Search found 13 matches

by bobbass4k
01 Nov 2018, 15:50
Forum: Boutique Stompboxes dissected...
Topic: DSM OmniCabSim
Replies: 60
Views: 20382

Re: DSM OmniCabSim

Re: Bajamans schematic - Thanks man, I wasn't too sure about the punch cap values and I checked the other filters against the manual but did it before I'd settled on the punch section, your values make a lot more sense. Just a disclaimer on the other changes - I think the manual probably uses neat r...
by bobbass4k
29 Oct 2018, 14:04
Forum: Boutique Stompboxes dissected...
Topic: DSM OmniCabSim
Replies: 60
Views: 20382

Re: DSM OmniCabSim

The pots are marked correctly as they should be as the circle indicates pin 3 (clockwise). This is how EasyEDA (and most CAD programs I've used) does it and as far as I'm aware the convention is to mark the clockwise direction (pin 3), I may be wrong though...
by bobbass4k
23 Oct 2018, 08:32
Forum: Boutique Stompboxes dissected...
Topic: DSM OmniCabSim
Replies: 60
Views: 20382

Re: DSM OmniCabSim

Yeah U1.2 can probably omitted - the original switching method was a bit weird, there seemed to be more buffers than necessary just because he had leftover op-amps in one of the TL074s. I included 1.2 because that is how the signal chain is when it's on, but it probably makes sense to omit it becaus...
by bobbass4k
05 Oct 2018, 13:26
Forum: Boutique Stompboxes dissected...
Topic: DSM OmniCabSim
Replies: 60
Views: 20382

DSM OmniCabSim

I thought I'd put this up a while ago but apparently I didn't. True story. A friend asked me to pad the XLR output on his and it would have been rude not to trace it out. This is the original one, and an early one at that (lots of mods/hacks on the PCB to make it functional). The only bit I'm not 10...
by bobbass4k
04 Aug 2017, 00:02
Forum: Modern Stompbox Effects (1975 - ...)
Topic: AMT Electronics - Slap Bass [schematic]
Replies: 12
Views: 4298

Re: AMT Slap Bass (Provisional Schematic) [schematic]

Finally got some quality time with the breadboard this week. With apologies to bool, the revised schematic is attached. The more I looked at it the more that 100k didn't make sense, there's a track from it that actually disappears under the input jack and comes back out, which I hadn't noticed, and ...
by bobbass4k
17 Jul 2017, 22:26
Forum: Modern Stompbox Effects (1975 - ...)
Topic: AMT Electronics - Slap Bass [schematic]
Replies: 12
Views: 4298

Re: AMT Slap Bass (Provisional Schematic) [schematic]

Imho you have the R3 placed wrong. It should go right from U1A pin1 to U1A pin2. And consequently the C13 should connect directly to U1A pin2 (now junction pin2, R3 and C13). It looks like a fixed souped-up mid-boost section. (perhaps as you mention this is intended for some "other" type of pedal)....
by bobbass4k
17 Jul 2017, 00:02
Forum: Modern Stompbox Effects (1975 - ...)
Topic: AMT Electronics - Slap Bass [schematic]
Replies: 12
Views: 4298

Re: AMT Slap Bass (Provisional Schematic) [schematic]

New schematic with provisional cap values below. I measured everything in circuit, any reading that didn't make sense I took the cap off to confirm, but there's still a few values that seem a bit odd. I was out of a few values so I'll to have wait for my parts order to arrive but it should get bread...
by bobbass4k
02 Jul 2017, 20:57
Forum: Modern Stompbox Effects (1975 - ...)
Topic: AMT Electronics - Slap Bass [schematic]
Replies: 12
Views: 4298

AMT Electronics - Slap Bass [schematic]

I acquired one of these in a trade many, many moons ago, and it's one of the only "branded" pedals i still have, it's always been so unique I could never let it go. I've wanted to trace it for ages and for some reason, after 6 years, I decided this weekend was finally the time. First off, this is in...
by bobbass4k
06 Mar 2017, 23:30
Forum: Boutique Stompboxes dissected...
Topic: Mantic Vitriol [traced]
Replies: 11
Views: 4878

Re: Mantic Vitriol [traced]

They're Gyrators rather than buffers - active cut/boost band-pass filters, there's a quick Jack Orman explanation here - http://www.muzique.com/lab/gyrator.htm . The advantage here is that they're active - they can boost frequencies rather than just attenuate them out. With a simple RC filter you ca...
by bobbass4k
23 Feb 2017, 00:24
Forum: Boutique Stompboxes dissected...
Topic: Mantic Vitriol [traced]
Replies: 11
Views: 4878

Re: Mantic Vitriol [traced]

New version, fixed a few things, added notes and optional mids control. In theory you can add as many bands to the EQ as you want, you could have a full blown 8 band EQ if you wanted, though that would be weird. The component values in the EQ gyrators are easily tweaked if you want a different voici...
by bobbass4k
22 Feb 2017, 10:09
Forum: Boutique Stompboxes dissected...
Topic: Mantic Vitriol [traced]
Replies: 11
Views: 4878

Re: Mantic Vitriol [traced]

D'oh... I drew the op-amp gyrator for the low EQ wrong, I mirrored the op-amp to make it fit better and forgot to move everything else around... I'll fix it tonight. On the plus side, breadboarded it (with the fixed gyrator) and it works a treat. Added the mids control from the FX86 in too and it so...
by bobbass4k
16 Feb 2017, 13:59
Forum: Boutique Stompboxes dissected...
Topic: Mantic Vitriol [traced]
Replies: 11
Views: 4878

Re: Mantic Vitriol [traced]

Here's a rough write up, electrically I'm pretty confident everything's fine, it's just a bit cramped and the proper voltage symbols seem to have disappeared from library so I used Vaa for +V and Vcc for the bias Voltage, I'll try and spruce it up tonight. It's mostly SMT but with a lot of through-h...
by bobbass4k
15 Feb 2017, 17:33
Forum: Boutique Stompboxes dissected...
Topic: Mantic Vitriol [traced]
Replies: 11
Views: 4878

Mantic Vitriol [traced]

Apologies for posting without a schematic but I was on the forum anyway so I thought I'd get the ball rolling. I took the plunge on one of these last week as it looked interesting, actually with no intention of tracing it out, but I was curious and tracing it out has kept me out of trouble for the w...