Author Topic: THE ENGINEER'S THUMB... At last, a better compressor!  (Read 223029 times)

tristanc

Re: THE ENGINEER'S THUMB... At last, a better compressor!
« Reply #740 on: March 30, 2021, 05:31:12 PM »
For now, is there anyone left producing circuit boards, preferably V3 or V4?

Is there a Vero layout for either of these versions?

I might have a couple remaining - drop me a DM. Or you can grab the KiCAD source / gerbers from https://github.com/tristancollins/pedals and get your own from PCBway or similar.

DIY Dood

Re: THE ENGINEER'S THUMB... At last, a better compressor!
« Reply #741 on: March 30, 2021, 05:53:15 PM »
For now, is there anyone left producing circuit boards, preferably V3 or V4?

Is there a Vero layout for either of these versions?

I might have a couple remaining - drop me a DM. Or you can grab the KiCAD source / gerbers from https://github.com/tristancollins/pedals and get your own from PCBway or similar.

Thanks... attempted PM, but it says your Inbox is full!


tristanc

Re: THE ENGINEER'S THUMB... At last, a better compressor!
« Reply #742 on: April 02, 2021, 06:25:13 AM »
For anyone else interested I have 5 boards available for the ET issue 2. Details and pics here:

https://www.diystompboxes.com/smfforum/index.php?topic=122355.msg1153513#msg1153513

Merlin has issue 4 boards available at his shop too.

scott17

Re: THE ENGINEER'S THUMB... At last, a better compressor!
« Reply #743 on: April 02, 2021, 07:57:48 PM »
Hello everybody, I'm new here.

Just an FYI for those that might be interested.
I purchased the Engineer's Thumb Compressor "parts only" kit from Das Musikding in Germany.
The kit came with everything except the enclosure and pot knobs, for $33.00 (27,90 EUR) including shipping.
I already had a project box, and including marking and drilling the box, this project took about 3 hours from opening the kit to completion.
YMMV, as I've been doing this kind of thing for a long time. This is a 5-knob kit, and as far as I can tell it is identical to the current schematic on Merlin's website with the exception of the MOSFET Millennium Bypass section, but it is true bypass via the footswitch.
The PC boards included are high quality. All resistors and diodes were soldered first, then IC/transistor sockets, then caps, then pots. I used a 1/8" spacer between the board and pots when soldering in place. Solder the switch to the switch PC board, then mount the LED to the enclosure first, then thread the switch PC board over the LED leads and tighten switch mounting nut before soldering the LED leads. I used different I/O jacks, but there is nothing wrong with the ones that come with the kit.
The circuit worked first time and sounds great! Thanks Merlin!




mdcmdcmdc

Re: THE ENGINEER'S THUMB... At last, a better compressor!
« Reply #744 on: April 02, 2021, 08:34:04 PM »
To the question about board availability, PedalPCB just released one.

DIY Dood

Re: THE ENGINEER'S THUMB... At last, a better compressor!
« Reply #745 on: May 03, 2021, 01:01:58 PM »
Following up on my inquiry... I just ordered the kit from Das Musikding in Germany per @scott17 's suggestion.

I'd need to hunt down buy nearly every component (aside from the box) as my stock is thin (newb). So, the slightly increased cost is worth it for me vs. buying a board from one of the folks here and then all components from a supplier like Mouser.

I'll report back after the build - or maybe before depending on the clarity of the kit.

garcho

Re: THE ENGINEER'S THUMB... At last, a better compressor!
« Reply #746 on: May 03, 2021, 11:44:25 PM »
You made the right choice, nothing wrong with a kit if you don't have many of the parts and aren't sure what you'll need in the future. And it's good to support businesses in the community. Without all the DIY/maker-friendly shops, prices would be higher for the weird old fashioned crap we use to build pedals with, and they would be much harder to find (compounding the price).
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eh la bas ma

Re: THE ENGINEER'S THUMB... At last, a better compressor!
« Reply #747 on: May 04, 2021, 02:55:57 PM »
I built the same kit than Scott17.

Despite the controls description in the document, I have some difficulties to hear what is happening, and find the right settings to hear some changes in the guitar's sounds when the pedal is engaged and when it's turned off.
How could I dial the controls to have the most audible setting, aside from the odd clipping effect when Ratio is CW, and Treshold, Release are CCW ?

What settings do you like, to "improve" your sound or to have a nice compression feeling?

I am not sure how the Ratio control works. On my build the sound gets "quieter" going CCW.

"At the extreme we get limiting, where the output signal is maintained at a constant level no matter what the input level. This is exactly what you want for maximum sustain" : "extreme" is fully CCW ?

When Ratio is fully CW, then the sound gets quieter when Treshold is turned CW. Does it mean that compression increases when Ratio is fully CW ?

"Attack- The time it takes for the compression to kick in when a loud sound comes along." CCW is short time CW is longer ?

"Release- The time it takes for the gain to recover after the loud sound has passed" : this one I can hear it allright

"Threshold- How big the input signal has to be before compression can happen" : CCW is "not big" and CW is bigger ?
« Last Edit: May 04, 2021, 03:38:34 PM by eh la bas ma »
"unity-gain non-inverting stage", "ground leg","post-pick moments", I love this colorful forum.

Kevin Mitchell

Re: THE ENGINEER'S THUMB... At last, a better compressor!
« Reply #748 on: May 04, 2021, 03:14:10 PM »
I am not sure how the Ratio control works. On my build the sound gets "quieter" going CCW.
With less compression it's going to amplify the signal less. So there's less compensation to keep the signal at a steady level.

If your input signal is too low the envelope will not function as strongly so the envelope sweep would be smaller.
If your power supply is too low you'll have less headroom and less of an audible difference, as it would cause a similar issue as I've mentioned above (being less wiggle room for the envelope and your signal)

If you think there's an issue with your pedal feel free to post voltages and photos.
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eh la bas ma

Re: THE ENGINEER'S THUMB... At last, a better compressor!
« Reply #749 on: May 04, 2021, 03:23:01 PM »
Thank you, I don't think there is an issue, I'm just a bit confused with the controls...
"unity-gain non-inverting stage", "ground leg","post-pick moments", I love this colorful forum.

Ben N

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Re: THE ENGINEER'S THUMB... At last, a better compressor!
« Reply #750 on: May 05, 2021, 08:52:27 AM »
Is there some way to eliminate some of that duplication?
Yes, use a switching jack socket:


What is the practical effect (usage) of a side-chain input when we're dealing with a single guitarist and a pedal?
None, AFAIK, but it can be handy when used in a more complex signal chain, for example after a filter or light overdrive, where you specifically want the compression after the other effect, but want to feed it a clean, full-dynamic signal with a minimum of noise. Split & buffer the signal at the top of the chain, sending one signal into the audio chain and the other straight to the compressor sidechain. This approach can be useful for other envelope controlled effects, like a filter after a compressor--normally the compression would make the filter ineffective, but feeding its envelope follower a pristine, unsquashed signal brings back max quack.A clean sidechain into a noise gate is also cool (see Boss NS-2).