Deltalab Effectron ADM-256

[Mark Black]

Any chance one of you guys can share or point me towards a schematic for the Deltalab Effectron ADM-256? It is an early one, not an Effectron II model.

I can't find anything even on the usual schematics-for-money sites. Did find one listing for a "II" model but not knowing how different they are I don't want to spend the money to find out...

Thanks!

[Enzo]

I have a generational copy that is all but unreadable now. All that series are similar, and I wind up using one of hte others to clue me in on what this one has. Scanning it wo0uld be silly at this point. What do you need to know about?

[Mark Black]

Hi Enzo & thanks for the reply -

Well so far I have ferreted out 3 bad chips: the LM339 which brought back the LED indicators, and both of the 4049's which have partially restored the delay function.

What I'm left with is:

> Delay of about .75 mS in all of the lower pushbutton settings with delay factor set to 1.0

> Delay of about 2.75 mS in 256 mS range, also with delay factor set to 1.0

> Delay factor control does change the delay, making it smaller when rotated to the .25 setting

> Modulation also has an effect, within the very short delay times.

All the switches seem to be working properly.

> The "Limiter" doesn't seem to actually be limiting in my usual understanding of that word - the LED comes on but it just squares the waveform. Maybe what's labeled "Limiter" is actually more of a peak indicator.

I've got a sense I may be looking at some bad RAM.

I guess I can just start throwing chips at it, although I don't have any of the RAM chips to play with. Got pretty much all of the CMOS 4xxxx series chips though - just a lot of desoldering with that approach and doesn't make me feel good about understanding the nature of the problem...

I found the bad 4049's by scoping pins & noticing no or low signal at places that should have had some. At this point there seems to be signal pretty much everywhere I would expect based on chip pinouts, although there does seem to be some level-shifting going on with +5V peaks at some and +12V peaks at others. Waveforms look reasonable and only rounded off at pins which have caps attached for timing functions.

I know what you mean about the generational schemo copy - and anything digital seems to need extra resolution if the original is small due to the large number of devices & busses.

I guess I'm just looking to get an idea where the components lie in the general chain of things - flipping the unit back & forth is getting kind of old...

[Enzo]

Jameco has always been pretty good about having some obsolete RAMs.

Send me an email with Deltalab schematic as the subject line and I will scan what I have for what it is worth. I'll throw in the other model for its clarity.

tmenzo at msn dot com

My expectation when I open one of these is that the pots will be bad, especially the blend one with the center tap. Then I take the ohm meter to all the push switch contacts.

I don't recall the limiters being anything sophisticated. You certainly never wanted anything going to digital to peak over 100.

[Mark Black]

Email sent - Thanks!

[Mark Black]

It lives!

Just thought I'd report back with results...

Enzo thanks for the schematics and Zen counseling.

When I finally got back to this thing after ordering some parts I found two (out of the four) bad 40193 chips.

The unit appears to working correctly now and it sounds...well...um...like an antique digital delay.

Thanks!

[Enzo]

Very cool. I have two units here that do not work. SOmeday when I have nothing to do...

And yep, that's what they sound like.

[Chessie]

Dead Effectrons

Gentlemen - I've got two dead effectrons (a II and III) and my limited technical skills haven't improved their condition. I was wondering if you have any recommendations on people who might work on them? Given their going rate, perhaps its cheaper to just buy used ones than have these repaired, but I figure I'd ask. thanks

[Enzo]

Not me, maybe Mark feels brave.

[Mark Black]

Not me, maybe Mark feels brave.

Ha! Never brave, and somewhat wiser now.

I don't see any particular reason to spend any money resurrecting one of those anymore, as they (in my opinion) don't sound all that special even when working perfectly.

For a vintage rack-mount DDL that does sound pretty good my money would be on the Roland SDE-1000 (or its more expensive cousin the SDE-3000). The 1000's can be had relatively cheap on Ebay from time to time. If the display isn't broken and the switches all work the (easily-fixed) usual culprits are cracked solders at the numerous multipin connector headers as well as at a row of resistors near the center of the board. The only down-side is they are pretty heavy and very deep so may require rear support, dictate the depth of the rack they are installed in, and obscure the connectors of less-deep adjacent units.

I would go with replacement rather than fix, unless you want to do it yourself for the sake of experience...

[Chessie]

Thanks

Thanks, Enzo and Mark for the prompt advice. I found a friend that's going to give them a once over and we'll see what we find. I'm sure you're right that it will be more cost-effective to just relegate them to studio props than get them fixed, but I'm pretty attached after many years of faithful use, so I feel I've got to give it a go, at least preliminarily. Thanks for the tip on the Roland. The 3000 looks particularly cool.

[syn-fi]

the common fault scenario with these is one of the 15 +/- rails goes down and the musician leaves the unit on. This can damage op-amps, ICs and DRAM, being the older type with two different rails 5+/12v.

Once you have them running they are spacey, grainy, dark and deep. The newer delays machines referred to have that 'hi-fi' sheen that is missing from the Delta Labs. Indeed the Delta Lab DL2 manual talks about rolling off 'highs' as the unit goes slewy if there is too much hi-freq content.

[polaris26]

Not to resurrect a resurrection of a dead thread (how ironic given the date) but I just had success getting a DeltaLab 256 delay unit working. It turned out to be 3 of the 4 CD40193BE weren't working so the delay was very short no matter what the delay settings (wasn't seeing activity on the two MSB pins of the 4116 RAMs). I had the 40193 in stock so I replaced all 4 of them at once (including the good one). Funny that some others commented on this being a problem also. Now it works and sounds amazing - very musical. I also took the time to redo the 8 pages of 'blueprint' schematics in grayscale and contrast-adjusted so they are actually 92% print-readable now. They aren't exactly the same (with regard to REF DES numbers etc) as the first issue unit that I have, but close enough to give guidance.

Regards,
Dave

[dmeek]

I have this extremely bad copy.

https://music-electronics-forum.com/...1&d=1586733004

[dmeek]

Here is a slightly better copy. I assembled it from 8 scans of a full-size blueprint I found I-don't-remember-where. Unfortunately the person who
scanned it didn't come close to overlapping the scans so there are gaps but what's there is more readable.

https://music-electronics-forum.com/...1&d=1586738111