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[gertk]

Mini Stereo SE

This is my latest DIY tube amp:

small stereo 2x3W ECL82
12 Volt DC powered with internal DC-DC converter for 200 Volt @ 75 mA
Amroh/Muvolet 7044 output transformers (NOS)
Cast aluminium enclosure
External power supply 12V 4A max. (the amplifier draws about 2.5 Amps)

 

[ballpencil]

@gertk: my kind of amp! love it.

Mind sharing the DC converter schematic?

 

[gertk]

@gertk: my kind of amp! love it.

Mind sharing the DC converter schematic?

This is the circuit but unless you can get hold of the same transformer it is probably not much use. The transformer came from a scrap alarm control board..
Circuit around the UC3843 is pretty much from the datasheet. Some tinkering was required with frequency, the snubber circuit and current limiting. For the power FET you can use anything with a voltage handling of about 100 Volts and low Rds.
I used two ultrafast high voltage diodes in series for the output voltage after a single one died after a few seconds.

 

[vermeero]

RH84 revision 2 build

Single ended pentode EL84, plate to plate feedback.
Schematics by Alex Kitic, as found on his RH Amplifiers blog.
Features auto bias and... an on/off switch!

It sounds very good, great bass on a pair of Yamaha NS-1000M.

 

[jamesfeline]

wow .. that's a nice little honest amp you have made, well done

JamesFeline

 

[zman01]

Vermeero, neat work!

 

[mc352]

Thanks much 6L6. I'm happy to read the positive comments. That's encouraging for my future builds. Next in line : Millett Starving, a bench regulated PS (somewhat boring) and the AX84 P1 guitar amp.

Happy to read I made good use of those terminals. I looked at many pictures of the Bottlehead Crack (would you have guessed) and tried to replicate things that I saw in this amp.

You headphone amp looks great. I recently built the Millett SS amp, it was a fun straight forward build.

 

[vermeero]

zman01 & JamesFeline thank you!

 

[hllbll]

Did some painting today for my diy tube amp kit ( UralTone amplification Web Store )

 

[ballpencil]

Just finished this desktop amp: SE 6LR8. Similar to gertk's amp on post 6601, this one is also powered by 12V laptop style charger with internal DC-DC converter raising 12V to 275V. Fitted some cheap FM radio+USB+line in module with remote control. I also use cheap 70v line transformer as OPT. They sound decent although having no gap for single ended application. Sorry for the crappy phone pics.

 

[JakubKubo]

Hi there, Im new here but i want to share with you just few weeks old amp I built. It's SE with 6P7S on output stage, 6N9S as preamp and 5AR4 rectifier. Hope you like it.... Any questions are welcome

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[Bigun]

Did some painting today

wow - your hobby ain't tubes, it's painting !

 

[Pano]

Very pretty work, Jaku.

 

[Cassiel]

Well,well,well.

Looks like I'm at the top of my game. Headphone amp for 32 Ohm headphones. Tube + Mosfet (here's my middle finger 6AS7).

 

[wlowes]

Cassiel
You are at the top of your game. Really nice. Work of art!

 

[Cassiel]

wlowes, you're the man! You see it as I see it.

 

[TonyTecson]

Easter MOD line amp....another Broskie CCDA line amp, this time using the 4KN8 twin triode tube....
this is a dual mono line amp, the channels each run on their own power supply
completely independent of the other...this is a prototype preamp, not for sale....
btw, this is not an AIKIDO preamp, many of those who bought the little preamp
like the sound of it more than the Aikido, so i made another version, this time
upping it one notch higher....i have at lest 5 notches still running in my head...

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

 

[Carlp]

Looks like I'm at the top of my game. Headphone amp for 32 Ohm headphones. Tube + Mosfet (here's my middle finger 6AS7).

Very nice. But clearly not enough room for a 6AS7 (even horizontal) so what tube?

 

[Cassiel]

Carl I'm no 6AS7 lover, I wrote that out of spite. The input tube, not needed as I don't need voltage gain, is a dummy. It's there but it's not there if you know what I mean. However I plan to use a tube in the future, this is the plan:

1. Just mosfet follower. Get used to the sound. I'm listening.
2. Add an input tube. Get used to the noise. Just kidding. Get used to the sound. Low voltage supply.
3. Build a decent power supply for the tube and mosfet, now it's running off a cheap SMPS. Compare and decide.

I have work to do now. See ya all.

 

[Carlp]

Carl I'm no 6AS7 lover, I wrote that out of spite.

Ah, I get it.