Collosalus Build

[Ny_racer_xxx]

I did a scratch build that turned out pretty good, my buddy wanted one, and I wasn't doing another scratch build.  Finally the boards were in stock, so here I go....

[jessenator]

Can't wait to see the final builds in their enclosures

Been thinking about a flanger, but haven't pulled the trigger yet. Too many other builds in flight.

[Ny_racer_xxx]

Can't wait to see the final builds in their enclosures

Been thinking about a flanger, but haven't pulled the trigger yet. Too many other builds in flight.

Everything was going fine until I put it in the enclosure!!!   I was going batty trying to trouble shoot, bad solder joint? Bad chip?
I went through the excellent trouble shooting guide, sound going into TP1, nothing coming out on TP2.  A few IC's had weird voltages, popped them out one at a time, popped them in my scratch build, no issues.  Started check transistor voltages, found Q2 out of whack and had the same voltage on the collector and emitter looking like a short in the transistor.  Pulled Q1 and Q2, tested them, Q2 was deff bad, tested new ones and replaced both.  BINGO!!!  All is right in the world again!!!

FYI Brian, the way you mirrored the pin assignments on IC7 CD4013 on the schematic, was driving me crazy!!

[madbean]

FYI Brian, the way you mirrored the pin assignments on IC7 CD4013 on the schematic, was driving me crazy!!

Sorry about that. Here it is expanded out if that helps.

[Ny_racer_xxx]

 No problem, found the bad transistor, working as it should...

Now question for you.  Looks like you added an opamp stage to the NE5532?  What was the reason for that?
To my ears, the original sounds thicker, it's pretty easy to bypass that stage and make it like the original.

[madbean]

No problem, found the bad transistor, working as it should...

Now question for you.  Looks like you added an opamp stage to the NE5532?  What was the reason for that?
To my ears, the original sounds thicker, it's pretty easy to bypass that stage and make it like the original.

The original MXR used one op-amp shared between the LFO and the audio filtering coming out of the BBD. For the 2022 version I split that into two different op-amps then used the free one as an input buffer to the circuit. I suppose I could have made that part switchable. Actually had not occurred to me.

The reason I added the buffer is that it can sometimes prevent any ticking one might have with LFOs/modulation circuits.

[Ny_racer_xxx]

No problem, found the bad transistor, working as it should...

Now question for you.  Looks like you added an opamp stage to the NE5532?  What was the reason for that?
To my ears, the original sounds thicker, it's pretty easy to bypass that stage and make it like the original.

The original MXR used one op-amp shared between the LFO and the audio filtering coming out of the BBD. For the 2022 version I split that into two different op-amps then used the free one as an input buffer to the circuit. I suppose I could have made that part switchable. Actually had not occurred to me.

The reason I added the buffer is that it can sometimes prevent any ticking one might have with LFOs/modulation circuits.

Thank you for that explanation!!!  Very much appreciated....

I was just trying to compare what is different from 2022 to the 2015 prototype board I built.  The power supply is slightly different from your designs as well. Minimum filtering, no diodes or caps on the input side of the regulator, and just a 100u cap on the regulated side...  I like using a diode for reverse polarity safety...

I'll experiment and report back.

CR

[Ny_racer_xxx]

Here's a clip of both the 2012 prototype and the 2022 PCB, one in each each channel, pretty damn close to me...

https://soundcloud.com/c-reinhardt-406023805/flanger-test?si=2da30fa38e804409986c80e204a473ad&utm_source=clipboard&utm_medium=text&utm_campaign=social_sharing