Sure Electronics New Tripath Board 4*100W class-D Amplifier Board

[snip6600]

Power supply

Hi, sorry if this has already been asked I admit to not having read the entire thread.

Is this board dependant on the characteristics of an SMPS power supply much?
I ordered one and already have some 500VA transformers at 18-0-18 so thought I might run one like that through a CRC filter?

//J

 

[kaporalu]

Found how to implement "active" DC offset, on Tripath EB-TK2050-6 datasheet!
Was a 6 ch. evaluation board; for each channel using one section of TL072 amplifier to adjust the DC offset.

I still waiting for my 4*100W amplifier, so is not yet tested.
Before tests, reccommend to use instead of speaker one 100 ohm/17W (if the inputs of TL072 are not correct phased to outputs, the offset will "jump" to Vcc - i think - and will be very "nice" to see speaker and TP2050 in flames!!!)

 

[poler]

Has anybody tried any mods yet on these new boards?

 

[soapdodger]

I'm having trouble getting enough level to drive all 4 inputs, should I consider a pre amp or a 1-4 input transformer.

the inputs are rated as 500mV 2V max rms. I presume I need a preamp with a 1V output?

In the case of the transformer, will I need any other circuitry or is the transformer all I need?

 

[AndrewT]

500mVac input to drive the outputs to what level?
Have you measured your output signal from any of your sources?

 

[Michele79]

Hi guys, just ordered my board from Sure...one question about :
on the board I can read "Power DC: 6-26V"...on the User Guide I find
"Operating Voltage Range: 10V-30V, maximum voltage 32V"...
on the TK2050 Tripath datasheet I read "Max Vcc = 36V - Absolute
Maximum Vcc = 40V".....sooooo, what's the right value ? What have you
tried as maximum without smoke ?
I have a transformer 300VA Pri 220V - Sec 24V, DC output with bridge and caps
is more or less 33VDC...if I try this one should I open windows... ?
(for the smoke... )

Thanks!

 

[teamacc]

On 33v you WILL need to put a FAN on it
keep in mind all elcos are 35v...
You might wanna consider some lower voltage...

 

[Michele79]

On 33v you WILL need to put a FAN on it
keep in mind all elcos are 35v...
You might wanna consider some lower voltage...

thanks teamacc for your reply!
...a fan ? oh, not good to me...But, anyway, should work without issues ? I think I'll follow your suggestion and I'll go with some lower voltage...
Guys, what's the best Vcc in your experiences ? 24VDC ? 28DVC ?

Thanks !

 

[the7trumpets]

Found how to implement "active" DC offset, on Tripath EB-TK2050-6 datasheet!
Was a 6 ch. evaluation board; for each channel using one section of TL072 amplifier to adjust the DC offset.

I saw that datasheet too, right before I read this thread

There is a note on the schematic though, that reads:

Nets "IN1" and "IN2" must be very short.

Does that mean it's not feasible as a mod? Or have you figured out a way to add a small board very near the chip somehow?

 

[jonners]

Hi guys,

These are some pictures i took of the board before painting the resistors with the conductive paint.

The first is what you can expect to see once you remove the heat sink.
The second is a close up of the resistors which need to be removed or shorted, marked in red. On my board they all had 104 on them. Once these are shorted/removed the trim pots become incredibly sensitive and should allow you to trim out any Offset you may have.

I have the 2x100W version of the 4x100W board.
The DC offsets were too high so I tried to trim them by the method described by Craig. This was successful on one channel (reduced from 110mV to 2mV) but on the other channel the offset remains at 300mV regardless of the trimmer setting. The relevant resistors are definitely shorted.
The part numbering is different on my board, but if I refer to the corresponding parts on Craig's second picture (below), I find that there is zero ohms between R19 and one end of R14 on the bad channel, whereas the equivalent on the good channel ( R33 to one end of R30) measures 2.3K. Hence it looks as if the pot on the channel I can't adjust is in effect being shorted out, but putting the meter on the pot itself shows it to be working OK.
Can anyone suggest what might be going on here please?

 

[jonners]

Further to my post above, here's the drawing made by Audio1st of the offset arrangement:

 

[jonners]

I'm coming to the conclusion that there must be a mistake in the board itself.
It's the large heatsink version btw:

 

[sendler]

different

The boards are different between the 2x100 which was a new design from the ground up, And the 4X100 which is an attempt to resurrect the board from a failed previous attempt with a different chip. There is no need to jump any resistors on the 2X100 board. You will get better help if you ask in the appropriate thread.
.
http://www.diyaudio.com/forums/class-d/143669-sure-electronics-new-tripath-board-tc2000-tp2050.html
.

I have the 2x100W version of the 4x100W board.
The DC offsets were too high so I tried to trim them by the method described by Craig. This was successful on one channel (reduced from 110mV to 2mV) but on the other channel the offset remains at 300mV regardless of the trimmer setting. The relevant resistors are definitely shorted.
The part numbering is different on my board, but if I refer to the corresponding parts on Craig's second picture (below), I find that there is zero ohms between R19 and one end of R14 on the bad channel, whereas the equivalent on the good channel ( R33 to one end of R30) measures 2.3K. Hence it looks as if the pot on the channel I can't adjust is in effect being shorted out, but putting the meter on the pot itself shows it to be working OK.
Can anyone suggest what might be going on here please?

 

[jonners]

Thanks for your reply Scott. The thread that you linked to seems to be about the version with the fan, whereas mine has the large heatsink - exactly like the 4-channel board but with only two channels populated.
Shorting the 100K resistors solved the offset problem on one channel. I don't see how the offset adjustment can work with them in place. They need to be more like 10K.

John

 

[sendler]

New name

Thanks for your reply Scott. The thread that you linked to seems to be about the version with the fan, whereas mine has the large heatsink - exactly like the 4-channel board but with only two channels populated.
Shorting the 100K resistors solved the offset problem on one channel. I don't see how the offset adjustment can work with them in place. They need to be more like 10K.

John

We need to give your board a new name. Calling it a 2X100 will cause confusion. Maybe it's a 4-2X100.

 

[jonners]

We need to give your board a new name. Calling it a 2X100 will cause confusion. Maybe it's a 4-2X100.

OK. Whatever we call it, it appears to have its own problems. Does anyone else out there have one?
Here it is: http://www.sureelectronics.net/goods.php?id=1044
John

 

[jonners]

I think I've got the problem sorted; the offsets are now around 1mV and 5mV.
What I had to do was:
1. Bridge across R8, R16, R23 and R30.
2. Remove R27.
3. Solder a 470K resistor between the wiper of pot R25 and the upper end (i.e. the end nearest the wiper) of R28. I used the physically smallest through-hole resistor I could find, and made sure there was adequate clearance to get the heatsink back on.
4. Adjust the pots for minimum DC offset and replace the heatsink.

Any change in supply voltage will alter the DC offsets.

John

 

[Baka]

Gain setting

Hi all,

I have recently got "4-2X100" (thanks, Sendler) version of the amp.

It works quietly and without any heat problems so far at 27,5V linear supply.

My source is a cd player through the 10k volume pot.

However, despite the relatively low 85db efficiency of the speakers, I have to turn the volume pot up to 1 or 2 clock to achieve a moderate loudness in a very small room.

I feel a little uncomfortable because of that.

Gain is fixed and the values of Ri and Rf are 22k. I am using 2,2 uF Ci.

Is it safe and convenient to increase gain a bit and what would be the recommended value of the Ri?

Thanks,

Baka

 

[AndrewT]

Hi,
if you keep increasing the attenuator does the speaker output suffer distortion due to overloading of the amplifier or the speaker?
If yes, then you do not need extra gain.

If no, and that max setting is loud enough for all uses, then you do not need any extra gain.

If no, and that max setting is adequate for most normal listening, but for some conditions, eg. during a party, would you want a bit more gain for these abnormal operating conditions? You make that choice, and face the consequences of damaged speakers.

 

[Baka]

Hi Andrew,

Well...

1. I would say that, maybe, i hear just a little harshness at 2 clock. I would say also that speaker is more capable than the amp regarding the power it can receive.

2. That max setting is mostly loud enough for me.

3. It is just for my own pleasure.

So, volume pot at 1 to 2 clock shouldn't worry?

Thanks, Andrew.

Baki