[dasmodul]

Hey guys. Do you know of any great first time DIY amp kits for someone who's never built one before? Meaning it comes with good directions? I've got a pair of Senn HD595s and a AKG 702 on the way and wanted to supply them with some decent power while I save up for a class-a amp like the Grace m902 or something. Thanks!

 

[jageur272]

Check AMB's Site for some great designs. The Mini^3 is a great place to start. A CMoy is another great starting point but doesn't quite come in kit form. However, these are both portable amps and have their limitations. However, they're a great place to start.

 

[Uncle Erik]

The best place to start is usually the CMoy.

I don't know if kits are offered, but the CMoy is extensively documented and you'll be able to get any question answered in the DIY Forum. Ordering parts isn't difficult, either. Besides, a lot of terrific projects aren't kits.

If you like the CMoy, then don't bother with commercial amps. If you enjoy building, put together something like a Beta22 instead!

 

[dasmodul]

I'm definitely the kind of person that if I can build it, I would rather custom rig it myself that buy commercial. Just have never taken a jab at audio electronics before. I'll check out the Cmoy and see what tools I need to get for it.

 

[linuxworks]

I skipped the cmoy 'stage' and started with a tangent amp (pimeta). it was easier since it has a pc board and it jumps right to a nice midlevel of 'fi'. quite low cost, too, as no expensive parts are needed and it can take 'any' op amp, basically.

 

[dasmodul]

Read the initial Cmoy intro and looks good. Gonna order some soldering pens etc. to get started. Do you guys recommend any books for 'understanding' electrical diagrams and what the connections do, etc? I'm going to be pretty much following Cmoy directions blindly without understanding how everything works this time, but would love to learn.

 

[MisterX]

The link below should get you started.

Lessons In Electric Circuits

 

[dasmb]

The PIMETA is a good amp if you just want to solder and listen. But if you truly want to learn electronics, CMOY is the way to go. I've tried to pick up audio DIY a dozen times in my life, having grown up helping my dad fix radios and televisions, and the only result was a lot of expensive broken valves and transformers. The first truly successful project I ever built was the CMOY. It's cheap, it sounds great, there's lots to customize, the circuit's simple enough that you will memorize it and once you understand it, you'll be in a much better position to understand what the more complex amps are doing.

Everything you need to understand about the CMOY is on Tangent's site, more or less. Read especially his various treatises on tweaks and so on. I will add the following:
- Get a multimeter. You will likely need to do some troubleshooting.
- Buy a couple 8-DIP TI072 op amps to test with, then slot in the Burr Brown once you're feeling comfortable. They're cheap and if you bend the pins or burn it out it won't matter as much as if you had a $6+ amp.
- Test with 9V
- Tangent has you build with a gain of 11, which is way too loud and actually causes instability with extremely low impedance headphones like iPod earbuds. I found the circuit unusable with ear buds until I got it down to a gain of 7; I'm currently amping Grados and 64 ohm Sennheisers with a gain of 2 and it's more than sufficient.
- Chu Moy suggests a small resistor at R5, or "DC coupling" the output if you use low impedence phones like Grados. -- http://gilmore2.chem.northwestern.ed.../cmoy2_prj.htm I couldn't hear the difference, and found that adjusting gain had the biggest effect on both sound quality and stability.

 

[linuxworks]

yes, gain of 11 is insane. very few need that level of gain. go for a much lower number.

(unless you like to learn how to unsolder resistors, then go with a gain of 11, lol!)

 

[adamus]

my advice is to build something to learn how to solder and recognise basic parts.

Then build something you will get wrong but have a chance of debugging. looking back, i learnt a most from making mistakes, not from stuffing boards.

 

[Aynjell]

Quote:

Originally Posted by linuxworks /img/forum/go_quote.gif yes, gain of 11 is insane. very few need that level of gain. go for a much lower number. (unless you like to learn how to unsolder resistors, then go with a gain of 11, lol!)

I did that on my cmoyv2.

Well, it's v2 to me, no variation in the design, only that I had to resolder it... went from gain 11 to gain 4.5 I believe... far more reasonable, and for me, much better sound quality.

 

[johnwmclean]

Quote:

Originally Posted by MisterX /img/forum/go_quote.gif The link below should get you started. Lessons In Electric Circuits

Wow that’s fabulous, I’m going to take a good look at this.

 

[Spacehead]

My first DIY project has been CMOY. I have been tweaking it a lot and my understanding of basic electronic circuits has been increasing overwhelmingly! I built two then I built third and now I've got a 3 channel Cmoy

There is still some tweaking to do. I think those output caps on ground channel op amp are bad?
Though it is virtual ground driver actually. I have not had success separating input and output grounds. If I let the TLE2426 drive the input and the op amp ( JRC 4558) output ground, (wires directly into the current circuit, which is LM7805 -> TLE -> OP AMP -> VGND) I get heavy hissing sound.
But as it is , I have very silent amp that gives strong bass into my Sennheiser HD-201. I have already accomplished what I wanted, strong bass and clarity with these 24 ohm headphones. But now I have addiction to DIY audio! And I need more to build, which would be easy cheap and hifi?!

EDIT:

I had to do it! I looked proper ways to do the ground channel and found Mini3 schematic:
The Mini³ Portable Stereo Headphone Amplifier

I copied the ground channel to my CMOY/CHA47/A47/META42/MINI3 hybrid

And after about hour of rerouting signal I completed it:

caps do the decoupling, I used 100 and 80 ohm resistors, those are on the edge of the board for easy tweaking. I just don't have 300 ohm resistors that are in mini3 schematic. The placement sucks, but it seems to be working. I think if my soldering job would have been better, sound would be brighter. I need to try to reflow those joints when I have more time.


This is the experience I got out of choosing CMOY as my first project. It just seems to grow and grow until I am doing something else. And I don't know how to stop it.

If I had chosen any different project, I might have just inserted the parts into PCB and then learned very little compared to what I have now.

 

[AudioCats]

for the very first project... a gainclone kit. I am talking about the kits using printed circuit board with the power supply section on the board. Get a 15v x2 transformer and you can get it done in a few hours.

It will push your various small speakers nicely. It can drive headphones too (common ground output), and at +/- 15V you can get away with using a small heatsink (if you use a metal enclosure, just use the case as heatsink) and small transformer. Keep it low power and simple.

then after you got tired of playing with the dynamic phones, this little amp will then drive your electrostatic transformer box.

(ok, I am triing to lure people to the electrostatic phones)