Folsom's great little 7297 Chip Amp

Folsom · « **Reply #1020 on:** 5 Mar 2018, 09:01 pm »

Quote from: lacro on 5 Mar 2018, 02:55 pm

Huh?

It's an upgrade to do this, I found, with how it sounds.

Folsom · « **Reply #1021 on:** 5 Mar 2018, 09:06 pm »

Quote from: BRN on 5 Mar 2018, 08:54 pm

Jeremy,

What is the purpose of cutting a space between each binding post? I assume you mean between the plus and minus of each post.

Thanks,
Brad

Well the short is, it makes it sound better. And yes between + and - of one channel.

Not doing it forms a turn around the panel and causes skinning RF currents to be inducted into the amplifier.

pocomo · « **Reply #1022 on:** 5 Mar 2018, 09:38 pm »

Only one channel? Would it be considered harmful to modify both?

Folsom · « **Reply #1023 on:** 5 Mar 2018, 09:51 pm »

Huh?

If you do it, do it to both... I just mean that there is no hole between the channels.

BRN · « **Reply #1024 on:** 6 Mar 2018, 12:17 am »

Quote from: Folsom on 5 Mar 2018, 09:01 pm

It's an upgrade to do this, I found, with how it sounds.

When I get a chance I will breakout the Dremmel and make the cuts and see if there is an improvement.

Folsom · « **Reply #1025 on:** 6 Mar 2018, 12:25 am »

I heard it. Just had to get around to trying it... did, and now I recommend it.

Hopefully it'll be as obvious to everyone else.

Danny Richie · « **Reply #1026 on:** 6 Mar 2018, 08:54 pm »

I just put one of these together and posted some information about it in our circle.

http://www.audiocircle.com/index.php?topic=156151.msg1671062

slefley · « **Reply #1027 on:** 24 Mar 2018, 03:00 pm »

I have an new & unused set of circuit boards (1 amp board and 1 antipole board) plus the electronic parts (resistors, caps, etc) that I will sell for what I paid - $122. I can send the BOM for the electronic parts if requested. The parts and circuit boards are unopened in their original packaging. I have permission to forward all assembly documentation as well.

fredcassidy · « **Reply #1028 on:** 30 Mar 2018, 04:36 am »

Hi Slefley, I may be interested, what additional parts would be necessary to get the amp fully operational, Transformer and what else? Thanks, Fred

mresseguie · « **Reply #1029 on:** 17 Jun 2018, 08:09 pm »

What damage occurs when a clever fool powers on the amp with just the right channel speaker connected?

I don't know if the left speaker cable leads were touching. As soon as I discovered the mistake, I powered down the amp. Then, I connected the leads to the left speaker. Then, I powered the amp on. Right speaker sounds great, but nothing is coming out of the left speaker.

Is there an internal fuse? Did I fry the left-side portion of the amp?

Any help would be greatly appreciated.

Humbly,

Michael

S Clark · « **Reply #1030 on:** 17 Jun 2018, 09:04 pm »

Quote from: mresseguie on 17 Jun 2018, 08:09 pm

What damage occurs when a clever fool powers on the amp with just the right channel speaker connected?

I don't know if the left speaker cable leads were touching. As soon as I discovered the mistake, I powered down the amp. Then, I connected the leads to the left speaker. Then, I powered the amp on. Right speaker sounds great, but nothing is coming out of the left speaker.

Is there an internal fuse? Did I fry the left-side portion of the amp?

Any help would be greatly appreciated.

Humbly,

Michael

Michael, know that you are not the first to fry one of these. The very first amp that this thread is based on fried the chip, then was repaired, then got fried again when I tried to put it in a metal case. That was fatal. So, these are not idiot proof, as I can attest. Hopefully Jeremy will give you some clues where to begin repair... I'd guess the chip. Good luck.

Folsom · « **Reply #1031 on:** 17 Jun 2018, 10:04 pm »

It would be the chip. But I haven't had any problems running single channels. Try leaving it off for a bit and try again, the internal protection may reset.

The chips can die, but they are pretty hardy, typically.

mresseguie · « **Reply #1032 on:** 18 Jun 2018, 06:23 am »

I opened a bottle of Ordinance Brewing Blackfisk Imperial Stout 9.5% alc. as an offering to the amplifier gods. After allowing them a couple minutes to absorb the vapors, I drank a toast. Then, I reconnected the amp; turned everything on and played some Marc Cohn. All is well.

I'll do my best to make sure that clever fool doesn't blow it again. Thanks, Scott and Jeremy.

Plund · « **Reply #1033 on:** 16 Sep 2018, 02:12 am »

Well, a few months ago I decided it was time to blow the dust off my Folsom amp and Antipole boards and get to building. Last night I reached "first-sound"... a few frustrations aside, building these two boards was a kick in the britches!

Jeremy, thanks for designing and making these jewells available! I decided to up-cycle a salvaged case...I am pleased with how the project turned out. ...I am still trying to figure were to land the winchester drive ribbon cable.

In comparing the Folsom Amp, with Antipole, to a Sure itteration of a TPA3116 (an amp I like), I found the Folsom to carry more weight in the bass and to sound "cleaner". The Folsom simply sounds a step or two closer to sounding "real". The speakers used here were some 3" Peerless full-rangers in a small labrynth enclosure. This TPA3116 is powered with a 5A laptop brick... makes me wonder how it might sound powered with the Antipole or a nice regulated supply.

In comparing the Folsom Amp, with Antipole, to my Pioneer VSX-D912 (also an amp i like), the Folsom made my Pioneer sound a bit rolled-off or even a bit muffled. Again, the Folsom has a "clean", balanced sound. The speakers connected here were MA 7.3 in Frugal Horns.

Jeremy, thanks again. I will keep my eye out for another available Folsom amp board... I think to integrate with a battery supply.

Pete

mzbrahce · « **Reply #1034 on:** 26 Sep 2018, 09:00 pm »

Folsom--Didn't read your notes carefully enough before starting work on the Antipole and mounted all 6 2.2 uf film caps with the same orientation. Couldn't remove the odd 3 without damaging them. Identical caps are back-ordered util January. I'm hoping you can recommend a replacement......
Thanks----------Mark

Folsom · « **Reply #1035 on:** 26 Sep 2018, 11:56 pm »

Show me a picture, you probably did it right.

mzbrahce · « **Reply #1036 on:** 28 Sep 2018, 06:05 pm »

Too late. I've already removed every other capacitor in the line. They were all oriented with the printed side facing the top of the Antipole board, with the board oriented so you can properly read "Folsom Audio."

Folsom · « **Reply #1037 on:** 28 Sep 2018, 08:04 pm »

Those capacitor orientations of the writing, the little gray ones, dont matter, on the Antipole.

WireNut · « **Reply #1038 on:** 29 Sep 2018, 01:50 am »

Hi Jeremy,

I'm interested in building your amp in the future. Hopefully it will be around for awhile.
I currently working on 2 of you other projects.

Folsom · « **Reply #1039 on:** 29 Sep 2018, 03:15 am »

I will update it before I retire it. Updates will just be more refined congruency oh mounting holes or what not.