Pigtronix - Mothership

General documentation, gut shot, schematic links, ongoing circuit tracing, deep thoughts ... all about boutique stompboxes.
User avatar
skywise
Breadboard Brother
Information
Posts: 79
Joined: 23 Dec 2011, 05:09
Has thanked: 48 times
Been thanked: 22 times

Post by skywise »

Saw these photos whilst browsing a for-sale advert.
PTMS01.jpg

PTMS02.jpg

User avatar
PmCimini
Breadboard Brother
Information
Posts: 113
Joined: 29 Apr 2008, 19:10
Has thanked: 23 times
Been thanked: 1 time

Post by PmCimini »

Pretty awesome pedal... There was another gutshot of a different version, with through hole components...

User avatar
teej212
Breadboard Brother
Information
Posts: 108
Joined: 03 Jun 2009, 00:24
Has thanked: 4 times
Been thanked: 8 times

Post by teej212 »

very interested in the frequency to voltage converter!

User avatar
PmCimini
Breadboard Brother
Information
Posts: 113
Joined: 29 Apr 2008, 19:10
Has thanked: 23 times
Been thanked: 1 time

Post by PmCimini »

I used to think that it was based on this design, but not so sure anymore... The freq to voltage converter is based around a loop with two CD4047, but I can't read the IC names...

User avatar
modman
a d m i n
Information
Posts: 4890
Joined: 19 Jun 2007, 16:57
Has thanked: 4394 times
Been thanked: 2131 times

Post by modman »

Mothership.jpg
Please, support freestompboxes.org on Patreon for just 1 pcb per year! Or donate directly through PayPal

User avatar
chicago_mike
Tube Twister
Information
Posts: 1754
Joined: 03 Jul 2008, 04:38
Has thanked: 22 times
Been thanked: 316 times

Post by chicago_mike »

I believe I spy some JRC OTA chips. 13600 or 13700. :D

I wonder what the empty sockets are for if this was a "during repair" type of shot.
Skyline FX 2013

User avatar
chicago_mike
Tube Twister
Information
Posts: 1754
Joined: 03 Jul 2008, 04:38
Has thanked: 22 times
Been thanked: 316 times

Post by chicago_mike »

http://www.idea2ic.com/LM13600/UsingOTAs2.pdf

This has pretty good info on these OTA chips. I think those definitely are ota.
Skyline FX 2013

User avatar
puppiesonacid
Cap Cooler
Information
Posts: 672
Joined: 02 Apr 2008, 14:41
Has thanked: 9 times
Been thanked: 12 times

Post by puppiesonacid »

some of the mystery IC's revealed.

User avatar
plush
Cap Cooler
Information
Posts: 640
Joined: 08 Dec 2015, 09:29
Location: Moscow, Evil Russia
Has thanked: 36 times
Been thanked: 171 times

Post by plush »

puppiesonacid wrote: 16 Jun 2020, 15:15 some of the mystery IC's revealed.
wat? :scratch:

User avatar
puppiesonacid
Cap Cooler
Information
Posts: 672
Joined: 02 Apr 2008, 14:41
Has thanked: 9 times
Been thanked: 12 times

Post by puppiesonacid »

i couldn't upload from my phone. i will post from my desktop later.

User avatar
puppiesonacid
Cap Cooler
Information
Posts: 672
Joined: 02 Apr 2008, 14:41
Has thanked: 9 times
Been thanked: 12 times

Post by puppiesonacid »

gutshots
Attachments
mothership 10.jpg
mothership 9.jpg
mothership 8.jpg
mothership 7.jpg
mothership 6.jpg
mothership 5.jpg
mothership 4.jpg
Mothership 3.jpg
mothership 2.jpg
mothership 1.jpg

User avatar
puppiesonacid
Cap Cooler
Information
Posts: 672
Joined: 02 Apr 2008, 14:41
Has thanked: 9 times
Been thanked: 12 times

Post by puppiesonacid »

i took a ton more of the trace side and values of components side. I have the unit for a little while longer. It would be great to get a full trace done. There are built in options for implementing portomento/CV gate in and out, a midi section too. Not sure what the empty IC slots are for but could be related to the midi unused midi section. 48v 520ma power supply needed.

the chip used for ring mod are the same as the EHX frequency analyzerAD633 (multistate vibrator chip) and dual flip flop for sub octave(CD4047)

VCO from LM13700? Not sure why the 4558 opamp label was scratched out, its very common.

It would be cool to add features of the v2 of the ringmaster and v2 of mothership while retaining all the functionality of the v1.

its likely that the chip labels aren't scratched out on the v2 versions of the ringmaster and mothership since they are smd. if we can get detailed pics of those maybe a hybrid could be developed.

I am not sure but since the mothership sounds similar to the Korg MS20, i think it may have served as a template for the inspiration of the mothership. Videos of just a guitar going into the Korg MS-20's External Signal Processing sound nearly identical to the mothership clips.

It would be sweet to be able to use this as shown by Dave Koltai in this video:




Other videos demonstrating a guitar being played through the Korg MS-20's External signal processor:












Explanation of ESP:




Korg MS series info:

https://www.korganalogue.net/korgms/mssermans.html

the MS-04 external control pedal seems VERY interesting/promising to use with Guitar being processed via the MS-20 ESP.


https://microcontrollerslab.com/cd4047- ... brator-ic/

https://www.theengineeringprojects.com/ ... d4047.html

https://www.analog.com/media/en/technic ... /AD633.pdf

https://www.madbeanpedals.com/projects/ ... eekout.pdf

User avatar
puppiesonacid
Cap Cooler
Information
Posts: 672
Joined: 02 Apr 2008, 14:41
Has thanked: 9 times
Been thanked: 12 times

Post by puppiesonacid »

also very curious about the "VCO loopback Switch" port left empty. What is a VCO loopback and what does making it switchable benefit in sound and performance? its the empty port to the right (i.e. "north" in the pics orientation) of the AD633 in the pic I posted above.

User avatar
puppiesonacid
Cap Cooler
Information
Posts: 672
Joined: 02 Apr 2008, 14:41
Has thanked: 9 times
Been thanked: 12 times

Post by puppiesonacid »

ok so i had a pigtronix disnortion laying around and took one of the foot switches out and plugged it into the vco loop back switch. it makes a clean compressed signal the most prominent in the sound with the vco or the ring mod seemingly in parallel in the background. interesting additional tones to mix in. the clean blend knob doesnt control the volume/mix of the clean, but rather the vco knob does controls the volume of this mixed signal. seems that the ring mod sound is more versatile/accurate pitch with this setting. have yet to test its possible effect on the gate out and vc output jacks. just ordered some from small bear and need to wire them up.

cool thing is that this other mothership v1.7 board pedal i bought has none of the chip labels sanded off.

after initially being disappointed in this pedal, i have a much better understanding of how it functions and how to dial in sounds. still, it would be so much better if it had two vco's that could be setup at different intervals/ranges and have even more variety in vco tones.

still, this and the ehx micro-synth are the beat synth pedals ive had on my board that get the classic synth tones i've been wanting to have at my finger tips.

User avatar
affos
Information
Posts: 4
Joined: 18 Jan 2010, 01:28
Has thanked: 1 time
Been thanked: 17 times

Post by affos »

I bought one of these (SMD) and traced it - it was hell. It is a multilayer board and there are signal traces on the inner layers, not just ground and power. The layout is such a spider-on-LSD affair that I have to think it was done on purpose to confuse this community. 😀 It took me quite a bit of time with DMM and microscope but I think I have it complete. I have been working on redrawing the schematic in a readable format but life has gotten in the way.. one of these days I will finish it up and post!

User avatar
Scruffie
Opamp Operator
Information
Posts: 1739
Joined: 13 Mar 2009, 17:59
Location: UK
Has thanked: 28 times
Been thanked: 170 times

Post by Scruffie »

affos wrote: 04 Sep 2020, 01:37 I bought one of these (SMD) and traced it - it was hell. It is a multilayer board and there are signal traces on the inner layers, not just ground and power. The layout is such a spider-on-LSD affair that I have to think it was done on purpose to confuse this community. 😀 It took me quite a bit of time with DMM and microscope but I think I have it complete. I have been working on redrawing the schematic in a readable format but life has gotten in the way.. one of these days I will finish it up and post!
Looking forward to seeing the fundamental extractor portion :D :popcorn:

User avatar
uncleboko
Cap Cooler
Information
Posts: 509
Joined: 25 Mar 2008, 20:19
Has thanked: 58 times
Been thanked: 41 times

Post by uncleboko »

I too look forward to seeing the fundamental extractor circuit, as I do my annual treacle pudding and custard allowance under my low cholesterol diet!!!

User avatar
puppiesonacid
Cap Cooler
Information
Posts: 672
Joined: 02 Apr 2008, 14:41
Has thanked: 9 times
Been thanked: 12 times

Post by puppiesonacid »

the one i have is the non smd version, double sided (not sure if there are layers) i took a ton of pics and can help with that if need be. for some reason none of the ic labels in mine were sanded off so... someone must have wanted the info out there haha. Its a Howard Davis design so its chock full of doo dads and whatnots. i wish there was a second oscillator section and the "intelligent" tracking for the oscillator with a knob to select an octave range for it to work in or dial like an Ms-20.

User avatar
Tomrcarre
Information
Posts: 22
Joined: 15 Dec 2017, 14:42
Has thanked: 7 times
Been thanked: 7 times

Post by Tomrcarre »

Can’t wait to see a schematic of this, I bet it’ll be a nightmare to layout on vero.

User avatar
uncleboko
Cap Cooler
Information
Posts: 509
Joined: 25 Mar 2008, 20:19
Has thanked: 58 times
Been thanked: 41 times

Post by uncleboko »

Tomrcarre wrote: 12 Sep 2020, 09:36 Can’t wait to see a schematic of this, I bet it’ll be a nightmare to layout on vero.
Only if you let it!

Post Reply