Blueshift from Aion FX question(s)

[matopotato]

Hi,
I am in the pricess of building the Blueshift fron Aion FX. Som components in the kit I got do not fit phisically. Especially C3 is too tall. It is 47uF/35V. I can bend it and solder a bit away from the base soit lies over some resistors, but would prefer to have a cap with lower profile. I have a 47uF half the height but it is 16V.
So I wanted to ask if that would work, or is the C3 exposed to some voltage pump(s) that could push it over 16V?
There is one cap elsewhere on 100uF/16V, but the location could be quite different between them.

[antonis]

As far as I can see, C3 is VR (+4.5V bias voltage) cap..
It can be rated as low as 6V..

https://aionfx.com/app/files/docs/blueshift_documentation.pdf

[matopotato]

Thanks!
I wasn't considering running on more that 9V either although I like to study build to see if it is possible or not. But not for this one.

[matopotato]

I managed to get the pieces together, and it does bypass and lights up, but no effect. Only thing I notice is a slight volume drop when engaged, but I take that as a sign the som parts work as expected.

Are the pins 3+3+3+5 all part of connecting the boards? As I need to trace and trobleshoot I would have to construct some connections if the boards need to be separated (so I can navigate and reach)

I managed to connect it to 18V for a short while before realizing my mistake. If that fried some part, which part(s) are most likely to have been broken?

Any other hints on "try this first" are much appreciated.

[iainpunk]

have you tried to bias it?
if the bias is all out of whack, theres a chance the signal is out of range fore the BBD's

cheers

[matopotato]

have you tried to bias it?
if the bias is all out of whack, theres a chance the signal is out of range fore the BBD's

cheers

Sorry for late reply. Biasing, you mean by the trims to be used for oscilloscope trimming? I only have those two.

[Kevin Mitchell]

have you tried to bias it?
if the bias is all out of whack, theres a chance the signal is out of range fore the BBD's

cheers

Sorry for late reply. Biasing, you mean by the trims to be used for oscilloscope trimming? I only have those two.

Yes that is what they mean. You have to level out the BBD's incoming signal so it's in the center of the power supply range for a clean signal processing. If it's out of range the signal through the BBD will be weak & noisy, distorted or totally lost. That's why antonis refers to the bias voltage as 4.5v as it's the center of a 9 volt supply.

[matopotato]

Ok, thanks. I will try. I think they are in the middle based on eyesight. I read that the detailed setting needs an oscilloscope and sort of middle was enough for basic test, but for sure I  will try. I was just expecting some sort of effect reaction at first plug in and switch flips.

[PRR]

> sort of middle was enough for basic test,

The "working zone" can be narrow, and is never quite centered.

If you have just one BBD, set up a looper to play steady while you diddle. You will soon find the working zone, and both edges where it craps-out. Center on that, then increase the level into the BBD and trim for best undistorted output.

IMHO (and I worked with early samples), the 'scope is a crutch. Simple delays are best trimmed by ear.

If this is one of those thinsg with 2, 3, 4 or more BBDs, you either break them up into single stages or fire-up the 'scope.

[matopotato]

Many thanks! (Hope is gradually returning)
The 2 16pin ones are V571 in my kit. I assume these are the BBDs.
Will run the looper and turn the trimmers tonsee what happens and report back.

[Kevin Mitchell]

The 2 16pin ones are V571 in my kit. I assume these are the BBDs.

Those are companders, not bucket brigade devices.
Not sure what they supplied in the kit, but it would have been a pair of V3207, MN3207 or MN3007.
There's also BL3207 but I doubt those are readily floating around still.

I hope you've considered the build notes about preparing the power supply traces for the choice of MN3007 and the lower voltage *3207 variants.

[matopotato]

Thanks!
The Aion FX BOM said
2x OPA2134
2x NE570/571
2x MN3207
2x MN3102
2x TL072
1x TL022

And it Became
2x V571 (= NE570/571)
2x V3207 (= MN3207)
2x V3102 (= MN3102)
5x TL072
In my kit.

I thought BBDs were 16 pins for no intelligent reason at all.
And I had naïevely assumed that the IC supplied by Das Musikding were already considered for the proper "power traces".
I hope they still were, but I probably have to do some more studying before building so.ething next time around.

[Kevin Mitchell]

Sorry let me correct myself - build doc says that the Blue Shift only supports MN3207/V3207.
I've built too many BBD based effects. Or not enough 
My recollection is a mess lol

The ICs that they had supplied you are correct for this build. Mostly modern Cool Audio alternatives.
V571 = compander
V3207 = BBD
V3102 = clock
TL072 = dual opamp

The OPA2134 in the original BOM are suggested as a *quality* dual opamp for the signal path. Not super critical and a TL072 will work fine.
Not sure but I'd guess the original mostly had RC4558 dual opamps as most boss pedals had.

The TL022 is in the LFO/modulation section. It may be worth while to use one for IC7 if the modulation isn't up-to-par.

[matopotato]

Thanks! I got 2 OPA2134/OPA2132 around I might try after suggestion. And I ha e maybe a TL022 as well. Just need.to get it to produce some chorus-y effect first. This weekend is lost as far as that goes but soon enough.
I now have a few things to try, and a probe to step around with. Any particular area to be extra careful with the probe?
I've done some random probing on a ThumbSucker compressor and it does pop quite a bit at some places.

[Kevin Mitchell]

Sounds like you're on the right track!
Just follow the signal path according to the schematic in the build doc going to and from each IC or transistor.

Example - on IC2, if the guitar/input signal is on pin 6 but not 7 then IC2 is suspected to be bad or an error on the supporting circuitry.

We just need to know if & where the signal drops out so we can advise further. From there providing voltages on the relevant IC or transistor would be easier on everyone instead of going through everything in one go.

A capacitor (like .1uF or so) on the tip of the signal wire should help popping when you go to probe.

[matopotato]

> sort of middle was enough for basic test,

The "working zone" can be narrow, and is never quite centered.

If you have just one BBD, set up a looper to play steady while you diddle. You will soon find the working zone, and both edges where it craps-out. Center on that, then increase the level into the BBD and trim for best undistorted output.

IMHO (and I worked with early samples), the 'scope is a crutch. Simple delays are best trimmed by ear.

If this is one of those thinsg with 2, 3, 4 or more BBDs, you either break them up into single stages or fire-up the 'scope.

So I tried to work the two internal trimpots. moving about each with the other in the middle, zero or "dimed", and vice versa. No change. Only audible was when TR2 is dimed, there is a slight scratch, but nothing chorus-y

[matopotato]

Sounds like you're on the right track!
Just follow the signal path according to the schematic in the build doc going to and from each IC or transistor.

Example - on IC2, if the guitar/input signal is on pin 6 but not 7 then IC2 is suspected to be bad or an error on the supporting circuitry.

We just need to know if & where the signal drops out so we can advise further. From there providing voltages on the relevant IC or transistor would be easier on everyone instead of going through everything in one go.

A capacitor (like .1uF or so) on the tip of the signal wire should help popping when you go to probe.

As far as IC2 goes, there is signal on pins 1, 2,3 and 5,6,7. It varies a lot from faint almost not audible to not so nice sound probably due to my lopper output + probe design. Still it is clearly from the looper.
I followed the signal on to the next PCB and here I have signal on IC3 pin3 and IC9 pin3, but nothing else on those two or any of the other ICs on that board.
Not sure that helps any. Let me know if I should find some readings on some ICs.
Cheers