Folsom's great little 7297 Chip Amp

Peter J · « **Reply #1160 on:** 16 Apr 2019, 07:13 pm »

Quote from: lacro on 16 Apr 2019, 03:01 pm

I vote for all black. I like it's subtle (KISS) statement. However, I would add 1-1.5 mm holes (eyes) on both sides of the head with the rear of the panel counter-bored to 3mm to receive 2 red LED's. When powered on the red eyes will draw attention to the subtle black image.

Your wish is my command...almost. I redrew "the bug" to keep more with original concept...the head just got too busy. Eye holes will cut as cones about 1/8" deep and I'd drill hole diameter of LED in bottom. Would sort of illuminate the pocket.

If you give me thru hole diameter and depth so I can cut backside pocket, I'll give it a go.

lacro · « **Reply #1161 on:** 16 Apr 2019, 11:03 pm »

I love it! But it's your build, and if a colored bug is your choice, go for it. PM sent for suggested dimensions.

Peter J · « **Reply #1162 on:** 18 Apr 2019, 01:36 am »

I just can't leave stuff alone, I guess. Seems one thing always leads to another. Today I made this. Black Corian and a makeshift lighting arrangement for demo.

mzbrahce · « **Reply #1163 on:** 22 Apr 2019, 06:19 pm »

Folsom--

If I'm running your amp with the Antipole, is there any benefit in also using your Fo-Felix?

Folsom · « **Reply #1164 on:** 22 Apr 2019, 07:28 pm »

Yes, it does help clean up the sound a bit more. It stops some noise from getting into the enclosure, for example.

rockdrummer · « **Reply #1165 on:** 23 Apr 2019, 05:25 am »

I have made lots of progress, not without a couple snags.

I spend most of my build time double checking design ideas so I don't overlook anything.

I have the binding posts wired, started the rca inputs. I am using the cardas inputs and they were really challenging to solder the ground as they have a goofy collar instead of a tab. Tomorrow I hope to finish connecting input wires, install the mica and heatsink, and get a finalized plan for the LED wired off the aux output of the power board.

Ben

Folsom · « **Reply #1166 on:** 23 Apr 2019, 05:29 am »

You have a heatsink for the chip, right?

Also, I hope you didn't drill the board for the speaker binding posts wire.

rockdrummer · « **Reply #1167 on:** 23 Apr 2019, 05:38 am »

Folsom, thanks for the reply. Yup, I have a heatsink, and no I didn't drill the board. I went back and forth trying to plan steps to best install the wires and heatsink.

I tapped the sink last week and I will get that installed tomorrow, I hope.

Folsom · « **Reply #1168 on:** 23 Apr 2019, 07:46 am »

rockdrummer · « **Reply #1169 on:** 24 Apr 2019, 12:21 pm »

Hi, here is my layout. I went back and forth with the psu position. I originally had the antipole backed up the same way but with the capacitors on the front side of the chassis. This ran the ac wires as far away from the amp board as possible. But I decided to change it. Adding the LED and testing are left.

Ben

Folsom · « **Reply #1170 on:** 24 Apr 2019, 05:16 pm »

Looking good. People will probably think it's a much more powerful amp than it is, purely by size!

Hirst · « **Reply #1171 on:** 24 Apr 2019, 09:36 pm »

If you have not done so already, remember to cut a slot between the posts, see pictures in previous page.

Paul

Folsom · « **Reply #1172 on:** 24 Apr 2019, 09:47 pm »

Quote from: Hirst on 24 Apr 2019, 09:36 pm

If you have not done so already, remember to cut a slot between the posts, see pictures in previous page.

Paul

It's not required, but it sure is a cheap and effective upgrade.

rockdrummer · « **Reply #1173 on:** 24 Apr 2019, 09:54 pm »

Yes, the size is totally overkill isn't it?

I'm regretting not cutting those slots. I didn't do it. To be totally honest, I was so focused on cutting out the large neutrik cutout for the power cord, and cutting for all the holes, I completely forgot. Head slap after I was going back and looking through the thread.

Ben

rockdrummer · « **Reply #1174 on:** 27 Apr 2019, 07:27 pm »

Hello, okay, this is the toughest part for me. Troubleshooting. I finished my amp, and since I'm very uninformed about testing circuits and basic knowledge to navigate such subjects, I opted to fully build then power on.

Did that, and my led didn't light up. No pop, or smoke, but no sound either. When measuring the ac into the psu, I get .003 volts on my meters auto range. So, I suspect I didn't hook up the transformer correctly.

I am using an Antek as 1215 which has been used by others in this thread.
Ben

rockdrummer · « **Reply #1175 on:** 27 Apr 2019, 07:36 pm »

I have a feeling I don't have the correct blue and green wires out of the transformer.
Ben

lacro · « **Reply #1176 on:** 27 Apr 2019, 07:52 pm »

Quote from: rockdrummer on 27 Apr 2019, 07:36 pm

I have a feeling I don't have the correct blue and green wires out of the transformer.
Ben

The AS1215 is a 15V transformer. You need 16V to power the Antipole. You should have got the AS1218. I don't know how well it will work with the lower voltage transformer.

To wire it for 120v: For the primary side, use the 2 red wires for one leg, and the 2 black wires for the other
leg. The purple wire goes to chassis ground. On the secondary side do the same, tie the 2 green together, and tie the 2 blue together.

rockdrummer · « **Reply #1177 on:** 27 Apr 2019, 08:13 pm »

Okay, I was under the impression that I should only use one green and one blue. I do have the black and red combined correctly. I was trying to follow some other builders who have used the 15v.

Thanks for the response. I will resolder the combined blue and green.

Again, I appreciate it.
Ben

Folsom · « **Reply #1178 on:** 27 Apr 2019, 08:17 pm »

15v will turn on but bass and gumption in general may be a bit (or lot) more limited.

borism · « **Reply #1179 on:** 27 Apr 2019, 08:18 pm »

Yardbird (p54) used an AS 1215 and got about 20V from the power supply board. He later changed to the 1218 transformer.