simple analog delay module?

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Kwote
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simple analog delay module?

Post by Kwote » Mon Jul 28, 2008 1:37 pm

anyone ever toyed with making one? after getting the time machine i've totally fallen head over heels :love: for delay in modular form.

but it got me realizing that i may not want to spring for a whole nother used TM. soooo... i thought why not DIY a simpler analog modular delay in frac. same panel size, similar delay, but just cut out a lot of the cv functionality as well as the built in lfo.

so then all you'd have is delay time, regen and wet/dry. perhaps throw in cv control over regen and delay time. or maybe just one of the two.

could probably work this out into a half size frac panel. only thing needed is schematics, pcb, parts. anyways, i hope someone out there would be able to help make this project come to life. i don't know enough about design at this point but i want to learn.
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Post by Kent » Mon Jul 28, 2008 2:42 pm

The simplest thing to do would be to gut a cheapo analog delay pedal and then add CV control to whatever you wish to control.

Or buy a Doepfer A-188 series and convert the mofo over to the Frac-side.

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Post by Kwote » Mon Jul 28, 2008 2:51 pm

Kent wrote:The simplest thing to do would be to gut a cheapo analog delay pedal and then add CV control to whatever you wish to control.

Or buy a Doepfer A-188 series and convert the mofo over to the Frac-side.
right. but i'm not trying to go uber cheap. just much cheaper then the 400-600 price tag surrounding the TM.

i like the thought of a half space frac delay. i think it should be done. even if i have to get all the parts myself and delve heavy into schematics so i can get a small run of pcb's together i'll do it.

but i'd love to have a partner or two on this idea.
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Post by Kent » Mon Jul 28, 2008 3:02 pm

Well, depending up on how much delay time you are looking to get & how many features you want to have accessible on the panel; you could easily fit an analog delay into a 1u Frac panel. Seeing as how these are designed for guitar pedal sized form factor, these PCBs & kits would be great starting points to investigate
http://www.generalguitargadgets.com/ind ... hop.browse

Glad to hear that you got the TM and have been freakin' it. I'm a bit of a delay freak, but almost all of them are rack-mount jobbies.

Speaking of; I just glanced at my racks and saw the Boss VF-1 sitting there. I'm betting that this mofo could be gutted and shoved into a Frac... hmmm... would look, but am too lazy.
Last edited by Kent on Tue Nov 18, 2008 7:08 am, edited 1 time in total.

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Post by Chuck E. Jesus » Mon Jul 28, 2008 3:14 pm

most of the analog delay pedals i've seen top off at about 300 ms or less...there is also a lot of steep filtering and companding going on to get a good sound...the Doepfer BBDs have none of this, but have a good raw sound people seem to like...mine has the 2048 chip, pretty useless for dub style delays but it's good for flange/chorus/signal destruction...i imagine the Blacet and the Moogerfooger are so expensive because of all the extra goodies in there (not that i've heard them in person)...i have an old Ross Delay pedal, it has a good sound, i added a jack to access the delay rate for CV...

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Post by Kent » Mon Jul 28, 2008 3:28 pm

Ross,

Have you a link to a schematic for adding CV to potentiometers? I think that this will be useful here.

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Post by Kwote » Mon Jul 28, 2008 3:56 pm

Kent wrote:Well, depending up on how much delay time you are looking to get & how many features you want to have accessible on the panel; you could easily fit an analog delay into a 1u Frac panel. Seeing as how these are designed for guitar pedal sized form factor, these PCBs & kits would be great starting points to investigate
http://www.generalguitargadgets.com/ind ... hop.browse

Glad to hear that you go the TM and have been freakin' it. I'm a bit of a delay freak, but almost all of them are rack-mount jobbies.

Speaking of; I just glanced at my racks and saw the Boss VF-1 sitting there. I'm betting that this mofo could be gutted and shoved into a Frac... hmmm... would look, but am too lazy.
is this the component side of the pcb? no labeling? that would fuck me up proper if so :)

http://www.generalguitargadgets.com/ind ... &Itemid=45
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Post by Chuck E. Jesus » Mon Jul 28, 2008 3:58 pm

Kent wrote:Ross,

Have you a link to a schematic for adding CV to potentiometers? I think that this will be useful here.
oopsie! i failed to mention i use the Doepfer Universal Vactrol mod...i just put a jack in and wired it to the delay pot, and then control it from the Doepfer...i also added jacks to several Doepfer mods (ADSR/LFO rate) and plan on adding lots more when i get my A-154 seq controller and Wavesplicer (thursday :sb: ) and reconfig my Eurorack...

there was a guy here who said he put vactrols in his EH Memoryman for VC, but several requests on how to do it were left unanswered...maybe once i get going with the DIY i'll look into it further...

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Post by Kwote » Mon Jul 28, 2008 3:59 pm

anyways, maybe it sounds silly but i'd really like an original pcb designed for this. basically just a super simple version of the TM circuit. i'm gonna have a look at the TM tonight and see what can be omitted.

does anyone have the full manual for the Time Machine? i printed the one from blacet's site but of course the online blacet manuals don't include, schematics, pcb layout, etc.
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Post by Roycie Roller » Mon Jul 28, 2008 4:41 pm

Once you've had a look at it, how hard do you think it would be to clone it?
It could be a good intro into doing your own pcb's.
If you do get one up, i'd be interested. Try to go for a 1 second design. The TS is 2 yeah?
Bloody nice delay that TS.
I wish they still made them.

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Post by Muff Wiggler » Mon Jul 28, 2008 5:10 pm

ross g wrote:there was a guy here who said he put vactrols in his EH Memoryman for VC, but several requests on how to do it were left unanswered......
aint that the truth! I'm pretty sure I know how he did it - the requests were to confirm that it doesn't accept any negative voltages and there's no way of getting it to take AC, and I think for some reason he didn't want to admit that truth about the thing... I dunno, I gave up asking after like the 10th time....

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Post by BugBrand » Mon Jul 28, 2008 5:29 pm

Hiya,

If you don't know the chip, then have a look at the PT2399 - ok, it is digital, but it has a good sound! Without getting into detail (partly 'cos I don't know it all) there are some filtering stages at the output to get rid of any digi noise, but this also gives it a nicer feedback sound.

Oh, and the best thing ---> seriously dropping the rate (it is spec'd at about 1/2 sec) you go through lofi crunch delay around 2-6 seconds and then into wondrous clippy digital noise decays from c.8seconds on down!
- this is a really nice effect.

The time is controlled by a simple pot in basic setups but it is possible to implement either a vactrol control or a current sink arrangement.
There's a few details around on the net (quite well grouped on this EM thread). I've tried it also with techniques roughly based on some good Thomas Henry approaches - has worked pretty good but needs some more detailed tweaking.

I don't know when I'll get around to looking at this chip some more, but I keep kicking myself to do so.
I don't have much of a sample, but there's an oldy (and choasy) here:
http://www.bugbrand.co.uk/audio/modular ... erMods.mp3

PT2399s are pretty easy to come by - ebay or www.futurlec.com in particular - or small bear for sure.

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Post by Cat-A-Tonic » Mon Jul 28, 2008 5:47 pm

There is already a CGS development board for the Princeton Technologies PT2395 Enhanced Digital Echo IC.

Is the PT299 better or easier to implement?

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Post by BugBrand » Mon Jul 28, 2008 5:52 pm

Cat-A-Tonic wrote:There is already a CGS development board for the Princeton Technologies PT2395 Enhanced Digital Echo IC.

Is the PT299 better or easier to implement?
Ah, yes, its quite different I think - though I've not really looked at the 2395 much -> that needs an external RAM chip making things more complex to setup. I've also not seen them about so often.

Hmm, one with data-lines (like the 2395 with external RAM) would be great for circuit-bends I'd have thought..

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Post by plord » Mon Jul 28, 2008 7:10 pm

There is a public domain circuit in one of the Thomas Henry books. It uses the SAD-1024, which is one of the harder chips to get ahold of, but the PCB design is in there along with a schematic and 1-2 pages of build instructions. I *think* I have this lying around at home, but no SAD-1024. MN3005s, I got...no simple circuit for this around that I have found :/

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Post by wetterberg » Mon Jul 28, 2008 7:55 pm

Danelectro Fab Echo. It's like 20 euros :razz: Easily circuitbent, too.

My question (and this is a broader pedal<->modular question indeed:)

with a pedal presumably 1vpp and doepfer signal levels at, what, 10vpp, how would one interface a modularized pedal without overdrive/clip city?

:help:

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Post by Chuck E. Jesus » Mon Jul 28, 2008 10:16 pm

Muff Wiggler wrote:
ross g wrote:there was a guy here who said he put vactrols in his EH Memoryman for VC, but several requests on how to do it were left unanswered......
aint that the truth! I'm pretty sure I know how he did it - the requests were to confirm that it doesn't accept any negative voltages and there's no way of getting it to take AC, and I think for some reason he didn't want to admit that truth about the thing... I dunno, I gave up asking after like the 10th time....
i forget who it was but it was a dude on the synth webs or similar...this needs to be a mission on the DIY forum, i'm sure it's very simple...regardless: if you can't answer a simple, direct question my attitude is "i'm not fond of that way of doing things"...

(edited to not be a dick)
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Post by Kwote » Mon Jul 28, 2008 10:18 pm

Roycie Roller wrote:Once you've had a look at it, how hard do you think it would be to clone it?
It could be a good intro into doing your own pcb's.
If you do get one up, i'd be interested. Try to go for a 1 second design. The TS is 2 yeah?
Bloody nice delay that TS.
I wish they still made them.
the only challenge would be securing parts and getting a clean look at the pcb without all the parts soldered on. or maybe i can sort things the way it is. but i wouldn't want to clone it. that would defeat the whole purpose behind my idea. simple analog delay that handles modular level signals in a half frac space with minimal cv. nothing more, nothing less.

a lot of the parts are basic. it's the chips that are more the issue. i read about one bbd chip that goes up to 600milliseconds and that old guitar delays like the maxon would use multiples of this particular chip to achieve longer delay times. so just employing two should get the 1 seconds worth. i'm not a big fan of longer delay times than that anyways. with the EHX memory man i was limited to 500ms and i was actually cool with that.
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Post by Kwote » Mon Jul 28, 2008 10:20 pm

here's the link to the CGS digi delay in question:

http://www.cgs.synth.net/modules/cgs44_ddb.html

it's funny you guys brought this up as i was wondering what would happen if you used a analog chip instead. my guess is it would be fucked since the board was designed specifically for the digi chip but the dumb idea still crossed my mind. entertained for a half a second :oops:
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Post by Kwote » Mon Jul 28, 2008 10:24 pm

anyways, if anyone who owns the original TM manual would be kind enough to photocopy or scan it and send it my way i'd be much obliged.

i just need a look see at the parts list, schematics and pcb layout.

my plan is to secure parts first then worry about everything else later.

thanks.

of course if no one can i'll drag the TM out my rack and examine the hell out of it and then start delving into research no man's land. i have to learn how to do this shit sooner or later. might as well be now.
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Delay

Post by Roycie Roller » Mon Jul 28, 2008 11:07 pm

wetterberg wrote:
My question (and this is a broader pedal<->modular question indeed:)

with a pedal presumably 1vpp and doepfer signal levels at, what, 10vpp, how would one interface a modularized pedal without overdrive/clip city?

:help:
Why, with the upcoming Harvestman Stilton Adapter, of course!
http://www.theharvestman.org/1979.php

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Re: Delay

Post by wetterberg » Tue Jul 29, 2008 9:30 am

Roycie Roller wrote:
wetterberg wrote:
My question (and this is a broader pedal<->modular question indeed:)

with a pedal presumably 1vpp and doepfer signal levels at, what, 10vpp, how would one interface a modularized pedal without overdrive/clip city?

:help:
Why, with the upcoming Harvestman Stilton Adapter, of course!
http://www.theharvestman.org/1979.php
I am asking what the process is when DIYing, not looking for a module that did it ;) I'm buying pedals to modify - the stilton adaptor is for people who don't want to modify anything ( or just have too much money to burn!)

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Re: Delay

Post by johans121 » Mon Nov 17, 2008 5:41 pm

wetterberg wrote:I am asking what the process is when DIYing, not looking for a module that did it ;) I'm buying pedals to modify - the stilton adaptor is for people who don't want to modify anything ( or just have too much money to burn!)
This is something that's been on my mind for a while as well. I've got a bunch of pedals that I would love to incorporate into my modular but don't because of the excessive clipping. Any pointers would be greatly appreciated.

-Jim

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Post by wetterberg » Mon Nov 17, 2008 5:48 pm

you need to attenuate going out, and amplify going back into the modular.

I ended up going for the middle ground, actually - the Doepfer a-138d - not as expensive as the Stilton, but more features that I liked. And no Y-cabling.

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Post by neandrewthal » Mon Nov 17, 2008 7:12 pm

Is blacet all done with with TM? As in, never planning to make any money off it again. I'm thinking about asking John for permission to have a batch of PCB's mnfctrd. We could go in as a group buy to bring the price down, or if not, I wouldn't mind spending $40 or so for one.

Kwote, if I read you correctly the TM manual contains the schematic?. If worst comes to worst I'd just build it on a protoboard, if a substitute project doesn't come in time.

I know there's the Scott Bernardi PT delay, but I'm a little bit reluctant on it because it seems like a crossbreed between analog and digital delays. I'd rather have a dirty as fuck analog delay, or a crystal clear digital with long repeats. I'm just concerned that it might not fulfill either need as much as I'd like.
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