Aion Blueshift

[TNblueshawk]

Ok, so I probed all the IC's actually. First, both BBD's pass zero signal on pins 7 and 8. Quite as a church mouse there. Of the 12 IC's the following are the only pins to pass signal.

IC 1 - pins 2 & 7
IC 2 - pin 5 barely audible but still there
IC 11 - pins 4 & 12
IC 12 - pins 2 & 6.

All other IC's and pins pass no signal or really any noise at all for that matter. No static etc...

Voltage readings:

IC 1:         IC 5:              IC 7:                                    IC 12:
1: 0           3.77-5.09       .6 - 6.0 ( quite the swing)       4.6
2: 4.6         .9-1.64         3.28                                       4.6
3: 4.6        1.5                2.1-4.5                                   4.6
4: 0            0                  0                                             0
5: 4.6         3.31              3.31                                       4.6
6: 4.6         3.31              3.31                                       4.6
7: 4.6         2.2-4.5          2.5-4.1                                   4.6
8: 9.21       6.24              6.62                                        9.21

[Scruffie]

Okay, you've gone a bit off course with your probing.

IC2 pin 7 is where you should listen for audio, should be loud and compressed.
Then, assuming that checks out you can follow to Q5 emitter and then pin 3 of each BBD.

If you get signal at pin 3 of the BBD and it wont pass at pin 7&8 with adjustment of the bias trimmer, might have to consider the BBD or clock again.

IC1 pin 1 voltage reading I'm going to assume is a mistake.

[TNblueshawk]

So pin 7 on IC2 is dead. No sound. Swapped it out for another Cool Audio V571 no dice.

Yeah that was a mistake. Pin one on IC 1 has 4.6v

Want pics at this point?

[Scruffie]

Sure, post some up of that area.

[TNblueshawk]

Had to step away from this one as I was getting irritated. I decided to reflow all the joints to be sure and then I got static. Went over it again and I had 2 solder bridges that I must have done when reflowing. Now I'm back to where I was. Here are some pics.

I can't imagine trying to figure out the audio path on this thing. Still dead at pin 7 of IC 2 as well as pins 7 & 8 of the BBD's.

Scruffie, I don't expect you to spend a ton of time on this (or any for that matter). Feel free to bail if it is just too deep. I'll just have to lick my wounds and move on from this thing.

[Scruffie]

It's not as complicated as it looks, no different to any other delay circuit really, just everything's split and doubled but to reach the BBD's, the signal must past through IC2.

I see tantalum capacitors, you didn't get them from Tayda, did you?

[EBK]

Maybe get a toothbrush and some alcohol and clean off some of the flux.  You might spot something you missed.  Also, my build of this circuit didn't work right away either.  But, it is well worth the effort.  It is a very nice chorus.  For what it is worth, my initial attempt had a bad ground wire.

[Bio77]

You are missing the two (3 pin) headers in the middle of the boards.

Agree with EBK, you should definitely stick with this one, it's worth it.

[EBK]

You are missing the two (3 pin) headers in the middle of the boards.

I was just now wondering about those myself.

[Scruffie]

Oh, is that what those are for, yeah, that sounds important.

[TNblueshawk]

1. I don't recall if I got the tants from Tayda. I got parts from multiple places when I loaded up to build all these. Are they notoriously bad?

2. Holy crap! The middle pin headers  . I was so focused on the connecting the outside pin headers I didn't see the forest from the trees and looked right past that 

Well I'll report back once I connect those.

[gordo]

I once tacked the outside pins on all the sockets on a Rust Bucket and then left it at that.  I trouble shot for hours staring at the board to make sure I didn't have any bad solder joints.  In my brain I guess I wasn't looking for MISSING solder joints.

So I'm not about to throw any stones :-)

[TNblueshawk]

Success! Just about peed myself.

So I fiddled with the trimmers after starting at 3.4v but have a question. Is this a subtle chorus? I ask because the switches change the sound a little but not a lot. Same with the trimmers. I'm wondering if I need to look at some other things to get more 'lushness'.

I realize by separating the boards I sort of created my own monster so I'll own it if by doing that I may have altered things.

Thanks for the sympathy thoughts Gordo 

[danfrank]

I don't know if I'd call it a subtle chorus pedal, it doesn't really sound like most others. If you have a scope to calibrate the pedal with, that will make it A LOT easier to do. Since this has two BBDs in it, the first BBD is easy to dial in (the pedal starts to chorus) but the second BBD is harder because it's sound gets placed "on top of" the other's chorus sound. If you don't have a scope, I guess the best way to describe it is that when the second BBD gets dialed in, the chorus sound gets "thicker".
A scope makes it so much simpler though ..
Hope this helps

BTW, switch "4" will give you the most pronounced chorus sound. The Blueshift kills when used as a stereo chorus. The "lushness" comes in when used in stereo

[Bio77]

Awesome, congrats!

You do need a scope to get it perfect but around 3.2-3.4 sounds right and should give you a nice sounding pedal. Once you get the trimmer above a certain threshold you won't hear a big difference, it will just start to clip when the input is too large. 

Not sure I would say this is subtle sounding, but it doesn't have a dramatic warble like other choruses.  That's what the two BBDs are all about.