Feeler: an "Eee-Zzz" christmas present...ez1073 and ez1073-500

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EarthTone

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Are you guys connecting the XLR d-tabs to star ground? Or are you leaving that open on the connectors? I have seen pictures and replies about people doing it both ways. What yields better results?

Also, whatsup with there being two holes for Mains Safety Earth? I connected only one to star ground. I don't know what to do with the other one. I saw some pics where it looks like there was a screw in the 2nd one, but I can't tell what's going on there...

Sorry I'm new to this. Help?

Matt

 

EarthTone

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Potato Cakes said:
Search for Mixer Grounding 101 by Ian Thompson Bell. Use this for all of your rack gear builds.

Thanks!

Paul

Hi Paul, thank you so much for your advice. That is what I was actually trying to remember to search for, couldn't remember the title of it and had seen some folks suggest reading it on here... Very helpful thank you kindly.

Matt
 

EarthTone

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One more question: Are you guys terminating the output at 600ohms or are you leaving it at stock? What's the difference in the sound? I'm plugging it into an interface, UA Apollo to be specific. Should I be terminating to 600 or leaving SW1 open?

Matt
 

Potato Cakes

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EarthTone said:
One more question: Are you guys terminating the output at 600ohms or are you leaving it at stock? What's the difference in the sound? I'm plugging it into an interface, UA Apollo to be specific. Should I be terminating to 600 or leaving SW1 open?

Matt

The instructions say solder those pads together, so I just do that. You can experiment and let us know what you think.

Thanks!

Paul
 

EarthTone

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Potato Cakes said:
The instructions say solder those pads together, so I just do that. You can experiment and let us know what you think.

Thanks!

Paul

Thanks Paul. I wish there was some more info than that for those of us less experienced, but thanks for your input!

Best,
Matt
 

EarthTone

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Phew! I just finished casing up two of these units. I am very proud of the way they turned out. Cases from Dan at Collective Cases and the knobs I bought from CAPI-Gear.

EDIT: Scratch that! I don't know what was wrong when I tried it yesterday, must've been plugging something in wrong. The line gain is working perfectly on both units.

Everything works! I am incredibly stoked. Beautiful sounding units. I love running a 2-mix through them on the stereo bus! I used these to record a live piano concert last night. They sounded incredible.

Thanks AML!

Photo 1: https://flic.kr/p/25V1ZWm
Photo 2: https://flic.kr/p/271C2DP
 

EarthTone

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I want to share some recordings I made of my sax through one of these puppies. I love the sound of these preamps! So warm and lovely.

First, flat EQ with no extra input drive: https://soundcloud.com/mattmarantz/ez1073-tryout-flat-eq

Some brighter EQ added from the ez1073: https://soundcloud.com/mattmarantz/zz1073-tryout-brighter-eq

Lastly, no EQ added, but some input transformer drive was used and the trim was backed off a bit: https://soundcloud.com/mattmarantz/ez1073-tryout-little-bit-of-input-drive

So cool that you can get so many sounds out of this box. This is the 1U rackmount version for anyone interested. Love it!
 

miscend

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bluespills said:
I just finished a pair of ez1073s,

One is working good, but there is a level drop when i flip the phase switch...?

The second one I have a very low output from the mic channel, and a lot of buzzing when i touch the mic gain knob... 

I have already gone over looking for bad joints and trying to clean up but no luck so far.

Any tips are appreciated!  ::)
Did you manage the solve the issue with the second unit?
 

EarthTone

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Yes! Found a bad solder joint. Everything's finished & working awesomely now. Thanks,

Matt
 

nitesbeats

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Dec 25, 2018
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Hi. I’m doing a build of the 500 series 1073 version. My knowledge of electronics is minimal. With gain at +60 I get an uneven noise from the preamp that seems to peek at around -28 dB. So quite a bit of noise. I’ve tried reflowing all the solder joints with no success.

Is there way to go through the board with a multimeter and check for any shorts or faulty components?
 

Potato Cakes

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nitesbeats said:
Hi. I’m doing a build of the 500 series 1073 version. My knowledge of electronics is minimal. With gain at +60 I get an uneven noise from the preamp that seems to peek at around -28 dB. So quite a bit of noise. I’ve tried reflowing all the solder joints with no success.

Is there way to go through the board with a multimeter and check for any shorts or faulty components?

Couple things. First, is this one of AML's 500 series kits? I didn't think he sells his 1073-500 as kits any more. Which exact module are you building?

Second, any 1073/1290 style preamp is not to be undertaken by someone with limited DIY experience. Yes, there is a way to check for shorts and faulty components with a meter, but these are things you should already have learned on easier projects or from Internet research. Not to try to be totally dismissive of your question, but that's pretty much the answer you'll get around here if you would get an answer at all. Also, as with most any single ended +24V audio device (that I can think of anyway) it needs to be biased, which might be the reason for your uneven noise.

Thanks!

Paul

 

bobtheninja

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Hi all,

So, a problem has shown up with one of my dear ez1073s. Basically my line input has stopped working, which is no fun because I love to run kicks and snares through my ez1073s eqs when mixing. They started going intermittent at first, but now I can't get anything to run through them.

The mic input is fine, and the EQ sounds great on mic input. When I turn up the line input knob I get more and more hum. It seems that it amplifies the hum as it should amplify the input signal, so I'm guessing that the amplification stages are working as they should. Looking at the schematic I get the feeling that my line input transformer is the culprit. Does this make sense to all you people way smarter than me? Should I just order a new VT9046? 

 

Potato Cakes

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Pull the transformer and measure the impedance of the windings and compare them to the spec sheet or ask Colin if he has any further detailed information. But it does sound like a bad transformer.....


Thanks!

Paul
 

bobtheninja

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Thanks for the quick reply! I tried pulling the line transformer and now I definitely need a new one. Not easy to get off the board in one piece. Anyway, it has to be the transformer so I don't think there were any hope for it even without me prying it off. Will order a new one asap and will report back.

Thanks again!
 

babaorum

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Sep 21, 2013
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Hello,
Just powered up my ez1073 for the first time and... i'm getting  J5 & J6 read 18.2 Volts (DC).  J3 & J5 read 48Volts and I was able to adjust 48V power by the R10 trimmer.

at the 220-240v Transformer I measure between the white wires : 23.1V and 41.7V between the red wires. (220V for France here)
Thanks
 

babaorum

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Now Alim is OK, it was white wires which were not good soldered, I have 24V and 48V like expected.

So for the R26 calibration I have 340mV instead of 130mV and R20 doesn't change anything when turns ...

I tested Mic, DI guitar and .... no sound !
:-[
 

babaorum

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What are the values I can try to measure in which point of the pcb ? Is there a shematic plan with typicals voltage values ?
 

Potato Cakes

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You have a bad solder joint or misplaced component somewhere. You're going to have to pull the board out and start checking solder joints and checking parts with the overlay in the build guide. It might take a while and get frustrating....

Thanks!

Paul
 

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