Chinese audio

[Haselsh1]

Chinese audio…?

In 2006 I was in a reasonably lucky financial situation and so bought via Ornec an Original 2008F HDCD CD player and a Yarland Pro 200SE 300B SE amplifier. Both of these units looked amazing and were very stylish by comparison with British units but of course I could not listen to either before purchase. The sum total of these two units after import duty was around seven hundred and fifty pounds.

In 2007 the Original stopped working but still had internal power as some of the solenoids were still clicking on power up/power down. I took the unit into a local electrical store and had their engineer take a look at it to see if he could fix it. It turned out that the mains toroidal transformer had burnt out and would need replacing. This was done at a cost of around eighty five pounds. The unit has worked perfectly ever since but in February 2010 was joined by a Beresford Caiman.

The Yarland lasted until 2008 when it developed blue flashes in the 300B’s on power up with loud cracking sounds coming from the speakers. This I now know is referred to as flash over and can often happen in the rectifier valve. I had a valve engineer take a look at the amp and he was to be polite, gobsmacked by what he saw inside the amp. He was disgusted by the internal construction of this amplifier and found out that along with the CD player, the amplifier had a European voltage mains transformer. This meant that all of the amplifiers internal voltages were out with some of the voltages being dangerously high. What I don’t understand is why it took a year and a half to manifest itself in the switch on of the amplifier. The Yarland was eventually sold as a chassis project for sixty quid.

This is simply an outline of my experience with Chinese Hi-Fi not all of which has gone according to plan. What are your personal views on this stuff and how has it affected you…? Would you actually buy any of this now that China has woken up and knows how to price their products…? Would you buy through a British importer who adds a couple of grand just because he has checked it over and modded it…? My personal view is that this Chinese stuff looks amazing but that is about as far as it goes. Yes I could have used a device to match the correct voltage going in but who the hell wants one of those in their lounge under the sofa…? My experience was not so good but I still love valve amps however the Yarland wasn’t a patch on the Croft I now have even though this has it’s fair share of problems.

[DSJR]

Much hifi bought in the UK now is of Chinese origin - Quad, some or all of Arcam? Cambridge, popular speakers from B&W, KEF etc

I appreciate that this isn't really what you're on about, but I think it's fairly common knowledge that much of the specialist gear sold directly is wired for 220V and as long as UK voltages don't drift too high, it's *just* usable.

I suppose the lesson to be learned is to have these units thouroughly checked out before use, so that transformers can be replaced if necessary, voltages checked and any possible bad assembly corrected. I hope Guy would also comment as he seems to take an imported product, makes it usable here and I suspect a fair proportion of his profit may be in getting the units "approved" for UK sale.

Of course, Glenn is a master of "less is more" and his carefully assembled products seem to work for decades without trouble unless one is extremely unlucky (my beautifully assembled unregulated Croft OTL power amp didn't like me or my speakers at all).

[Techno Commander]

This is a problem with most of the Chinese offerings, especially those on ebay. Many are made with 110/220 volt transformers which is fine for USA and Asia. Some may have 230 volt transformers which is OK for Europe but not for the UK where mains can often exceed 250 volts.

In a way, I am glad you have started this thread, as I have also been looking at getting a Chinese valve amplifier. However, I have also been doing my homework. :)

From what I have found so far, there are 2 main issues with Chinese kit. These are the afore mentioned mains transformer issue and secondly, there have been a number of concerns regarding assembly and quality control.

Superficially, a number of the Chinese offerings appear to offer superb value for money and if you lived elsewhere in the world, then that may be the case, but as you have alluded to, you would need to have a stepdown transformer hidden somewhere to prevent the eventual fireworks that are likely to happen when something is fed with far too many volts.

The only way to prevent this is to find a product that has a 240 volt transformed installed in it during the manufacturing process. So far, I have only found one manufacturer that does this and this is Meixing/MingDa. I know this for 2 reasns. Firstly, I have contacted the factory as I am interested in one of their amplifiers. I have received a reply stating they do indeed use dedicated 240 volt transformers in their products. Secondly, they are an OEM manufacturer for Icon Audio. Tis means they are bulding products designed in the UK for a UK market. Therefore all relevent UK and Eu safety and legislative requirements need to be met.

The factory stated they would be prepared to sell me a 240 volt specified amplifier direct, rather than going through a middle man and (possibly) getting what ever they had to hand. The factory option also comes with a warranty.

The other questionable fact with Chinese products is QC, or in some cases lack of it. I have seen some shoddily assembled PCBs on equipment. Admittedly, the message is slowly getting through and things are slowly improving, but this is more at the higher end products. The "cheap" equipment is still cheap for a reason. I do believe that within a few years there will be some absolutely stunning equipment emerging from China with relevent Eu safety approvals. Hopefully some of it will be designed/constructed to UK specifications.

Anyway, if we return to the Meixing products, the other thing which impresses me is the quality they employ in their construction. All their amps are hard wired and the quality of this construction appears to be impeccable.

http://i17.servimg.com/u/f17/11/30/47/15/dsci0110.jpg

I therefore feel confident that buying one of these amps will be far less of a gamble than purchasing many of the other offerings that are available. I am sure there are other products available that will also be OK for use in the UK, but I would ensure that you sufficiently research your purchase prior to investing your money.

[DSJR]

Looks very neat indeed and inspires confidence. Inevitable servicing should be easy in the future decades too.

[Haselsh1]

First of all I definitely question that validity and value of a warranty that's offered by a manufacturer located in China. Just how much do you think it's going to cost to transport a 28kg amplifier back to China for a repair...? Also, the amplifier I bought was sold to me as being a 230V AC unit. This was clearly bullshit.

Regarding the internal assembly, the Yarland has a valve rectifier but also has SS rectifiers inside and resistors that are doubled or in some cases tripled. The whole thing appeared to be cobbled together in some sort of fashion that almost certainly wouldn't have been in the UK. It was supposed to be dual mono but clearly wasn't. Now I am aware that even the revered Audiolab these days is Chinese but for the majority of valve equipment made in China, I'm not 100% sure these people know what they are doing. Maybe that's why Icon Audio have to put so much effort into modding their amplifiers.

[Techno Commander]

I agree with your point about a warranty being somewhat superficial. Where did you buy your amp from? As I mentioned, many are built as 110/220v and if sold through a "middle man" they are likely to say anything to achieve a sale. Also remember that UK mains can reach 253 volts and still be "within specification". Stuffing this into something designed with a 220 volt transformer is going to cause severe ( approx 15%) overloading of the circuits. The DC heater circuit in a valve amplifier is particularly vulnerable.

[Jason P]

I think it's a case of 'caveat emptor', but don't tar all of their products with the same brush. It would be more appropriate to have a go at the distributors who say stuff is 240 when in fact its not!

I had a Yaqin MC10L. It was fine, never missed a beat, and apparently was 240v (according to the box). Sounded great too. Without getting an engineer involved, I had no way of knowing if this was the case - but it worked flawlessly for the months I had it.

Now I have an Image i65... 30-odd kilos of chi-fi loveliness. Built like a tank, point-to-point wire and decent componentry, all for around £500. It sounds great and I have no qualms about longevity, as any competent tube engineer would be able to fix it...

http://cgim.audiogon.com/i/rv/s/f/1220732145.jpg

So not all Chi-Fi is crap, I think there are some genuine bargains to be had...

[lurcher]

First of all I definitely question that validity and value of a warranty that's offered by a manufacturer located in China. Just how much do you think it's going to cost to transport a 28kg amplifier back to China for a repair...? Also, the amplifier I bought was sold to me as being a 230V AC unit. This was clearly bullshit.

Regarding the internal assembly, the Yarland has a valve rectifier but also has SS rectifiers inside and resistors that are doubled or in some cases tripled. The whole thing appeared to be cobbled together in some sort of fashion that almost certainly wouldn't have been in the UK. It was supposed to be dual mono but clearly wasn't. Now I am aware that even the revered Audiolab these days is Chinese but for the majority of valve equipment made in China, I'm not 100% sure these people know what they are doing. Maybe that's why Icon Audio have to put so much effort into modding their amplifiers.

I am not suggesting its not cobbled together, but you would expect to find SS rectifiers in any valve amp that uses DC heating, and often the driver stage is powered by a separate supply that is SS rectified. Having this second supply may be more beneficial that the entire amp using the supply that goes through the valve rectifier. So the presence of SS rectifiers of its self is not a clear indication of a problem.

Likewise running resistors in parallel is a good way of increasing their power handling, and again not itself a problem.

I have seen good and bad amps from China, and some that were both at the same time :-), but I am just saying those two points you mentioned are not what I would use to judge. The most important points are as mentioned before, does the mains transformer primary mean the heater supplies are out of spec, does it mean the power supply caps are over voltage, does it push B+ and anode dissipation beyond their limits, or does it push the reverse voltage rating of any rectifiers beyond their limits. But before that I would check simple things like is it earthed? I have seen them with nothing connected to the earth pin of the iec connector.

I have seen all the above points in the past from imported amps. I have also seen very good Chinese amps.

[hifi_dave]

I have no real beef with Chinese products personally imported. You're all big boys now and should know the score and what you're getting into.

As for 220 volt transformers and our voltage, this is not just relevant for Chinese equipment. Quite a lot of USA manufactured equipment has the same problem becuase it is not worth the companies getting geared up to produce products to work on our 250 volts when they sell so little of it here.

What I object to is the Chinese companies which pretend they are the well established British companies we all know and trust. You have to look long and hard to find any mention of Chinese manufacture behind these names. Surely, if the products were up to the mark they could sell them under their own names ?

Isn't it time these companies were made to state where the products are manufactured ?

[Techno Commander]

Jason: Do you have any more info on the amp you pictured above? It looks most impressive.

[Rare Bird]

I've been using a Chinese 24/96 DAC come pre come headphone amp for ages now, it gets a hell of a lot of use, cost me about £130.00. The only problem i had was using my low impedence headphone which did output a slight hum, all i did was reduce a couple resistor values which cured it, not a product fault in any way..

I don't care about hifi anymore as a rule & i never get attached to any product no more so this suits me fine, anything that goes wrong at this price whats worth getting it fixed! just buy another, this is how it's suppose to work these days isnt it??..I'll probably buy the new amp they make now it's available to compliment it (again cost peanuts)..This company btw are one of the best i've ever dealt with & aftersales are brilliant.

Paying heaps of money for hifi is a mugs game imho.

[Jason P]

Jason: Do you have any more info on the amp you pictured above? It looks most impressive.

Sure, TC - it's manafactured by Image Audio... (http://www.imageaudio.cn/en/index.asp)

and the thread I 'borrowed' the pic from is here... (http://forum.audiogon.com/cgi-bin/frr.pl?ramps&1220733371&&&/Image-Audio-65i-Tube-amp-)

I'm certainly very happy with mine - only problem I have is not having instructions (bought s/h) I'm not sure about bias values for the valves (currently Golden Lion KT88s)

Hope this helps!

Jason

[Techno Commander]

Thank you. :)

[Ali Tait]

If the amp has 220v transformers,it's easy to run it from a variac or bucking transformer to keep voltages in spec.

As for build quality,it is variable with this kit.I've had a Mr Liang 845 which was built like a tank,and used decent components,indeed the pcb's looked as well made as anything I've seen.Sounded great too,and even better after a couple of tweaks.The transformers were very good too.

The other amp was an Audioromy using 813 output valves.Build quality was iffy,but it did sound very good driving my statics.This one did die though,the mains trannie expired,though I daresay it would have been ok run at 220v.

[Effem]

If the amp has 220v transformers,it's easy to run it from a variac or bucking transformer to keep voltages in spec.


As I was reading through this thread about chinese amps designed for a 220v mains input, I thought I would mention bucking transformers and someone has beaten me to it :lolsign:

For those that don't what a bucking transformer is, here is a link:

http://www.dms-audio.com/bucking-transformer-diy

[Marco]

Oi, stop your bucking swearing! :lolsign:

Marco.

[spendorman]

This does look neat, but I am wondering if some of those resistors leads are bent too close to the resistor bodies.



This is a problem with most of the Chinese offerings, especially those on ebay. Many are made with 110/220 volt transformers which is fine for USA and Asia. Some may have 230 volt transformers which is OK for Europe but not for the UK where mains can often exceed 250 volts.

In a way, I am glad you have started this thread, as I have also been looking at getting a Chinese valve amplifier. However, I have also been doing my homework. :)

From what I have found so far, there are 2 main issues with Chinese kit. These are the afore mentioned mains transformer issue and secondly, there have been a number of concerns regarding assembly and quality control.

Superficially, a number of the Chinese offerings appear to offer superb value for money and if you lived elsewhere in the world, then that may be the case, but as you have alluded to, you would need to have a stepdown transformer hidden somewhere to prevent the eventual fireworks that are likely to happen when something is fed with far too many volts.

The only way to prevent this is to find a product that has a 240 volt transformed installed in it during the manufacturing process. So far, I have only found one manufacturer that does this and this is Meixing/MingDa. I know this for 2 reasns. Firstly, I have contacted the factory as I am interested in one of their amplifiers. I have received a reply stating they do indeed use dedicated 240 volt transformers in their products. Secondly, they are an OEM manufacturer for Icon Audio. Tis means they are bulding products designed in the UK for a UK market. Therefore all relevent UK and Eu safety and legislative requirements need to be met.

The factory stated they would be prepared to sell me a 240 volt specified amplifier direct, rather than going through a middle man and (possibly) getting what ever they had to hand. The factory option also comes with a warranty.

The other questionable fact with Chinese products is QC, or in some cases lack of it. I have seen some shoddily assembled PCBs on equipment. Admittedly, the message is slowly getting through and things are slowly improving, but this is more at the higher end products. The "cheap" equipment is still cheap for a reason. I do believe that within a few years there will be some absolutely stunning equipment emerging from China with relevent Eu safety approvals. Hopefully some of it will be designed/constructed to UK specifications.

Anyway, if we return to the Meixing products, the other thing which impresses me is the quality they employ in their construction. All their amps are hard wired and the quality of this construction appears to be impeccable.

http://i17.servimg.com/u/f17/11/30/47/15/dsci0110.jpg

I therefore feel confident that buying one of these amps will be far less of a gamble than purchasing many of the other offerings that are available. I am sure there are other products available that will also be OK for use in the UK, but I would ensure that you sufficiently research your purchase prior to investing your money.

[Jonboy]

As has been mentioned before use a Variac or simular to be safe

I have a Pair of Ming da 845 sets' and a matching pre, i have had no problem with the pre but the power amps used to distort when the volume was turned up, this was caused buy the 250 odd volts coming in to them from my supply, so i bought a variac and now run them at 220 volts the problem has gone away, something to do with the valve biasing going out of spec we think due to higher than tested voltage when built in China,

As for build quilty these are lovely underneath and very well built indeed

[anthonyTD]

hi all,
as nick and others have sugested, The main things to look for when considering a chinese made amp or any valve equipment are,,, earth bonding and correct mains voltage,,, ie: 220v equipment from experience and from extensive testing etc i have found that on some amps the primary voltage needed was as little as 207v for everything to be correct on the secondary windings.
as you can imagine when you put 250v on it the first thing to be well out is the heaters, this then leads to the ht voltage probably being over what the power supply caps are rated at etc, all in all eventualy the valves go into thermal runaway and something lets go big time!!!:eek:
not all chinese equipment is bad but quite a bit of what comes from hong kong via e++y is not directly suitable for our mains voltage.
anthony,TD...

[Thermionic]

Back in the days when hand done point-to-point wiring was the norm one of the main rules was that components should be supported at both ends, either by turret lugs or tag strips. And their wires should form a mechanical joint first, with the solder only making the electrical connection. This made for reliable circuitry and prevented components flapping about in the breeze during transit. Take a look at any old Leak or Quad amplifier to see how it should be done.

IMHO (though I was once a prototype wireman taught to do point-to-point) while the equipment in this thread looks neat, some of it does perhaps have a rather amateurish feel about it. As Spendorman suggests some of the resistors have leads bent much too near to the bodies thus causing strain on the end cap termination and possible premature failures. In another image what look like capacitors have solder joints made much too near to the bodies, probably damaging their internal dielectric. In the same picture, while very neatly wired, some of the components seem to be left with one end free to ‘flap about’.

Not wishing to offend anyone but this is the sort of wiring that I or an amateur might do for ourselves and be perfectly happy with (apart from those capacitor joints), it would not though have got past my old inspection department. And if anything went wrong later we could be in there with scope and soldering iron sorting things out. But probably not what the general user might expect to do half across the world without a handbook or service manual.

So it looks that for this type of equipment some manufactures are still very much in the learning curve and one needs to be conscious of this when ordering, especially with the mains voltage issues.

Yes I have bought Chinese equipment direct, but this a was well regarded bit of high technology where they seem to have learnt or been taught international standards of production engineering and quality. But with valve equipment the old production standards for this type of labour intensive wiring had probably been lost long before it became fashionable again.

[Rare Bird]

Jason: Do you have any more info on the amp you pictured above? It looks most impressive.

Does dosent it..

[Techno Commander]

I am inclined to agree about the components being bent a little too close to their bodies. Usually I place a pair of needle nosed pliers next to a component body and then bend the lead outside of that.

I was doing some research into Cayin, another Chinese company tied in with a European (German in this case) design team. Originally Cayin produced electronics for military use, which probably goes some way to defining the higher manufacturing quality employed in their products.

Link to big internal photo. (http://img144.imageshack.us/img144/8364/biasa88tahs1.jpg)


I suppose we should also consider that 5 years ago, we probably wouldnt even be talking about Chinese audio equipment as back then it was almost unheard of and what was available was of very poor quality and built as cheaply as possible. In the intervening years thay have realised that quality is a better selling point than low cost alone and a number of manufacturers are trying very hard to bring their products up to the level expected by customers in the western world. I think we are very likely to see "high end" products with an Asian origin becoming a lot more common place before too long.


http://www.dussun.com/chinese/product/products/r10_top_l.jpg

http://www.tonewinner.com/uploads/2008-4/2008429133232899.jpg

http://www.dussun.com/chinese/product/products/r30_front_l.jpg

[Techno Commander]

Now this looks interesting. :)
Shame it "suffers" with the 230V transformer syndrome.

Sinovt (http://www.sinovt.com.cn/index.asp)

http://www.sinovt.com.cn/img/tb/6sq7-kt66.jpg

Nice to see a manufacturer who is prepared to show the circuit diagrams (http://www.sinovt.com.cn/download/dlz004.png) of their amps.

They also have a number of interesting looking kits as well.

[Jonboy]

very nice looking KT66 SET, very simply built by the looks of it

[Ali Tait]

Yes,looks good.

[anthonyTD]

looks good!
very simple design with switchable triode/tetrode connection for the output stage too!:)
anthony,TD...

[Ali Tait]

Looking at the diagram it appears to have tappings for 220,230 and 240v.If so,it would be fine for UK use.

[Techno Commander]

Well spotted. I'm gonna drop them an e-mail this evening when I get home. :)

[Ali Tait]

Good stuff Andy.Let us know if you get one.Not heard a KT66 in triode,but meant to be very good by al accounts,quite 45 ish.

[Ali Tait]

Let us know the price too if you don't mind.

[Clive]

Yes, it looks interesting and simple to work on.

[Ali Tait]

Aye,I thought that too Clive,easy to upgrade caps etc.

[Techno Commander]

No worries chaps, just got in so will fire off a mail soon. Probably be next week before I hear back, but I will keep you all informed. :)

[Ali Tait]

Grand!

[Techno Commander]

I have mailed them for confirmation of 240 volt operation and cost.

[Ali Tait]

Don't forget postage and customs have to have their bloody pound of flesh!

[Techno Commander]

I did ask shipping costs.

"commercial sample":eyebrows:

[Ali Tait]

Aye,good idea!

[Techno Commander]

Apologoes for the delay in updating this. I have spent a couple of days laid up with the dreaded man flu.:eek:

Anyway, here is the response I received from Sinovt.


Dear Andy,

Thank you very much for your letter telling us you are interested in our amplifier.

The maximum windings of our Power Transformer can reach 240 volts, which can be used safely in the UK, where voltage sometimes could reach 250 volts.

The wholesale price of our 6SQ7-KT66 SE amplifier is 158 pounds each and the express cost to UK is 126 pounds each. As to the payment, we only accept the T/T.

I enclose the brochure of our latest products for your reference.

We are looking forward to your early reply.

Yours faithfully

John

You will notice the quote mentions "wholesale pricing". Due to the interest being shown, I asked for pricing for 5 amps. I also sent another e-mail asking if surface shipping was a (cheaper) option. John replied that for 5 amplifiers there would be a saving, but for individual amps, the saving was negligable. He said he would get an exact cost if we wished to progress further with a purchase.

[Techno Commander]

looks good!
very simple design with switchable triode/tetrode connection for the output stage too!:)
anthony,TD...

Anthony, I notice there doesnt appear to be any pots for adjusting valve bias. I presume this is not an issue with this design, can you explain why this would be so? Thanks.

[Clive]

Anthony, I notice there doesnt appear to be any pots for adjusting valve bias. I presume this is not an issue with this design, can you explain why this would be so? Thanks.
Auto-bias. Very commonly used.

http://www.glass-ware.com/tubecircuits/Tube_Auto_Biasing.html

[Ali Tait]

Aye,as in all the WAD and WD amps AFAIK.

[Techno Commander]

Excellent, thats something which makes living with an amp a lot easier.

[Techno Commander]

Anyone fancy a 5 channel valve amp? :)

http://www.cattylink.com/_wp_generated/wp66ef7379_0f.jpg

Linky (http://www.cattylink.com/page450.html)

[Ali Tait]

Wouldn't fancy paying to revalve it!