My newest super-cheap Chinese tube amp

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Archguy

My newest super-cheap Chinese tube amp
« on: 28 Jul 2017, 01:20 am »
Newest tube amp just arrived from Douk Mall in Shenzhen.  You know, Shenzhen.  Where everything comes from.

I like this one more than the last one because it has more tubes and two VU meters instead of one.  My needs are simple.  It's also sounding great, considering the fact it was almost free.  Given how much of the cost is profit for the import/export guy, I figure these things cost about $10 in Shenzhen.


Unlike my last one (the Monoprice) this one came with the tubes wrapped separately, which I think is a very good idea.  Shenzhen is a long way from here.



The device came with NO instructions or description of any kind, unless that sheet of Chinese characters means something.  Fortunately I do know how to install tubes.  If nothing else.



Here it is atop my 1937 Zenith, where I 'induct' all my new tube amps. 



And ready to go.  Plugged in, wired up...



And energized!  And it didn't explode!   It even plays music, which you can see at the following video, though be warned I may be the world's worst videographer.

https://youtu.be/kzByapzpq04

The MP does have these neat cages for the tubes.  Very dressy.



I'm still amazed at how good these cheap tube amps sound.  Particularly since I buy them as novelty items.
 

charmerci

Re: My newest super-cheap Chinese tube amp
« Reply #1 on: 28 Jul 2017, 01:36 am »
Newest tube amp just arrived from Douk Mall in Shenzhen.  You know, Shenzhen.  Where everything comes from.

I like this one more than the last one because it has more tubes and two VU meters instead of one.  My needs are simple.  It's also sounding great, considering the fact it was almost free.  Given how much of the cost is profit for the import/export guy, I figure these things cost about $10 in Shenzhen.

I'm still amazed at how good these cheap tube amps sound.  Particularly since I buy them as novelty items.


Almost free? I see $160 - they probably make a $100 off of it. You're probably buying direct from the factory. Looks pretty good.


ttan98

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Re: My newest super-cheap Chinese tube amp
« Reply #2 on: 28 Jul 2017, 02:43 am »
Archguy,

Any spec on this tube? eg Power o/p, what tubes are use, etc. Thanks.

Archguy

Re: My newest super-cheap Chinese tube amp
« Reply #3 on: 28 Jul 2017, 05:10 am »
Archguy,

Any spec on this tube? eg Power o/p, what tubes are use, etc. Thanks.

Greetings!  Output power is listed as: 6.8W x 2 channels.  I love it! 
Low power amps are my thing these days.  Esp if they're sporting tubes.

Absolutely no information was included with the amp, except a couple of sheets in Chinese.
  They may just be versions of the transit bills.

But the listing (which appears accurate) reads:
"Douk Audio 6P1 Vacuum Tube Amplifier Stereo Class A Single-Ended Amp Handcrafted"
"Tube Complement: (1) 5z4p - (2) 6H8C - (4) 6p1 "
http://www.ebay.com/itm/263086446487

Additional notes, particularly in comparison with the MP:
Very heavy output stage...the thing weighs as much as a concrete block.
The vu meters actually relate to output (the MP is just goofy)
No issues with hum or buzzing, etc...so far.  Very quiet amp.
The volume control is detented which is a nice touch. No tone controls or need for any.
The sound is good and getting better. fingers crossed.  very smooth & silky.
This amp is hot hot hot...when's winter coming??? 



This was also tempting, but I'm a tube wh*re and whichever has more tubes, I buy
http://www.ebay.com/itm/281312152025

My Zenith has 12 tubes I believe, well looking it up it says ten.
I have another which is still boxed from my move.  All told eight tube amps and counting  8)

-------------------------------------------------------------------------------------------

ETA: This also looks like fun.  Have them do as much of the work as you want, then you do the rest.
This way (among other things) you can have tasty Russian tubes from the outset
http://www.ebay.com/itm/300B-6SN7-5U4G-Single-ended-Class-A-Tube-Amp-Amplifier-DIY-KIT-For-HIFI-8W-8W/281346767313

My MP amp has run several hours a day every day without a hiccup since I got it over three weeks ago,
though I seem to recall it switching itself off one time.  Hoping for the same or better luck with this one.

raindance

Re: My newest super-cheap Chinese tube amp
« Reply #4 on: 28 Jul 2017, 11:52 am »
That essentially an EL84 P-P amp. To get such low power out of a pair of the 6P1 tubes I would guess it is run in triode mode which would likely give about 5 watts RMS per channel at about 5% distortion, depending on the circuit. I believe you can get (or build) adapters that will allow you to try EL84 tubes. It should sound sweet. It is hard to screw up an EL84 amp, they are just great tubes. A bit light on bass though.

I have another amp from Doukmall that is rated at 7.5 watts per channel, but I only manage to get just about 3 watts per channel from it before hard clipping, likely due to transformer limitations.

Note from a web search: The Chinese 6P1 and the Russian equivalent 6P1P also have no Western equal. The only other sub is the Russian 6N1N. These are all electrically like the USA 6AQ5, but have a 9 pin base, making adaptation difficult.

The 6H8C is similar to a 6SN7, FYI.

It would be great to find out how your amp is wired - whether it is triode strapped or run in pentode mode.

Note that their amps are designed for 110 volts and all the operating points including output stage bias will be slightly too high. I don't recommend leaving it on when you are not present. The cathode resistors may smoke. If you get an APC Line-R - the 600VA unit will work - and set it to permanently output 110 volts, you will be safer. It is MUCH cheaper than a variac and includes filtering :)

Douk Audio really do provide some nice cheap toys.

wushuliu

Re: My newest super-cheap Chinese tube amp
« Reply #5 on: 28 Jul 2017, 05:27 pm »
+1 on getting an APC 600/1200 and setting to 110.

FullRangeMan

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Re: My newest super-cheap Chinese tube amp
« Reply #6 on: 28 Jul 2017, 05:48 pm »
Great amp, it even have tube rectification. :thumb:
6H8C is the Russian 6SN7, cheap and good sound.
Congratulations

FullRangeMan

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Re: My newest super-cheap Chinese tube amp
« Reply #7 on: 28 Jul 2017, 05:50 pm »
6P1 is a 9 pin tube, maybe EL84 Chinese version, the 6H8C is the 6P1 driver.
Do you would inform us if it use point to point wiring or PCBs?
Well just see it, it use Turret bridges:

Russell Dawkins

Re: My newest super-cheap Chinese tube amp
« Reply #8 on: 28 Jul 2017, 06:21 pm »

This was also tempting, but I'm a tube wh*re and whichever has more tubes, I buy


So then you'd probably like Carver Silver Seven. They used to sell for around $17,000 27 years ago, but I'll bet the Chinese could make a reasonable copy for $2,000.




sebrof

Re: My newest super-cheap Chinese tube amp
« Reply #9 on: 28 Jul 2017, 10:30 pm »

Almost free? I see $160 - they probably make a $100 off of it. You're probably buying direct from the factory. Looks pretty good.
Reminds me of lyrics from a Keb Mo song
"We pay a high price to get more for our money these days"

fredgarvin

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Re: My newest super-cheap Chinese tube amp
« Reply #10 on: 29 Jul 2017, 03:09 pm »
This EL34 Aiqin amp gets a lot of interest on other forums,  It's around $275 after shipping


« Last Edit: 29 Jul 2017, 04:10 pm by fredgarvin »

FullRangeMan

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Re: My newest super-cheap Chinese tube amp
« Reply #11 on: 29 Jul 2017, 05:27 pm »
This EL34 Aiqin amp gets a lot of interest on other forums,  It's around $275 after shipping
Any link? Do you mean say Yaqin?

srb



Archguy

Re: My newest super-cheap Chinese tube amp
« Reply #14 on: 29 Jul 2017, 10:55 pm »
Guh. It's all I can do not to buy one of those for my collection.

The extra $25 for the "Luxury" upgrades seems well worth the cost.

Quote
    Teflon silver plated wire partially used in main path in the machine
    ALPS's Exponential potentiometer
    Top HIFI levels capacitors:
      Using BHC, Philips, RIFA or Ruby Filter capacitor
      Using USA CE,CDET or TRW Coupling capacitor
      Using RIFA,SPRAGUE, Philips or Mallory Cathode capacitance
    CLC filter inductor
    Power output transformer is Handmade
    Optimized PCB routing and Extremely low noise
    Containing silver Soldering
    Gold plated connection for all connections

However with shipping they're well over $300.  Not that there's anything wrong with that.


Archguy

Re: My newest super-cheap Chinese tube amp
« Reply #16 on: 29 Jul 2017, 11:01 pm »
That essentially an EL84 P-P amp. To get such low power out of a pair of the 6P1 tubes I would guess it is run in triode mode which would likely give about 5 watts RMS per channel at about 5% distortion, depending on the circuit. I believe you can get (or build) adapters that will allow you to try EL84 tubes. It should sound sweet. It is hard to screw up an EL84 amp, they are just great tubes. A bit light on bass though.

I have another amp from Doukmall that is rated at 7.5 watts per channel, but I only manage to get just about 3 watts per channel from it before hard clipping, likely due to transformer limitations.

Note from a web search: The Chinese 6P1 and the Russian equivalent 6P1P also have no Western equal. The only other sub is the Russian 6N1N. These are all electrically like the USA 6AQ5, but have a 9 pin base, making adaptation difficult.

The 6H8C is similar to a 6SN7, FYI.

It would be great to find out how your amp is wired - whether it is triode strapped or run in pentode mode.

Note that their amps are designed for 110 volts and all the operating points including output stage bias will be slightly too high. I don't recommend leaving it on when you are not present. The cathode resistors may smoke. If you get an APC Line-R - the 600VA unit will work - and set it to permanently output 110 volts, you will be safer. It is MUCH cheaper than a variac and includes filtering :)

Douk Audio really do provide some nice cheap toys.

Thanks for your remarks, many of which I even understood!  I shut off all this sort of stuff when I leave the house for longer than a dog walk, and when I go to sleep etc.  Tell me more about the voltage thing.  I thought 110/120 meant anything in that range is okay.  The Japanese equipment I like is at 100 therefore needing  a step-down transformer, which makes sense.  Is this present device so particular that it must have exactly 110v?   I don't mind buying the APC unit if it'll make a difference in safety, longevity, performance etc. 

look at this one, probably the simplest tube amp ive seen:

http://www.ebay.com/itm/Douk-Audio-Stereo-EL34-Vacuum-Tube-Amplifier-Single-Ended-Class-A-Power-Amp-8W-2/252824999249

Nice.  Much cleaner inside than that rat's nest I bought :)




Hah!  Love it.  "Get your tubes! We got yer tubes here!"

Archguy

Ooh I think they're on to me
« Reply #17 on: 1 Aug 2017, 08:20 am »

raindance

Re: Ooh I think they're on to me
« Reply #18 on: 1 Aug 2017, 11:50 am »
Archguy

The APC box will improve safety and longevity - transformers will not run so hot, tubes will run at or close to correct voltages.

Tube amps don't use regulated power supplies, so an amp made for 110 volt use on a typical mains circuit here in NC, for example, will get as much as 126 volts. This translates to roughly 15% overvoltage on every single voltage in the amp. So 6.3 volt heaters will now be 7.2 volts, and so on. If the high voltage supply was supposed to be 350 volts, it will be just over 400 volts. I have confirmed this by measurement, but it isn't something for subjectivists to be alarmed about :)

Sometimes the effects of the increased voltage are mysteriously magnified by the transformer being ever so slightly more efficient at 60Hz (when it is designed for Chinese 50Hz).

A lot of people think the USA mains is 115 volts. It is actually nominally 120 volts which is already about 10% high for Chinese 110 volt gear. 10% is a lot at high voltages.

Hope this makes sense.

Russell Dawkins

Re: Ooh I think they're on to me
« Reply #19 on: 1 Aug 2017, 05:42 pm »


http://www.ebay.com/itm/Douk-Audio-24PCS-6J1-Vacuum-Tube-Class-A-Headphone-Amplifier-Stereo-Hi-Fi-Preamp/272612501858

Only $240 including shipping from Shenzhen! What's not to love?

ETA: This one's even less.  $129 including shipping--it's almost free.

http://www.ebay.com/itm/Douk-Audio-10PCS-6J1-Vacuum-Tube-Headphone-Amplifier-Class-A-HiFi-Audio-Preamp/282416134795

Strange—there is no mention of power output in the specs. In fact, there is almost no meaningful information about this device!