EQN build thread

[12volts]

Peter, is this right for the switches?

I stuck resistor leads in to show the placements.

This is for the top 2 switches.

Dan, summat else.

On top of your pin location problems ...... If you look on the photo, you haven't filed down the PCB
'pips' left over from routing. The metalwork sits flush on this edge. The 'pips' have to be removed before
assembly .......



Frank

 

[peter purpose]

Frank... he's obviously a muso in a hurry.

 

[12volts]

Frank... he's obviously a muso in a hurry.

I have a soft spot for musos. Because of them I drink.

Frank

 

[peter purpose]

Frank.... That's why I got out of the studio business.... I still drink though..!!

 

[dandeurloo]

Thanks for the compliments guys.  I do make my living from making music and working with musicians... not circuits as I am sure you can tell.    Because of that I do have plans for this wonderful project as soon as I can get it wrapped up. 

Frank I do have plans for a little file time once I go to the shop again.  Sharpe eye!

 

[peter purpose]

Dan... don't try to seduce Frank to into giving you the answer you lazy twunt.... read something.!!

 

[dandeurloo]

Wow Peter...

 

[zayance]

Sorry Mr Peter for helping out  ;D Here is the instructions for the Grayhill if you still need it. And IIRC, when watching the switch from the front with pins flat on the desk, you have to put a pin at 12o' clock, and one at 6 if you want it to switch 6 position etc...Seeing your pictures you just got the switch at 90°, if you check at the back you'll see the numbers according to the positions. Correct me if i'm wrong. And just have to make sure the point 1 of the instructions, if this can help?

 

[dandeurloo]

Thank you good Sir!

 

[dandeurloo]

I am 99% sure I got the switches correct thanks to some info from zayance!  So, if anyone else gets hung up on the same thing I did here are a few things.

1. 12:00 on the switches is with the eq laying down pins against your work surface.  Not in the standing up position that it will be in the 500 rack.

2. With this as your starting point the info on page 6 makes sense!

3.  The other thing I kept getting hung up on was the orientation of the flat portion of the shaft.  In this application it doesn't matter other then in making sure you have it start opposite position 2 on the switch.  I was thinking that the screw of the knob would screw into this portion of the shaft like they generally do, but that is not the case!  Just get the positions to work correctly then line up the knob so it points properly on the faceplate.  Not the flat part of the shaft.

Hopefully that info will help anyone else from getting hung up on the switches. 

 

[technut]

Been Stuck for a couple of days. Fired it up. Power seems to be getting where it needs to and measures correctly but i'm not passing any signal with the eq in or out. Can someone give me a clue on where to start on this. I have resoldered every point on the board.

 

[dandeurloo]

got any pics?  Is the output tranny wired correctly?

http://www.groupdiy.com/index.php?topic=38884.0

 

[technut]

I will check again tomorrow but I'm almost 100% sure it is.

 

[briomusic]

@technut: have you tried toneprobing or scoping around the circuit to see how far the signal gets?

in my case it was 'broken' right at the input transformer and the source (dodgily balanced output of behringer headphone amp) ended up being at fault.

good testing points are R7 (right before the eq section) and C48 (right before the output amp).

 

[peter purpose]

Any overnight joy technut?

 

[technut]

Just got to work. Output transformer is wired correctly. Will probe during lunchbreak.

 

[technut]

Ok i tested at r7 and c48. both are very faint but the same level at both. Maybe its the input tx. I have the right wires connected to the proper places on the pcb. Maybe i dont have the right stuff strapped together on it. Heres how I have it wired. 2 to 4,3 to 5,3 to 4,7 to 8 and 9 to 10.

 

[peter purpose]

OOOO NO...... !!
Have another look at that schem..... 3-4 as a starting point.

 

[technut]

Ok I will. Thanks Peter!

 

[technut]

All fixed!!!!! Just need to calibrate. Thanks again!