Guide to fix up a Cmoy 2

[jasonhanjk 0]

Yes, they can give you 18mW but very distorted, normally 10% THD.

 

Cmoy 2 18mW is at 0.002% THD.

[kross 0]

ok...thanks. then if i set up as a portable set-up, can i still feed in 12V through a transformer + converter instead of batteries when I am using it at home and not outside?

[Username 0]

http://headwize.com/projects/showfile.php?file=cmoy2_prj.htm

 

See figure A4

 

[kross 0]

ok...get it..thanks. maybe i'll go and order the pcb to give it a shot during my holidays.

[Kube 0]

Ok...I'm now just going to coalesce all the parts needed...so just a question...for the all minor parts like IC sockets and the resistors, I can just get from SLT, right? If not where's the best place to get high quality components of the above? And also, is it possible to just pick and choose components at Farnell at their counter? Cause I don't know where to find good volume pots...

[Kippei 0]

Koba in PPC Chinatown have most of the stuff. I like that place cause you can ask whatever you dont know

[Kube 0]

Cool...do they sell ALL the stuffs? I mean, maybe I still have to get the hammond and opamps from farnell?

[magicpocket 0]

Hey I fixed a cmoy2 up, all went well, but I get horrid distortion when the pot is in the sort of 'middle ground' of its travel. The amp works fine at both lower and higher volume levels, but in the inbetween causes what appears to be loads of white noise over the sound. Is the pot ruined? Any advice appreciated.

[jasonhanjk 0]

Cool...do they sell ALL the stuffs? I mean, maybe I still have to get the hammond and opamps from farnell?

You can get the film resistor from SLT. Hammond and Opamp can get at Farnell. More details on first page.

 

You should get those high end components when you mess around with M cube.

Edited September 28, 2005 by jasonhanjk

[jasonhanjk 0]

Hey I fixed a cmoy2 up, all went well, but I get horrid distortion when the pot is in the sort of 'middle ground' of its travel. The amp works fine at both lower and higher volume levels, but in the inbetween causes what appears to be loads of white noise over the sound. Is the pot ruined? Any advice appreciated.

Hmmm. Maybe, but first. Let's see the front and back of the picture of your Cmoy2.

[Username 0]

Jason:

 

I was wondering if we can modify the power supply of CMOY2 by adding another breadboard and adding the rail splitter circuit and by passing the onboard power supply altogether... ?

 

Thoughts?

[Kube 0]

Ok...got most of the stuffs, except 2 jacks and the pot which I'm waiting from Farnell...film resistors, switch, led and sockets from Koba. Lol, got lost today, went to PP COMPLEX instead of CENTRE...

Just asking though, for the LED, the auntie there told me that most Led's are 3V. A little hazy on which resistor to use. If I use a led, and 9v battery....I should then buy a 1/2w film resistor 1.2kohms, right? Hmm...my resistors from R1 to R8 are 1/4w - 2 10ohms, 6 10kohms - is that correct?

 

Hmm...gonna go SLT to find some gold jacks...

 

 

[jasonhanjk 0]

Jason:

 

I was wondering if we can modify the power supply of CMOY2 by adding another breadboard and adding the rail splitter circuit and by passing the onboard power supply altogether... ?

 

Thoughts?

You mean remove the LM6171 and replace with a rail splitter?

[jasonhanjk 0]

Ok...got most of the stuffs, except 2 jacks and the pot which I'm waiting from Farnell...film resistors, switch, led and sockets from Koba. Lol, got lost today, went to PP COMPLEX instead of CENTRE...

Just asking though, for the LED, the auntie there told me that most Led's are 3V. A little hazy on which resistor to use. If I use a led, and 9v battery....I should then buy a 1/2w film resistor 1.2kohms, right? Hmm...my resistors from R1 to R8 are 1/4w - 2 10ohms, 6 10kohms - is that correct?

 

Hmm...gonna go SLT to find some gold jacks...

Here's how you should calculate:

 

Led need 3V.

9V-3V=6V

 

Led need around 5mA:

 

0.005A=6V/R

R=1200 ohm

 

Power rating for resistor:

I x I x R= 0.03W

A quarter watt will suffice.

 

Your resistor value are correct.

Since you guys kept asking me the same question of the first page, seems that I need to furhter tidy up.

[Kube 0]

Hah, no, no, there's nothing wrong with the first page, it's crystal clear. I'm just checking before I go off to solder...cause it's pretty damn hard to remove solder from this board. A question about the jacks though...what happens if one decides to use the cheap plastic jacks from SLT? They come with 6 pins...so is it possible to still use them?