Dynamic Haircut v2.0 (Barber Gain Changer)

[MattG]

Build Rating

5.00 star(s)

Here's a complete do-over of my "Dynamic Haircut", which is a clone of the Barber Gain Changer. Here's the build report for v1.0, which I did almost four years ago. I sold that build a while ago. I had long since given away my last v1 PCB, and someone recently messaged me asking if I had any left. That got me thinking about this circuit, and eventually I decided it was time to revisit it.

Funnily enough, the PCBs for v2.0 were delivered while I was working on the PedalPCB Sliver (Barber LTD SR). That motivated me to quickly build the Dynamic Haircut so I could compare them side-by-side.

You can see the big, mostly-empty space at the bottom of the PCB. That's space for my still-in-the-works Buffer + Bypass "Quasi-IC" Module. The mechanical 3PDT switch is a temporary stop-gap until the module is ready for use. The same JLCPCB order that included this PCB also included an (assembled) SMD PCB that is essentially a sub-set of the quasi-IC module (but for a different purpose). Unfortunately, that doesn't work, and in fact started smoking not too long after I applied power, so I've got some debugging work ahead of me - the quasi-IC might not be ready as soon as I'd like!

Anyway, this is a great, highly recommended circuit for a fairly transparent, well-tuned light overdrive. The higher-gain Unlimited side gets into pretty decent mid-gain drive as well. I'm a big fan of the user interface: three knobs and two switches gives a lot of flexibility and tweaking capability, but at the same doesn't feel overwhelming, or feel like there are more knobs than necessary.

The enclosure is the April, 2026 limited edition finish from Love My Switches. It looks sorta yellow in this picture, but it's actually more like a lime green. The graphic is from Robert Jordan's Wheel of Time fantasy epic. I recently read all 14 books and the prequel.

I have a few PCBs available if anyone wants one, just PM me.[/i]

Edit: see post #3 below for an update to this build.

 

[mckillacuddy]

Nice parts selection smorgasbord! Several fine flavors in there

 

[MichaelW]

Here's a complete do-over of my "Dynamic Haircut", which is a clone of the Barber Gain Changer. Here's the build report for v1.0, which I did almost four years ago. I sold that build a while ago. I had long since given away my last v1 PCB, and someone recently messaged me asking if I had any left. That got me thinking about this circuit, and eventually I decided it was time to revisit it.

Funnily enough, the PCBs for v2.0 were delivered while I was working on the PedalPCB Sliver (Barber LTD SR). That motivated me to quickly build the Dynamic Haircut so I could compare them side-by-side.

You can see the big, mostly-empty space at the bottom of the PCB. That's space for my still-in-the-works Buffer + Bypass "Quasi-IC" Module. The mechanical 3PDT switch is a temporary stop-gap until the module is ready for use. The same JLCPCB order that included this PCB also included an (assembled) SMD PCB that is essentially a sub-set of the quasi-IC module (but for a different purpose). Unfortunately, that doesn't work, and in fact started smoking not too long after I applied power, so I've got some debugging work ahead of me - the quasi-IC might not be ready as soon as I'd like!

Anyway, this is a great, highly recommended circuit for a fairly transparent, well-tuned light overdrive. The higher-gain Unlimited side gets into pretty decent mid-gain drive as well. I'm a big fan of the user interface: three knobs and two switches gives a lot of flexibility and tweaking capability, but at the same doesn't feel overwhelming, or feel like there are more knobs than necessary.

The enclosure is the April, 2026 limited edition finish from Love My Switches. It looks sorta yellow in this picture, but it's actually more like a lime green. The graphic is from Robert Jordan's Wheel of Time fantasy epic. I recently read all 14 books and the prequel.

I have a few PCBs available if anyone wants one, just PM me.[/i]

How does it compare to V1 tonally?

 

[MattG]

How does it compare to V1 tonally?

Impossible to say, I sold v1 quite a while ago. But I recycled the schematic from v1, so I would expect it to be exactly the same. Really, the only difference in v2 is the PCB layout.

 

[MattG]

I finally realized the Buffered bypass "quasi-IC" module I've been working on for a while now. This "Dynamic Haircut v2.0" was designed to be the first victim of the module.

But of course the success wasn't realized without a comedy of errors. The long-term goal for the quasi-IC is to have crenulated edges, so that it can be direct-soldered to the parent effect PCB. But until the design was proven good, I had planned to use pin headers. I received the modules today, and went to solder up the pin headers... only to realize, the ones I have on hand don't mate properly (the male parts are too big for the female parts - layup for jokes intended). So partly out of over-confidence and partly out of impatience, I used only the male pin header parts to direct-solder the module to the effect PCB.

First power up and... nothing. No bypass, no effect, no status LED. I was immediately deflated. With great sadness, I got out the DMM and checked to see if the quasi-IC module was even getting power - it wasn't. Before I could even scratch my head, I realized the problem: I had soldered the module upside-down!

So then I spent an inordinate amount of time undoing the solder so that I could right the daughter board. I re-soldered it, correctly oriented this time.

Test #2: bypass works, the LED lights up in engaged mode - is this an end to my sadness? No, no sound in engage mode.

With my frustration renewed, I started checking the signal path with an audio probe. Quickly I discovered that there was no connection between the module's effect-send and the actual effect's input. I tried reflowing the connection between the PCBs, but that didn't help. I think I destroyed the plated through hole of the effect PCB when I did the unsoldering. But it's an easy fix: a quick patch job with a jumper wire, and the connection was made. I sanity checked the other connections with my meter - they were all good.

Test #3: finally, success! What should have been a five-minute solder job and a night of enjoying the fruits of my labors turned into a series of bone-headed moves and frustration.

But in the end it works, so that's the main thing!

 

[OD is Glorious]

Thanks for the report. i love your labels