STOXX
Thanks, yeah I totally get it. I have built power supplies in separate enclosures and other experiments in the tube gear realm.
Chipamps are uncharted territory for me so I am trying to learn why some circuits are done the way they are.
I did find a post elsewhere indicating that some people use 2 rectification circuits with 1 transformer, 1 on each secondary of an Antek type transformer with 2 identical secondaries. The reason being that they felt it was risky to wire both secondaries in parallel with the center taps.
Thanks, yeah I totally get it. I have built power supplies in separate enclosures and other experiments in the tube gear realm.
Chipamps are uncharted territory for me so I am trying to learn why some circuits are done the way they are.
I did find a post elsewhere indicating that some people use 2 rectification circuits with 1 transformer, 1 on each secondary of an Antek type transformer with 2 identical secondaries. The reason being that they felt it was risky to wire both secondaries in parallel with the center taps.
That sounds odd to me. There are various power supply configurations available depending on what windings you want vs what windings you have and half wave vs full wave etc but I am not aware of any power supply configurations introducing risk unless poor decisions and eronious work were at hand.
I see a linear power supply for an audio power amplifier as a basic fundamental operation. I have never associated or factored risk into such an endeavor. I find that intriguing yet nothing I would encounter in standard practice.
Stick to normal practices and avoid strange arrangements and weird experiments unless that is your thing...
I wonder why he solders the opamps on himself? I see it is SMD but just one on the board.
See the listing, at the side are:
$33 per kit stereo out of China, and $85 for a mono kit out of Santa Monica, California.
YMMV.
And you need power supply, box, switches, connectors and so on...
$33 per kit stereo out of China, and $85 for a mono kit out of Santa Monica, California.
YMMV.
And you need power supply, box, switches, connectors and so on...
That's indeed the plan. I'm working on updating the design as some of the components have gone obsolete. I'll probably also start offering the circuit as a kit.
Tom
The designer of those boards is a member here, but hasn’t been active since last April. (Kaltecs). He also has a site for TDA7293 based composite amps at kaltecs.com. I think a few people here have built them, although I am not one of them. Searching here will find quite a few links.
Me too, indeed!
I hope we will see how this amplifier performs else I will assume that competition isn't desirable at the Done-Right playground.
By the way, in my opinion 0.002 - 0.01% THD is all we need and "wanishingly" low distortion is plain Snake Oil.
EDIT: I wil place and order for the board and publish my results.I hope it will be a pleasant surprise...
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I don't know man but with two LM3886's idling on the toroidal and full bridge from the Audiosourse 100, I think the DC rails will fall right into spec. very close to +_35VDC. You could dial it up on a VARIAC during your build and verify. If it is too high, you can still use the supply and your VARIAC as a DC lab supply.
I received two boards today. I ordered the TDA7293 and received the TDA7294 (fully assembled boards). I'm not sure if I like these things; at first glance, they don't look good, and they're completely overpriced.
To be honest, the Kaltec boards are rather unprofessionally constructed. The Chinese boards, which I usually use for TDA7293 composite feedback setups, are much better. I use the OPA1656 as the op-amp and the OPA277 as the servo. The component values can be adopted from the Chinese board. It sounds very good; compared to my Naim Nait5si, the power is a bit lower, but dynamically, the Chinese board keeps up; the highs are even finer, and the spatiality is wider.
Always fun to review LM3886 product info page at TI
The have changed AN-1849 Application Note for power supply construction a few times
for guide line to build power supply.
Seems to be at Revision C
Finding older copies a fun read too. Of course can be scaled up or down for application.
And of course can use or ignore the snobby overpriced transformers recommended.
The have changed AN-1849 Application Note for power supply construction a few times
for guide line to build power supply.
Seems to be at Revision C
Finding older copies a fun read too. Of course can be scaled up or down for application.
And of course can use or ignore the snobby overpriced transformers recommended.
I remember the Blue Boxes National Semiconductor put the Overture© samples and datasheets in back in 1996 when they were introduced. Some of the LMxxxx chips were in little plastic 'jewel' cases. They made thousands of sample circuit boards to get you up and running. I fell in love instantly.
These?
This particular one is one of the newer ones as you can tell by the stylized logo. We had many of those floating around at work and I still have a few kicking around. They're pretty nice antistatic boxes.
The LM3886DR is back, by the way: https://neurochrome.com/products/lm3886-done-right. Now in revision 1.2.
Tom