Allen & Heath Zed 10 Distortion Problems

[_brian_]

Hi, I have a simple set up. The only preamp I use is a DAV BG1 along with an avalon U5 and these run into an RME interface which output to an Allen and Heath Zed10 mixer. It's a bit of a waste, but this is an easy control for speaker & headphone volume and it cut out the computer noise I was hearing when connecting my monitors and headphones directly to the soundcard.

Anyway, I got back into recording and thought I'd build myself a big mult-speaker cabinet loaded with different speakers, the build went well. I miked it up and trialled a recording.

I tried close and distant miking with an SM57 and SM57 Beta, this ran into the DAV BG1, but I could hear some excessive colouration. I was confused because the preamp wasn't peaking and I know the BG1 should be transparent, the RME software wasn't peaking and cubase wasn't peaking.

I heard this colouration through the speakers and through my headphones connected to the Zed 10. I assumed it was everything but the mixer, but I came to that last and swapped it out for a little crappy Mackie mixer - clean sound straight away.

The only thing I can say is I remember when I first connected everything up and started using the Zed 10 again a few weeks ago, there was loss of signal on my headphones which was only rectified by turning the volume right up and over-loading the channel - then bang - volume comes back and I'm able to hear at normal levels.

It looks to me as if there might be a bad connection inside zed 10, maybe a component failing, any idea where I start? It's out of warranty now.

Cheers

 

[mjbphotos]

Are you running balanced cables out of the RME to the A+H? If so, are you plugging into mic channels (could be overdriving the mic preamps)? The fact that you were getting 'computer noise' without the mixer is suspect - how did you have things hooked up that way?

 

[_brian_]

Are you running balanced cables out of the RME to the A+H? If so, are you plugging into mic channels (could be overdriving the mic preamps)? The fact that you were getting 'computer noise' without the mixer is suspect - how did you have things hooked up that way?

hi mjb

the computer noise is not relevant to this, it's something that's very quiet and probably wouldn't annoy most people, but i hear it, it's probably due to a grounding issue. it's like you can hear an audible sound of the computer working. i wear ear defenders along with sound isolating earbuds so i protect my hearing when playing drums, it means i can hear the click without having everything too loud, this also means the sound is so faint that I can hear everything coming from the computer including noise. this distortion sound is very different from this sound.

the rme line outs are going into the allen and heath line ins. i've tried another line level channel strip and it's the same.

i use balanced cables whenever i can. remember the noise completely vanished when i put the mackie in its place, and there was a problem with my headphones which sounded like a distorted intermittent cutting off of sound, then it cut off completely. was fine one minute, then the next no sound. i thought it was a dirty pot so i exercised it, and when nothing much happened when i turned the headphone volume pot back and forth, i turned it right up and when it got to near full volume the sound came back with a bang.

it didn't sound like a dirty pot at that point, it really does sound like a weird intermittent distorted sound. after a while it's adding distortion to everything i send to the mixer, and the level isn't near peaking on the A&H, it's all in the green.

sorry, forgot to add, i connected my yamaha monitors directly to the balanced main outs on the rme, and there's a headphone socket on the sound card as well which i connected my buds to. it's an RME HDSPE AIO card i have. like i said though, this isn't really a problem. i think if i paid for one of those expensive clean power supply units it would clean that noise problem up, or if i dropped a ground - but like i said using the zed 10 eliminated this problem in the past.

 

[Gtoboy]

I might suspect a loose solder joint on the Zed jack. Use a cable and an DMM to check your resistances.

 

[CoolCat]

it doesnt really surprise me the ZED10 could be adding its own sound-color etc...and you have the Mackie data point that says everything else is clean when its used.

and from everything Ive read the DAV Bg is type preamp even the dudes recording symphonys and quartets and operas use....(so no NEVE blurry distortion wanted or added).... Mics and Mic cables seem to be quantified by using them thru the Mackie = Clean....DAV BG = clean. not the mics , not the cables.

so the ZED... is it. as you say. did something die, is something partly dead and blurry?

stuff breaks down...I went to use my dual preamp the other day and one side, just died.
is it worth fixing? probably not...I imagine the electronics shop charges more than its worth.
I might poke around but the OEM doesnt even want to look at it, obsolete old cheap gear. So its probably
a MONO unit until it goes to the garbage bin.

the more stuff in the chain, adds poop in the loop, the more noise and problems and noise floor.
the more tools the more problems. sos.... can you get another ZED anywhere and plug it in then you'd know for sure.

good luck, hope its a pad button stuck, or something easy!

 

[_brian_]

I might suspect a loose solder joint on the Zed jack. Use a cable and an DMM to check your resistances.

I think I'll go over all the solder joints (if they're reachable) and heat them up and melt them to see if it cures the problem then, a wee bit of new solder shouldn't do any harm as well.

I'll give it a shot, the unit's going to cost too much to repair anyway and at the moment it's spares and unusable.

 

[_brian_]

it doesnt really surprise me the ZED10 could be adding its own sound-color etc...and you have the Mackie data point that says everything else is clean when its used.

and from everything Ive read the DAV Bg is type preamp even the dudes recording symphonys and quartets and operas use....(so no NEVE blurry distortion wanted or added).... Mics and Mic cables seem to be quantified by using them thru the Mackie = Clean....DAV BG = clean. not the mics , not the cables.

so the ZED... is it. as you say. did something die, is something partly dead and blurry?

stuff breaks down...I went to use my dual preamp the other day and one side, just died.
is it worth fixing? probably not...I imagine the electronics shop charges more than its worth.
I might poke around but the OEM doesnt even want to look at it, obsolete old cheap gear. So its probably
a MONO unit until it goes to the garbage bin.

the more stuff in the chain, adds poop in the loop, the more noise and problems and noise floor.
the more tools the more problems. sos.... can you get another ZED anywhere and plug it in then you'd know for sure.

good luck, hope its a pad button stuck, or something easy!

sadly it's nothing so simple as a pad button, so i think you're right it's just knackered. it's adding so much audible distortion i thought the vox amp was over-driven at first, i mean it's not in your face but more of a fizzle at the top end.

i just happened to marry up the vox amp with the creamback for the first time, so there was another variable there which had me questioning if it was something else. as soon as i went into the other room (because i keep the amplifier in the studio and the guitar speakers in a treated separate room) and put my ear up to it there was no distortion or fizzle to my ear.

i was second guessing myself a bit too much because i've been away from recording properly for so long.

just annoying because the A&H has never seen heavy use.

if i can't fix it i'll probably just use the little mackie mix8 to drive the speakers and the headphones, i can't see the sound quality being so low as to effect the signal chain too much. mind you it's only a £70 unit!

 

[ecc83]

I have have had a ZED10 for several years (it's a Mk1 16bits) and I can assure all here gathered that it does NOT add any 'character' or coloration to the signals passing through it. A&H are an old and honourable audio company, why would they do such a thing?

But, as mentioned, things do go wrong and yes, from what has been said, very likely a solder joint, we call them "dry" joints.

I have never had mine apart but I cannot see it being hard to do? It would be sensible to try to isolate the fault into a section...I suspect it is in the monitor section. Are the AUX, Rec out, FX out clean? You can use the Mackie mixer as an audio "test probe" with reference to the block signal diagram.

Dave.

 

[_brian_]

I have have had a ZED10 for several years (it's a Mk1 16bits) and I can assure all here gathered that it does NOT add any 'character' or coloration to the signals passing through it. A&H are an old and honourable audio company, why would they do such a thing?

But, as mentioned, things do go wrong and yes, from what has been said, very likely a solder joint, we call them "dry" joints.

I have never had mine apart but I cannot see it being hard to do? It would be sensible to try to isolate the fault into a section...I suspect it is in the monitor section. Are the AUX, Rec out, FX out clean? You can use the Mackie mixer as an audio "test probe" with reference to the block signal diagram.

Dave.

I'll have to do some fault finding tomorrow when I've got time then, what you say makes sense that I could narrow down the fault a bit more before sweating the joints.

I'll let you know how I get on.