There is something I forget to mention about those three V2 versions :
The total current and dissipation per tube at full power (with a sinusoïdal) ...
V2A : 143,23ma and 24,1064W
V2B : 179,86ma and 31,9289W
V2C : 197,84ma and 35,6313W
Since the V2C current is 54,61ma higher than the "original" V2A current, the supply voltage may drop more at full power, with a "yoyo" effect ... But if the supply is a LC type with a big choke, it will help to stabilise it.
The dissipation per tube at full power seem to be high but this is with a steady sinusoïdal ... The music power is much lower and intermittent !
Alain. 😉
The total current and dissipation per tube at full power (with a sinusoïdal) ...
V2A : 143,23ma and 24,1064W
V2B : 179,86ma and 31,9289W
V2C : 197,84ma and 35,6313W
Since the V2C current is 54,61ma higher than the "original" V2A current, the supply voltage may drop more at full power, with a "yoyo" effect ... But if the supply is a LC type with a big choke, it will help to stabilise it.
The dissipation per tube at full power seem to be high but this is with a steady sinusoïdal ... The music power is much lower and intermittent !
Alain. 😉
He got is 807 for about nothing and 2A3 or 6B4 are hard to find for under 45$ each ...
But the 4P1L are interesting and very cheap but they don't look very powerfull !
He can get over 12W with is triode connected 807 amplifier with less than 2% THD "with no negative feedback at all", I think it is very good for cheap tubes like that. 🙂
Thanks again Alain. Now I don't plan any major change, except for dropping the cathode follower anode voltage. I am also considering to DC couple the CF to the output tubes, and capacitor couple the phase splitter to the CF.
Basically I want to use the existing chassis and tubes as much extent as possible. Perhaps one time I build a SE ...
Basically I want to use the existing chassis and tubes as much extent as possible. Perhaps one time I build a SE ...
I got a pair of used teflon ux5 sockets and top caps for my RH807 for £10 ( approx $15 ). The seller threw in a pair of RCA 807's as a sweetner, 807's are that cheap!
807's are ideal for the budget end builder providing good sockets and top caps can be sourced cheaply ( and look real cool......😎 )
The 4.2 vac filament voltage for the 4P1L looks interesting as I have a very large mains transformer that has a 4.2 vac heater coil, not sure if the rsh7 octal socket is easy got though.
The 4P1L datasheet ... Their base is "Loctal" and have 8 pins thinner than on the octal type and a different pin in the middle, I don't think they fit very well in octal sockets ...
Alain.
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Not only is the 807 cheap (quads from Russia are very cheap) but they also sound excellent in the right circuit. They can easily stand their own against much pricier valves. However pentode is the best way to use them, especially in SE.
Shoog
Shoog
The humble 807 is more efficient in class C as an HF switch, so possibly a good class D output stage?
I may make one to see. A novel idea.
I may make one to see. A novel idea.
Not really. The 807 is a 6L6, originally intended for audio PA use, repackaged in a glass envelope with a top cap, and the then standard five pin base as an RF amp. 6L6-oids were briefly used as TV HD finals, but not for very long, as CRTs grew bigger.
You'd do better with one of the TV HD finals as these were designed to function as fast switches, and that could pull some bigamps at very low Vpk. Some of these compactron types include the damper diode in the same bottle, and those would do better for Class D than any 6L6-oid.
THE 807 was tested by the AWA valve company for use in the Williamson KT66 amplifier triode connected.
And was found to easily handle 400 volts.
STC also runs 807's at 400 volts for 15 watts output 3K A-A.
VTL has triode connected 807's running at 600 volts 36 ma.
I have used 807's at 500 volts triode connected for many years.
Phil
And was found to easily handle 400 volts.
STC also runs 807's at 400 volts for 15 watts output 3K A-A.
VTL has triode connected 807's running at 600 volts 36 ma.
I have used 807's at 500 volts triode connected for many years.
Phil
It's very interresting and valuable thread for me. I'm going to use 807s for my first PP amp and V3C looks very nice. I bought some original TESLA E88CC to use them in it.
Mira.
Mira.
I have used the 807 as a triode but using the Williamson circuit at 400 volts; fixed bias.
You need to use 5687's or the Russian 6N6P, as drivers not 6sn7's to get sufficient drive.
Better to use El34's as triodes much easier to drive. but 807's are cheap.
Phil
You need to use 5687's or the Russian 6N6P, as drivers not 6sn7's to get sufficient drive.
Better to use El34's as triodes much easier to drive. but 807's are cheap.
Phil
Aren't they rated as 1.5w output as triode and 20w as pentode. Seems there are far better candidates for triode use.
Shoog
Shoog
Yes, 807 is rated aprox. 1.5W output as triode in SE A-class amp, but PP AB-class can, depending how close it is to A-class, give much more.
Mira.
Mira.
I ran 1625s (12 volt version of 807) push pull ultralinear in a car stereo amplifier for a few years.
I ran plate and screens at about 420 volts without any poblems. Never had to change tubes and they matched perfectly after about 18 months of daily use.
I ran plate and screens at about 420 volts without any poblems. Never had to change tubes and they matched perfectly after about 18 months of daily use.
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