http://tangentsoft.net/audio/

Bible for beginners like me.

I dont understand the op amp part, can all type of circuit use a type of amp?

How much does a good op amp cost?

There are many models of op-amps. They all have different specifications such slew rate and bandwidth. You have to select the op-amp to fit your amp's design. An op-amp usually does not cost more than few ringgit.

wow! excellent link, tfs.

wanna ask, does it mean a cmoy is superior to a class A headphone amp or is it the other way around?

Depend on you take which "class A" amplifier as reference.

Here some link for you to understand more about class A amplifier:

http://www.tpub.com/neets/book7/25e.htm
http://www.passdiy.com/pdf/a40.pdf
http://www.passdiy.com/pdf/leaving_class_a.pdf

If you are really interested into DIY, do read it. When it come into real HIFI, it's no
longer a matter about enjoyment of listening, everything is into damn measurements.

That's what the actual meaning of High-Fidelity.

This post has been edited by chchyong89: Feb 8 2011, 02:30 AM

w0w! thanks for those links. My head is spinning from trying to digest the info but it's all good!

A cmoy can be biased into a Class A easily using the right CCS.

you're getting the wrong impression about Class operation.

Class A, Class B, Class AB etc are output stage operation classes. They are configured to operate at "different" classes. It's a configuration rather than an individual amplifier by itself.

The CMOY is a whole block of working amplifier. Its output stage might work in either classes.


CMOY is a single chip opamp so depending on which chips you use, it operates at a prefixed "class", which varies differently from one chip to another. Most opamps due size, is limited to Class AB. Class A forces the output stage to run at max operating current all the time so it's going to be hot.

ahh thank you LittleGhost for the info. I find your postings very educational.

*data input overload* *brain shutdown imminent*

Got some people think class A amp mean "A class" amp. Class A amp not suitable for battery operated, coz, all the time it draw current for biasing. The 1 advantage of class A is no crossover distortion, but u wasting power for this..

link:
maybe useful
Class A

This post has been edited by Bida Bing: Feb 14 2011, 03:42 PM

Like always, there're some good points and bad points on each amplification topologies... and each can be chosen for specific needs and functions.

Just something to share here. Just got my cMoyBB 2.03 from JDS Labs. One of the famous and also most expensive cMoy for sale in the market .
It worth every sen spend on it, the board is neatly printed and not some prototype board.

One of the very important aspect is it is very stable to roll with opamp. I now replacing the original OPA2227 with LM4562. And it sound like a home hifi in my px100.
They also customize the cMoy to fit low impedance headphone and smaller gain.
I have tested the amp with AD823 as well, and it already sound more delicate then OPA2227 which is very laid back but with thundering low freq. AD823 is warm and quite comfortable to listen to it and it also has more detail compare with OPA2227.

The LM4562 is really something special, the sound is amazingly clear and every instrument is so focus and detailed. It's definitely the most transparent among the three but some people might not like it as it's too analytical and don have warm sound like tube did. For I love it and it really make me crazy to go through my music to pick up everything I miss previously.

Why not build this myself? Emm yes maybe I could do it but that's many many little secret and detail that the seller has tremendous experience in it. If this to be build by myself may be I need to do many many experiment to get this right. So I save the trouble to get one from eBay.

After 3 days burning opamps ...
Something to add on, the cMoyBB does not have enough voltage for the LM4562 so it only sound good let say for 20 min then suffer. So now only switched back to opa2227 or AD823. Will replace my hifi dac opamp (currently OPA2134) with the LM4562 when I am free.

Updates...
Using 8.4v rechargeable battery solve the issue, now all opamp (includes LM4562) sounds better.

This post has been edited by ssyycc: Feb 27 2011, 12:21 AM

i need a linear psu, anyone can help me out?

Be specific please.
Built commercial unit or DIY.
Output voltage/current/single/dual etc.

Actually if you 'google' there are 'tonnes' of circuits available.

Offtopic: I just had a nightmare that my DIY amp and cable broke.

This post has been edited by mengsuan: Feb 26 2011, 12:07 PM

It could be worst...

This post has been edited by jazzy939: Feb 26 2011, 04:23 PM

Check yr blog, all yr photos there is with a "frozen frog" image...

I think you need a better image hosting service...

The imageshack crap affects Lowyat.Net as well. It will show up if you have registered an account with imageshack. I have also wrote to imageshack to whitelist my blog URL. Quite disappointed with imageshack this time.

Very good. You're progressing. Obsession is always good.

I had dreams where it solves the many of the bugs on the amps I was working on.

[sorry, off topic]
If you are on blogspot, why dun u just upload pics directly to blogspot, image won't go missing...
Nowdays so many image hosting to choose from anyway...


Back to the main topic...



I built my very first DIY "audio" electric guitar headphone amp using LM386 for my 12 years old nephew.

I just blindly follow all the circuit from the net...




Since it is for elec guitar with lots of distortions, don't think it is audiophile quality.. hehe

I had a switch to switch between clean ( 10nF caps ) and distorted ( 10uF or 22uF caps ) sound...

I later soldered everything into a perfboard with 2 pot to control the volume control and distortion level and put everything into a smalll project box with a 9V input connector... ( forgot to take pictures )

Making the casing is really challenging with all the drilling, mounting the board & pot and measurements....


The feedback from the customer ( my nephew ) says it sound "quite" good and the parents are happy cos no need to hear
all the noisy guitar sound when he is practicing..


A few questions that I don't really understand, how come changing to higher value of the capacitor, it makes it more distorted sound ( which is a good thing in elec guitar )...

Any suggestions to improve this amp ?


I'm still a newbie in electronics and I self taught myself in electronics with no background or studies in electronics ...



This post has been edited by stan001: Mar 1 2011, 10:58 PM