DC offset will change with different power supply voltages. With the 2x100 board, if you change the supply voltage you have to re tune the offset.
The heatsink on the 4x100 is in the way of the adjusters and should perhaps have had 4 holes to access the trimmers?
The problems are all because they modified an old board.
The heatsink on the 4x100 is in the way of the adjusters and should perhaps have had 4 holes to access the trimmers?
The problems are all because they modified an old board.
Interesting. How can we contact Sure about this? What is the fix?I think I have found the problem... Sure have added 100k resistors to the trimmers and this is preventing them from working
These are the resistors; R11, 19, 26, 33, 39, 47, 54 and 61..
Can anyone summarize the most important mods to make to this board? Any resistors, capacitors, or inductors to remove or upgrade?
I think I have found the problem... Sure have added 100k resistors to the trimmers and this is preventing them from working
These are the resistors; R11, 19, 26, 33, 39, 47, 54 and 61..
Don't those resistors just make the voltage adjustment more precise? In the Tripath circuit, the pot would swing the DC bias voltage all the way from 0-5V, making it hard to tune exactly. Putting symmetric resistors on either side like Sure has done reduces the range to 2.38-2.61V. They seem like a good thing to me. Am I missing something?
That sounds likely to me. The 100k resistors may restrict the range too much. I notice that the tc2000 spec sheet says at one point that DC bias should be "2.5V typical," at another point, it says "approximately 2.4V." If the 2.4V number is right, then it's awfully close to the minimum their setup will allow, 2.38V.
Has anyone adjusted bias with the heatsink off but no signal, or will that fry the chips?
Those coils are junk even though they are rated higher. I tested a bunch of
coils on the tripath amps and the best so far is from Wurt. They are even better than custom wound coils I have on my Amp11.
Do yourselfs a favour and try 10uH Wurt coils. They changed my 2x100
Shure from good to Fantastic. No kidding here. The hights went from
annoiing (compared to my my other modded Amps) to plesant.
They should not have gone from surface mount to through hole on the
4x100.
Adequately modded these TK2050 amps can put very expensive Amps to shame. All my modded amps:Charlize, AKSA 55N, SKA150, Amp11, Accuphase E303, EL84 Tube, are all no match for the slightly modded 2x 100 Shure TK2050.
Greets,
Klaus
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Wurt coils?
Do you have a link to the Wurt coils that you like? I am still waiting for some Sagami to try.
Must have meant Wurth
I have these which are the same and available for $4 in the US as Coilcraft 2900 series.
.
WE Produktkatalog
.
They look really impressive but can't quite hang with the sonics of Ferroxcube or the air cores even after I potted them.
You must have meant Wurth.
I have these which are the same and available for $4 in the US as Coilcraft 2900 series.
.
WE Produktkatalog
.
They look really impressive but can't quite hang with the sonics of Ferroxcube or the air cores even after I potted them.
I am embarrassed, but I don't know exactly which one I have.
they are from Schuricht (Disrelec) Germany.
I chose 10uH and the highes available amperage that I could find.
There are two options and another that was not there when
I ordered them.
I think it would not break anybodies bank if all the options would be ordered.
WE Produktkatalog
WE Produktkatalog
WE Produktkatalog
Here is a pic of mine:
Greets,
Klaus
Attachments
No those are not the ones I have.
Look at the pic on my reply.
I put them against the air coils of my charlize and they are better.
I think allot of the coil issues are also system dependent.
The Shure with those coils and my AK4396 bords with passive-out setup is a dream combination, that's for sure.
Greets,
Klaus
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Hisssssss
Hi guys! I have been testing my amp with just the one channel via the Rane AC22B active X-over and I am getting considerable hiss, I mean hiss that rises with the input, when there is no volume there is barely audible output if I put hy ear near the mid / high driver. Anyone had similar problems? I do not have another amp at the moment to check if it the rane but I am a bit dubious tbh. Otherwise, there is detail a plenty, but I would like a bit more treble...
Many thanks.
Steve
Hi guys! I have been testing my amp with just the one channel via the Rane AC22B active X-over and I am getting considerable hiss, I mean hiss that rises with the input, when there is no volume there is barely audible output if I put hy ear near the mid / high driver. Anyone had similar problems? I do not have another amp at the moment to check if it the rane but I am a bit dubious tbh. Otherwise, there is detail a plenty, but I would like a bit more treble...
Many thanks.
Steve
Hi guys, sorry i have been busy, I work for Waitrose and this is the busiest time of the year for us!
Firstly i have had the amp running on a 12v 5A power supply from my Topping TP10 for a couple of hours to test the board as suggested by Sure, on some old bookshelf Tannoy E-11 ( I also ensured my understanding off bi-amping with this amp on them as well) on 12v the heatsink is only warm to touch however i didn't measure any offsets at this voltage.
I then went on to the Meanwell 24v 14.6A power supply this is giving out a constant 24v although is adjustable via a trimmer by a couple of volts. it was at 24v i took my DC offset readings, which were to high/low for me to be comfortable with.
I removed the heatsink by removing the four screws on the underside of the board, the heatsink then came away from the board easily, the thermal compound looks like that from a computer and does not appear to be adhesive. I left the board powered for about 10 minutes with no audio source connected and the chips became warm to the touch but by not Hot. I decided to use the trim pots whilst connected to the power source, and it looks as if Sure had set the DC offset as low as it was possible to already as the trim pots only increased the DC offset.
I have contacted Sure a couple of times regarding this and they keep giving me the same info which is to adjust the trim pots, just seem to be going round in circles with them here.
Audio1st, I am willing to be a guinea pig in removing those resistors but are they easy to reach? or are they under the daughter board like the previous resistors which were already removed?
Many Thanks,
Merry Christmas,
Craig
Firstly i have had the amp running on a 12v 5A power supply from my Topping TP10 for a couple of hours to test the board as suggested by Sure, on some old bookshelf Tannoy E-11 ( I also ensured my understanding off bi-amping with this amp on them as well) on 12v the heatsink is only warm to touch however i didn't measure any offsets at this voltage.
I then went on to the Meanwell 24v 14.6A power supply this is giving out a constant 24v although is adjustable via a trimmer by a couple of volts. it was at 24v i took my DC offset readings, which were to high/low for me to be comfortable with.
I removed the heatsink by removing the four screws on the underside of the board, the heatsink then came away from the board easily, the thermal compound looks like that from a computer and does not appear to be adhesive. I left the board powered for about 10 minutes with no audio source connected and the chips became warm to the touch but by not Hot. I decided to use the trim pots whilst connected to the power source, and it looks as if Sure had set the DC offset as low as it was possible to already as the trim pots only increased the DC offset.
I have contacted Sure a couple of times regarding this and they keep giving me the same info which is to adjust the trim pots, just seem to be going round in circles with them here.
Audio1st, I am willing to be a guinea pig in removing those resistors but are they easy to reach? or are they under the daughter board like the previous resistors which were already removed?
Many Thanks,
Merry Christmas,
Craig
Craig,
If you are in touch with Sure you might refer them to the thread, or the specific information in post 102 http://www.diyaudio.com/forums/clas...w-class-d-amplifier-board-11.html#post2013613
Above, one or two people concur with you that the trim pots do very little to change the offset. And the guy in post 102 is saying why. It sounds like you are ready to cut or bypass some resistors to try to resolve the problem. I am eager to see your results.
One other thought, from the thread about the 2-channel sure board, of course keep the input voltage from the meanwell constant. I think I read the 4-way board doesn't take as high a voltage. Anyway if anyone twists the pot in the Meanwell, they then need to check and trim their offset voltages.
If you are in touch with Sure you might refer them to the thread, or the specific information in post 102 http://www.diyaudio.com/forums/clas...w-class-d-amplifier-board-11.html#post2013613
Above, one or two people concur with you that the trim pots do very little to change the offset. And the guy in post 102 is saying why. It sounds like you are ready to cut or bypass some resistors to try to resolve the problem. I am eager to see your results.
One other thought, from the thread about the 2-channel sure board, of course keep the input voltage from the meanwell constant. I think I read the 4-way board doesn't take as high a voltage. Anyway if anyone twists the pot in the Meanwell, they then need to check and trim their offset voltages.
Hello Craig,
The resistors could be the smd's either side of the trimmers. Check the resistor numbers I gave earlier. The resistors will have 104 on them. They need to be bridged with solder or wire. Try just one channel..
If you could post a picture of the trimmers I could show which ones.
Too jumpy
This will make the adjustment so jumpy that you will barely be able to touch the pot with your screw driver without the value flying all over the place.
.
Is the pot already all of the way to one side? If not, changing the resistors won't help. Only hurt. Keep in mind that these amps are 8 channels bridged to make 4 and you are trying to adjust the offset between two outputs with one pot.
This will make the adjustment so jumpy that you will barely be able to touch the pot with your screw driver without the value flying all over the place.
.
Is the pot already all of the way to one side? If not, changing the resistors won't help. Only hurt. Keep in mind that these amps are 8 channels bridged to make 4 and you are trying to adjust the offset between two outputs with one pot.
Hello Scott,
You have the the 2x100 board and 2 trimmers, the 4x100 board has 4 trimmers, still one per channel. There are no 100k resistors on the 2x100 board, they are coarse but they do work.
Craig,
Also check before you go any further that trimmer one does adjust channel one and not channel two. Also check that channels 3 and 4 are not crossed over as well?
You have the the 2x100 board and 2 trimmers, the 4x100 board has 4 trimmers, still one per channel. There are no 100k resistors on the 2x100 board, they are coarse but they do work.
Craig,
Also check before you go any further that trimmer one does adjust channel one and not channel two. Also check that channels 3 and 4 are not crossed over as well?
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