EQN build thread

[jsteiger]

peter's suggested part is 130mA...

Yes I did see that.

i have a feeling a neve class A line stage can pull more than 100mA surge at startup? can't remember....

There was some back and forth banter with Dan K. about this in Peter's original thread. Nothing definite was ever mentioned in public but I think that there is some delay circuitry involved before the DC-DC converter to limit the inrush current. The last mention is here. http://www.groupdiy.com/index.php?topic=36096.msg445440#msg445440

 

[haima]

there's also this thread - http://www.groupdiy.com/index.php?topic=28577.40 - in which dan kennedy gave us the delayed turn on DC-DC converter circuit from his 500 series mic preamp.

dan said:

"I also used a simple transistor turn-on circuit that keeps the converter off until the rack is near full supply, or it's initial surge will cause the regulators of the rack to current limit."

still not sure about the total current drawn though those inductors though. i believe a properly biased 1073 draws around 110mA? this circuit would be slightly less i think?

 

[peter purpose]

130mA each on two rails.... not had a problem with said part.

 

[Marcocet]

Does anybody have a good scan of their PCB available? I built all of mine and now am having some difficulty following the traces in order to troubleshoot one of them.

The rest all function perfectly (though I have noticed that there's about a 1db gain loss when they're inline, both while engaged and bypassed) but on one of them the mid band doesn't seem to do anything. I pulled the mid amp card and swapped it as well as checked out all my solder joints and everything looks pretty good, but it's hard to follow exactly where the signal's going without a map and I stupidly didn't keep a photocopy of one of the PCBs around.

Thanks for any help!

-marc alan goodman

 

[canidoit]

Does anybody have a good scan of their PCB available? I built all of mine and now am having some difficulty following the traces in order to troubleshoot one of them.

The rest all function perfectly (though I have noticed that there's about a 1db gain loss when they're inline, both while engaged and bypassed) but on one of them the mid band doesn't seem to do anything. I pulled the mid amp card and swapped it as well as checked out all my solder joints and everything looks pretty good, but it's hard to follow exactly where the signal's going without a map and I stupidly didn't keep a photocopy of one of the PCBs around.

Thanks for any help!

-marc alan goodman

I have one up here if you need it.
http://www.groupdiy.com/index.php?topic=38884.msg492539#msg492539

Download the links for a larger and high resolution version of what I have so far.

 

[Marcocet]

Thanks dude!

 

[haima]

marc - you've finished a few channels? how do you like the sound? i'm pretty close to finishing my pair - just waiting for a few parts to come from the US...

 

[peter purpose]

I have noticed that there's about a 1db gain loss when they're inline, both while engaged and bypassed

Have you tried adjusting RV4 (fader) to make up the loss?
If you have, then R29 needs to be reduced to increase the gain in the output amp.

 

[Marcocet]

Ahh. Yeah, I calibrated it, but until just now I didn't know exactly what R29 was responsible for. I just threw a 1k in there. Any suggestions on what range I should jump to?

They sound awesome. I've put one of them up against my 1064s in some quick listening tests and they were almost identical, however I'm doing my first real session with 7 of them in the console today.

Here are some quick phone photos:

 

[zayance]

Looks super nice, funny i wanted to use these kilo aluminium knobs also, i had some for one stompbox, and it was looking killer on EQN, very nice  8)

 

[funkymonksf]

Awesome work Marc. I agree that the Kilo knobs look killer. I'm actually surprised how good thy look. Might do it myself.

Does anyone have any tips or instructions on how to bias and setup the 1084?

Has there been any common decision on what value to use for R29? What are you using Peter?

Thanks to you all,
Brice Conrad

 

[haima]

looks amazing! where's the drool icon?!?

yes, those knobs look great - where did you get them? they'll do - at least until jeff comes though with his red and blue numbers 

nice studio too marc, checked out your site...

 

[jsteiger]

Nice desk Marc. That looks like it is a PW tweener? Between the Saul Walker era 2488's and before Paul started with the Legacy line? The bus modules look familiar. I quoted a guy in SF on making 40 new custom bus modules. He said his were all dead and useless.

Are those 4 band APSI parametrics off on the right?    Nice.

Good to know you are digging the EQN's. After today's UPS, I should have everything on hand to build out my pair. I hope the wife gives me enough space to get that done this weekend!!    I also hope she never reads this post!!  :

Best, Jeff

 

[zayance]

yes, those knobs look great - where did you get them? they'll do - at least until jeff comes though with his red and blue numbers 

Digikey has all the Kilo knobs catalog, my favorite aluminium knobs  , the Knurled Straight are not cheap tough

 

[haima]

Digikey has all the Kilo knobs catalog, my favorite aluminium knobs  Smiley, the Knurled Straight are not cheap tough

darn. i knew you were gonna say that - i JUST placed my digikey order for the DC-DC converters! and at $30 shipping to australia i won't be doing another one for a bit  :'(

jeff - i believe marc's desk is a 1608!

 

[jsteiger]

...
jeff - i believe marc's desk is a 1608!

Haha! Right you are! My stare was so focused on the EQN's and then directly to the APSI's...that I never even noticed the meter bridge! Duh!!

 

[haima]

any movements on the coloured knobs front jeff?  :-*

 

[jsteiger]

any movements on the coloured knobs front jeff?  :-*

I talked to them yesterday about a big 3-50 pointer knob delivery. She reassured me that the owner had my price request for the EQN and would be handling it himself. I have not heard yet. I will follow up with them again Tuesday. Monday is Independence day here!! 

 

[zayance]

darn. i knew you were gonna say that - i JUST placed my digikey order for the DC-DC converters! and at $30 shipping to australia i won't be doing another one for a bit 

Sorry about that, but just for info, Digikey has free shippings worlwide for purchase over 65 euros, or dollars don't remember, anyway, those 30 dollars would have been for other things, like knobs yes  , but dont want to be a PITA just wanted to let you know if you missed that one  :

 

[Marcocet]

Yip. 1608. Yes they're APSI parametrics. I have a pair of the 559 Graphic modules too in a rack off to the side, as well as 4 Aengus EQs which are my favorite things in the friggin universe.

As of a few weeks from now the desk will be 16 EQN - 8 APSI 562 - 16 Purple ODD. Extremely excited

Anyway did my first session with them today. Ended up using them on almost everything. If I was eqing on the way in I used the 1064s, but I didn't bother patching them in at all during the mix. EQNs were killing it.




Onward: I haven't had a lot of time but I've been trying to figure out what could be wrong with my 8th module. If the mid band is off it passes signal perfectly, but if I turn it to any of the settings i lose my signal. I checked all my solder points and tried to trace the lines out but I can't quite figure why I would be losing all of them except for off. If anybody has any clues it would be greatly appreciated.