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AlexanderGrant

cmoy question....

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cmoy question....

just finished building a cmoy based on williamneo's layout and tangent's circuit using for the tle2426..

 

for some reason everything sounds fine with the creative stock earphones & mylar x3i's, but when i use a pair of shure e3g's the sound starts have a lot of distortion & noise (the shures are working okay when plugged into other things).

 

any suggestions on what the problem might be? thanks in advance..

 

 

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Edited by AlexanderGrant

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Hi ,

Googled the Shure e3g, what an exorbitant priced pair of earbuds,even the

pdf broshure does not explain what technology or how it works.So secret that

people believe the marketing.The specs say it is 29 ohm impedance just a little

shy of the standard 32 ohm so this should not pose a problem to any well

designed/proven headphone amp.

 

Since I believe the Shure e3g is new the wires should be in good condition

so that leads me to suspect the earphone jack on the cmoy or components may have come loose

on the pcb.Check with your multimeter or visual inspection.

 

Good luck.

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Distortion sometime caused by clipping, when the supply voltage is too low, or too low for the op-amp to work properly, or sometime when the op-amp cannot supply enough current to the driver.

 

Try to increase the supply voltage, like using 2x 9 volt batteries, or try other op-amp that has higher output power.

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the opamp goes into oscillation caused by capacitive load from the shure earphones.

same thing happens as u described with the fxc-70s (dynamic) no prob, but q-jays have problem.

 

problem can be solved with voltage buffer after gain stage in opamp, or simply increasing the gain.

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Hi ,

Googled the Shure e3g, what an exorbitant priced pair of earbuds,even the

pdf broshure does not explain what technology or how it works.So secret that

people believe the marketing.The specs say it is 29 ohm impedance just a little

shy of the standard 32 ohm so this should not pose a problem to any well

designed/proven headphone amp.

 

Since I believe the Shure e3g is new the wires should be in good condition

so that leads me to suspect the earphone jack on the cmoy or components may have come loose

on the pcb.Check with your multimeter or visual inspection.

 

Good luck.

 

Absolutely agree with this post.

Sometimes its just gain problems.

But usually if its diy and PCB it could be as simple as a bad solder on the Earphone Jack

or the internal of the earphone jack has erroded.

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sorry if OT..

 

anybody here has spare amb mini3 pcb? the one from amb, not hohodiy..i figure i'd ask here since buying from amb is quite expensive for building 1 unit only

 

sorry again if i'm out of topic, i don't find it appropriate to make new topic just for asking this :)

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sorry if OT..

 

anybody here has spare amb mini3 pcb? the one from amb, not hohodiy..i figure i'd ask here since buying from amb is quite expensive for building 1 unit only

 

sorry again if i'm out of topic, i don't find it appropriate to make new topic just for asking this :)

 

this ? http://glassjaraudio.com/product.sc?produc...25&categoryId=2

 

frankly get a kit easier, u run around sim lim tower, here and there, is not worth it all(sometimes cant find too), maybe save $20 only

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this ? http://glassjaraudio.com/product.sc?produc...25&categoryId=2

 

frankly get a kit easier, u run around sim lim tower, here and there, is not worth it all(sometimes cant find too), maybe save $20 only

 

my intention was actually asking for fellow members here who maybe happen to have spare or extra mini3 board..not asking where to get the board from local shop :)

 

if someone has the amb mini3 pcb, not the one from hohodiy, or alvin (the one with slightly wider pcb), please PM me

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my intention was actually asking for fellow members here who maybe happen to have spare or extra mini3 board..not asking where to get the board from local shop :)

 

if someone has the amb mini3 pcb, not the one from hohodiy, or alvin (the one with slightly wider pcb), please PM me

 

well too bad, u miss my order... my amb sigma22 stuff just arrive 2days ago

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well too bad, u miss my order... my amb sigma22 stuff just arrive 2days ago

 

oh man, not my lucky day i guess..

 

if you don't mind, plese let me know if you order something from amb again :)

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did you mean it on my post? if so, thank you :D

 

I hope its going to work fine :blush:

 

You do understand you need to implement the virtual ground portion of the circuit as well, right?

 

 

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You do understand you need to implement the virtual ground portion of the circuit as well, right?

 

the mini3 schematic presented the POWER, GROUND, LEFT & RIGHT.

 

On the CMOY, it has POWER, LEFT & RIGHT.

 

So you mean, did I put the ground of the mini3 to the cmoy scheme? If so, yes I integrate it to my revised schematics. Is it correct? Thanks :))

 

-------------------------------------------------------------------------------------------------------------------------

I have a problem on the bass boost that I have added,

 

this is the one I found here

 

and the schematic is this one:

 

IPB Image (for each channel)

 

and i followed that scheme and make my own:

 

Left

IPB Image

 

Right

IPB Image

 

now the problem is, i dont know why it doesnt make any changes when i turn it on/off.

 

questions are:

 

1. is the original schematic (1st image) correct for bass boost?

2. are my own schemes (2nd & 3rd image) correct?

3. did i burn or damaged my "bass boost" resistor and cap?

4. it is still working perfectly right now, even with the bass boost switch is on/off, its just that it doesnt make any changes when i select it. if it was damaged (#3), does the amp still work?

5. as you can see, the values in the original bass boost circuit, especially the cap is different from the one i did? I know the fact that the higher its values, the lesser it cuts off the low frequency. but at least i can hear difference because of it, am i correct?

 

thanks :D

Edited by jmwreck

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