the tv underrated tubes

[v4lve lover]

i just stumbled across some tv damper diodes and cant stop thinking these must be pretty damm underrated .

take for example the py500 its extremely rugged . cheap . and can withstand a punishment from hell cathode is rated for something like 1A peak the cathode surface is bigger than any power tube ive stumbled across . its also readily avalable dont be fooled by 15 ebay hits . every one whit a stack of tubes will have them . once there is a demand more will pop up

i think two of these half wave rectifiers should be good upto 300-400ma .
when air cooled
what im not getting is why is nobody using them in 211 /845 amps ?

same story goes for some sweep tubes 519 is rated for 35w then you have your amateur radio operators using them at 100w per bottle . whitout any problems cathodes are HUGE . edit most of these are even available whit 6v filaments

[Rod Coleman]

TV Efficiency (Damper) diodes really are good for power amps. They are my first choice, especially for the slow 30s warm up. Use them hybrid-bridge style with 2x UF4007 and a snubber RC network, and you can use a simple secondary transformer - the performance is unbeatable. I bought a box of PY500As a while ago, to keep stocked up.

Lundahl Transformers - Hybrid power supply

The PL519 is no secret though, and I think the good ones (Mullard of course) are near to exhaustion. Tim de Paravicini (E.A.R.) probably bought them all. I haven't tried the Russian 6C4x yet, but I am sure they will be excellent value.

With the P-series valves [300mA series heaters], the only precaution to be aware of is that these have heaters designed for series operation, and will draw a very large turn-ON current pulse if you run them directly across a transformer secondary (eg 42V for a PY500A). To do it right, allow 15-20% excessive voltage, and add a series resistor to soak it up. Or, Run them dc with a CCS to control the current.

[Eli Duttman]

Another great damper is the 6AU4. For less demanding situations, the 6BY5 is 2 distinct damper diodes in a single bottle.

With its little cathode cap, the Russian 6Д22С (6d22s) merits consideration. A MAGNOVAL socket is needed.

[Yvesm]

Originally Posted by Rod Coleman

. . . Or, Run them dc with a CCS to control the current.

And you'll obtain a looooonger warm up time

[radiostar]

Originally Posted by Rod Coleman

... I bought a box of PY500As a while ago, to keep stocked up.

PY500 is really suitable rectifier for audio use, I've tested them few year ago and I bought 20 pieces for future project with GM70 ...

[KrankKall]

I'm using a Coke-bottle shaped 6BY5G as a rectifier in my SE amplifier.
Works quite well, and doesn't cost much $$ either.

Steve

[TheGimp]

Looks like they withstand a lot more capacitance than most rectifiers, so better filtering as well. Although a downside is larger current spikes to charge the caps which puts more harmonic distortion back on the mains.

[v4lve lover]

that brings me to another great tv tube . its a driver for CTR's has very high ma/v its still avalable for 1/4 of the cost of a new 12ax7

now im not gona say the name . out loud course supply is limited and to avoid the crazies buying em all . but if you figure your lucky

oh yeah i took one apart . its crazy build . everything hard metal gold plated and then carbonized . and after serving in a TV it looked like it took a heluva beating

kudo's if you know what im talking bout .

[Rod Coleman]

You might be thinking of the lovely PL802 with its extraordinary 40mA/V.

But the IF pentodes are as good sounding as any valve:, EF8x EF18x, 6F2x, 30F5

Connect in shunt cascode, and get wonderful sound, gain of 300 - 400.

[v4lve lover]

hmm dont forget the junkbox pcf types might even be usefull .
these are avalavle in abundance