[mikkelmmk93]

Necrothread
But hi all, Have just been reading through all this since someone linked it to me.
He said that I should use the NJM4556 for the amp. any comments? as to maybe design changes or anything.
And does anyone have a pcb layout for this amp that I can make myself?

 

[skree]

saw this thread just now and read it through. I'm going to build myself a stripboard CMOY. Or two. I had to post about that eclipse tin CMOY though that's IT i want that amp.. looks so perfect in that little tin.. beautiful amp.. must set mental note to pm fred when i'm closer to doing that build... simple cmoy first.. once the component shops open 

 

[WarrenG]

Hi
 
In your schematics you have to pots? is that correct in your other images there i can only pick up one pot.
 
Regards
Warren

 

[Fred_fred2004]

The simple drawing program I used could not do a dual pot so I showed each channel as a single pot, in reality you will use a dual ganged pot
 
cheers
FRED

 

[Bogaty Smak]

Hi Fred.  New to this forum and this thread.  I have been studying the cmoy design for a bit now and I am wondering if there is a specific original description of the basic design somewhere.  My apologies if this question is out of place for this thread.  What I'm wondering is, the Cmoy design seems to be a fairly generic opamp circuit.  What did Chu Moy do specifically to get his name all over it? 

 

[dawek1]

Hey,
 
Thanks a lot for this project. 
It works well, but after i take off R7 and R8 and use some cable to connect it. Before this i have distorted music in my phones.
I don't now why but it helps and it's working fine now. 
 
In the beginning i replace resistor few times, with same result.
 
 
I have question. Do you now why TLE2142CP is not working in this case? Now i use OP275GPZ.
Do you thing OPA2228P will be better than OP275GPZ? It is 3x more expensive but i don't now that is worthy to invest.
 
My phones are Ultrasone PRO 900.
 
 
David

 

[kahei036]

  Hey,
 
Thanks a lot for this project. 
It works well, but after i take off R7 and R8 and use some cable to connect it. Before this i have distorted music in my phones.
I don't now why but it helps and it's working fine now. 
 
In the beginning i replace resistor few times, with same result.
 
 
I have question. Do you now why TLE2142CP is not working in this case? Now i use OP275GPZ.
Do you thing OPA2228P will be better than OP275GPZ? It is 3x more expensive but i don't now that is worthy to invest.
 
My phones are Ultrasone PRO 900.
 
 
David

Hi David,
If you are referrinf R7 and R8 stated in first post, those 2 resistors are in the feedback loop, they control the gain of your amplifier. If you get distorted with 10K resistor but not a straight cable (assuming 0ohm), I would suggest you first listen it at low volume, and hear if it distorts. If it only distorts at higher volume, probably the gain is larger than the power supply rail to the opamp that it starts clipping.
 
What power supply are you using for your cmoy?
 
TLE2142 is a dual opamp base on its datasheet, and it has a quite low requirement on rail power supply of +-2 to operate. Can't think of a reason it doesn't work while a op275 plays.
 
Haven't had a chance to hear opa2228. I find OP275 is a little bit colourful with my Beyer cups.
Or you may want to share your view on OP275 and how you want it to be improved in an opamp thread so that ppl can help you out there.

 

[Mr Goat]

So im building a cmoy next week if the parts get here. The thing is that im realy bad at understanding "schematics" like the ones they have on tagentsoft's guide. Can i follow this guide but use the part list on tangetsoft?

also is that design out of date or is it still up to date during 2016?

 

[Avro_Arrow]

A cMoy is what a cMoy is. It doesn't really go out of date.
Tangent's guide is pretty good at holding your hand through the process.
Just read it all the way through.
Let us know how it goes!

 

[serman005]

  A cMoy is what a cMoy is. It doesn't really go out of date.
Tangent's guide is pretty good at holding your hand through the process.
Just read it all the way through.
Let us know how it goes!

I would like to jump into this cMoy thing, but how technically proficient and knowledgeable does one have to be to pull it off? I have never before built anything electronically sophisticated. Just how much knowledge is required? Thanks!

 

[FallenAngel]

 
I would like to jump into this cMoy thing, but how technically proficient and knowledgeable does one have to be to pull it off? I have never before built anything electronically sophisticated. Just how much knowledge is required? Thanks!

 
It's the first step into audio amplifiers, you can do it! Good luck.

 

[kahei036]

 
I would like to jump into this cMoy thing, but how technically proficient and knowledgeable does one have to be to pull it off? I have never before built anything electronically sophisticated. Just how much knowledge is required? Thanks!

Cmoy is a very popular circuit due to it's simplicity (which actually is how an non-inverting opamp amplifier operates). There are a number of projects even with layouts on a breadboard. So if you have basic soldering skills, simply follow those guides then solder stuff up, it should able to sing.
 
If you have little basic knowledge on electronics (like V=IR, voltage divider, etc..). and are more enthusiastic to know more about the circuit, Tangentsoft provides very good explanation to this circuit. After that you should able to know how a non-inverting opamp operates in this circuit, therefore the reason why that value of parts are chosen, and how that parts play its role in the circuit.
 
It's indeed an entrance to DIY amplifier, highly recommend you to go and do not hesitate in asking questions in the forum. People are more than happy to help you out.

 

[tangent]

  I would like to jump into this cMoy thing, but how technically proficient and knowledgeable does one have to be to pull it off? I have never before built anything electronically sophisticated. Just how much knowledge is required? Thanks!

 
That's the first question in my CMoy Pocket Amplifier tutorial FAQ:
 

This is a somewhat technical project. You won’t need to understand how the amp or its components work, but you will have to be able to follow some pretty exacting directions. If you build it incorrectly, it can take hours or even days of troubleshooting to find the problem.
 
Yet, the CMoy is a good choice for beginners because this amp and variants of it have probably been built by thousands of people over the years. Many of these thousands are ready to offer their help in one form or another. 

 
My guide is about 15 years old now, and the original project even older, and my guide has received many updates over that time. You should therefore start with the assumption that your question has already been answered in the guide or on the forums.

 

[Mr Goat]

So im in the middle of building 3 cmoy amps. But i was hoping to use 1 of them as a test bench and test different gains out. In Tangents guide there are 2 resistors you can switch out to change the gain but im not sure which those are in this stripboard design? I would like to think its r5/6 but i just want to confirm it before i start testing

Also, is there any real way i can just mess this up so bad that i will destroy my headphones?

 

[Fred_fred2004]

If you are using the original "Strip board Cmoy" change R5 & R6 to alter the gain
 
use Tangents formula