Questions regarding building the CMoy

[augustineRS 0]

er the R1 is as according to tangents.Linked to the LED one.

using opa2312.

hmmm...mayb read up more.thanks for the input

[tropicalrips 0]

i should be going too if eveything goes well, my offday is on friday. i'll be bringing the CHA47 & mini Cmoy or Cmoy with LM6172 op-amp if i can finish it, still listening to it on the proto-board

[augustineRS 0]

put back the R1.Funny thing is now every sounds alrite.is more of too much gain.

with the px200, one channel louder than another, koss plug is too loud but both channel sound the same level.the bass now is really too much, overrall too loud...

ARGHHH.

[Q00 0]

use a volume pot to control the level or set the gain lower?

[tropicalrips 0]

good luck augustineRS my first sucessful cmoy took abt 1 week

 

go though the drawing again, i think the tricky part is at the output / R4 / R5 side, the rest of it is quite stright forward

[augustineRS 0]

had hard time figuring out the vol pot connection.think will set the gain lower.but wat u think of the channel drifting(is this the term) on the PX200?

one side louder than another.

[tropicalrips 0]

signs of the op-amp dying it happened to me too, thought everthing fixed, then put into case...then no sound at all

 

u used meter to measure the voltage? try (+) and ground & (-) and ground, they should be about the same

[augustineRS 0]

signs of the op-amp dying

 

hopefully not.

I hate troubleshooting.This is worst than car.

[tropicalrips 0]

but once u get it to work , u would hav learn a lot of things & see how simple it really is

[augustineRS 0]

Stop troubleshooting the CMoy.

When I use the headphone out jack everythinig wascrystal clear.The analog line out was terrible.Very LOUD and Distortion.

 

The problem of right side louder than left still present.

 

Using 4.3k as R3.

Perhaps reduce the gain abit.

 

Enuff for the day.

 

Maybe some1 came across such problem?

[tropicalrips 0]

if u use the line out jack u must a volume pot to control it or it will be too loud

u can't control the volume output on the line out side

problem on one side of headphone could be damge headphones cause your volume was too loud

Edited November 27, 2003 by tropicalrips

[Q00 0]

Lineout is an unamplified signal in its purest form out of the player... so yer cmoy is actually doing its job but u need to add in a volume pot to control volume. From what yer saying it sounds like u dont have any form of control unless its out of the headphone jack. Also, the problem u say is not there when using the headphone jack so i think its because yer blasting yer headphones and one of the drivers is not as loud as the other but i THINK it should be ok at lower volumes.

[jtfoo 0]

guys, still don't know what rail-to-rail means

 

Rail-to-rail, is basically the supply voltage from V+ to V-.. Many Opamps will still operate as long as the rail to rail voltage is maintained within the spec stated in the datasheet. So at times, it may not be neccessary to have equal V+ and V-, but as long at the voltage across V+ and V- is within spec the opamp will still function.

 

e.g. in your thread 'the cheaper cmoy', the supplied voltage to the kitset opamp is a +ve DC supply, not a +ve and -ve. But as long as the the measure voltage across Pin 8 and Pin 4(rail to rail) is within spec, it'll work.. But for audio application, having equal +ve and -ve supply is desirable.

[augustineRS 0]

Sorry maybe i never made myself clear.

The problem of R side louder than L is present even in headphone line out thought every thing sound refine.

Think I have to get a multi meter to figure the thing out.

 

The volume pot how to fixed?

With the shaft pointing towards me, there total 3 roles of connection with 2 connection in each row.6 pin in total.Left Centre Right.First 2 to Left, follow by Right then Ground?

 

 

[tropicalrips 0]

its actually 2 rows of 3 pins each

 

pin 1 to input before the cap

pin 2 to after the cap

pin 3 to ground

 

this is 1 channel, need to do the same for the other channel as well

 

if u want the volume pot to increase or decrease the other way round, just swap pin 1 & pin 3

 

i hav tried line out from my discman to the cmoy with a volume pot, its still loud, its like there is only 3 steps of control, very low , loud & ear-drum breaking loud i think u will need a good volume pot if u want more control, like the Alps pot, but that doesn't make sense cause the pot cause more then the amp

 

so now i just use the headphone out and leave the amp potless, it also sounds better cause the cmoy is very hash, sounds very raw & bright when run from line-out, its more like a headphone driver then an amp, so u can use good phones on portable players like those tiny mp3 players

Edited November 27, 2003 by tropicalrips