6P15P Tubes: Push Pull Possible?

[maal1605]

Hello!
I´m a new member on this forum. A real newbie when it comes to tubes. I´m about to finish my first tube-project ever, a headphone amp with EL84 tubes. When it´s finished, my next project is to build a small intigrated amp. Something like this:
http://www.tnt-audio.com/ampli/sophia_baby_e.html

My question is: i have a set of 6pcs of the Russian military tube 6P15P. I would like to make a small push pull amp with 2x15w. The problem is that i can´t find any schematics or building description of a amp with this tubes included. I know that EL84 tubes can be replaced by 6P15P tubes (in some amps, not all). So, i would be really happy if somebody can help with some information so i can start my next project. THANKS!!

[ArtG]

The tube to which you refer can be directly substituted for the EL-84 in any circuit where the screen grid voltage is kept at 150 volts or less. You may want to check the following link:

http://www.decware.com/paper62.htm

If you use the search feature for this board, you will find many, many circuits published and discussed that employ EL84/6BQ5, and perhaps SV83 (6P15P) tubes.

[motherone]

Not to go off topic, but what EL84 headphone amp are you building?

[maal1605]

Thanks Art. But trust me, i have searched and read about so many amps. But none of them has the 6P15P tube included. So you mean that as long as the screen grid voltage is kept at 150 volts or less. Can i use some of the building-instructions for for amps that is based in EL84 tubes as long as it´s under the 150 volts limit? Is it that simple . As i wrote before, i´m a real rookie about tubes. By the way, i also have 4cs of the Russian type of ECC83 tubes. Many of the ampbuilding instructions i´ve read, has 2 of the EL84 and one of the ECC83 in a push pull mode.

[Eli Duttman]

6p15p = SV83 = EL84N. Data sheet here.

If you are going to build a pentode mode circuit, use a VR150 gas regulator in the screen grid supply. If you are going to use ultralinear topology, connect the screen grids to the UL taps on the O/P trafos via 1 KOhm resistors.

As long as appropriate steps are taken to protect the fragile screen grid, the 6p15p may be used in a circuit designed for the EL84.

The 6p15p pins out differently than the EL84, but sockets set up for the 6p15p work with EL84s without change. The other way around is not true.

[Wavebourn]

Do you see differences?

http://wavebourn.com/images/audio/6p14-15-3.gif

[maal1605]

Originally posted by motherone
Not to go off topic, but what EL84 headphone amp are you building?

Here´s a link to the building-instructions (in swedish ):

http://www.home.no/drdead/ror/R%f6r_...st%e4rkare.pdf

Scroll down to the schematics. It´s easy and cheap to build, and what i´ve heard it sounds really nice. To you think it´s possible to replace the EL84 with my Russian tube 6P15P in this curcuit?

I´m really lost in this thing with tubes, so if i´m going to build an amp i must have some kind of buildning instructions. What i am looking for, is a instruction where my 6P15P tubes fit in. What about this?:

http://dortoh.ca/zenclone/index.htm

[Wavebourn]

Do you see any differences between the 2'nd grid in 6P14P (EL84) and 6P15P?

I don't...

People believe that 6P15P has weak 2'nd grid, while I believe that different specs are given for different guarranteed results because 6P14P (clone of EL84) was sold for audio, 6P15P was sold for linear video amplifiers.

What do you think?

[anatech]

Hi Anatoliy,
Please check here and here .
They very clearly put a limit of 150V on the screen. So it is "weak" as you say. You can't tell just from pictures, but the manufacturer has rated them that way for a reason.

Anyway, no one is attacking them as bad tubes. They are just a little different.

-Chris

[Wavebourn]

Originally posted by anatech
I sure did, did you?

No.

I turned what you said around a little.

No. I said that different grid voltages give different plate curves of the same toob, and this can be the single reason for different specs since toobs were sold for different applications.

If some tubes work well at higher screen voltages, and some don't it would point to very loose quality control from that manufacturer = junk tubes.

Did you try them on higher screen voltages? Are you sure they don't work the same as 6P14P?

I did not try, but I am not sure.

If Tubelab did not (I know he is famous torturer of toobs), I will try and report my results. I suspect that 6P14P/EL84 with up to 200V on the 2'nd grid will have the same excellent linearity like 6P15P.