| beau2317 |
I wanted to share details of these new monoblocks I just acquired to go with my Aikido linestage.
They are TS501 50W monoblocks, made by an almost unknown company in Thailand, TS Audio.
They seem to be based on the Ongaku circuit with some changes:
-- 2 parallel 211 output tubes instead of 1
-- only 2 5AR4 rectifiers instead of 4
-- DC heaters on the 211s
-- slightly different resistor / capacitor values
Apart from that they seem to follow the circuit. They use NOS 6072 and 5687; chinese 211s and sovtek 5AR4s
They are built using good quality (but nothing special) parts, point-to-point wired. A MusiCap coupling capacitor is used in the signal path. They weigh 27kg each. The transformers and p/s choke are potted.
They sound pretty good. They drive my magnepan 3s just fine...but the killer is the price. About us$2000 new (for a pair)
TS Audio make a whole range of amps, all single ended, at quite amazing prices, for instance, they do an EL34 9W+9W integrated amp for about us$200 , and they do a 300B integrated amp for about $800. Both of these look at lot more expensive than they cost. You can see a review of the EL34 amp here
http://www.tnt-audio.com/ampli/norh_se9_e.html
where it's been rebadged and re-priced.
The prices I am quoting are the prices you can get if you walk into their showroom in Bangkok. Problem is that they don't speak much english.
But if anyone is on holiday in Thailand they are worth checking out. It's not just the chinese who are making affordable tube amps...
Contact me if you want their address, etc. |
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| Miniwatt |
2 parallel 211's? :bigeyes: Whoa, lots of power there!!
Do you have a scheme?? Quite curious about this one... |
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| beau2317 |
I have not got drawn a schematic yet, not in electronic format anyway, just one I was using to trace the circuit. But after a while I realized that it was the Ongaku circuit.
First I suggest that you get hold of the Ongaku circuit, available on the net various places.
What they have done is to have two cathode followers being driven from the first 5687 voltage amp stage (instead of one). Each follower drives a single 211 grid. Both 211 plates are connected together, to the output transformer.
That's about it. They do seem to be quite powerful. Enough to make my maggies rattle if I turn it up loud. |
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| rick57 |
Hi Beau
What is the quoted signal/ noise on those monoblocks?
Some 211 amps can sound a little edgy I believe – any trace of that?
Or now that you’ve had them a few months, any comments on sound quality?
Thanks
Rick |
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| beau2317 |
I have done quite a lot to them since I had them and they are now sounding superb:
Initially they sounded OK but not as good as I was hoping, but after these mods they have improved a lot.
-- adding decoupling caps to electrolytics
-- replacing signal path capacitor with Jensen PIO
-- the common-cathode middle stage did not run at high enough current (5687 running at less than 1mA) so I upped this to 10mA
-- I added a small amount of neg feedback from the driver (cathode follower) back to the first stage. This sharpened thngs up in the treble range and did not seem to have any adverse effects
-- I have components on order to further tweak - nice resistors, caps, etc.
Now it blows away my previous pp tube amps and makes my gainclone sound silly. And it's drving my Magnepan 3.6's just fine (not bad to SE DHT)
All in all I am very pleased. |
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| beau2317 |
I noticed I did not answer the question; there's no quoted s/n ratio. They seem to be pretty quiet; you can hear a bit of hum close to the speaker but that's all. No hiss noticable.
They don't seem to be at all edgey; very smooth and musical. |
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| Miniwatt |
Maybe an unnecessary tip, but I changed my chinese 211's for new GE's, and boy, was I pleased!!:D
(I was also pleased with the price I paid for them, on a sort of dutch E-bay-clonesite I saw someone bidding € 1500,- for a new pair:bigeyes: :bigeyes: :bigeyes: I suppose it was a joke or a mistake.... They came with the original boxes though...:smash: ) |
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| rick57 |
Hi Beau
Sounds like a great amp
What was the approx total cost of all your mods?
Do you know if they do a 211 SE (18 watts)?
(I see TS Audio work with Thai speaker maker Norh)
Have you come across a TS website? What contact details do you have?
Thanks & Regards Rick |
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| beau2317 |
They do a KB211 model, monoblock, 35 watt (they say), which I am sure is a single 211 version. On my pricelist the cost is 50,000 baht, but I know that you can get 10% off that price just by asking. So that makes it 47,500 baht or us$1200
The build quality is not great, but for the price you can't expect perfection. Even if you just consider it on parts it's a pretty good deal.
Now the problem might come buying them; they don't have a website, and basically nobody in the company seems to speak english. I had the advantage of a thai wife.
Maybe you need to schedule a holiday in Bangkok :D
I got mine shipped by UPS as we have an account, but to tell the truth they did not pack it very well. You might be able to speak to Norh; that company at least has an english speaking person who you could talk to, but they might want to add their cut; when they sold the 34.1 amp they basically doubled TS Audio's price. But that was a much cheaper amp.
The mods : mostly not much. You could use fairly cheap polyprop caps, or you could go exotic. If you just use normal type components you can do the mods for say $50 or even less. But if you want to be silly you could spend a lot more. The most important mods sound-wise were (a) putting the proper current thru the middle tube - that's just changing two resistors per channel. and (b) adding some NFB, a capacitor and resistor per channel. So they can be had quite cheaply. I could explain how to do both of these if you needed help.
Rgds
bob |
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| rick57 |
Hi Bob
I have had a lot of great times in Thailand, but can’t afford to go there for a while. Last year I nearly bought in Hong Kong a Chinese made 845 SE integrated, apparently well made with Ongaku styling – brand Pride, IIRC about 12% more than the KB211 monoblocks. They had a slightly sweet but *very muscular sound for 18 watts, driving 88 dB speakers.
But monoblocks would suit me better. I sent an email to their partner Norh yesterday but haven’t heard back. I might see if the Thai consulate can help.
Thanks for the model info & further pointers on the mods. :)
It’s been said that 211s more so than just about any other tube, require a high operating point.
Do you know the plate voltage in your TS501s or the KB211s??
Rgds
Richard |
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| beau2317 |
I have not measured the plate voltage; I am afraid to go near that part, and my test meters don't go that high.
However it is driven from a 380-0-380 transformer, thru tube rectifiers and a choke; this is identical to the Ongaku, and the plate voltage marked on the circuit diagrams I have seen is 960V. This also matches what you would expect from a setup like this: (380 * 2) * root 2 = 1074V. It's believable to lose 110V on the recifiers and choke.
I think this could do with being a bit higher from what I've read, but it's not too bad.
If you are really interested, I might be able to persuade my wife to help a bit; she's also going to Thailand in Feb to see family so she might be able to pop in and talk to them. Contact me directly on bob at beausoft dot com
Rgds
bob |
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