DIY Electronics???

[Modvlar]

Hi,

Wondering if anyone is doing any DIY hardware projects (for example, amplifiers, preamps, mixers, etc). Any successes?

Kits tend to be either too cheap, or too expensive it seems.

Just finished a smallish simple but overbuilt (to my specs) headphone amplifier. Works fine. Uses a 4881 Boomer chip. Sounds pretty good, but noticibly harsh mids from such a cheap chip (but good output levels). May consider attemptiing a burr-brown version at some point, possibly driving a fet output. (like a mini power amp). Lots of luxury recording studios replace the op-amps in their mixers to the BB type.

[michael_w]

You'd probably have a ton more luck over at Diyaudio.com. They do this kinda stuff all the time.

I myself stick to speakers when it comes to diy...

[Modvlar]

Yup, been there done that too.

Built a few pair of speakers; some big, some small, all with varying success. Never completely satisfied. May attempt "the final" pair some time in the long future. The only part I hate is the finishing (vaneers and glues).

Just looking for some new fun project ideas. Will take a peek at DIYaudio...

[phoneisbusy]

www.headwize.com might be of interest to you too.

regards

Dave

[ian1386]

I too was in need for a headphone amp, but I got really irritated since I have ALL of the parts already except for the IC itself, which means that in order to order it online I'd have to pay like, $10 shipping for a $4 part, which pisses me off. I then remembered that I had some cheap pc speakers I was just about to get rid of since only one channel worked. They already had a headphone output, and so I ripped them open, stole the board out of it, attached some rca jacks instead of the miniplug, and everything worked fine. The quality out of it is actually very very good considering how bad the speakers were themselves.

Now I'm pissed off though, because it seems The Source (the new ****ty store that used to be radio shack) no longer has a project box that will fit the board (2.5"), and so I don't have anything to put the damned thing into. I WOULD just leave it open, but since I'll be leaving it in my home theatre rack I wanted a nice little black box so that it would look nice (I'm using it ONLY as an amp for my XRT12 tuner, since there is no built-in headphone port and i like listening to it with headphones while my wife watches TV).

[cmy330go]

Is it a CMOY like this?

http://www.polkaudio.com/forums/showthread.php?t=35083

[Modvlar]

I was looking at the cmoy, a high-quality FET type scematic, bought a PA2v2 (....something like personal amp, or portable amp...) just because it looked like a more thought out design (comes with a charger too), and is pretty well made, except the pot in mine is a touch crunchy. Works well with my discman. The guy who makes them lives nearby, and does it as a homebrew buisness (www.electric-avenues.com, i think).

At the same time while was looking at the PA2v2 (and others), I did my own research, and thought it looked like an easy project to do, plus easy to upgrade some ratings.

The picture is of the guts, I haven't shot a picture of it closed up yet, will toss it in next time. Did turn out well, dead quiet, high enough output. Just find a $0.50chip a bit too harsh in the mids. Having a strong 5v regulated power supply, ferrite filters, and huge output capacitors helps. I had bought film caps for the inputs, but didn't put them in for some stupid reason.

Was fun to do. Hate cutting/drilling/filing metal though, but this time wasn't so bad.

BUT, after all that, I ran into the same situation as ian1386. Spent $30 bucks on a variety of parts (including 2 boxes) with several trips downtown, then looked in my closet and found something that works much better. I have enough spare parts to build a second (almost).

[phoneisbusy]

Hi ian1386,

A lot of electronic shops will have similar project boxes. Are you in Canada? I think only the Canadian RS got renamed. Active Electronics comes to mind. You might also consider other sources for a box. Some craft stores have wood boxes for jewellery and such that would look very nice stained and finished. Heck, some fancy cookie boxes and tins have potential. heh...

regards

Dave

[Modvlar]

Active Electronic/Component tends to be quite overpriced, although they occasionally have better quality parts. Daiwa Semitron is where I got mine, and everything is decently priced. Supremetronic also is good, but they just moved to the middle of nowhere. There's a whole bunch of shops south of Vic Park and Steeles. Just have to explore around there.

[phoneisbusy]

Vic Park and Steeles... that I'm guessing puts you in and around Toronto?
Vancouver doesn't have as many shops but there are some. Exploring is fun though. ;)

regards

Dave

[ian1386]

I know that there are a lot of things that I can put my amp into, but since I just want to leave the amp as a permanent fixture in my rack, I want to find something other than a mint tine to put it in :)

I liked the suggestion to look in craft stores...never thought of that....but unfortunately there aren't any electronic stores around here (Kitchener/Waterloo) that I know of.

I was also thinking that, since my headphones have a volume control right on their cord, I could just leave the amp hidden away somewhere set to a loud volume, and then get a headphone extension cable so that just the extension cable plug is visible...but I'm not sure yet...

[ian1386]

Also, "exploring" is tough for me, as I'm a poor student with nothing but a KW bus pass :)

[phoneisbusy]

Have you considered dumpster diving? I've salvaged some nice enclousure from the IT dept. a few times. Old scsi units or external hard drive cases have potential. Maybe check the computer stores? The external 3.5 drive bays are pretty slick looking and cheap these days. I'm betting they have a few around UofW. :)

Welcome btw.

regards

Dave

[cmy330go]

Here is a link to some project boxes and parts express.

http://www.partsexpress.com/webpage....ctGroup_ID=208

Just a thought.
Dave

[Modvlar]

Hi,

Yup, I'm in Toronto... and depressed about it.

Haven't seen them for a long time, but at one point Daiwa used to carry true rack-mount cabinets. I had used a half-sized version for a passive preamp (of course, no amp whatsoever). Nice anodized black.

Dumpsters are wonderful. Got a ton of great art supplies from some.

I completely forgot about Electrosonic!!! A huge mail-order electronics parts store here, with a huge catalog. Maybe you can find something with them.

[mhardy6647]

This is the one I built, designed by Pete Millet:
http://www.pmillett.com/hybrid_head.htm



Cute, fun, inexpensive, sounds good, and no pesky high voltage B+ to kill you. It uses low plate voltage "space charge" tubes developed for car radios in the late 1950's.

An upscale version was developed by some folks associated with Head-Fi:
http://www.diyforums.org/millett.html

[schwarcw]

Nice job! Did you buy this as a kit? How much did it cost you!

[Modvlar]

Well, I guess if we're having a slideshow...

Here's the finished front of my box....

[Stew]

I change opamps in my Yamaha CDC-745 cd player. AD843 for I/V and AD8620 for output buffers proved to be the magic combination. I found lots of good info and help at diyaudio.com.