is a russian 6J9P ( E180F ) , the circuit is a MTA ( Multiplied Transconductane Amplifier ) as described from Frank Bloehbaum in Linear Audio Vol 6 and 8 .
The picture is made from Holger Barske at the ETF and it is the amp in the middle of the picture , between the 811 mono amps from a friend .
Kind regards and happy christmas ,
Alexander .
P.S.: The four 0D3 ( two per cannel ) stabilize the lower voltage for the driver stage .
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Finally finished my 6p21s spud amp. It's driven from a 4p1l line stage so no driver needed.
6ax4gtb bridge choke input ps with polypropylene caps and Rods filiment boards. Quiet enough to be silent with 100db/w speakers. 250v ak 60ma 5k load filiment bias with a 22//26r so 9 ish volt gk.
Sound is very good, less coloured than my 300b and I'd need to hear them side by side to choose between them. Sadly 300b is having a little surgery at the moment.
6ax4gtb bridge choke input ps with polypropylene caps and Rods filiment boards. Quiet enough to be silent with 100db/w speakers. 250v ak 60ma 5k load filiment bias with a 22//26r so 9 ish volt gk.
Sound is very good, less coloured than my 300b and I'd need to hear them side by side to choose between them. Sadly 300b is having a little surgery at the moment.
Dear EnzoAstro,
I know performing measurements is not that easy and eats up quite some time.
I therefore would like to encourage by indicating that I'm highly interested in your findings.
And obviously for a simple reason: I'm thinking about an amp based on a 6p21s maybe driven by a 4p1l plus something, maybe an input transformer 1:3.
Kind regards,
Ulrich
I know performing measurements is not that easy and eats up quite some time.
I therefore would like to encourage by indicating that I'm highly interested in your findings.
And obviously for a simple reason: I'm thinking about an amp based on a 6p21s maybe driven by a 4p1l plus something, maybe an input transformer 1:3.
Kind regards,
Ulrich
i'd also love to see any information you have, Enzo & RE604... i've got a few of these kicking around and a DHT implementation would be very cool to see.
Just checked back to this thread from a long break from audio stuff.
I moved to using 4p1l in that spud amp. To begin with the 21 was as good as the 4p1l in treble and midrange but much better bass. After tens of hours the 21 started distorting badly, I made the assumption that this was the effect of the reported short cathode life and didn't persuse the 21 any further.
I moved to using 4p1l in that spud amp. To begin with the 21 was as good as the 4p1l in treble and midrange but much better bass. After tens of hours the 21 started distorting badly, I made the assumption that this was the effect of the reported short cathode life and didn't persuse the 21 any further.
