Np and thanks. did you just use generic 12v regulators? Anything specific?

I'll post schematics and case design tommorow hopefully

I sent him a message, thanks for the tip.   I do have to say that the people we sell to are a bit different though. I'm marketing to people who might want my product to "just werk" so having sound quality degrading and possiblity of idiots frying their phones might not be an option...I'll...

Thank you. I'm trying to see if I could design a product I could sell locally and maybe eventually on the web. (always looking for ways to get a little more cash ;) ) so the issue of headphone killing DC offset from a real ground was rather scary. I know I could implement the protection circuit...

I finally got all the parts I wanted for the base model of my CMoy++ so I started to prototype it out on a board from RadioShack. (I'll borrow a friends camera to show how it looks later) It's basically a CMoy with a real ground, buffered outputs, bass boost, and a DC jack for charging the...

After removing global gain and only using local gain on both opamps I recieve a "crackly" sound (especially when there are bass hits) when I use the OPA2134 as the first (amplifying) opamp. When I switch to the 4556 it goes away....I believe I'll just have to reimplement this circuit later If I...

Ok to anyone who comes looking at this thread for an answer here is what I found:   The circuit does work as i showed in the schematic. What I didn't show was the bass boost that I tried to implement (didn't work) and I believe that the global gain loop is also sitting doing nothing. I'll post...

I believe I may have fixed it (isnt spitting high dc any more (1 mv on one channel 0 on the other)) I added a local feedback resistor for the OPA that was 47 ohms. I'll test it and post my findings for anyone else who ever has a similar problem

cool. do you mind posting the schematic for that here? I've become very interested in the CMoy recently and I'd like to see how you implemented this (I have a generic psu that I'd like to see if I can get clean enough to power the thing)

Yes I thought I might be wrong on the inverting input which is why I asked to clarify. I have a copy of LTSpice on Fedora but I've had to run Windows the past few days for a project and haven't gotten around to downloading it because I've been so busy.   I do apologize for the fubar text crap...

So after reading this article, I think I have a better understanding....so, if I have say, +50 mV of offset on a channel, I can take a high value pot, hook V- up to one end and ground to the other, and then the middle pin to the inverted input, between it and the input, put a 10 ohm resistor to...

no matter what I changed values to it didn't seem to work. I even tried to add local feedback to both but I dont think it was working (tried a lot of configurations today not sure if it worked or not) finally got it working by seperating feedback loops (basically having both have their own local...

bud. Im a programmer. I'm very technical. If I had a camera, I'd use it. I have a dumb-phone that unfortunately does not even take pictures (at least not ones that would mean anything to anyone. They are dark and distorted and you can barely make anything out, let alone circuits). I had it...

My opamps that I had ordered (OPA2134PA and NJM 4556AD) came recently and so I have been tampering with my CMoy again. I tried both and found that the 4556 worked much better for my purposes (low impedance headphones with a bass boost circuit implemented) the only issue was, with the bass boost...

      ok I swear to god that wasn't there when i searched it. I searched lm317 and it did not come up! I swear! I did search before posting I promise both of you.   Thank you for the replies though   P.S. the mouser link doesn't seem to be loading...it just sits there forever trying to...

where would you find an LM317? I wanted to get it from mouser but they don't seem to carry it....I /think/ I found it on amazon but it had 4$ shipping (if I plan on building more of these I'd like to get the components from the same place so that I only pay one shipping fee)

First things first, power it with batteries.   Did that solve the issue? No? continue on   I built one a few days ago that had the exact same issues at first. The issue got better (wasn't completely fixed) when I moved components around a bit and did some resoldering (mine was a little more...

I print my cases (<$1 per) volume pot is the alps (will not go lower and it saves money on a switch) psu is as cheap as can go. I'm not worried about the main opamp (going to use a nice opa2132/4) I'm worried about the output buffers (offerring bass boost in some models (and my personal one will...

I've been thinking of using the OPA2132 with an output buffer (either a discrete one, a BUF634, or an opamp <----about this....I CANNOT afford to put a bunch of $7 chips in this thing (plan to sell them and can't have that much in it) I know the BUF634 is good...but out of these options...

I have a burr brown on the way. The power measurement for idle was most certainly correct but under load I would really have to check again. As for the socket measurements I thought i had seen it on your page but it must have been someone on the forum in a different post who mentioned something...

headphone amplifier version of what? Since you're using single opamps it would probably have ok power handling even without the buffer...

I bought some quad opamps today to play with and after jamming a little bit after configuring the first two amps up as a normal setup I decided I would try to "stack" the amp by wiring the corresponding inpus/outputs to the ones on the amps already wired (all this was done on a breadboard so it...

  I'm sorry, It said on your page to ohm out the socket.....(the TL082 is out)     I measured while it was playing music at roughly 80% volume     this one showed mA off the battery (said norm for a 9v was 25mA for its measurement purposes and all were within 22-25mA)   Quote...

thank you for this I'll make sure to study it.   Thanks for the explanation. I believe the first thing I'll do for my cmoy then is an output buffer.