Right channel out of dac is toast

concealer404

Alright, i hooked up my new DAC today, and the right channel is outputting nothing but garbled crap.

It's an Audio Alchemy DDE V1.1.

Is this even worth trying to fix? It's definitely in the output stage of the dac, i've swapped the ICs, and the garbled channel follows the cable. System sounds perfect with the DAC out of the loop.

Am i wrong in thinking that the optical cable can't possibly have anything to do with it since the left output on the DAC is working properly?

Any ideas or suggestions? I'd like to fix it, but i'm pretty sure it's going to be far beyond what i'm capable of, and i doubt there's a huge customer service support for this unit considering it's 16 years old and the company is out of business. I can't even seem to find an active link for the schematic.

Halp.

billbillw

The cable shouldn't have any effect. If you are getting digital lock, then all is good.

I'd say, open her up, look for obvious circuit damage (swelled caps, burned components, cold solder joint, etc). Might be an easy fix if you can see something. If not, I'd say its probably a lost cause. Repair costs from a tech would probably exceed its value. Did you just buy this? If so, what does the seller have to say?

concealer404

I just bought it, trying to see if i can fix it, because working, it was a good deal. I already PM'd the seller asking if he had a schematic, waiting on reply.

I'm not about to call them out or anything, i just got it today, it's not outside the realm of possibility it was damaged in shipping or whatever, i'd just rather fix it.

I'll open it up here in a couple minutes, thanks!

concealer404

Can't get a good picture of it, but all i could see that may have been out of the ordinary is this weird liquid stuff on the bottom of the PCB board, by the leds pictured. I haven't gone over it with a magnifying glass yet, i'll try that tomorrow if i can.

Anyone think it may be worth trying a digital coaxial cable instead of the optical cable i've been trying to use?

billbillw

If its hardened liquid, then its probably just residual flux. Not your problem.

You might try the digi coax connection too. Just try it with any old RCA interconnect, shielded preferred. Video cables work fine.

Face

Can't you send it back?

I doubt switching from optical to coax will fix your problem. And if it's broken, why would you want to keep it anyway?

concealer404

Waiting on the seller to get back to me.

I'd rather fix it, since i don't really have the budget right now for another one.

I'll give the coax cable a shot tomorrow, but i don't have my hopes real high about it.

But yes, if it's broken and it's not something i can fix, i don't particularly want to keep it.

kcoc321

FRACK...sucks dude...hope it is something easy to fix....

billbillw

Have you left it plugged in for say 12+ hours? Some DACs need to 'warm-up' for a long time. Long shot, I know, but worth trying.

vc69

billbillw wrote: »

Have you left it plugged in for say 12+ hours? Some DACs need to 'warm-up' for a long time. Long shot, I know, but worth trying.

That's a new one on me.

tonyb

I don't know if that Dac is even worth fixing. Did you have all the connections made before plugging it in ? If you can get your money back, I would do it asap and jump on another Dac.

billbillw

The owner's manual for my Entech tells you to plug it in a few hours prior to listening. Same thing with my DB-12 phono preamp.

concealer404

billbillw wrote: »

Have you left it plugged in for say 12+ hours? Some DACs need to 'warm-up' for a long time. Long shot, I know, but worth trying.

I have not tried that. I'll give it a shot when i get home, nothing really to lose at this point. I don't think that's the problem though, since the left channel is working perfectly. If the right channel has to warm up over a period that long, then i'd assume that there's some pretty serious issues with the unit anyways.

concealer404

tonyb wrote: »

I don't know if that Dac is even worth fixing. Did you have all the connections made before plugging it in ? If you can get your money back, I would do it asap and jump on another Dac.

Yeah, i powered down the whole setup, made all my connections, and then fired it all up. Didn't have any weird pops or noises when i turned everything on, and i just had the garbled mess.

I'm hoping i can just uncover a blown resistor or something that i can fix for 50 cents or whatever. I don't think i'd be able to find another DAC anytime soon with the budget i'll be having. Bummer.

Waiting on seller to reply.

unc2701

Garbled mess like a CD skipping or heavy distortion or something that sounds like a blown speaker?

concealer404

unc2701 wrote: »

Garbled mess like a CD skipping or heavy distortion or something that sounds like a blown speaker?

Heavy distortion, thought i blew my speaker at first. (i was PISSED) It's just static, sometimes i could hear a voice faintly through it. The volume is way lower in that channel than the left as well.

heiney9

When I received my used Squeezebox I wanted to output the digital signal into my stand alone dac using the coax, but it had all sorts of popping and static (diginoise) I used the Toslink output and it was fine. The seller claimed he never used the coax so was unaware. I could have sent it back but we agreed on fair partial refund. Since I have both inputs on my dac I really didn;t care which I used if the price was right...........and it was!!! . I bought a $299 Squeezebox in perfect like new cond. (except the coax issue) for $75 in the end.

So yes, try ALLthe digital inputs AND outputs etc. Do you know for sure it's on the analog end? How do you know it's not on the digital end at the input?

H9

billbillw

heiney9 wrote: »

So yes, try ALLthe digital inputs AND outputs etc. Do you know for sure it's on the analog end? How do you know it's not on the digital end at the input?

H9

Good point. I'd try the DAC with another digital source if possible. Computer, DVD player, anything really...

concealer404

The Optical out on the CDP works fine, i tested it on the receiver it came with, and it sounds fantastic. Honestly, not even a whole lot worse than the 2-channel setup does, so that was a hard pill to swallow. But that's why i was excited about the DAC, because the analog stage on this CDP blows.

I'll try the Coax when i get home and see where that gets me. It'd be nice to have both working, though, so i could run my cable box through it if the need strikes me. As long is one is working i'll be happy, though.

Good point on not knowing exactly where the problem lies. I guess i was foolishly assuming that because the left channel was working with no problems, then the input was fine. (one cable, right? )

tonyb

I could be wrong....again, but weren't those dacs having problems with the analog outputs ?

concealer404

tonyb wrote: »

I could be wrong....again, but weren't those dacs having problems with the analog outputs ?

I have no idea, to be honest. But if they were... how else would i use this thing? My pre only accepts analog inputs.

concealer404

Alright, i've got a Coax cable on the way. Are there any possible negative repercussions in trying a regular RCA in the meantime? I don't know if i have any shielded video cables lying around. I use HDMI for the TV, and the PS2 has it's own connectors, obviously.

heiney9

Nope.............I've used both an RCA and an "official 75 ohm" RCA and never heard a difference.

Face

concealer404 wrote: »

Alright, i've got a Coax cable on the way. Are there any possible negative repercussions in trying a regular RCA in the meantime?

You'll be ok.

concealer404

Cool. Cross your fingers for me, i'll be trying this in about 4 hours.

unc2701

Don't get your hopes up too much. The fact that it's just one channel probably means that it's at the DAC chip or further down the signal path...

concealer404

Yep. That didn't do a damn thing.

I left it powered on overnight, i'll try one more time when i get home, but i'm sure it's toast. Gotta get out the magnifying glass and take a closer look, but i'm about done with this thing.

Seller still hasn't replied.

unc2701

Given the way samples are interleaved, I'd have a hard time imagining a way that you could get just one channel due to something prior to the DAC. The good news is that what you describe sounds like analog issues, so it could be a loose connection, bad cap, bad opamp, etc.

concealer404

unc2701 wrote: »

Given the way samples are interleaved, I'd have a hard time imagining a way that you could get just one channel due to something prior to the DAC. The good news is that what you describe sounds like analog issues, so it could be a loose connection, bad cap, bad opamp, etc.

So your thinking sounds like it's something down stream of the DAC, so there's a good chance it could be pretty cheap to fix if i don't get my money back? (If i can find a schematic, that is. I've looked for hours, can't find anything.)

I was pretty sure it was analog from the beginning, simply because the left channel sounds just fine.

billbillw

It might be a cheap fix if you could DIY it, but if you have to take it to a technician, forget about it. Most have minimum charges of $60+ to diagnose, which usually will be applied to the repair. You got any DIY buddies who could poke around it with a multimeter?

Just curious, how did you purchase this? Ebay? A-gon?

concealer404

billbillw wrote: »

It might be a cheap fix if you could DIY it, but if you have to take it to a technician, forget about it. Most have minimum charges of $60+ to diagnose, which usually will be applied to the repair. You got any DIY buddies who could poke around it with a multimeter?

Just curious, how did you purchase this? Ebay? A-gon?

Purchased here. Seller has gotten back in contact with me, he's trying to find a schematic for me. He's appreciative of the fact that i'm going to try to fix it first, since he sold it as part of a selloff to help build a nest egg for his family, and i appreciate that he's going to let me poke around it first, since i really don't have the money to buy the other DAC i had my eye on at the moment. (Face's DacMagic.)

Yeah, i'm not going to bother taking it to a tech. I either fix it myself, or bribe someone here to take a look at it for me, or nothing. I've got a multimeter or two kicking around, will probably take a look at it today or tomorrow while the girlfriend is at work, and see if my laughable skills can pick up anything.

I'm just crossing my fingers that it may just be a couple resistors. That's well within my skills i think.