My 6E5P amps (SPUD)

[matejsirk]

First try (version 1)

Power: around 1.3W
Sound: very, very good

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[matejsirk]

Second try: LED bias (instead of resistors LED string)

Power: the same as version 1
Sound: better bass, but worse mids and hights
I like v1 more

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[matejsirk]

Version 1.1 (with preamp)

I found I need preamp for more power, I test different tubes and interstage caps. I found the best sounding combination 6N16B + Jantzen Audio SIlver Gold caps

 

[matejsirk]

Third try (with stepup transformer)

Power: around 3W
Sound: very, very good, as version 1, maybe even better
I build new power supply - LCLCLC, caps are Jantzen Audio CrossCap


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[matejsirk]

fourth try (class A2)

Power: around 6W
Sound: very, very good, I realy like it

THX to ARTOSALO for idea
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[matejsirk]

My speakers:


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[Bigun]

very nice speaker building kills!

what did you do with the screen grid in you 6E5P ?

 

[matejsirk]

very nice speaker building kills!

what did you do with the screen grid in you 6E5P ?

Screen grid is connected to anode with 180Ohm resistor.

 

[VladimirK]

How many tubes did you measure for obtaining matched pairs?

 

[yagoolar]

fourth try (class A2)

Power: around 6W
Sound: very, very good, I realy like it

THX to ARTOSALO for idea
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If I were you I would replace RC connected to both cathodes with 12 to 15 red LEDs ie. 3 LEDs in series and such chains then connected in parallel. Sound should be much better.

 

[Bigun]

I found the difference between R+C and LED to be very subtle and would have been happy with either - the LED being slightly cleaner sounding, but only slightly. When using 6E5P as power tube there's plenty of current to keep the LED at a point of low impedance so it should be fine to use a single one ?

In the end I used a single LED in my SPUD amp because it was physically much smaller and I like the golden glow (amber LED) inside the chasis !

Unfortunately, I didn't like the 6E5P, it was a bit too clean, slightly harsh (I used grid stopper, careful lead dress and no evidence of oscillations on the 'scope) so I ended up with 6P15P instead.

Maybe I'll try the 6E5P again.


p.s. I agree with Vladimirk, these tubes have high gm, so physical construction requires extremely tight tolerance but in the end they usually have quite a variation in parameters. If you parallel tubes you probably have two different tubes in reality. Maybe helps to have separate cathode resistors ?

 

[matejsirk]

I tested LED bias, but I like RC bias more. In the future I will test bias with CREE C3D02060F.

 

[matroxpower]

Hello, nice amp! Please tell me about the output transformator, what are the Ra load?

 

[andyjevans]

Yes, some updates would be good. Did you try the Cree SIC diodes?

 

[supernut]

no preamp, can I?

fourth try (class A2)

Power: around 6W
Sound: very, very good, I realy like it

THX to ARTOSALO for idea
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Can I just use 50Kohm potentiometer and feed signal from DAC to this simple amp?

 

[Bas Horneman]

Can I just use 50Kohm potentiometer and feed signal from DAC to this simple amp?

Yes. You can.

 

[nikon f]

Here is a photo of mine. Very simple design, minimal parts and great sounding.

 

[matejsirk]

and this is my latest version:

9W (like 300B) of very pure audio.

and schematic:

 

[pcan]

Did you use a commercial output transformer or was it custom built?

 

[matejsirk]

I use this one:

Ogonowski.eu - profesjonalne transformatry do wzmacniaczy lampowych

It is very good.