5003 eq building and help.

[dandeurloo]

Myles,
I think you have two of the secondary leads swapped on the output transformer, which would explain your reduced output.
I think the output should be (from top to bottom)
red
gray
green
blue
yellow
purple
The picture you posted looks like yellow and purple are swapped.
The primary is, from top to bottom (to have in-phase output)
red
brown

Hey guys, I just did a little side by side with the eq's today compared to a 550b.  I was just checking the same frequencies to see how it sounds.  It sounds good!  The only thing was the eq's where 180 out of phase with the API 550b's. Has anyone else came across this.  If so I think we got the output transformers wired out of phase.

I think Orange and Purple need swapped then?  This is for PeterC's transformers.

 

[dmp]

Red and brown is the output, so if you are 180 out of phase you would want to flip those two. Mine was in-phase on a scope (input to output).
I'm not sure I understand the in-phase comparison to another eq?

 

[peterc]

As DMP said, swap the red  & brown

Regards
Peter

 

[dandeurloo]

ok, I can do that easy enough.  I just want to make sure i did have it wrong.

so the correct wiring on the output should be like this top down then?

orange
grey
green
blue
yellow
violet
brown
red

I was at a friends studio and I am now wondering if his tie line could have been wired out of phase so a clarification on the wiring would help.  I'm gonna ask him about the tie line phase as well.

Thanks

 

[dmp]

I'd suggest you verify which gives you in-phase output (red/brown, brown/red) and then report back.
i tried mine with red/brown both ways using a generator and scope and found for in-phase output, it was
red
(above)
brown.

 

[dandeurloo]

no scope.  could I just run a sine wave through it and see if it flips it?

 

[dmp]

Yes I think so... if I understand correctly. If you have a way to see a sine wave, compare the input sine wave to the output and if it is in-phase it means that they look the same.
http://en.wikipedia.org/wiki/Phase_(waves) 

 

[kazper]

I'm presently getting a quote together for some of the correct fitting pots from Omeg. I'll hit up Slender Chap over at Audio Maintenance first and see if he is going to stock them. If not I'll organize an group buy for them in the black market and put a post here.

I need to find thinner ty-wraps or another way to mount the inductors, they don't sit flush enough and are flexing the PCB a little to much for my liking.

 

[dandeurloo]

Guys, I just check the phase again and sure enough it was flipped.  So, put brown above red and checked again and it is now correct.

My test was pretty simple. 
1. I ran a loop of a kick sample out of the daw and back into see what the phase of that would be.  Basically, looking at the wave to see if the wave started above or below center.
2. ran the loop through the eq to see its phase.
3. flipped brown above red.
4. checked phase again to be certain it was correct.
5. i also confirmed the phase by running the loop through a few pieces I know are correct.

I feel good about this now.  So, maybe both of my wires had been colored wrong but I doubt it.  You guys should check phase as well with your systems. 

Hope this helps.

 

[dmp]

Tried them last night for acoustic guitar and vocals. Just need to order a switch cap from Jeff...

 

[dmp]

And inside...

 

[dmp]

I have one issue with my pair. When the knobs are at 12 o'clock or in bypass, the EQs are silent. When the LF knob is turned either + or - beyond about 6 or 9 dB, a low freq buzz, like a ground loop is noticeably. the MF and HF do this also but much less noticably, as the frequencies are higher.  I (perhaps foolishly) did some things differently when I built these, and I'm wondering if someone else who built them has this issue.

 

[janczmok]

Anybody got a spare black cap for the IN/OUT switch for me ?

 

[kazper]

Anybody got a spare black cap for the IN/OUT switch for me ?

I'm kicking myself for not ordering up some when I order a few things from Jeff at ClassicAPI.com


Here go's round 2..

 

[pjdiy]

I'm mating up the 5003 eq with Jeff's mic pre in a 1u case. I have the Five Fish psu that will power both.
One question I have is it better to keep them wired up seperately with their own input/output xlrs. Or do you
run the output of the micpre into the eq then to an output?
I'm still waiting on a faceplate from Peter.

 

[peterc]

IMHO I would have connectors for both on the back panel for independent usage, but put in a switch on the front panel to link them internally.

Peter

 

[dmp]

Word of caution, I'm pretty sure mine has 60 Hz hum because the rack psu is in the 11th slot. With metal shielding in between. you might not want to have your power transformer that close to the inductors.

 

[technut]

Just a warning. I had two bad traces in one of my boards. Make sure you look them over carefully.

 

[peterc]

Phillip

Can you take some pics & send them to me, if possible.

I need to take this up with the PCB plant.

Many thanks
Peter

 

[pjdiy]

Where were your bad traces located on the pcb?
Can you visually see them or did you find them with your DM?

thanks,
PJ