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

[phaedra74]

99,9% bad solder joint

 

[EstockAudio]

OK guys.  Last one, I promise.

I've got one pre up and running 100% and it sounds AWESOME. 

The second unit works perfectly with one exception:  when the EQ is on, but the low and mid frequencies selection points are set to "off" I get no audio.  The moment I move the EQ's to a selected frequency, I get level.  The is much more noticeable on the mid-band.  It's almost like I'm not getting the original, dry signal.  It seems like I'm only hearing what's added. 

Any tips?

 

[delichef]

How quiet should these be? I've built three so far, and they sound awesome...but I get hiss on the two highest gain settings of the mic input. I assume these are the +60 and +65db settings. Nothing connected to the input. Is that normal or have some people figured out a way to make it dead quiet all the way up?

For people looking for answers on the standoffs and wire...I went with 3mm standoffs and added an extra 1-2mm nut to the screws furthest from the front  panel and the 3mm standoffs by themselves on the row closest to the front panel. This seems to work well on the collective cases.

I used Mogami console wire for the wiring. Which is 2 conductor cable with a shield. I use the conductors for hot and cold, and the shield from the XLR to SCN on the pcb. I didn't ground anything else on the XLR's. For star ground, I did PCB main, Toroid and IEC to star ground. If there are optimizations here that reduce hiss...i'd love to hear ideas. Thanks!

 

[EstockAudio]

Any help on the post above?

 

[delichef]

The second unit works perfectly with one exception:  when the EQ is on, but the low and mid frequencies selection points are set to "off" I get no audio.  The moment I move the EQ's to a selected frequency, I get level.  The is much more noticeable on the mid-band.  It's almost like I'm not getting the original, dry signal.  It seems like I'm only hearing what's added. 

Any tips?

For no audio problems, I built the billm audio probe. Basically a nail, a capacitor and a computer speaker. I used an app on the iphone to generate a test tone and feed it into the mic pre. Super simple and if you don't have a scope...gives you a way to listen to the signal as it goes through the circuit. It was really helpful in figuring out where the signal stops to narrow down where to look for problems.

For the issue you describe...are you sure the pins were inserted correctly when setting up the pot? Assuming yes, then i'd check for grounding issues and solder joints. But knowing what connections to look at can make it easier. Using the probe, you can actually hear the signal make it to various stages...comparing it to your working one will also help make it easier. Good luck.

 

[phaedra74]

How quiet should these be? I've built three so far, and they sound awesome...but I get hiss on the two highest gain settings of the mic input. I assume these are the +60 and +65db settings. Nothing connected to the input. Is that normal or have some people figured out a way to make it dead quiet all the way up?

My 3 unit don't have a noise/hum/hiss problem.
The noise floor is very very low.
If I still have the screenshot of the spectrum analysis, I post it.

 

[Potato Cakes]

OK guys.  Last one, I promise.

I've got one pre up and running 100% and it sounds AWESOME. 

The second unit works perfectly with one exception:  when the EQ is on, but the low and mid frequencies selection points are set to "off" I get no audio.  The moment I move the EQ's to a selected frequency, I get level.  The is much more noticeable on the mid-band.  It's almost like I'm not getting the original, dry signal.  It seems like I'm only hearing what's added. 

Any tips?

What the guy above you said. I had a similar issue with a different preamp engaging the HPF, and it was a bad solder joint/, even though I was certain it wasn't.  So either that or a bridge, which could also be considered a "bad" solder joint in certain circumstances.

Thanks!

Paul

 

[phaedra74]

My 3 unit don't have a noise/hum/hiss problem.
The noise floor is very very low.
If I still have the screenshot of the spectrum analysis, I post it.

Here is the noise floor

 

[dane999]

Hi,
my unit was working perfectly, but since recently, a light buzz appears when I switch the EQ circuit on. Any of you have noticed this issue , or have a lead I can follow to track this ?

 

[phaedra74]

Is a problem too general.
Control the eq section; and FIRST, check for bad solder (re-check the joint for each component connected at the analog ground).

 

[delichef]

Here is the noise floor

Thanks for posting! Mine are very quiet, the hiss on the two highest levels of gain seem in line with other units I have tried...but I do notice a tiny bit of hum on a couple of mine that is only audible if you're looking for it. I ordered a couple of Trafo shields to see if that will help. I can hear the difference when I turn off power to the units...there's a window of time between power off and when the sound goes off where you can hear what it sounds like without the toroid in play.

It does make me curious tho...what is involved in moving the toroid out of the box? If I built a box and put the IEC inlet and transformer in it...could I just run the red/white/green wiring up to the pre? Has anyone done this yet?

 

[Gbracam]

Hey guys, I need a little guidance on building this ez1073 correctly. This is my first project so I opted for the built up option, I just do not have the time to solder and I still need a little practice at it. I have ordered my case enclosure from Collective Case (should be here any day now), and a few parts from Mouser (XLR’s & IEC – Schurter).

1 - Should I desolder and remove the existing XLR's that were installed?

2- Do I need to add a power switch, and if so is there any particular one I need to get.

3 - Will there be any surprises / additional items I will need to get this installed in the case (mounting screws, stand off's)

4 - What fuses are you using and where can I get them? I think I saw 100mA, anti-surge or slow-blow.

Thanks for the help..!



Gib

 

[BluegrassDan]

Hey Gib,

1. If you're using Dan's case, you will need to remove the PCB mount XLR connectors and use TWO of these for mic and line inputs: http://www.mouser.com/Search/ProductDetail.aspx?R=NC3FD-L-B-1virtualkey56810000virtualkey568-NC3FD-L-1-B

...and ONE of these for output: http://www.mouser.com/Search/ProductDetail.aspx?R=NC3MD-L-B-1virtualkey56810000virtualkey568-NC3MD-L-1-B

2. I widened the IEC inlet cutout to accommodate an IEC with fuse drawer and power switch.

www.mouser.com/Search/ProductDetail.aspx?R=DD11.0114.1111virtualkey69300000virtualkey693-DD11.0114.1111

and the fuse drawer is sold separately...

www.mouser.com/Search/ProductDetail.aspx?R=4301.1405virtualkey69300000virtualkey693-4301.1405


It installs horizontally and requires only a slightly wider cutout than the suggested IEC without power switch.

3. You will need a couple dozen 5mm nylon standoffs and screws/nuts to mount the PCB, IEC, and XLR connectors.

4. 250V 100mA 5X20 glass fuses are what you need: http://www.mouser.com/ProductDetail/Schurter/00343107/?qs=sGAEpiMZZMtxU2g%2f1juGqbdCHRI5TALuDi72lbWGCM0%3d

Good luck!

 

[Gbracam]

It seems I am on the right track. I just received the case and it looks great! I am just waiting for a few more items then I can start the installation.
I appreciate the the help!

 

[Potato Cakes]

Thanks for posting! Mine are very quiet, the hiss on the two highest levels of gain seem in line with other units I have tried...but I do notice a tiny bit of hum on a couple of mine that is only audible if you're looking for it. I ordered a couple of Trafo shields to see if that will help. I can hear the difference when I turn off power to the units...there's a window of time between power off and when the sound goes off where you can hear what it sounds like without the toroid in play.

It does make me curious tho...what is involved in moving the toroid out of the box? If I built a box and put the IEC inlet and transformer in it...could I just run the red/white/green wiring up to the pre? Has anyone done this yet?

I just finished one and I wrapped it in transformer shielding from Don Audio. No hum.

For the hiss, I get this at the higher gain settings when I have a line from my converter plugged into the mic input (following calibration). When I plug a dynamic mic in, it's super quiet. Plus, the higher gain settings with the trim all the way open is way too much signal for converters. At least any one that I've used.

Thanks!

Paul

 

[innercityman]

Hi everyone,

I've just finished building my EZ 1073 and... It just doesn't't work. The led doesn't light up. I measured the voltage between J5 and J6 and I got a poor 0,5V. I measured J3 and J5 and I get 56, 7. I tried to trim it to obtain 48V but the trimer seems to have no effect. I get no voltage at R26. I have 12,5 and 12.7V ont the white secondary wires from power transformer. I get 19,7 and 20,4V on the red wires.

It seems that I need some help.

 

[innercityman]

Ok I found the problem... I inverted the two regulators  ;D  now it's time for desoldering.  :-\

 

[innercityman]

Ok so,  bulls...t repaired. I get the correct values now. I've been able to adjust the Phantom Power and the Output. Great! Now it's time to put a mic on it... 8)

 

[innercityman]

Unit tested with a mic on it and it works great, so nice!!! But I got an issue with the line input. Very low signal even when putting the line gain and trim to maximum, the sound is sharp... No bass, no low mids... but no buzz or hiss.
I'll continue reading the 45 pages of this thread and see if someone experienced that already, but any help would be welcome.

Pierrick

 

[phaedra74]

I have the same problem with the new unit.....
I have a bump when I switch the pot (not in all position).

In the week I check the line section....
mmm, first the stage2.