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

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EarthTone

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OK really lively responses to my questions about this preamp above, thanks chaps! Sarcasm intended!

On a more related note, what is the best faceplate/case for this? Does the Collective Cases case fit well? I read where some people had a tough time fitting it into that unit, but it looks like the most complete faceplate/case available and it also has the power switch hole drilled which I would prefer. That one and the Don faceplate are the only ones I'm aware of. Are there more?
 

kante1603

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Maybe this one,here in germany,you can ask Frank Röllen (owner of this company) if you need modifications,he is cool:


https://www.frontpanels.de/miscellaneous-frontpanels/ez1073/


Best regards,


Udo.
 

Potato Cakes

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I second Frank's work. He's done a number of mods to standard cases for me and is really great to deal with. One thing to consider is that his cases are deeper than Dan's at Collective Cases if that is a consideration for you. If you need you can have Frank make the front panel with drill holes for Dan's cases.

Thanks!

Paul
 

EarthTone

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I just ordered two 1U rack mount version kits from AML! I am so phsyched for these builds. Here in NYC we have an electronics store called BH Photo where they have a demo room full of mics and preamps you can try. They had a Heritage 73'jr which I tried and loved. I tried it out with my sax. They had the preamps plugged straight into a converter so you could hear them. The Heritage preamp was sans-EQ, but it sounded amazing. I hope the ez1073 sounds like that! From everything I've heard, it should. Looking forward to these builds! I have read through the colourbook and have a friend who has built 4 of them I've already bugged a bunch so feel like I'm prepared, but I'm sure I'll have some questions along the way.

Cheers,
ET
 

EarthTone

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sr1200 said:
I'm on LI, couple blocks from the LIRR if you wanna hear what they sound like.  I have a pair of the AML and i have 8 of Martins.

Oh, cool! Really nice studio website! What are Martin's preamps? I see on your site you've got listed 8 1290 clones, is that what you're referring to? I'd love to hear them.

I'll hit you up when they're built maybe we can have a little gear hang. I've been building some mics too...
 

EarthTone

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Also, I'm wondering if anyone here has had the opportunity to compare the ez1073 w/EQ rack version to the new 500 series preamp-only kit? If so, how does it sound when compared to the preamp section of the rackmount version? Like if the EQ is all zeroed out on the rackmount, I wonder if the tone of the preamp is essentially the same.
 

EarthTone

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Quick question for those who have built one using a Collective Cases 1u rack case: which sized standoffs did you use, 4mm or 5mm? Thanks!
 

EarthTone

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Sorry to bug, but anyone build the rackmount version with the Collective Cases case and know which size standoffs will work? 5mm? 6mm? Any preference on standoffs with threaded leads poking up through the PCB vs. female ends with mouthing screws coming in from the top of the PCB? Thanks.
 

EarthTone

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Hi,

I ordered all my stuff for this project at the same time and I made the mistake of assuming that the CAPI Gear Neve style knobs would fit my potentiometers in the ez1073. I'm almost at the end of hte project (I built two) and just started assembling the knobs on the front panel when I noticed the trim and EQ pot knobs I bought do not fit. The shaft size of the pots is much larger than the shaft bore of the knobs. The macaronis for the preamp gain do fit, though. I am talking about this stuff: http://capi-gear.com/catalog/product_info.php?cPath=202_203&products_id=398

Is there anything I can do? Should I try to exchange the knobs for macaroni knobs, or is there a way I can easily and reliably bore them out with a drill?

I bought these which do not fit: http://capi-gear.com/catalog/product_info.php?cPath=202_203&products_id=398

Is there a way to change the shaft size of the pots?

Thanks,
ET
 

Potato Cakes

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EarthTone said:
Hi,

I ordered all my stuff for this project at the same time and I made the mistake of assuming that the CAPI Gear Neve style knobs would fit my potentiometers in the ez1073. I'm almost at the end of hte project (I built two) and just started assembling the knobs on the front panel when I noticed the trim and EQ pot knobs I bought do not fit. The shaft size of the pots is much larger than the shaft bore of the knobs. The macaronis for the preamp gain do fit, though. I am talking about this stuff: http://capi-gear.com/catalog/product_info.php?cPath=202_203&products_id=398

Is there anything I can do? Should I try to exchange the knobs for macaroni knobs, or is there a way I can easily and reliably bore them out with a drill?

I bought these which do not fit: http://capi-gear.com/catalog/product_info.php?cPath=202_203&products_id=398

Is there a way to change the shaft size of the pots?

Thanks,
ET

You can drill them out to 1/4" with a press and be fine.

As a note you ordered the inner concentric knobs, which are meant for 1/8". It is labeled as inner concentric on the website with the shaft diameter.

I believe you were looking for this: http://capi-gear.com/catalog/product_info.php?cPath=202_203&products_id=430.

I have done the same thing. I drilled out the hole for the knob and everything was fine.

Thanks!

Paul
 

EarthTone

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Potato Cakes said:
You can drill them out to 1/4" with a press and be fine.

As a note you ordered the inner concentric knobs, which are meant for 1/8". It is labeled as inner concentric on the website with the shaft diameter.

I believe you were looking for this: http://capi-gear.com/catalog/product_info.php?cPath=202_203&products_id=430.

I have done the same thing. I drilled out the hole for the knob and everything was fine.

Thanks!

Paul

Thanks Potato Cakes! Much appreciated. I have figured it out with the supplier of the knobs. Going to get replacements, thankfully! Almost done with these builds. I am so excited to turn them on and see what they sound like.

ET
 

EarthTone

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I just built two of these. I decided to wire one of them up to power first to see if there were any trouble spots before I wire up the 2nd one to power.

I’m kind of amazed since this is my first DIY preamp, but almost everything works perfectly on the 1st one! Mic gain, EQ, trim, it sounds great.

The only thing not working is that even though I measure 48V correctly across the 48V power rails,  no condensers work. The mics do bot seem to be receiving phantom power. Dynamic mics sound fine.

Any ideas?

Thanks,
ET
 

Potato Cakes

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There is a schematic of the PSU in the build guide. You'll have to look at it and follow it to find where the problem is. Somewhere in there you have a bad solder joint or misplaced component. It is very possible but unlikely you have a bad component unless it was destroyed in the build process.

Nice work on the rest of it. These things are pretty great.

Thanks!

Paul
 

EarthTone

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Potato Cakes said:
There is a schematic of the PSU in the build guide. You'll have to look at it and follow it to find where the problem is. Somewhere in there you have a bad solder joint or misplaced component. It is very possible but unlikely you have a bad component unless it was destroyed in the build process.

Nice work on the rest of it. These things are pretty great.

Thanks!

Paul

Hi Paul,

Man, thanks so much for the help, really appreciate it! So, I built two. I powered the other one up tonight and that whole thing works perfectly. I'm both thrilled and amazed that it works! I've never done this before. I guess that means the kits are very high quality. Man, it sounds great. Phantom works perfectly on that one.

Regarding the other one which has the phantom problem, I hear a loud "pop" when I engage phantom power. The 48V phantom test terminals are showing 48V. So I guess the 1st part of the 48V section is working up until at least the terminals. It must be after that. Could it be the switch? Probably not, right...

I think I understand the PSU schematic. I've reflowed solder on all those points. No luck. The components on the 48V line are in the exact same positions on both units and the same orientation on the polarized ones.

Thanks,
ET
 

EarthTone

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OK! I found the problem. Sorry to make so much noise on here when it was my own fault. I took the ez1073 without phantom power outta the case and took a much closer look in the light. I had already racked it before testing. Overanxious to get going I guess. Anyway I found a solder bridge at the input transformer. I also reflowed solder over the entire 48V section and a bunch of other places again. Nowwwwww it works!

I now have 2 fully functional ez1073's on the first try. They sound amazing. I guess they really do live up to they're "EZ" name.

Thanks Colin! AML all the way. Might buy a few more of these suckers.

Cheers,
Matt
 

EarthTone

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What are the steps to properly ground this unit? There are two “mains safety earth” connections on the pcb. Do I need go connect both of them to star ground, or only one?

Also, on the XLR chassis connector jacks, do I connect the d-tabs to pin-1? Or do the d-tabs go to star ground? Or do I leave the XLR jack d-tabs open?

Thanks!

ET
 

fistman

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Feb 9, 2018
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Hey all -

So I’ve got two units.  One I just finished and the other just needs the mains hooked up to the transformer.  Couldn’t wait to try out the completed build... and... the fuse blows.  Immediately.  No light no power to the test points. 

I took the heat sink off in stage 3 to check that the lock washers hadn’t come off the pad.  All was good there.  Took the bottom of the case off and tried a new fuse to be sure I wasn’t grounding out somewhere there.  No dice.

Anyone have any recommendations where to look next?  I blew 3 fuses in a row so I’m doubtful of a bad fuse.  I’m assuming some sort of grounding issue, but if anyone has any advice I’d greatly appreciate the help. 

Feeling pretty bummed as I’ve built a few other diy kits previously with no issues and I’m generally very meticulous when putting these things together.

Thanks,
JF
 

EarthTone

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fistman said:
Hey all -

So I’ve got two units.  One I just finished and the other just needs the mains hooked up to the transformer.  Couldn’t wait to try out the completed build... and... the fuse blows.  Immediately.  No light no power to the test points. 

I took the heat sink off in stage 3 to check that the lock washers hadn’t come off the pad.  All was good there.  Took the bottom of the case off and tried a new fuse to be sure I wasn’t grounding out somewhere there.  No dice.

Anyone have any recommendations where to look next?  I blew 3 fuses in a row so I’m doubtful of a bad fuse.  I’m assuming some sort of grounding issue, but if anyone has any advice I’d greatly appreciate the help. 

Feeling pretty bummed as I’ve built a few other diy kits previously with no issues and I’m generally very meticulous when putting these things together.

Thanks,
JF

Hey man ~ I'm sure you've been over it several times but I think you've just gotta keep checking for solder problems. I was sure I didn't have any on mine until I unhooked it from the case and looked really, really close. I caught 2 solder joint problems. In the end I'm not sure exactly what fixed my phantom power, but after I removed a solder bridge and redid some questionable joints, I reflowed solder on most of the joints on the board just to see if that would make a difference. Something I did fixed it.

So I would encourage you to do that too.

If you built two units, compare the two and see if you've got any misplaced parts anywhere. It's pretty easy to do this visually since the resistors are color coded.

There's always the chance you misplaced something on both units though. If it's a misplaced resistor, it's going to be pretty time consuming to find it. You are basically gonna have to go through the whole build again and measure resistors from step 1.

Look for shorts. Try a different power cable. Check your power transformer wiring, did you wire for the correct voltage? Look at the teeth on your input transformer pins. Anything bridged? Electrolytics placed the correct polarity? Transistors facing the right direction?

Could be a bunch of different things.

Check that your LED is orientated the correct way if it's not lighting up. If you're viewing the unit from the front, the positive leg goes to the right. It's the opposite of the Electrolytics polarity, if memory serves. That's not marked anywhere, I found it in this thread buried deep somewhere when I was trying to figure out which way it went, too.

Good luck. When you finally get it working, you will love the way it sounds.

Best,
Matt
 
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