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6P15P hybrid amp schema?

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Hello everyone,
I'm new to diy and i'm going to try it at home.
Can someone help me with 6P15P SE schematic?
I'm going to try to build a cheap project tube amp or maybe hybrid amp using an opamp preamp.
So i can learn it on the cheap way :) using ss rectifier and chip preamp to have a hybrid amp this way.
May anyone here help me with a schematic if i'm gonna use bb opa2134pa as a preamp stage and 6P15P as the output stage, so i can try to build it here :)

Thanks.


Sincerely,


Jimmy
 
Thanks Chris.
Sorry because i'm new to diy so i think it's called hybrid amp if using opamp preamp and tube power amp :).
So there is exactly the same circuit as use in 6p14p Power amp?
The difference between 6p15p power amp and 6p14p power amp only the pinout of the tube?
In your schematic there is 6n1p, is this tube as a preamp stage on that amp? Can that tube being changed with opamp like opa2134?

Thanks for your kindness.

Best Regards.

Jimmy.
 
6P15P is more linear version of 6P14P (EL84) made for video amplifiers.

Slightly different construction, better grid alignment and more rugged fixation of grids. Also, a separate 3'd grid pin.

However, more linear parameters are guaranteed when a voltage on grid 2 is lower than specified for 6P14P; anyway it is a good modern practice to regulate lower G2 voltage since high voltage solid state devices are cheap.
 
Hi Jimmy;

try this one.

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L30N^_^H34RT said:
Dear Wavebourn,
Thanks for your kindness.
I'm going to collect parts first :).

Regards.

You are welcome, and
Good luck! :smash:

For the beginning you may eliminate:

1.) Vactrol -- it is an anti-clipping optical compressor that I use in my concert amps, as the result they never distort when occasionally overdriven. Leave just a LED1 as an overload indicator and short LED2.

2. Positive feedback by current: it is needed to linearize bass response of a speaker. The amp will work well without it, so short R10, remove the potentiometer R13, connect R11 to ground instead of to R13.

The amp was designed in mind and calculated on napkin (you gave me an idea, so I could not resist thinking about it), I am going to breadboard it soon and probably correct some values for best optimal result.

The amp should have very low level of distortions determined by the OpAmp, and a tube should live very long life until completely exosted.

To run this amp you will need a B+ voltage supply, something like 200V 20W; 6.3V to power filaments of output tubes of both channels; and a bi-polar +/- 18V power supply to power OpAmps.
You should consider that the tube is connected to the - rail of the 18V power supply so it has to deliver an adequate current (i.e. more than is needed to power the entire OpAmp). I assume you can figure out and calculate it, right?

One more option is, to get a power for OpAmp without additional supplies from additional zeners in cathodes of tubes, but the entire amp has to be redesigned accordingly.
 
Wavebourn said:
6P15P is more linear version of 6P14P (EL84) made for video amplifiers.

I was under the impression the 6p15p had lower voltage and dissipation limits. Significantly lower, such that many circuits designed for the 6p14p would quickly eat the 6p15p.

The data sheets suggest they are closer in specs than I was led to believe:
http://www.tubes.ru/techinfo/HiFiAudio/6p14p.html
http://www.tubes.ru/techinfo/HiFiAudio/6p15p.html

It appears, as you have already pointed out, the 6p15p likes to see a much lower voltage on G2. Perhaps in ultralinear designs (Dynaco SCA35, ST35) where G2 is run hard the 6p15p may not hold up well.
 
Ty_Bower said:


I was under the impression the 6p15p had lower voltage and dissipation limits. Significantly lower, such that many circuits designed for the 6p14p would quickly eat the 6p15p.


Are there some experimental data you have to proof that?

Edit: I already pointed out that manufacturers guarantee end results specified for the tube on lower G2 voltage. I did not say that the tube itself loves it; in order to obtain more linear results I use 6P3S and 6L6 tubes with significantly lower G2 voltages than specified by manufacturers. Should I call them now 6P4S and 6L7? ;)
Also GU-51 since I use GU-50 with higher G2 voltage than specified...
 
By the way, R5 is selected for maximal power dissipation. To run the tube in more relaxed mode R5 should be accordingly increased.

Also, it may be a good idea to run the OpAmp from an asymmetrical power supply, say +5 and -24V, in such case D1 should be for 15V instead of for 10V. This Zener must be rated for 80 mA current at least. If to use a Zener with less current rating one appropriate power transistor should be added instead of the Zener, while Zener connected between it's collector and base.
I'll correct the schema.
 
Wavebourn said:
Are there some experimental data you have to proof that?

Unfortunately, no. I just recall having read more than once (on this forum and on others) that 6p15p tubes don't make a good substitute for EL84 in all designs. I'm not trying to state any facts, I'm merely sharing the impression I have been given by others. It's through forums like this one that I learn more about the capabilities of various tubes. I'm appreciate your insights into the 6p15p, and I'm intrigued by the possibility of its "improved linearity".

I see the 6p15p 2nd grid has been debated to death already here:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=94949
 
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