[lacro]

I'd say lacro is being a little modest here, this compact and clean layout was mostly his brainchild. Between us, we managed to put "twelve pounds of potatoes in a ten pound sack".

While doing this he also checked fit for most recent amp board which I understand is longer. It would indeed fit, but I'll let him speak to the details should someone else decide to use this particular case.


Should be plenty of heat sinking there, no?

The Chinese 2109 case really is a great choice for the Folsom amp. I did check the fit with the latest, longer Folsom amp board, and it will work with the transformer shoved into the front corner. I checked with Antek, and was told it's OK to have the transformer touch the sides. The fact that the case already has a heat sink, there is no need to buy the one listed in the BOM which comes to about $16 total for the heat sink, cutting charge, and shipping.

The case is easy to work with as front, back, sides, top, and bottom are all separate pieces making for easy interior access by removing one or more pieces.

Can't wait to see Peter's custom front panel installed.

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

[WireNut]

Hi Jeremy,

I was looking at the BOM and noticed the two options for the 12 aluminum polymer caps are 560uF or 330uF.
The Panasonic's are 560uF, 20 volt, while the Nichicon's are 330uF, 25V.
Are they suppose to be the same uF value, typo maybe?

Thanks.

https://www.mouser.com/ProductDetail/Panasonic/20SEPF560M%2bT?qs=%2Fha2pyFaduhzHJzzPX6Io3y3EIFd0mSHh3UAKFhbYh3cwIQ7io48SQ%3D%3D

https://www.mouser.com/ProductDetail/Nichicon/RNU1E331MDN1PH?qs=%2Fha2pyFadujVIAFfwoA35%252B2IYhgmyzi0EJJlJz5ifHvhjFt2xEOB3w%3D%3D

[Folsom]

No. Nichicon doesn't offer as big of value, but they have a different sound.

[drew_t]

I was about to order the rest of the parts I need to finally finish my Folsom amp, but the six film caps for the power board -- https://www.mouser.com/ProductDetail/871-B32560J1225K -- are out of stock.  (This is the part # I had in my project list on mouser.com; not sure if they're the ones originally specified or a substitute which at some point was suggested.)

I did a search for a part with the same specs, but it doesn't look like they have anything.

Is there anything that will work that is currently in stock at Mouser?

EDIT:
Would the version of the part rated for 40VAC/63VDC work?
https://www.mouser.com/ProductDetail/EPCOS-TDK/B32520C0225J000?qs=Xovllr2ZOuYQ7EvLeHnsdg%3D%3D

[Folsom]

There are alternative part numbers in the Antipole build notes.

[Peter J]

The following is minutia that has little to do with the actual amp, but it's fun for me because I learned some new things about LEDs and light fiber. I thought y'all might like it too.

 What I was after was to illuminate the eye sockets but not have piercing little LEDs staring back at me. Conclusion is no matter how much I dimmed the tower LEDs in the 2mm holes it was still more intense than I wanted. It seem to me it needed not just dimming but diffusion. Next step was 2mm light fiber which I've never worked with either.


The setup





The result. Still not what I'm after






I filed ends of fiber, stuck in holes from rear and ground flush









After more experimenting, I cut a little piece of clear acrylic and stuck LED into side.






Applied black out tape

 



To end up here.





I'll tidy things up, but it looks like I wanted now. I'll probably have nightmares about bright eyed dragonflies...

[WireNut]

That is wicked, I love it 

[WireNut]

Looks like you went with a simpler toolpath with a small ballmill. Looks great.

Peter J. You are very talented. Not many have your skills. Keep up the good work.

[Peter J]

Thanks Wirenut. I actually used a 60° V cutter, but did spray with conversion varnish which probably makes the bottom of carving look rounded.

Made a mo' betta acrylic block, sprayed all but bottom side with texture black, glued in place, cleaned up wiring and Bob's your uncle. Lacro left a connector for me to plug LED into. I need to get a preamp figured out so I can listen to it!










Forgot to mention two people who were instrumental in getting this done. Lacro, take a bow.


Also Nick at          https://lighthouseleds.com/    who answered my many LED questions and supplied the LEDs and fiber optics.

[Folsom]

Definitely build Keantoken’s buffers with a chinese DACT for volume. 

[limits]

Looking good, Peter J!!

What Folsom said...or...https://www.diyaudio.com/forums/pass-labs/313612-b1-korg-triode.html --I have both, and they are both great solutions.

Either way, use the exact same case for the pre, etch a mosquito on the faceplate, and stack the pre on the amp. Then Bob really is your uncle! 

[Peter J]

Definitely build Keantoken’s buffers with a chinese DACT for volume. 

Jeremy, give me clue man. Where will I find Keantoken and his buffers?

[Folsom]

https://www.diyaudio.com/forums/analog-line-level/251413-kuartlotron-keantokens-simple-error-correction-superbuffer.html

I haven’t heard the Triode B1, but I have a board and NuTube.

[Folsom]

Looking good, Peter J!!

What Folsom said...or...https://www.diyaudio.com/forums/pass-labs/313612-b1-korg-triode.html --I have both, and they are both great solutions.

Either way, use the exact same case for the pre, etch a mosquito on the faceplate, and stack the pre on the amp. Then Bob really is your uncle! 

Or a lizard?

[limits]

Or a lizard?

Ooohh, I like it...the hunter becomes the hunted...

I live in northern MN, where in the spring we have a literal armada of dragonflies patrolling the forest clearings for those pesky mosquitoes. So, from my perspective, the dragonflies are on the prowl.

You should build it, Folsom (the Korg B1). I just used the stock parts and it sounds great. My NuTube is very microphonic (high pitched ringing), but once isolated, it is great. Really easy build, too...


limits

[WireNut]

Is this what you guy's are talking about?

B1 Buffer with Korg Triode PCB + Fairchild JFETs

https://diyaudiostore.com/collections/kits/products/b1-buffer-with-korg-triode-pcb-and-jfets

[limits]

Is this what you guy's are talking about?

B1 Buffer with Korg Triode PCB + Fairchild JFETs

https://diyaudiostore.com/collections/kits/products/b1-buffer-with-korg-triode-pcb-and-jfets

Yep, that's it, WireNut. 

limits

[Danny23]

Or a lizard?

@ Folsom - Would you mind providing a comparison between this 7297 chip amp, and your new 7293 chip amp?  How are they similar, and how are they different?  Will the new 7293 have a battery option?

I haven’t seen much about the 7293, other than the GB on the other site.  Thanks!

[Folsom]

It's better. It does everything better. It's a lot more power. You can't battery power it because it needs +, PG, - power supply. It also needs a higher minimum voltage for the regulator to work that provides power to the LED board (that shines on the PVI cells and powers the feedback much more stable than the PSU and any regulator can). We provide a BOM that includes PSU stuff that's tuned for the Antek transformer that's a great fit. The Antek is nice because at 200/300VA they have a shield between the primary and secondary that keeps RF down.

This amp is kind of special given that the front end is totally discrete. OPAMP front ends have clamps, protections, compensators, etc. They are the type of things a lot of people want to avoid (even when they're benign) in audio. You can also tune it by swapping around a couple of the caps that deal with signal.

Overall it employees a lot of the same PCB stuff we did with the 7297, but it's even better. It's got CFC, copper pours, tracing for signal that reduces field sizes, etc.

[zek]

Some link for new 7293 amp, please.