Folsom's great little 7297 Chip Amp

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Nahuelitsn

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Re: Folsom's great little 7297 Chip Amp
« Reply #1360 on: 20 Mar 2021, 03:48 am »
I will Folsom!!I will !!! :lol: :lol: :lol: :lol:

Thanks for everything!!

vilding

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  • Musician. Audiophile on a budget.
Re: Folsom's great little 7297 Chip Amp
« Reply #1361 on: 22 Mar 2021, 03:19 pm »
Hi again!
The amp is running smoothly and keeps remarkably cool with the 86-87db 6ohm speakers that are plugged in at the moment.
However, I have a slight ground hum.  You hear it when you're within a little over a foot from the speaker. Would you guys look at my layout and see if there are any obvious mistakes there? Or other ideas?


Folsom

Re: Folsom's great little 7297 Chip Amp
« Reply #1362 on: 22 Mar 2021, 06:23 pm »
Wiggle all your IC's to make sure there is not change. A disconnected ground is a sure way to get a hum.

vilding

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  • Musician. Audiophile on a budget.
Re: Folsom's great little 7297 Chip Amp
« Reply #1363 on: 22 Mar 2021, 10:58 pm »
Ok, so I've been crawling around on the floor, wiggling, reconnecting, changing cables and swearing  :lol:
With just the phone plugged in to the amp, it's dead silent. The biggest cause of noise seem to be the dac, or it's power supply. When everything else is plugged in (dacs ic's still connected to preamp) and I pull the wallwart for the dac, almost all noise disappear. This kinda sucks since my listening is probably 75% through that thing.  :cry: Any ideas..? Been trying to read up some on grounding but don't really know what to make of it.

Folsom

Re: Folsom's great little 7297 Chip Amp
« Reply #1364 on: 23 Mar 2021, 12:17 am »
So a loop is forming through the DAC.

Does the DAC have a 3 prong?

vilding

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  • Musician. Audiophile on a budget.
Re: Folsom's great little 7297 Chip Amp
« Reply #1365 on: 23 Mar 2021, 10:27 am »
No, it's a two prong double insulated little wallwart.

Folsom

Re: Folsom's great little 7297 Chip Amp
« Reply #1366 on: 23 Mar 2021, 12:13 pm »
You could try this on the amp's ground between the socket and chassis. It'll reduce common mode noise, and ground noise.

You can test if it'll work by disconnecting the ground temporarily.


vilding

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  • Musician. Audiophile on a budget.
Re: Folsom's great little 7297 Chip Amp
« Reply #1367 on: 24 Mar 2021, 09:52 am »
Thanks! Will try but it'll have to wait until I need some more stuff from Mouser, or it will be one expensive little coil.  :icon_lol: I'm gonna try and troubleshoot using the guide from DIYA-member Bonsai. Simple enough even for me...  :P Listening to some Chris Potter on vinyl rn and the amp is dead quiet between tracks and sounds scary good.

SGI

  • Newbie
  • Posts: 1
Re: Folsom's great little 7297 Chip Amp
« Reply #1368 on: 30 May 2021, 07:04 pm »
Anyone has another 7297 amp board / antipole board for sale?  My friend just built mine and he was testing it out w/o even fully broken in and now wants one!  :)  Please PM me or email me if you do have one.  Thanks!

Terry U

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Re: Folsom's great little 7297 Chip Amp
« Reply #1369 on: 10 Jun 2021, 09:09 pm »
I have a kit for a complete 7297 amp minus the case that I am looking to move on.  I do not want to separate the boards however.  Might you be interested in this.   terryu55@comcast.net