good that you found the probable cause.I'm currently struggling with figuring out this very odd problem with my DIY Objective Amp... Desktop version is being fed through my audio jack and into my headphones. no DAC as of yet. just from onboard audio through the amp to my headphones.
When turned on low volume with normal gain, it is "stereo" but eminating from my right headphone can only. As i increase the volume knob on the amp the audio balances out and left is equal to the right.
As a new audiophile user, I am confounded by this property. Since i've tested my headphones with a seperate amp/dac combo i know it is not their fault... Strangely enough, when I coupled this amp with the seperate amp/dac combo the balance issue dissapeared as far as i can tell.
Is this normal?
Im super paranoid on this and im afraid something may be faulty!
When turned on low volume with normal gain, it is "stereo" but eminating from my right headphone can only. As i increase the volume knob on the amp the audio balances out and left is equal to the right.
As a new audiophile user, I am confounded by this property. Since i've tested my headphones with a seperate amp/dac combo i know it is not their fault... Strangely enough, when I coupled this amp with the seperate amp/dac combo the balance issue dissapeared as far as i can tell.
Is this normal?
Im super paranoid on this and im afraid something may be faulty!
That in itself sounds like poor tracking of the two gangs of the volume control... a common issue. The mis-matching can be poor at very small angles of rotation (low volume).
That problem is compounded if the source is putting out a high level because that forces you to turn down the volume. If that is part of the problem then a simple change of resistors R3 and R7 to something like 15k may help considerably.
Update: So i replaced the r3 and r7 resistors with 15k resistors from radioshack (damn theyre hard to cram in) and it is considerably better! But I can hear the faintest of difference in balance. The right still being slightly favored on lower volumes but you have to be listening closely to hear the difference. Still, the higher the volume knob, the more balanced it becomes (although very slightly).
This help alot though! If I wanted to continue with fixing and balancing should I consider higher resistances or a new volume potentiometer?
This help alot though! If I wanted to continue with fixing and balancing should I consider higher resistances or a new volume potentiometer?
Yes! After mangling the previous (defective) potentiometer, and replacing it with a new one from mouser, the system works flawlessly! Thank you kindly for your guidance!
JDS Labs panels w/ 1/4" output and w/ rear RCA input
Just finished updating my few-years-old O2 to a more deskable configuration that i can still take portable. Yeah a lot of people would just install an odac and have some other amp for portable use but I have a fully optioned y2 DAC so the odac is redundant.
Basically I bought panels from JDS Labs that i wish had been available when i first bought my kit.
Just want to move power and input to the rear, and use RCA input.
Also got the Neutrik 1/4" jack and isolated power jack from JDS. If they sell isolated RCA jacks i didn't see them.
The holes for the RCA jacks were a bit tight for my isolated jacks. The bushings with my jacks are a fraction of an mm loose so maybe my jacks are to blame. I just drilled the holes out another mm.
The 1/4" jack requires moving C8 and C9 off-board. I suppose it's possible you could replace them with surface mount tantalums but i just moved them on wire leads so that they are sitting on top of one of the output opamps.
These look very good, but IMHO need a revision.
There is a recess milled into the front panel for the 1/4" jack. This recess means that the jack will be loose unless you shim it from behind. I found an o-ring that stretched over the jack. it's possible that a 12mm wave washer would work too.
The left RCA jack needs to be moved over a couple MM. It's a very tight squeeze with the batteries. The batteries have to sit diagonal to make this configuration possible.
Lastly, the holes for the screws need to be drilled out slightly because they are tight around the threads of machine screws, which means they will be even tighter around self-tapping screws.
I retained the front panel 1/8" input jack for portable use. Naturally the little ground traces that mute the input have to be cut.
Just finished updating my few-years-old O2 to a more deskable configuration that i can still take portable. Yeah a lot of people would just install an odac and have some other amp for portable use but I have a fully optioned y2 DAC so the odac is redundant.
Basically I bought panels from JDS Labs that i wish had been available when i first bought my kit.
Just want to move power and input to the rear, and use RCA input.
Also got the Neutrik 1/4" jack and isolated power jack from JDS. If they sell isolated RCA jacks i didn't see them.
The holes for the RCA jacks were a bit tight for my isolated jacks. The bushings with my jacks are a fraction of an mm loose so maybe my jacks are to blame. I just drilled the holes out another mm.
The 1/4" jack requires moving C8 and C9 off-board. I suppose it's possible you could replace them with surface mount tantalums but i just moved them on wire leads so that they are sitting on top of one of the output opamps.
These look very good, but IMHO need a revision.
There is a recess milled into the front panel for the 1/4" jack. This recess means that the jack will be loose unless you shim it from behind. I found an o-ring that stretched over the jack. it's possible that a 12mm wave washer would work too.
The left RCA jack needs to be moved over a couple MM. It's a very tight squeeze with the batteries. The batteries have to sit diagonal to make this configuration possible.
Lastly, the holes for the screws need to be drilled out slightly because they are tight around the threads of machine screws, which means they will be even tighter around self-tapping screws.
I retained the front panel 1/8" input jack for portable use. Naturally the little ground traces that mute the input have to be cut.
Anybody bought one from here?
EHP-O2Di Desktop Headphone Amplifier/DAC | Epiphany Acoustics
EHP-O2Di Desktop Headphone Amplifier/DAC | Epiphany Acoustics
Objective 2 Headphone Amplifier
I am taking voltage readings from my Objective 2 kit. On D4 I am only seeing -15.2v on the banded side, -14.6v on the non-banded side. Then on D3 I am seeing only -.3v on the banded side and -15.2v on the non-banded side. After following the troubleshooting guide I thought this sounded like a serious offense. But everything seems fine all components are in the right place and soldered well. Also I should note I am not sure about the power supply I am using. I bought a 15V 1000ma wall ac adapter from radioshack. I originally had the polarity backwards is that going to cause problems? I'm hoping not everything is fried. Any clues as to where I should start are appreciated. Thanks.
-Clay Spencer
I am taking voltage readings from my Objective 2 kit. On D4 I am only seeing -15.2v on the banded side, -14.6v on the non-banded side. Then on D3 I am seeing only -.3v on the banded side and -15.2v on the non-banded side. After following the troubleshooting guide I thought this sounded like a serious offense. But everything seems fine all components are in the right place and soldered well. Also I should note I am not sure about the power supply I am using. I bought a 15V 1000ma wall ac adapter from radioshack. I originally had the polarity backwards is that going to cause problems? I'm hoping not everything is fried. Any clues as to where I should start are appreciated. Thanks.
-Clay Spencer
It is the model I have linked. It has a reversible tip for polarity.
Enercell 15V/1000mA AC Adapter : AC Adapters | RadioShack.com
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The link doesn't work, but a reversible tip indicates DC output for sure. They're calling it an AC adapter because it's mains AC input.
Is it model 273-332? That one clearly states
As mentioned, you need an AC/AC supply, i.e. nothing more than a dumb transformer inside. NwAvGuy's recommendations for 120V territory included Triad WAU12-200 (minimum), WAU16-400 and Xicon 412-218054.
Is it model 273-332? That one clearly states
As mentioned, you need an AC/AC supply, i.e. nothing more than a dumb transformer inside. NwAvGuy's recommendations for 120V territory included Triad WAU12-200 (minimum), WAU16-400 and Xicon 412-218054.
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Yes, you should be able to get a refund from Radio Shack. That adapter won't work without some 'just not worth the trouble' modifications. And it doesn't appear that they carry an AC-AC wall wart you can use.
This 12VAC 500mA wall transformer is the sort of adapter the O2 needs, and it's a lot cheaper than anything Radio Shack, even with s&h costs.
If you are east of the Mississippi, this 16.5VAC 40VA transformer is a bit overkill but the price is right!
You can order from whichever is closer if you want quicker delivery.
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