[Artsi]

It's a little dubious to start thread about my DIY amp, since i'm not any pro with these electric things. Just have made couple working headphone tube amps before this. 
 
So here is photo of my contraption with 6080WC tubes.

And here is schematics for one channel.

 
 
 
As you can see it is simplified from some schematics from internet.
 
And what a mess it is inside.

 
Box is little too small for this kind of amp. Cast aluminium Hammond 1550J 275x175x63mm.
 
B+ supply is made with full wave bridge rectifier. After that is 1H 300mA choke and then two parallel 1000uF 250v capacitors. After that there is 1000uF's for each channel loaded with 68ohm resistors. Heaters have also DC with 22000uF capacitor. 
 
Volume potentiometer is ALPS 100k stereo LOG. Transformer is inMADout TA34M100.
 
Amp works perfectly with 6SN7's as powertubes too. Driver tubes run very low power, I think 470ohm resistors could be as low as 270ohm, but how much this could add amp output power, i do not know. Also from 6AS7's could take much more power with lower resistance resistors, but i have not needed more power. Total power consumption of amp is around 85w with 6SN7's and 6080's.
 
At least i'm very happy that this thing works without hum and measured frequency response is totally flat between 10-20000hz. Now i just need more tubes to roll.
 
 
I DO NOT SUGGEST BUILDING ANY TUBE AMP WITHOUT ANY EXPERIENCE OR UNDERSTANDING. Voltages inside these amps are pretty much lethal.
 
Edit: changed something to schematic. 6AS7 anode resistors from 270ohm to 150ohm.

 

[superdux]

Artsi it looks fantastic!
I'm not into electronics but when i see creations like these i'd love to get off my lazy bum and do some learning, lol.
Instead i can only admire the work you and the DIY folks do.

 

[TrollDragon]

Exellent Job!
 
It's hard to fit everything is a small case but you did a great job with that space.

 

[Artsi]

Here is photo of this amp with russian 6N13S and 6N8S.

There is brown tape round the bases of 6N8S that they do not mix with other same tubes. '73 6N13S tubes sound far more better than rather new Philips ECG 6080WC's. I was little disappointed about sound when i listened it with 6080WC's, but problem was only with powertubes.
 
Here is photos of some amps that i have made.

Amp for four 6SN7's
 

And pan-amp with 6A6 as driver and 6SN7's as powertubes.

 

[TrollDragon]

Excellent, I just love the look of the 6N13S's!

 

[i luvmusic 2]

That is one good looking AMP.

 

[nikongod]

Neat amp!
How much current does the output stage pass?
Have you thought of swapping the "top" 6sn7 for a SS CCS?

 

[Artsi]

Neat amp!
How much current does the output stage pass?
Have you thought of swapping the "top" 6sn7 for a SS CCS?

I'm not good at calculating those mA's. With 6080 tube cathode resistor is 220ohm, Voltage after this is around 17 and between this and another triode anode is 106v difference.
 
And what does SS CCS mean?

 

[nikongod]

V=I*R
Volts=current*resistance
Algebra:
17V/220ohms=0.077A=77mA

SS CCS is a solid state constant current source. You could get down to 3 bottles that way, and possibly improve overall performance.

In any case, maybe just for the next one. It is quite cool to see a 6as7 working like this. Very cool.

 

[Artsi]

V=I*R
Volts=current*resistance
Algebra:
17V/220ohms=0.077A=77mA

SS CCS is a solid state constant current source. You could get down to 3 bottles that way, and possibly improve overall performance.

In any case, maybe just for the next one. It is quite cool to see a 6as7 working like this. Very cool.

I like how this amp sounds as is. Perhaps with next amplifier i'm going to use rectifier tube to make things even more oldschool.

 

[stupidmop]

Nice! Drooling Thanks for posting

 

[Artsi]

  Nice! Drooling Thanks for posting

No, thanks to you for your kind words.
 
Been listening diligently this my newest amp and i have came more and more pleased with this beast. Been listening mostly with pairs of Russian 6N8S '65 and Philips ECG 6080WC and i have newer heard this kind of evolution in sound. Could even capacitors get better with some usage... My initial impressions for these 6080WC's were very bad and i tried to avoid listening with these, but in the end i had to use these, since one of my 6N13S tube is not working perfectly.
 
Amp is totally silent from 0% to around 60% volume, and after that there is audible electric interference noise. This does not bother me, since my normal listening levels are around 20-40% volume.

 

[Artsi]

I have made couple amps more.
 
First this round cute amp. 6X5 rectifier, 2x6SN7 and 6SL7. 

Hope my wife takes this on her desk...
 
And next this little amp. 6X5 rectifier, 2x6N6P and 6SL7/6SN7 driver.

And photo from inside. Not much room for more parts.

One could be thinking what is that "volume" knob on amp. It is feedback (gain) adjuster.
 
Both amps are insanely good sounding. 

 

 

[TrollDragon]

Nice, very Nice!
The bottom amp looks great, I had a look at that chassis in the Hammond catalogue and yes it is compact!

Love the power button.

Whenever you are tired of that one feel free to ship it my way.

 

[Artsi]

Nice, very Nice!
The bottom amp looks great, I had a look at that chassis in the Hammond catalogue and yes it is compact!

Love the power button.

Whenever you are tired of that one feel free to ship it my way.

It seems that i'm not going to get tired with this one in the near future. 

 
Now look at this

RCA 6AS7G as a driver tube. Surprisingly it sounds amazingly good! Gain is much lower, but this amp is otherwise so sensitive, that i get easily enough power to my headphones.
 

Rare ECC230 tube is a driver tube too. 

 
 
I have also octal to 6DJ8 and octal to 12AX7 adapters, so i can use many many different tubes with this one. Waiting impatiently 6BX7GT and 6BL7GT tubes to arrive soon. They have gains 10 and 15.