diytube.com

Great tube in SE E236L Telefunken with little cosmetics adjusting: https://picasaweb.google.com/1095707775 ... 5944848034
Output power in triod mode about 5 W.

That's like an EL36. BEAUTIFUL sounding tube in triode

Geek wrote:That's like an EL36. BEAUTIFUL sounding tube in triode

Not....EL36 is like E236L....

I recently got two more 5902 and a pair of 5719 to make up a submin 2W PP-amp. I will use Hammond 125B PP trannies and propably have Frag Jan Zuerst to wind med 150V HV- transformer - propably a toroid. In myc stores I have dug up an old nice and heavy external HDD-bay that will house all parts perfectly (I hope ).
Will share some photos later.

I have seriously fallen in love with the tiny tubes, ofen called submin tubes or pensize tubes and would like to have a go at the compactron tubes (like the heap of 50CA10 I have collected for a comin project).

And, not to forget to include this in your new circuit

I lost and found the links to the two similar versions of a simple PP-amp using subminpentodes 5902:

http://www.seekic.com/circuit_diagram/Amplifier_Circuit/PREFERRED_AUDIO_POWER_AMPLIFIER.html

http://www.leradiodisophie.it/Download/Nicola-del-Ciotto-Amp5902.pdf

So, I now have a quantity of ten 4P1Ltubes newly arrived.... Not from Russia, but from Malaga, Spain. And a lot of questions to ask

So far I haven't found any detailed operating characteristics of these tubes, just two different very "generic" and not-too-informative mini-data sheets, both of which are from Russia, though in English language. .

It appears that VA = 150VDC, IA = 50 mA and approx. -8.5V control grid bias, is nominal operation, into a 4.5K plate load.

What is the specification for triode strapped operation, as far as internal plate resistance, transconductance and voltage gain?

If I were to triode strap these, I presume that the usual G2 connected through a 100 ohm resistor to the plate would be good. Should the 3rd grid be connected to the filament CT or ground, or directly to the plate? Update- it connects to the plate trough a resistor, same as for the screen grid.

Plan B would be to operate these in Class AB1 Push-pull, not sure of the best OPT A-A impedance to use for this application, I would SWAG 8K A-A, or should it be lower, perhaps 4.3K A-A, or even 3.3K A-A, or perhaps higher - 9 to 10K A-A ? Just considering OPTs that I already have available...

Just pondering another "weird tube" amp project...


УНИВЕРСАЛ ТЕХНО-КОНТРОЛЬ

/ed B

Just stumbled across some new 4P1L information, including triode strapped operation, from the UK:

http://www.bartola.co.uk/valves/2013/09 ... -improved/



More 4P1L information and experimentation: http://www.bartola.co.uk/valves/tag/4p1l/








/ed B

Those curves look great, Ed: very linear and a nice low impedance. Only negative I see is their low dissipation. Kinda like a 6BX7.

Shannon

Have sort of different problem. Got a small box ith 12 6S19P and decided to build something smallish to test the tube. However I need a 2K5 SE-tranny but right now I have just 3K5 trannies to spare. That's OK, but I also have some 5K transformers (maybe 3 pairs) and have really no clue what tubes to mate them with. I guess they are Ok for amsp <5W.
Ideas??

I have tubes like 4P1L, 6L6, 6V6, ECL82/85 and some more.

650mA on that driver tube, eh?

Filament current is 650 mA parallel connection (2.1V) or 325mA series connected (4.2V) .

The 25 ohm resistor in series with the driver stage filament drops the filament to 4.2VDC, and also applies 16.7V "cathode" bias on the filament, referenced to signal ground.

He is (mis)using the term "CCS" for a current-regulated power source, for filament and for grid bias for the two paralleled output tubes.

/ed B

Oh geez! I shouldd'a seen that

https://picasaweb.google.com/1095707775 ... 7091783346
PP unknown great tube 815 - two penthodes in tube. I recommend You to try..../PS - in black box in left side/. I added gas stabilitron СГ4 for 150 VDC for second grids - not shown near to 815.