Folsom's great little 7297 Chip Amp

Folsom · « **Reply #880 on:** 15 Sep 2017, 04:00 am »

Well you certainly need a thin tip for the iron.

undertowogt1 · « **Reply #881 on:** 15 Sep 2017, 04:36 am »

OK, I will have to pick one up, mine is a little too big I guess. Thanks Folsom, this amp is already a blast to build.

Another question, why do I have 5 INSUL SHOULDER WASHERS? I know 1 is for the Chip and bolt, where do the other 4 go (or are they not needed)

Folsom · « **Reply #882 on:** 15 Sep 2017, 05:42 am »

Oh, I guess I could reduce those. For awhile they were useful for the mountain screws, on the old boards.

drmike · « **Reply #883 on:** 16 Sep 2017, 04:44 pm »

hello,
where can the epcos 2.2 uf caps be bought?
thannks,
drmike

Folsom · « **Reply #884 on:** 16 Sep 2017, 05:28 pm »

http://www.mouser.com/ProductDetail/EPCOS-TDK/B32560J1225K/?qs=%2fha2pyFadui2wUXthMXfNAix%252baxXKxYxqvjE9tkd0sVFEXD4CLkiBw%3d%3d

Did you not get the BOM?

pocomo · « **Reply #885 on:** 18 Sep 2017, 01:01 pm »

New Build working

Build is basic, using the standard BOM (++ Jantzen input caps) in a Galaxy 3U case from the DIYAudio store.

This was to be my first amp building project, but when I actually looked at the soldering skills required I was not up to the task. I researched a bit and found Radu Tarta of CT who usually builds very nice DHT amps who did a great job for me. You can reach him through his project blog: https://simplepleasuretubeamps.wordpress.com/projects/.

Still breaking in, but so far the sound is very, very good. Especially at low levels where you can still hear detail and dynamics which I really enjoy. Bottom end is full, tight and detailed; top end is shimmery yet sibilance is perfectly controlled (pet peeve of mine). Great job Jeremy.

undertowogt1 · « **Reply #886 on:** 18 Sep 2017, 02:35 pm »

Look very nice pocomo.

Thanks for the pics. What is that "extra" piece above the PSU?

pocomo · « **Reply #887 on:** 18 Sep 2017, 02:47 pm »

Thanks!

That's a thermistor-controlled chassis ground connection, which can be easily removed if there are problems with ground loops. This was Radu's little innovation.

limits · « **Reply #888 on:** 18 Sep 2017, 03:59 pm »

Looking good, pocomo

enjoy!!

limits

undertowogt1 · « **Reply #889 on:** 19 Sep 2017, 03:14 pm »

So I discovered I made a small error when ordering the heat Sink for my amp. The heat sink "fins" will be running horizontally when I attach it to the chip (due to chassis height) . I realize now that I should have ordered a size allowing me to have the fins running vertically. I was planing on having he heat sink inside the case and NOT mounted to the back of my chassis but I can always change that idea or cut the heat sink

So overall is this an issue if the fins are running horizontally? or should I cut to size?

Here is the link to the one I have now
http://ca.mouser.com/ProductDetail/Wakefield-Vette/557-140AB/?qs=%2fha2pyFaduiG2q9R1p1wFwcJKjK4nkUZWllLfOfAWOG%252bC6PYgLkYRQ%3d%3d

Folsom · « **Reply #890 on:** 19 Sep 2017, 03:44 pm »

Verticle works much better if it has airflow on top and bottom. You could use a silent fan.

undertowogt1 · « **Reply #891 on:** 19 Sep 2017, 03:54 pm »

Quote from: Folsom on 19 Sep 2017, 03:44 pm

Verticle works much better if it has airflow on too and bottom. You could use a silent fan.

I figured vertical is the way to do it properly. Will it work as needed horizontally, I will have airflow side to side?

Folsom · « **Reply #892 on:** 19 Sep 2017, 04:25 pm »

No air really flows side to side unless you force it. Up and down is convection.

It'll work but you may want to monitor it because if it gets hot you lose power.

S Clark · « **Reply #893 on:** 19 Sep 2017, 04:28 pm »

Why not take a Dremel and a cutoff disc or a hacksaw and cut vertical slots? It will reduce mass a bit, but increase air flow.

BRN · « **Reply #894 on:** 19 Sep 2017, 05:13 pm »

pocomo,

That is a very nice build. I'm going to build my second amp, when I can find the time, with the new boards and was looking at a chassis and like the one you used. What are the dimensions and did you have to cutout the opening for the IEC inlet?

By the way my original build was with the stock BOM with the exception of Nichicon caps. The amp sounds great and I still never feel the need to change it like I do with other gear in my system.

Thanks,
Brad

undertowogt1 · « **Reply #895 on:** 19 Sep 2017, 05:18 pm »

I am really new at this, but wouldn't the easiest solution be to cut the heat sink to fit my case, then rotate it. I did a crazy paint drawing to illustrate what I would do so there is not confusion ( I hope)

OR after cutting would the heat sink be too small to be useful?

pocomo · « **Reply #896 on:** 19 Sep 2017, 05:50 pm »

@BRN

Hi Brad -

There are a lot of choices on the DIYAudio store https://diyaudiostore.com/collections/chassis; we chose the biggest Galaxy 3U at 330mm x 280mm which gives plenty of room for layout plus height for heatsink clearance with a still pretty reasonable overall footprint (~ 13"w x 11"d). Radu did punch openings for connectors and the power switch but I believe you can order them pre-cut.

Good luck with your next build!

Hirst · « **Reply #897 on:** 19 Sep 2017, 10:09 pm »

This is an excellent and easy build for those with "hobby" level skills. My soldering station crapped out on me and I had to use an old and abused 30 watt soldering iron without any special tips. No, it was not pretty but there is ample room on the board. The PSU is even easier. I would not recommend the iron that I used. The layout is very accommodating so do not be intimidated and grab this amp/psu, order the parts and have some fun.
For those like me that have to be careful where their funds go I ended up using an old computer case. No pictures as this is version 1 and I still have to replace the face.
The sound is incredible and the power is more than ample. I have the gr research X-LS speakers in a 13' x 15' room and the volume adjustment is at 12% for casual listening and I anything over 25% is uncomfortable. I did have to buy an inexpensive DAC as my music is played through an old "business" PC with on board sound.
Buy two kits and give one as a Christmas gift.

undertowogt1 · « **Reply #898 on:** 21 Sep 2017, 03:46 pm »

Quote from: S Clark on 19 Sep 2017, 04:28 pm

Why not take a Dremel and a cutoff disc or a hacksaw and cut vertical slots? It will reduce mass a bit, but increase air flow.

I took your advice SClark. Man is my arm tired

undertowogt1 · « **Reply #899 on:** 22 Sep 2017, 06:09 pm »

Hi All,

Another question from the newbie. I am in the process of wiring the RCA signal input to the amp board. Looking at the board I see L SG R by the input section. How do I know which holes to use for the ring and the tip of each RCA jack?