Folsom's great little 7297 Chip Amp

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skrstc

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Re: Folsom's great little 7297 Chip Amp
« Reply #1040 on: 21 Nov 2018, 07:35 pm »
My left channel is not working. There is 17.6V DC. Is TDA7297 died or something else?

Folsom

Re: Folsom's great little 7297 Chip Amp
« Reply #1041 on: 21 Nov 2018, 08:18 pm »
Make sure the binding posts are isolated from chassis. Check continuity on RCA cables and check wires for cold solderes. Turn it off for a bit and back on if everything seems ok. The internal protection can take a turn on and off or two to come back.

No drilling in PCB, right?

skrstc

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Re: Folsom's great little 7297 Chip Amp
« Reply #1042 on: 22 Nov 2018, 07:48 am »
Binding posts and RCA are OK. When I get back from work, I'll check soldering again. Thanks.

On Saturday I soldered beater wire on RCA and binding posts and the amplifier worked until yesterday.

skrstc

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  • Posts: 11
Re: Folsom's great little 7297 Chip Amp
« Reply #1043 on: 23 Nov 2018, 04:44 pm »
Everything looks OK.

Folsom

Re: Folsom's great little 7297 Chip Amp
« Reply #1044 on: 23 Nov 2018, 05:04 pm »
Well if everything is OK then chip replacement makes the most sense. But I will say that most of the time it isn't the chip.

If you are going to replace the chip I recommend cutting the old one off first. You need some small side cutters to do it. You don't have to be accurate or cut close to the board. Hell, if you have some big ones you can cut directly through the chip. Then touch the solder and pull each leg out with tweezers/needle nose. After that give each hole a spot of solder and then use solder wick to suck up the solder and you'll have holes that a new chip will easily go into.

It's not super easy, and some care is needed, but in general it's not too bad.

skrstc

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Re: Folsom's great little 7297 Chip Amp
« Reply #1045 on: 23 Nov 2018, 07:35 pm »
Thanks.

1108

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  • Posts: 9
Re: Folsom's great little 7297 Chip Amp
« Reply #1046 on: 30 Nov 2018, 01:19 pm »
Will there be another run of boards?

Folsom

Re: Folsom's great little 7297 Chip Amp
« Reply #1047 on: 30 Nov 2018, 06:40 pm »
I still have some.

yardbird

  • Jr. Member
  • Posts: 27
Re: Folsom's great little 7297 Chip Amp
« Reply #1048 on: 21 Dec 2018, 10:37 pm »
The BOM now has 2 options for the 12 caps on the 7297 board. One is for 560uf 20v Panasonics and he other is for 330uf 25 v Nichicons.


Want to make to sure the 2 different values are OK and to see if folks have noted any differences.


Thanks,
Jeff

Folsom

Re: Folsom's great little 7297 Chip Amp
« Reply #1049 on: 21 Dec 2018, 11:58 pm »
They just sound different. Nichicons sound slightly more open. Obviously, since I put them both in, nothing is wrong with either.

WC

Re: Folsom's great little 7297 Chip Amp
« Reply #1050 on: 30 Dec 2018, 01:52 am »
Jeremy,

On the Antipole, is there a certain orientation that the Bourns choke has to go? All your photos had the coilcraft choke.

Folsom

Re: Folsom's great little 7297 Chip Amp
« Reply #1051 on: 30 Dec 2018, 02:01 am »
Nope

WireNut

Re: Folsom's great little 7297 Chip Amp
« Reply #1052 on: 30 Dec 2018, 02:28 am »
I can't wait to build your amp :bounce:.
In the long run I will most likely be driving your amp with a Mesmerized DCB1, I can't afford to build the Pass BA-3 preamp.

The gain of the DCB1 is 1.
I don't know if zero (1) gain will work with the 7297 amp or not :scratch:

Currently I'm using an old Pioneer SA8500mk2 integrated amp as my preamp (pre-outs) and it never gets pass 10 o'clock.

Folsom

Re: Folsom's great little 7297 Chip Amp
« Reply #1053 on: 30 Dec 2018, 02:42 am »
no gain is good for it, generally

WireNut

Re: Folsom's great little 7297 Chip Amp
« Reply #1054 on: 30 Dec 2018, 03:06 am »
no gain is good for it, generally

Awesome, That's what I was hoping for. My system doesn't seem to need any gain from a preamp.
BTW, your Fo-Felix is working perfectly. I'm extremely happy with it :thumb:.

Oh, and your instructions on the 7297 amp and Antipole are fantastic  :rules:









WC

Re: Folsom's great little 7297 Chip Amp
« Reply #1055 on: 30 Dec 2018, 03:49 am »
How would it work being driven from a DAC directly? My DAC is a Soekris Dam 1021 with 1.4V, 625R output. I am putting them together in a single enclosure.

Folsom

Re: Folsom's great little 7297 Chip Amp
« Reply #1056 on: 30 Dec 2018, 05:21 am »
Does it have volume control?

WC

Re: Folsom's great little 7297 Chip Amp
« Reply #1057 on: 30 Dec 2018, 01:46 pm »
Yes, it has a volume control.

Folsom

Re: Folsom's great little 7297 Chip Amp
« Reply #1058 on: 30 Dec 2018, 06:25 pm »
That sounds fairly ideal then, as long as your speakers aren't very low efficiency. For example Magnapans sensitivity isn't super low, but they're so inefficient that there's no way to power them.

WC

Re: Folsom's great little 7297 Chip Amp
« Reply #1059 on: 30 Dec 2018, 07:57 pm »
It will be powering the shop speakers. Most likely they will be JBL G100 bookshelf speakers at 86 dB and 6ohm or BA HD9 speakers at 90 db and 8 ohms. Don’t think it should be an issue.