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Yaqin......Oh Dear........Another mistake.

Discussion in 'Hi Fi Systems & Separates' started by KoThreads, Oct 19, 2007.

  1. KoThreads

    KoThreads Active Member

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    If your thinking of buying any Chinese amp off eBay please think more than twice.

    A while ago I posted about my NS1000 speakers that I was planning to bring back to life.

    After re-wiring them (QED Silver Anniversary) and fitting binding posts I was somewhat surprised at only a slight increase in clarity, not as much as i expected, but the internal wiring looked fine before, not what i was expecting considering other peoples experiences, just a bit thin.

    I rechecked all the rewiring and it's 100% correct.

    I decided it was probably the amp or CD NAD521BBE and NAD C352 so as I was impatient looked at what I could buy with what funds I had. To cut a long story short I bought the VK2100 off eBay :suicide:

    All in it cost £127.99, arrived in 3 days, weighs a tonne. My Brother (an electrician thank god) was here when it arrived. It was plugged in and it worked (Brother very surprised) The sound was detailed but a bit lean, the loudness button sounded awful.

    After a few days the selector knob got fussy only wanting to randomly let both channels work (email to seller worthless, no reply, as to later ones, this i expected) My Brother fixed this fault quite quick for me but was amazed at how well it looked built but like others was dubious about some of the components originality, He was also quite shocked at how much heat the unit gave off.

    Well after 3 weeks the unit was giving off a burning smell and on closer inspection there is discolourings on the board and i've decided to leave it off till my brother has time to pull it apart and rebuild it if it's worth it.

    To add insult to injury DHL sent me a VAT invoice for £27.53 this mornng for the unit.

    If you think you want one THINK VERY HARD.
  2. alexs2

    alexs2 Active Member

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    I think it's worth saying that many of the Chinese grey imports are intended for 220V supplies,and certainly many valve amps have been problematic due to inadequate HT rectifiers when used in the UK.

    Warranty issues also may be a problem as the UK importers often will not cover grey imports,and then you are left with a return to manufacturer.

    The heat I can just about understand as it's a tube/transistor hybrid,but a lot of the discolouration doesnt sound right.

    Whilst the weight and build quality of these amps is often pretty good,some manufacturers do operate in the lower end of the scale as compared to e.g Shanling and others,and the first thing to go is the quality and tolerances of the components used.

    The lesson though about distance buying of goods from the Far East is a very valid one,and has been raised here and elsewhere many times.
    Some grey importers based in the Uk can be very helpful,and others less so,although the price savings from going this route are always tempting.
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  3. Cable Monkey

    Cable Monkey Active Member

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    Firstly I would have rewired the NS1000's with copper. It would have been cheaper and no worse, and then I would only have done so if the inspection warranted it. Secondly the Yaqin has a cover does it not? I would be looking to run it without any casing once you have confirmed it is electrically sound.
  4. alexs2

    alexs2 Active Member

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    I think you should have a look at what's exposed first before recommending this....there's an awful lot of exposed wiring,some of which will be carrying up to 200+V for the tube anodes.

    It's not really designed to be operated without it's cover in the way that many tube amps are,and all of the PCB tracks and components with the exception of the mains transformer will be exposed.

    What I'm saying in short is that this is not an amp that I would run with the top plate off,given what I've seen of the internals.
  5. wickfut

    wickfut Member

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  6. alexs2

    alexs2 Active Member

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    If that were done,it would need to be via the classifieds.

    Thanks
  7. wickfut

    wickfut Member

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    sorry i dont totally understand what you are saying

    are you saying that a person cannot email me if he knows that i am interested in purchasing something he owns?

    isnt it the sellers choice if he wishes to advertise it on your classifieds and not yours ?

    thanks
  8. KoThreads

    KoThreads Active Member

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    I went simply with what I had left over from my last cable buy. But as mentioned above every review that i read said the cable was quite poor quality, and brittle after a few years. Mine are over 30 yet apart from it being quite thin showed no signs of either.
  9. KoThreads

    KoThreads Active Member

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    One small point. My brothers a qualified electrician, if he can't make it safe i wouldn't even consider selling it just in case one day it went up in flames.

    Sending it back under it's warranty would not make financial sense either, but i knew that was the risk i was taking.
  10. alexs2

    alexs2 Active Member

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    What I am getting at is that trading if done here,should be via the classifieds.

    If members wish to do something between themselves,that's another matter entirely.

    That's all,and simply to ensure that no-one falls foul of the trading rules.
  11. wickfut

    wickfut Member

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    fair enough. I would really consider getting it fixed and maybe a variac though

    ive got chinese gear , i bought a dussun v8i and a esound cd-e5 cd. I cannot fault either as they are both excellent bits of kit and both are working fine.

    to be honest , after seeing what i got for my money going chinese ill find it hard buying uk store price hifi.
  12. KoThreads

    KoThreads Active Member

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    Even if checked ok I think it would be very unwise to, someone, someday would end up touching an exposed part.

    http://www.yaqin.co.uk/vk2100.htm

    Bottom left and right pictures (clicking on them enlarges them). Under the back cover to the left is a huge transformer (the biggest i've ever seen and seems to be the main weight of the unit) The rest just has wiring to the speaker and RCA sockets.
  13. alexs2

    alexs2 Active Member

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    I understand...the problem is that many buy from grey importers,not neccessarily aware of the warranty issues and are then left high and dry when something breaks down.

    If you go into it with all the angles covered or known about,then you know exactly what you are getting,and in many cases the result is excellent value.
  14. wickfut

    wickfut Member

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    yeah , i buy with the mentality that it is new condition used equipment so if it goes balls up then im left alone.

    luckily that amp doesnt look like rocket science inside it and so would probably cost about £100 to get the power supply up to uk spec and a few mods to the board to handle the extra power.

    still a nice amp though - an asbestos board under it would work well :)
  15. alexs2

    alexs2 Active Member

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    Luckily many amps are quite simple,and whilst hybrids are a bit more complex,straight tube amps are pretty easy(must be if I can build one!).

    There are plenty of good reliable folk to upgrade or repair amps of this type and at least thats a possibility with this type of trchnology.
  16. Cable Monkey

    Cable Monkey Active Member

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    The item is overheating and needs a solution that helps with cooling. Also the thread starter has a brother who seems to be clued up. Making a good looking and functional cover that allows better ventilation would be quite easy once it had been made safe and been modded to work ok at UK voltages.
  17. alexs2

    alexs2 Active Member

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    Thats true,but obviously my reply was in relation to the suggestion to run it without a cover.

    Many tubed amps are designed in such a way that aside from the tubes themselves there is little danger in operating them without a cover,but this one was not,and there are a lot of exposed wires and PCB tracks.

    Its a significant possibility as has been the case with many other imports,that the transformer and rectifier are designed for 220V and the rectifier is running very close to its limits.
    Another possibility,looking at the amp is that a number of the resistors are as you would expect,wire-wound with heat dissipating cases but those are usually mounted on the chassis or other heat conductive surfaces to permit heat dissipation....again in this case they are not,being mounted directly onto the PCB....no doubt saving costs,but cutting corners as opposed to a hard-wired tube amp.
  18. KoThreads

    KoThreads Active Member

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    And that's exactly what we did yesterday. I now have a mesh steel cover replacing the lid, luckily this thing has 13 screws holding the casing in place. My brother can't understand the slight discolouring as everything he tested seems ok. His main view was that if i'm going to crank it up it might be an idea to invest in a quiet desk fan.
  19. Cable Monkey

    Cable Monkey Active Member

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    Excellent. Keep us posted on your progress because I am interested in how you get on, as are others here.:)
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  20. KoThreads

    KoThreads Active Member

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    Thanks everyone.

    I was expecting 'Told you so' and the like so it's good to know people are interested, and if it wasn't for idiots like me who else would find out if these products were any good or not.
  21. alexs2

    alexs2 Active Member

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    I don't think many here will give that sort of response,as we could just as easily have done the same.

    I,like everyone above,hope that you manage to sort this out,and that when you have,the amp works as intended.

    If there is a lesson,it's simply that buying from grey importers can be a bit of a risky business,although there are lots of happy customers who have had no problems.
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  22. dandini

    dandini Member

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    Check out my page here with a general page about yaqin amps and a link to a thread I participated in to reduce the operating voltage on various Yaqin amps I've had.

    http://www.slickpepper.org.uk/valve-tube-amps

    Direct link:

    http://www.diyaudio.com/forums/showthread/t-97618.html

    Best of luck,

    Dan
  23. satie

    satie Guest

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    Hi, been researching and bought a yaqin (yaoin ?) ms 6v6 (that had the chinese pp 6v6's replaced & re-biased to russian jj 6v6's). In australia we have 240v (this yaqin is chinese 220v grey import). I was concerned about 240v being at the upper end of tolerances for the 220v design, especially when the fuse is set to blow at 250v.

    So I got a second hand APC Line R 1200 power supply regulator ($60-$90) and set it to supply 220v (stable) from the 240v supply that we have here in australia.

    To the touch, the yaqin on 240v runs with the power transformer running hot, on 220v (throught the APC Line R, 1200) it runs lukewarm.

    The yaqin sounds fantastic and vastly (read hugely, massively) superior to my (soon to be ex) NAD C340, also second hand, but worth about the same (ie about $350) through second hand 4ohm 75w B&O speakers circa 1976.

    I think the yaqin is very good value, but if you have 230 or 240 power supply and using an unmodified 220v chinese unit, I suggest getting a power regulator such as the APC or similar. It should protect the yaqin from wear and shortened life arising from operating at over-rated voltage at the high end of its tolerances. While 240 is with 10% of 220, supplies are variable and can peak outside the upper tolerance range.

    In general, I am convinced of the superiority of class A valve ulta-linear amps over solid state. The yaqin is cheap, but it is damn good.

    Yaqin .... seems like a really good buy to get class A action at a budget price.

    cheers
    satie

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