New TK2050 board

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#1,481
I've contacted Nick and hopefully he can send me a new board, I can swap the Alps pot myself onto it if necessary. I can send the old board back to you guys if you wish so U can see if it's a design or assembly issue, or just a one off bad component.

Kinda disappointing, I was enjoying the sound too! My Topping TP30 just aint the same! But I appreciate the quick replies to my emails and hopefully we can get it up and running again soon.

Cheers.
 
#1,482
I've ordered a new board anyway without the alps pot, and keep this one as spares. Otherwise I won't see a replacement for weeks. Maybe I can just replace the three blown components myself and get it running again. Is there a circuit diagram anywhere I can work with to double check whats on there? Maybe with 36v there was a wrong resistor or cap somewhere, or it was just plain bad luck! I'll get a few spare caps and transistors and some STA510A.
 
#1,483
gethin said:
I've ordered a new board anyway without the alps pot, and keep this one as spares. Otherwise I won't see a replacement for weeks. Maybe I can just replace the three blown components myself and get it running again. Is there a circuit diagram anywhere I can work with to double check whats on there? Maybe with 36v there was a wrong resistor or cap somewhere, or it was just plain bad luck! I'll get a few spare caps and transistors and some STA510A.
Click to expand...
Hifimediy| Downloads
T1 schema is ok for ST510A, althought few values are different. Doubble check with the board.
 
#1,486
Hi,

I would like to make my first DIY project based on a TK2050 board. I am looking for a project which doesn't need modding, that's why I'm leaning forward to the Hifimediy boards over the Sure boards for example, but I'm open to any advice! Do you think a T1 with ALPS would be a good starting project? I would like to drive some vintage B&O S45 Mk2 speakers with it but in the future I would build some proper DIY horns. Would you recommend the T1 100W ALPS as a starting project? Or the 80W? What else do I need to buy? Just a Meanwell PSU and the RCA + speaker plugs?

Specs (I don't know what value to look at):
http://www.beoworld.org/prod_details.asp?pid=666
http://www.bang-olufsen.com/product-archive?ProductName=BeoVox S 45-
 
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#1,494
gethin said:
Do you hear the relays click on a second after you apply power? Or is the hiss immediate? Do you have the STA510A version?
Click to expand...
I bought the T2 TK2050 board v2.1 with 4700cap for SMPS power. The hiss occurs as soon as the relays click on which is about a second after the power is switched on.

v-bro said:
How does it go with the inputs shorted?
What kind of power supply are you using?
Click to expand...
I'm using a 27v SMPS power supply made by B&G. It was brand new and untested previously. Shorting the inputs makes no difference, neither does disconnecting the input cable all together.

Here's a picture of how it's all connected:
An externally hosted image should be here but it was not working when we last tested it.


I'm going to try and get it onto battery power if I can find one suitable.
 
#1,495
Ok I just tried my 19v laptop power supply on the amp and the hiss was there also. I'm starting to think that this has to be the board that's faulty as there isn't any steel chassis etc to cause distortion. Do I need to ground the board? From the other pictures I've seen, it doesn't appear to have been done by other people.. All help greatly received - I really want to start enjoying some music!!
 
#1,496
There is also the DC offset you have to tweak, put a meter across the speaker outputs and get it as close to 0mV as possible by tweaking the blue pots on the amp board.

I doubt that a wonky DC offset would cause that much hissing but it's worth checking. I would connect a ground to that SMPS that you pictured for safety. There is a signal ground plane on the amp pcb if I understand, not sure if leaving the AC ground disconnected on the smps would play a part in the hissing. I mounted my amp board on plastic isolators.

Do the LED's light up on the amp board at all?

Laptop bricks can be sketchy. Try and find two 12v batteries and wire them in series to get a nice clean 24v.
 
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#1,497
Hi gethin,
Thanks for the reply. I'll try and find 2 12v batteries, but I'm living in a new country with few tools never mind old batteries lieing around!

Thanks for the tip re the DC offsets - I have approx .4mV on each side now when I put the multimeter across the + & - of each channel. When I compare both + and both -, I have 18mV.

I just found a 3 core cable with plug attached, so I'm going to swap out that and see if it makes any difference.

Both LEDs light up and it makes music but the hiss can be heard easily 2.5m away from the speakers so it's pretty loud.
 
#1,498
DC offset has nothing to do with it.

Neither does earthing the PS.

These amps run silent on almost any dirty PS. Ok, there are quality differences, a nice stiff well regulated voltage tightens up the bass a bit, but noise...?? No....

This amp is no good, probably some 100nF ceramic cap is failing on you, or there could be a defective diode (notorious white noise generators when faulty)

How sensitive are your speakers by the way?
 
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