[Nahuelitsn]

I will Folsom!!I will !!!

Thanks for everything!!

[vilding]

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]

Wiggle all your IC's to make sure there is not change. A disconnected ground is a sure way to get a hum.

[vilding]

Ok, so I've been crawling around on the floor, wiggling, reconnecting, changing cables and swearing 
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.  Any ideas..? Been trying to read up some on grounding but don't really know what to make of it.

[Folsom]

So a loop is forming through the DAC.

Does the DAC have a 3 prong?

[vilding]

No, it's a two prong double insulated little wallwart.

[Folsom]

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]

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.  I'm gonna try and troubleshoot using the guide from DIYA-member Bonsai. Simple enough even for me...  Listening to some Chris Potter on vinyl rn and the amp is dead quiet between tracks and sounds scary good.

[SGI]

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]

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

[drew_t]

I finished my build a couple of years ago at least. It's alternated between sitting on a shelf unused and being hooked up to one of my computers -- most recently the latter,  powered up for at least a few months 24/7. I noticed that the power LED was off yesterday. I checked the fuse, saw that it was blown, put in another one, turned it on, the power LED lit up, but I immediately heard a "zzzzttt" sound that lasted about a second, and the LED slowly faded out. 

I have never pushed this amp even remotely hard; it has not been exposed to power surges; it has not been dropped, gotten wet, or anything like that.  There are no scorched wires, burned components, leaking caps, bad smells, or anything else obviously amiss.  The power transformer is one of whichever Antek toroids were recommended. The fuse (same one that has been in it from the start) is a 1.6 amp one. I used one of the combination IEC socket/power switch/fuse holder deals (I know, I know, it's not a boutique audio-type part) and built the amp in an old computer case. 

Any ideas what the issue might be?  Could the Antek have just crapped out?  Should leaving the unit powered up for an extended period of time with the sound source (computer) asleep have done any harm?

[lacro]

I suspect the IEC socket/power switch/fuse holder. Try disconnecting the Antec toroid from it's primary and secondary and power the primary with a different 120v source power cord, then check it's secondary output voltage (16-18v).

[ctviggen]

Are these still for sale?  If so, where?

[EJHickert]

Hi there! I have just joined Audiocircle and heard about this great little chip amplifier from GR research. I have searched on google for the circuit designed by Folsom with no success.

I would really appreciate it if someone could point me to the right location where I can purchase the circuit board and a really good power supply to run it.

Thank you in advance!

Eric

[Folsom]

Sorry I don't have any boards.

[pbzepplin]

Hey everyone,

I am new here just got a pair of XLS encores built up. They are pretty exciting speakers and I was looking for DIY an amp to get the most out of the speaker. I hear these chip amp's might be a good pairing. Any idea on where to find a board or recommendations for a different DIY AMP that would pair with the XLS encore?

Thanks,

Steve

[PeterC]

Can someone let me know where I can find the parts list and instructions to build the amp and power supply?

I have both circuit boards and have decided I should do something about it.

Thanks...