Folsom's great little 7297 Chip Amp

Folsom · « **Reply #1120 on:** 25 Mar 2019, 07:31 pm »

Sockets I think? Something I was playing with.

Folsom · « **Reply #1121 on:** 25 Mar 2019, 07:33 pm »

Quote from: rockdrummer on 25 Mar 2019, 05:13 pm

Hey everyone. I am waiting on some parts to be delivered, and will need to start layout planning soon. But I am still asking questions.

Up front, I appreciate all the help.

1. Can my divider wall have holes in it? I was going to order a chassis from DIYstore, and use the riser walls to separate the boards. They have a grid of holes pre drilled in them. Will those play the role of divider or do I need a solid sheet of metal for it to do it's job?

2. I see some people are using terminal blocks inside the amp to connect transformers to the boards. Also, I think that maybe where some switches are attached. I wasn't aware of those and wonder if I need to try to use one.

3. Can I use solid core 16 gauge wire everywhere in the amp? Or do i need to use signal wire and power supply wire that is different gauges? Also, I wouldn't know how to choose since I don't know if it matters or not.

Antek transformer wiring and switch/LED questions to come later

Thanks for any advice,
Ben

1. Don't worry about it. Just use what you got and drill when you need.

2. I'm not sure what ones people are using.

3. I'm pretty sure I have the sized that work written in the guide.

KR500 · « **Reply #1122 on:** 26 Mar 2019, 07:35 pm »

Recently I moved my Folsom chip amp up to my dormer room and have been using it for vinyl playback
It is a good match to my ears.

Source is Rega P3 with Elys cart
Bellari tube phono preamp ( with Sovtek 12LPS tube )

rockdrummer · « **Reply #1123 on:** 29 Mar 2019, 07:05 pm »

I'm really liking this project. I have learned a lot from all of your posts, and responses. Also, thanks to ebag4 for his help with my transformer wiring.

I'm ordering resistors from Mouser today for the LED and the capacitor bleeder resistor on the power board.

Does it matter what kind of resistor I order for the cap bleeder application? The large film resistor looks so much different from the metal film ones, as long as the numbers are 10K ohms and 1 watt, does it matter which one i order?

Ben

Folsom · « **Reply #1124 on:** 29 Mar 2019, 07:32 pm »

Doesn't matter

rockdrummer · « **Reply #1125 on:** 31 Mar 2019, 11:44 pm »

Hey, I have capacitors that were replacements for backordered ones on the power board.

They are not lining up for what I think are the proper places for the circles Folsom indicated. They are supposed to alternate sides where the circles are, right?

I am posting a picture because I think it is easier to see than explaining. I circled the same spots that are indicated in the info from Jeremy. And I put a yellow dot where I have leads from capacitors. They are too wide to get them any closer together.

Thanks for any advice.

Folsom · « **Reply #1126 on:** 1 Apr 2019, 12:00 am »

Yellow dots look good.

You can check with a DMM. The dots shouldn't connect with nothing no the board that you're using for the capacitors. If they connect then the holes are wrong.

The spacing is meant to fit those capacitors, so the yellow ones are correct.

rockdrummer · « **Reply #1127 on:** 1 Apr 2019, 12:10 am »

Okay, then I clearly dont understand the circles. I appreciate how many times you have helped me, Jeremy.

Ben

rockdrummer · « **Reply #1128 on:** 1 Apr 2019, 01:02 am »

Every yellow dot on the right has a circle and connects to each other on the right. The ones on the left are all connected but don't have circles. I'm sorry, I don't get it.

Each capacitor end doesn't connect with its other end.

Folsom · « **Reply #1129 on:** 1 Apr 2019, 01:46 am »

I don't follow. Put them in the holes that make them parallel on the board and solder.

rockdrummer · « **Reply #1130 on:** 1 Apr 2019, 01:51 am »

Okay. I must be making this harder than it really is

I was trying to make each capacitor not have a circle on the same end as it's neighbor.
I will go with it.
Ben

Peter J · « **Reply #1131 on:** 1 Apr 2019, 02:27 am »

Hi all. Man, am I ever late to this party! Was fired up and rarin' to go in the beginning, but lost my steam somewhere along the line. Lacro has been checking in with me from time to time and we've agreed to cooperate on finally getting this done. I'll prep the case and then send his way for completion.

Some time ago I purchased these on eBay. I believe this is the one:

https://www.ebay.com/itm/2109-Aluminum-Preamplifier-enclosure-case-amplifier-chassis-BOX-with-heatsink/252933969731?hash=item3ae40a1743:g:kysAAOSwjI5at24A

Me being me, of course I can't just leave it alone, gotta put my spin on it! I modeled the faceplate in V Carve so I'll have a cut file. Been thinking wood or solid surface or maybe just engrave the one it came with, which I've never done. Could look like this:

Cut one from scrap ply to make sure hole spacing was right

Parts are on order, we'll update as things progress.

slefley · « **Reply #1132 on:** 4 Apr 2019, 08:50 pm »

Are the power supply boards and BOM still available?

Peter J · « **Reply #1133 on:** 8 Apr 2019, 01:24 am »

Moving along a bit since collecting all the bits and pieces. Lacro and I have been emailing back and forth figuring a way to get all in this into an almost-too-small chassis. I'm using a combo IEC/switch.

Here are some rudimentary layouts done in SketchUp. Weird dimensions are a result of some metric conversions. There'll be yet another conversion as I'm going to try cutting back panel on router which likes decimals.

Here's "floorplan"

And back panel cutouts. RCAs down low on left, speaker binding posts up high and IEC on right. Bulkhead drawn in for reference.

Folsom · « **Reply #1134 on:** 8 Apr 2019, 01:27 am »

Add the slots between the speaker binding posts, and the RCA posts.

Peter J · « **Reply #1135 on:** 8 Apr 2019, 01:37 am »

Quote from: Folsom on 8 Apr 2019, 01:27 am

Add the slots between the speaker binding posts, and the RCA posts.

Will do. I'll post CAD file once done that will show more detail, including slots. Slots between RCAs as well, huh?

Folsom · « **Reply #1136 on:** 8 Apr 2019, 01:44 am »

YES. The grounds on the RCA sockets need to be able to "see" each other electrically. The results are very nice.

undertowogt1 · « **Reply #1137 on:** 8 Apr 2019, 04:14 pm »

Quote from: Folsom on 8 Apr 2019, 01:44 am

YES. The grounds on the RCA sockets need to be able to "see" each other electrically. The results are very nice.

Hi Folsom,

What does this mean exactly. Are you cutting slots in the metal between the binding post? Do I have that right?

Folsom · « **Reply #1138 on:** 8 Apr 2019, 06:01 pm »

Yes. Just each channel, and each pair of RCA's. The slot can be relatively small.

lacro · « **Reply #1139 on:** 8 Apr 2019, 08:18 pm »

Quote from: Folsom on 8 Apr 2019, 06:01 pm

Yes. Just each channel, and each pair of RCA's. The slot can be relatively small.

Can you point to any discussion or reference material regarding this slot. I am intrigued/curious about the science of it, even though it's probably way over my head.

Is 1mm too narrow for a slot?