AION BLUESHIFT (BOSS DIMENSION C CLONE) QUESTION

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tedsorvino

Well-known member
Joined
Aug 1, 2018
Messages
74
Location
Athens, Greece
I don't know if anyone is familiar with this pedal (original or clone project)
I've built it and it works quite well.
But there are some minor issues.

Firstly, one side of the BBD ICs (IC 9 and  8 ) have quite different voltages to the nominal ones and the other side of BBD ICs - IC 3 and 4 (even if the effect sound on both outputs is pretty much the same).
And the voltages on all test points seem correct. I have to admit that I haven't used an oscilloscope for calibration. Just a DMM.

Another issue, is that according to the layout and schematic a TRS socket has to be used on one of the two outs (output B). Both outs were working well in Mono. But in Stereo mode that particular out was causing a problem of stoping the effect (just dry signal) from the other out (output A- a simple TS out), when a normal TS jack was plugged in. I decided to disconnect the Ring connection from the PCB and socket and now everything works as it should (?). Good amount of effect on both outs.

Is this a normal behaviour? Any ideas about possible problems? Does the different voltages on IC 9 (not the callibrating pin 3) affect the overall behaviour (even the outs issue?
You can check the schematic and layout on the aionelectronics site if you want https://aionelectronics.com/project/blu ... -c-chorus/

Thanks in advance
 
tedsorvino said:
I don't know if anyone is familiar with this pedal (original or clone project)
I've built it and it works quite well.
But there are some minor issues.
I never used those specific parts but look like typical BBD ASRs.
Firstly, one side of the BBD ICs (IC 9 and  8 ) have quite different voltages to the nominal ones and the other side of BBD ICs - IC 3 and 4 (even if the effect sound on both outputs is pretty much the same).
The BBDs are IC3 and IC9 ,  IC8 and IC4 are clock driver chips. Besides generating the two phases of clock waveforms, they may also generate a bias voltage used by the BBD.
And the voltages on all test points seem correct. I have to admit that I haven't used an oscilloscope for calibration. Just a DMM.
Some of those pins have high frequency square waves (clock waveforms) so DMM may not give accurate measurements.
Another issue, is that according to the layout and schematic a TRS socket has to be used on one of the two outs (output B). Both outs were working well in Mono. But in Stereo mode that particular out was causing a problem of stoping the effect (just dry signal) from the other out (output A- a simple TS out), when a normal TS jack was plugged in. I decided to disconnect the Ring connection from the PCB and socket and now everything works as it should (?). Good amount of effect on both outs.
maybe don't plug a TS plug into a TRS jack as that will short ring to sleeve.
Is this a normal behaviour? Any ideas about possible problems? Does the different voltages on IC 9 (not the callibrating pin 3) affect the overall behaviour (even the outs issue?
do both sides pass similar level of audio cleanly?

If one side is low/distorted perhaps chip is bad, but confirm that clock and bias voltages are correct.

NMOS chips are high impedance and can be damaged by mishandling, or even shorting pins while probing.

Do no harm.

JR
You can check the schematic and layout on the aionelectronics site if you want https://aionelectronics.com/project/blu ... -c-chorus/

Thanks in advance
 
Thank you so much for the time and kind advice John

JohnRoberts said:
"IC8 and IC4 are clock driver chips. Besides generating the two phases of clock waveforms, they may also generate a bias voltage used by the BBD. "

They are clock drivers. The BBD Bias pins are pin 3 on both IC 3 and 9 (the BBD ICs). The correct voltage is around 3.5V for both. I will also try an oscilloscope, as soon as I get hold of one.

JohnRoberts said:
"maybe don't plug a TS plug into a TRS jack as that will short ring to sleeve. "

That's what I thought. That's why I changed the wiring to a TS one. According to the instructions the TRS socket is supposed to work as a switch and presumably it is supposed to work with a TS jack - Mono guitar cable.

JohnRoberts said:
"do both sides pass similar level of audio cleanly?"

There never was an issue of uneven and unclear signal. But since changing the output wiring the effect amount is similar to both outs. But I still wonder why the TRS socket doesn't work.
 

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