6c19p se otl

[ailouros6]

Hi there

I have 50pieces of some svetlana 6c19p tubes and i want to built a single-ended otl amp.
I do not need too much power.My speakers are 97db efficient.

Where can i get some schematics?Can anybody help me?


Is there any way to use the tubes in inverted mode(plate as grid/grid as plate)?

Thank you

[planet10]

Here is a drawing i transcribed from another schematic (sent to me along with some 6c19p) .... i know nothing about it.

dave

[ErikdeBest]

Hi

A search at google images turned out this result.
http://www.kaponk.com/node/254

I think it is the same schematic as shown by Dave.

Do a search for 6C19P and 6S19P, I think those OTL's have already been discussed...and if I am not mistaken one member built one!

Good luck, Erik

[planet10]

Originally posted by ErikdeBest
I think it is the same schematic as shown by Dave.

Yes, that's the one.

dave

[ailouros6]

Wow
Thanks both of you.
One question though....
what is the 8r resistance after the cap doing there?
What's the purpose?I think it is not needed there,or am i ignoring something?

Thank you again

Steve

[ErikdeBest]

Hi Steve

That 8r is most probably representing the loudspeaker. You surely do not want it there if a speaker is attached, as it will only lower the output power (but maybe a 1k resistor is good??).

I think you already knows this, but output power is dependent on the load. Basically it is Power = current * current * speaker impedance. Current is limited to whatever value you bias the 6S19P's (about 100mA, each, I think), so a total of 400mA. This would give 640mW into 4R, 1280mW into 8R and 2560mW into 16R. Not much, actually...

Erik

[ailouros6]

Thanks Erik.
I though so too,that it repsesended the speaker.

I will not use just 4 if i finally get to uilt it.I have 50 sitting around and i was thinking about 16

So,that's about.. 20W.

That's impressive for an otl

[ErikdeBest]

Hi Steve

That is surely not flea power anymore.

16 units in parallel run at 100mA each imply in a current of 1,6A. I do not know of any off the shelf choke up to that job, do you? If so, please let me know. On the other hand one can also use some Mosfet based CCS. Such CCS would not have to drop to much voltage, so it will not produce much heat either.

Erik

[ailouros6]

We could custom made one?Could we?

Also how could we implement the ccs?

[ErikdeBest]

Hi Steve

Custom made is surely possible, if you know a source I am all ears I know some Dutch winders who could do the job, but have no idea about the price. One should also have to find out about the required inductance...

About the CCS, have a look at the first schematic of this link (the one with the IRFP250). Some reshifting is necessary, I think that the attached schematic would perform well. The -40V is a random figure, could probably be somewhat less (a drop out of 10V for the IRFP250 seems reasonable + about 15V corresponding to the negative swing of the output when dirving 1,6A into 8R).

http://www.tubecad.com/2007/06/blog0111.htm

Erik