Just for fun: $160 Douk 6N2 + 6P1 tube amplifier kit

[JeffS7444]

There's no particular logic behind this particular purchase, except that I had fond memories of a similar 3-tube amplifier I once owned: Just a few watts of power, but that older amp sounded decent, and didn't radiate too many BTUs into the room, so using it in mid-summer was an option. It may be another month or so before I officially start this project, and am planning on doing it at a leisurely pace

I do like what I'm seeing in this kit! Main part of chassis is brushed stainless steel (shown here still in it's protective wrapping. And they definitely got the nostalgic touches with the burly toggle switch and bakelite volume control knob. I'm not sure what kind of wood the side panels are made of, but the lacquered finish is surprisingly well done. Supplied tubes include a Beijing 6N2, and a pair of Shuguang 6P1s.

Assembly instructions are very basic: Just a parts list, and the schematic as shown. Which is no problem for me, as it's a simple circuit, and I've assembled a number of tube amplifiers previously. Looks to be your basic single ended ultralinear design, and super-easy to tune via the feedback loop.

Minor gripe: The edges of the sheet metal chassis were only roughly finished, and though they won't be visible once the amp is assembled, I spent an hour smoothing those areas, just because.

 

[mhardy6647]

Adorable.
Kind of a minimalist P/S design.
Does the kit use point to point or PC board construction?

 

[DWPress]

Hope you keep this thread updated as you build. Adorable indeed!

 

[mhardy6647]

So... according to the internet -- the 6N2 is a high mu twin triode, functionally very similar to a 12AX7, but with two 6.3 VAC heaters in parallel (only), rather than the center-tapped 12.6 VAC heater arrangement of the 12AX7.
The 61P is a beam power output tube, essentially equivalent to a 6AQ5 or 6V6 but in a 9-pin miniature envelope.

Do "we" know if the Douk outputs are wired as triodes or as pentodes? If the latter, are the run ultra-linear or otherwise?
I cannot quite make out the schematic in the photo posted earlier (translation: I am too lazy to try too hard to read it ).
EDIT: N'ermind -- it was easier to read than I expected it to be.

 

[restorer-john]

It's very cute!

 

[Ron Texas]

Soldering therapy...

 

[mhardy6647]

Soldering therapy...

Rosin core 60/40 smells better than napalm in the morning.

 

[JeffS7444]

Couple of details which are not noted in the schematic:

No specific instructions are given regarding Earth ground, so current plan is to connect Earth terminal to the chassis, and from the chassis, I thought I'd borrow an idea from Pete Millett and connect Earth to power supply ground via a set of series diodes. His writeup of Engineer's Amplifier has a brief description of this "ground loop breaker" circuit: http://pmillett.com/DCPP.htm

Then, there's a mysterious green/yellow wire on the primary side of the power transformer. Not sure, possibly I could connect to power supply ground, else leave unconnected. Manufacturer photos appear to show it soldered to the power supply capacitors.

My original intent was to use all of the original parts. I've never heard of Samxon or Sam Young-brand capacitors, and the latter seems like they're trying to pass as Panasonic parts at a casual glance, but whatever, they're probably fine. But I'm feeling less confident about the main power supply capacitors, which yes, are actually branded as "NAPFCM CEBNYCON".

 

[mhardy6647]

a priori I like your grounding idea(s).
I certainly'd be wary of all of those electrolytics -- but it's "only" $160 for a reason (perhaps for many reasons).

EDIT: Since (as is written in Ecclesiastes 1:9) there is nothing new under the sun, I just looked for threads about this amp (or as close as I could get) at audiokarma. You might (or, frankly, might not) enjoy leafing through this thread:

Douk Audio Tube Amplifier Kit Assembly Advice Needed!

Hi all! I've had the fun pleasure of assembling electronic kits since the P-board offerings from Radio Shack! From there, I've assembled Heathkit and Dynaco kits in the 70's. I was even able to bring an HK A50K back to life, which I had posted on this forum. What they all had in common was that...

audiokarma.org

and/or this much shorter one

Douk Audio Amplifier Kit - It's Alive!!!

Hi all! Drum roll please!! I just completed my Douk Audio Amplifier kit and am ecstatic to report that it is complete...and sounds excellent! I had visions of it going up in smoke when I flipped the power switch, or at least be greeted with lots of hum! The output is hum-free and makes my...

audiokarma.org

I mean, the guy was successful in getting it to work

 

[JeffS7444]

a priori I like your grounding idea(s).
I certainly'd be wary of all of those electrolytics -- but it's "only" $160 for a reason (perhaps for many reasons).

EDIT: Since (as is written in Ecclesiastes 1:9) there is nothing new under the sun, I just looked for threads about this amp (or as close as I could get) at audiokarma. You might (or, frankly, might not) enjoy leafing through this thread:

Douk Audio Tube Amplifier Kit Assembly Advice Needed!

Hi all! I've had the fun pleasure of assembling electronic kits since the P-board offerings from Radio Shack! From there, I've assembled Heathkit and Dynaco kits in the 70's. I was even able to bring an HK A50K back to life, which I had posted on this forum. What they all had in common was that...

audiokarma.org

and/or this much shorter one

Douk Audio Amplifier Kit - It's Alive!!!

Hi all! Drum roll please!! I just completed my Douk Audio Amplifier kit and am ecstatic to report that it is complete...and sounds excellent! I had visions of it going up in smoke when I flipped the power switch, or at least be greeted with lots of hum! The output is hum-free and makes my...

audiokarma.org

View attachment 366719
I mean, the guy was successful in getting it to work

Oof, not a fan of soldered connections floating in mid-air, but nice to know it's working for him!