Guide to fix up a Cmoy 2

[Fresno bob 0]

Thanks jasonhanjk for the info i have those opa2132's around here so i will use two of them.

[alvin2038 0]

i tried using opa2228's in place of the opa2134's and found that the bass tends to get badly distorted. do i need to change any other components if i want to try the opa2228?

[Fresno bob 0]

Try incressing the cap size to 470uf @25-35volts this may help i'm sure some of the more better builders will have more to add. I myself plan to use 470uf 50volt caps.

[skyskraper 0]

i would say check your power if you are getting distortion, it may be a low battery

[alvin2038 0]

thanks for the inputs guys.

 

not sure its the battery since the bass is fine when i switch back to the 2134's.

 

increase caps to 470µF? you mean the ones at c3 and c4? i could give that a shot but need to get some of those caps first. ok..pardon my ignorance cos not familiar with this stuff. how will increasing the caps help?

[Fresno bob 0]

From http://tangentsoft.net/audio/cmoy-tutorial/tweaks.html

 

 

Edited May 5, 2005 by Fresno bob

[alvin2038 0]

From http://tangentsoft.net/audio/cmoy-tutorial/tweaks.html

thanks

[kahchun 0]

Anybody knows can I use opa637ap the cmoy2??

[heady 0]

Anybody knows can I use opa637ap the cmoy2??

Theoretically, you can. But you need two adaptors, each to convert two 637s into one dual opamp, so you will need four 627s plus the two adaptors. Which probably won't fit into the small board that the CMOY2 is.

 

And you will need to get the 627 for the ground channel, you can't use 637 for ground as it is not unity gain stable. So you need a grand total of 5 expensive chips.

 

It is like putting a Formula one racing engine in a Kancil, it may not fit and if it does, will you be able to get the max benefit out of the engine?

 

Why not just pop for the Pimeta then?

[Guest starushz]

jsut completed my moy2..not bad...the sounds are more distinct and the instruments have more space inbetween them.....But sometimes the treble can be abit jarring....Btw the elctroc caps i used Rubycon's 1000uF. Does it affect the sound it is it jsut for DC block? Anyway had a hard time soldering..hahha..long time never solder.

Also went to farnell to buy the LM6171. Quite fast...waited for 5 mins to get the IC.

[jasonhanjk 0]

If it is at C1 and C2, yes it will. Blocking cap should not exceed 470uF and it should be non-polarity one.

[Guest starushz]

Its the cap for C6 C7. Does it affect?

[Guest starushz]

Guys, I got abit of problem...sometimes i get a "wheee" sound....is it oscillation or is it picking up RF?

And when i unplug and plug the headphone jack a few time then it goes away...

[Fresno bob 0]

Sounds like RF. do you hear radio stations or any thing other than the music thats playing and this whee sound. other wise it might be oscillation.

[Guest starushz]

Sounds like RF. do you hear radio stations or any thing other than the music thats playing and this whee sound. other wise it might be oscillation.

nope...jsut a whee sound....hmm..does keeping the length of wires to a min help? Althougth i think it would help reduce RF pickup.