Sorry for missing link.
https://www.diyaudio.com/community/threads/amplifier-modules-and-pcbs-for-sale.238156/post-7308378
It's cheaper even if you have to buy an balanced board than TPA3255.
Still to hear also if it's compatible in that speciel 3D sound.
Never heard an TPA32XX that have it.
https://www.diyaudio.com/community/threads/amplifier-modules-and-pcbs-for-sale.238156/post-7308378
What do you think i like?🙂
It's cheaper even if you have to buy an balanced board than TPA3255.
Still to hear also if it's compatible in that speciel 3D sound.
Never heard an TPA32XX that have it.
Pardon my French but that is a product that that member sells commercially. What do you think people say about their own wares? "Yeah my self designed amplifier is worse than a 35 Euro ChiFi amplifier, don't bother" 🙂
I am sure it sounds even better than Pass stuff. Oh oh, that's a sin.
I am sure it sounds even better than Pass stuff. Oh oh, that's a sin.
That isn't the final version of my mods, so ignore it. B and D are stacked 1uF 16V acrylic caps. B are not there in the final mod. C is just added supply bypassing for the op-amps.
The attached pic is the final schematic. The original 50k linear pot was replaced with a 20k log.
The attached pic is the final schematic. The original 50k linear pot was replaced with a 20k log.
Attachments
Ok! So you skipped the B mod. I understand C now - thanks!
D are the caps in the output filter I suppose?
I think I won't bother with the OP-amp even if I can appreciate that it would make a change for the better.
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D are the caps in the output filter I suppose?
I think I won't bother with the OP-amp even if I can appreciate that it would make a change for the better.
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Thinking about it I do have OPA1612 and 1632 readily available... which one to choose in case I was inclined?
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edit: 1632 is a single so... no 🙂
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edit: 1632 is a single so... no 🙂
D are the coupling caps between the op-amps and the MA12070 inputs.
The biggest improvement from my mod is not even from changing the op-amps. The entire input circuit was reconfigured, which lowers distortion by nearly 10x, even if you keep the TL072.
See this image of the original circuit to compare...
https://www.diyaudio.com/community/attachments/original_input-png.1044601/
The biggest improvement from my mod is not even from changing the op-amps. The entire input circuit was reconfigured, which lowers distortion by nearly 10x, even if you keep the TL072.
See this image of the original circuit to compare...
https://www.diyaudio.com/community/attachments/original_input-png.1044601/
OK re: D.
I would really like to take away the pot. Is that a difficult to do change?
I compared the two schematics - it hurts my brain to do these kind of changes on an existing board ;-D
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I would really like to take away the pot. Is that a difficult to do change?
I compared the two schematics - it hurts my brain to do these kind of changes on an existing board ;-D
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If we can do it you can do it too.
For the potentiometer (that you will miss as it is a kind of fuse) you can use the Gentle Total Demolition method with a 160 or larger side cutter. Carefully desolder the leftover pins after that.
For the potentiometer (that you will miss as it is a kind of fuse) you can use the Gentle Total Demolition method with a 160 or larger side cutter. Carefully desolder the leftover pins after that.
Okay, you are afraid of the direct coupling of amp to speaker. I'm a bit more adventurous here and of course also prepared to take the consequences - for the gain of a somewhat purer signal path.
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Strange inconsequent way of reasoning 😀
BTW I am not afraid. I quite often solve or repair the issues the more adventurous persons like to create.
BTW I am not afraid. I quite often solve or repair the issues the more adventurous persons like to create.
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It is not just about the quality but what the resistance exactly does. That is the primary thing.
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Let it rest. You have now thought about it for a week ;-) My case was to provide a headamp with a not to low impedance. Lets move on...
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No I thought about it today when I wrote a reaction on the removal of the potentiometer. It is you that mixes 2 different issues or reply to the wrong person.
You could think like those that already learnt the drawbacks of open amplifiers and use 2 resistor attenuators where they should be to protect the usually way more expensive loudspeakers. The purest signal path created with highest quality resistors to a PCB with armies of X5R caps and chinese SMD resistors 🙂
You could think like those that already learnt the drawbacks of open amplifiers and use 2 resistor attenuators where they should be to protect the usually way more expensive loudspeakers. The purest signal path created with highest quality resistors to a PCB with armies of X5R caps and chinese SMD resistors 🙂
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