That sounds like a physical problem in the construction somewhere, maybe something shorting to something else. There is a known problem (not sure exactly what fault it causes) of the gain switches ??? being to close to something and touching.
A careful visual check should find the issue, if not a scope would locate the problem area in seconds.
A careful visual check should find the issue, if not a scope would locate the problem area in seconds.
Hello!
I have a distortion problem. I have now tried different wiring solutions for my O2 + ODAC setup but I always hear distortion when using the ODAC's signal (line level out) to my receiver. I want to have the possibility to use the ODAC's signal straight from my computer via USB to my stereo amplifier, but unless I turn on the power of the O2 I get massive distortion. I tried to disconnect the ODAC completely and noticed there was no distortion i.e. no problem with the ODAC itself.
Does anyone else experience the same problem and if, how have you fixed it? Or is the only solution to have the O2 and ODAC separate or always turn on the power of the O2? That sucks...
I have a distortion problem. I have now tried different wiring solutions for my O2 + ODAC setup but I always hear distortion when using the ODAC's signal (line level out) to my receiver. I want to have the possibility to use the ODAC's signal straight from my computer via USB to my stereo amplifier, but unless I turn on the power of the O2 I get massive distortion. I tried to disconnect the ODAC completely and noticed there was no distortion i.e. no problem with the ODAC itself.
Does anyone else experience the same problem and if, how have you fixed it? Or is the only solution to have the O2 and ODAC separate or always turn on the power of the O2? That sucks...
Hi! I had the same "problem". Se Mooly's answer http://www.diyaudio.com/forums/head...eadphone-amp-diy-project-425.html#post4234264
Okay, so I guess you have the configuration where the O2 input only works as input and then use a separate rear line level output from the ODAC (same as I have)? So the problem is solved by plugging in an open cabel/plug into the O2 input.
Thanks!
Hey all!
im almost finished building my O2 and have reached the testing section. NwAvGuy: O2 Details
when checking for resistance, all were close to what is expected, except for my R5 being at 232k ohm (meassured with a really cheap ebay DMM). is this a problem?
i then went ahead to the next step and tried with the wall ac adapter (15 vac). Under "Briefly Check The Supply Voltages" in the testing section it says you should check between the outermost of the four battery terminals i got a reading of 25v. as i dont really trust the DMM to be very accurate i thought it is close enough to 24 so i turned on amp for a few sec, led turned red and i got a reading of 24.6v.
directly after this i removed adapter from the wall to go read some more in the testing section but after this the adapter was dead. is it possible i killed it with my amp? or was the adapter about to die from the begining (even though its new ordered from head'n'hifi along with O2 kit)? dmm shows 0v from adapter and when i connect it to the amp nothing happens
could really use some help
im almost finished building my O2 and have reached the testing section. NwAvGuy: O2 Details
when checking for resistance, all were close to what is expected, except for my R5 being at 232k ohm (meassured with a really cheap ebay DMM). is this a problem?
i then went ahead to the next step and tried with the wall ac adapter (15 vac). Under "Briefly Check The Supply Voltages" in the testing section it says you should check between the outermost of the four battery terminals i got a reading of 25v. as i dont really trust the DMM to be very accurate i thought it is close enough to 24 so i turned on amp for a few sec, led turned red and i got a reading of 24.6v.
directly after this i removed adapter from the wall to go read some more in the testing section but after this the adapter was dead. is it possible i killed it with my amp? or was the adapter about to die from the begining (even though its new ordered from head'n'hifi along with O2 kit)? dmm shows 0v from adapter and when i connect it to the amp nothing happens
could really use some help
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Im testing it with meter set to AC and result is 0.00. when i connect it and do the same test at the battery terminals as before (where i got 25v) i now get 0.00. its dead but why? can it break if theres something wrong with the amp? i have double checked and am pretty confident i have placed everything where it belongs.
as for the guide, would it have the same readings with batteries? with batteries the led lights up.
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If the adapter is an AC output (which it should be for the 02) and you have no voltage from it when its not connected to the 02 then yes, its faulty. A short on the O2 could possibly damage an adapter by either blowing an internal fuse or by excess heat tripping a thermal fuse within the transformer... not usually replaceable.
Does the 02 work correctly with batteries ?
If you have another adapter then we should be able to rig it up to safely test without damaging anything, probably by using a bulb limiter on the secondary side (input to the O2).
Does the 02 work correctly with batteries ?
If you have another adapter then we should be able to rig it up to safely test without damaging anything, probably by using a bulb limiter on the secondary side (input to the O2).
I have searched the house for an adapter with ac output but out of the ~15 i have found, all have DC output. guess i will have to order a new one, and try with bulb limiter. havent heard of this before but i searched on google and it looks really clever, like a easy to change fuse outside of adapter.
cant find anywhere to order or buy nearby so it will take some time to get it
on batteries my O2 lights up but not sure if readings are correct etc, im still in the testing section and never got to installing the opamps. maybe if i install them and try with some cheap headphones i will know if it works? but then again, maybe i will just fry them if something is wrong?
on nwavguy's blog:
does the "at least 200 mA" mean it can go higher to lets say 1A, with 200ma as minimum?
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It means you need at least 200ma to power the O2. There is no upper limit to the transformer size.
Because this is all such low power stuff the bub tester if used on the primary (mains side) would have to be very small, something like a fridge lamp. You could also use a low voltage bulb on the secondary side instead.
Because this is all such low power stuff the bub tester if used on the primary (mains side) would have to be very small, something like a fridge lamp. You could also use a low voltage bulb on the secondary side instead.
Great! In that case i have found one with the right plug and 15vac 1A.
im really not sure how to build the bulb limiter though. by primary and secondary, do you mean having the bulb limiter before or after the ac adapter? Would a 3w 34v candlestick light be too low? i also have some different bulbs of 15-60W, 240v.
Thanks
A 3watt 34v should be ok (a filament bulb, not LED) wired in series with the adapter output could be a start. The O2 probably would be low on volts with that but it should let you see if voltges start to come up.
You are looking to see that the positive and the negative rails appear at the regulator inputs.
You are looking to see that the positive and the negative rails appear at the regulator inputs.
you sure are fast at replying
i just got an idea on something i should test, i took the multimeter to test for shorts and on first try it beeps on these:
i know one of them is ground, are they supposed to be somewhat connected and make ampmeter beep? or might that be what broke my ACadapter?
reason i started checking the powerinput was because it has stupidly large holes and required plenty of solder to fill. was thinking maybe the solder make a short on the other side of the board if too much ran down the hole to the other side?
I've not got the circuit in front of me on this PC. Checking for shorts is a good idea and you need to measure across where the AC input feeds in. There should be no short present.
Hard to tell from your picture whether what you measure is normal or not. Check from the diodes (right at the PSU input) to ground. There should be no short.
Hard to tell from your picture whether what you measure is normal or not. Check from the diodes (right at the PSU input) to ground. There should be no short.
looking at this image:
It looks like there is no ground on it, i assumed there was a ground since there are 3 solder points on it but maybe a 3rd is just added for stability? would explain why they are connected to each other.
wish i was better at electronics, but i guess its a good opertunity to learn.
anyway, once i get my new adapter i will try the bulb limiter. Should i connect the bulb to the "outside" of the psu connector or the inside?
It looks like there is no ground on it, i assumed there was a ground since there are 3 solder points on it but maybe a 3rd is just added for stability? would explain why they are connected to each other.
wish i was better at electronics, but i guess its a good opertunity to learn.
anyway, once i get my new adapter i will try the bulb limiter. Should i connect the bulb to the "outside" of the psu connector or the inside?
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Ground believe it or not is often an arbitrary point we decide on and that becomes a reference point for measurements and signal 'grounds'. In the 02, ground is that 'centre line' between the two regulators, in fact there is a ground symbol further along it.
So there should be no short measuring between that ground and both ends of D3 and D4. That small bulb fitted in series with either output lead of the adapter will allow you to check the power supply. Have no batteries fitted for testing initially and set the O2 power switch to off. If all is well you should have +12 volts DC and - 12 volts DC at the output of the two regulators.
So there should be no short measuring between that ground and both ends of D3 and D4. That small bulb fitted in series with either output lead of the adapter will allow you to check the power supply. Have no batteries fitted for testing initially and set the O2 power switch to off. If all is well you should have +12 volts DC and - 12 volts DC at the output of the two regulators.
I feel a bit stupid but i cant really figure out where that 'centre line' ground is on the PCB
In nwavguy's testing section it shows BT1- as ground IMAGE
So i tested from BT1- to both sides of D4 and D3. with DMM in "beep/short-mode" it gives a reading of ~710 on all except striped side of D3 reading 003 and beeping.