[hsnam]

hi everyone, it's been a while--first year in med school leaves little time to tinker with anything!

anyway, this summer i had built --with much help from everyone here--an amp based on Kevin Gilmore's design, using good components, e.g., hand-matched vishaydale resistors, wima caps, nobel pot, etc etc. i had also designed the pcb for a power supply and built it to use with the amp. now, the amp works, but since it was my first DIY project, it lacks polish (and i still haven't mounted everything onto a proper box). if i were to sell the power supply + amp combo in its current unpolished state, do you think anybody would want to buy it?

 

[aos]

Cool, another person who has built Kevin Gilmore's amp

. Why are you selling it? Mine sounds wonderful, and I doubt you'll be getting anything much better than it. With a good power supply it's pretty much (one of) the ultimate headphone amp(s).

If you can find someone who has no problem with drilling holes and making cutouts but is shy of soldering iron, they might be interested in buying it. But even people who don't mind soldering can find it useful, as getting all the parts, assembling and troubleshooting takes time and patience...

 

[Apheared]

but since it was my first DIY project

Ambitious. And that power supply board was your 2nd? Yeow.

And you want to sell it? Is it a money thing or is it a lazy thing? Or is it you just don't know how to put it in a case?

I was just thinkin about you, I had to go dig up a link to your iDisk account for ppl's portable schematic...

 

[Budgie]

Strangely enough, I have a couple of unused project boxes, with no guts to go into them. Maybe we should talk?

 

[hsnam]

yeah, ambitious, i hear that word a lot about my attitude.

Budgie:
next weekend, i will post some pics of the amp. then you can decide if you want it.

anyway, the reason i'm selling the old one is, i want to make a (cosmetically) better version of the amp and also add KGilmore's ultra-regulated power supply. since i don't want to gut out the components, and i don't need a 2nd headphone amp at the time, why not sell it to somebody who wants one?

at the moment, the power supply and the amp are on a separate pcb. with all the cables between the line-in, headphone out, ground-breaker, etc, the amp looks too busy.

since i don't have much time to tinker with things, i thought i'd build over this thanksgiving the "ultimate" amp that i can use for the next 12 months or so.
the new version of the amp would have
1. a new pcb which contains both power supply and the amp
2. separate xformer for each channel (this might not fit in the case)
3. attenuator instead of pot
4. better line-in connector, etc

anyway, any other suggestions are welcome!

 

[Serow]

Would you consider making an extra PCB for me?

I'm looking to build this amp this summer, but I don't have any of the equipment for making PCB's.

 

[hsnam]

sorry, i can't do it anytime soon.
mainly because the holes are very small and it's a pain to drill them. (i ruined all my drill bits on one board!) i can etch them and sell you that, but drilling holes is too much.

 

[Budgie]

If you want to e-mail them to me, thats fine also. Your choice.

 

[Apheared]

==========
sorry, this thread was running away... the drilling discussion has been moved to:

http://www.head-fi.org/forums/showth...&threadid=3453

To the topic at hand, do we have any offers on hsnam's KGilmore board?

-Apheared
==========

 

[Budgie]

I have PM'd him to ask what he thought a fair price would be. Have'nt heard anything from him. I presume he is busy or thinking about it or something.

 

[hsnam]

hi,
the photos can be found here:
http://homepage.mac.com/hyungsongnam/PhotoAlbum4.html

i'm sorry about the blurry close-up images. the camera cannot focus well at such range.

as you can see, i never quite finished it--was never drilled a hole for the headphone jack, etc...

 

[Possum]

Your PCB's look very cleanly made. I don't recall what it was that you used to transfer the layout to the boards (I'm a bit too lazy right now to look it up). Was it the fluorescent light technique? Where did you obtain the materials used to transfer the layout to the board?

 

[hsnam]

i used a pre-sensitized PCB. a bit expensive, but it worked well for me.

I printed the PCB layout on a transparency X4, make a sandwich like this:
glass plate, transparency X 4, pcb. then hold the sandwich together with one of those black paper clip things.

expose with low wavelength UV light (well, I'm close to labs, so i have easy access to that) for like a minute or so

NaOH for couple of minutes,,
then ammonium persulfate at 37 deg for 30 min or so...