Doepfer Dark Energy MK1 envelope question

Any music gear discussions that don't fit into one of the other forums.

Moderators: lisa, Kent, Joe.

Post Reply
User avatar
nuketifromorbit
Wiggling with Experience
Posts: 291
Joined: Thu Aug 13, 2009 3:47 pm

Doepfer Dark Energy MK1 envelope question

Post by nuketifromorbit » Thu Dec 26, 2019 3:20 pm

I had a dark energy mk1 years ago, foolishly sold it, but recently got another in a trade. I'm noticing that the decay knob on the adsr seems to just accent the decay time and doesn't fully sustain even at the max setting when I hold down a key. Is this normal?

User avatar
Blairio
Super Deluxe Wiggler
Posts: 1687
Joined: Mon Oct 07, 2013 9:50 pm
Location: Glasgow, Scotland

Re: Doepfer Dark Energy MK1 envelope question

Post by Blairio » Thu Dec 26, 2019 10:02 pm

I you haven't dialled in any sustain, then the decay will eventually fall to zero. Try setting the sustain to e.g. 12 o'clock, and see what happens when your amplitude falls to that.

User avatar
nuketifromorbit
Wiggling with Experience
Posts: 291
Joined: Thu Aug 13, 2009 3:47 pm

Re: Doepfer Dark Energy MK1 envelope question

Post by nuketifromorbit » Fri Dec 27, 2019 9:42 am

Blairio wrote:
Thu Dec 26, 2019 10:02 pm
I you haven't dialled in any sustain, then the decay will eventually fall to zero. Try setting the sustain to e.g. 12 o'clock, and see what happens when your amplitude falls to that.
I definitely have the sustain dialed in. I've been messing around with synths for over a decade and can't help but feel that something is off.
Last edited by nuketifromorbit on Sat Dec 28, 2019 1:16 am, edited 1 time in total.

User avatar
nuketifromorbit
Wiggling with Experience
Posts: 291
Joined: Thu Aug 13, 2009 3:47 pm

Re: Doepfer Dark Energy MK1 envelope question

Post by nuketifromorbit » Fri Dec 27, 2019 12:26 pm

To elaborate further, even at max settings the sustain knob seems to only increase the decay time. In other words a held note will still decay into silence even if the sustain knob has been turned all the way clockwise.

User avatar
Blairio
Super Deluxe Wiggler
Posts: 1687
Joined: Mon Oct 07, 2013 9:50 pm
Location: Glasgow, Scotland

Re: Doepfer Dark Energy MK1 envelope question

Post by Blairio » Fri Dec 27, 2019 7:49 pm

On my DE MK1, if I set attack, decay and release to zero, and sustain to 12o'clock, when play a note via midi the note starts immediately and lasts as long as the key is held down - at the same volume. It then stops immediately I release the key.

If I set sustain to a greater or lesser value, the behaviour is the same, except the note is louder or quieter.

If your DE MK1 does not behave in the same way, then I suspect it is faulty.

User avatar
nuketifromorbit
Wiggling with Experience
Posts: 291
Joined: Thu Aug 13, 2009 3:47 pm

Re: Doepfer Dark Energy MK1 envelope question

Post by nuketifromorbit » Sat Dec 28, 2019 1:07 am

Blairio wrote:
Fri Dec 27, 2019 7:49 pm
On my DE MK1, if I set attack, decay and release to zero, and sustain to 12o'clock, when play a note via midi the note starts immediately and lasts as long as the key is held down - at the same volume. It then stops immediately I release the key.

If I set sustain to a greater or lesser value, the behaviour is the same, except the note is louder or quieter.

If your DE MK1 does not behave in the same way, then I suspect it is faulty.
Yep, theres definitely something wrong with it. Thanks.

User avatar
Navs
Super Deluxe Wiggler
Posts: 4075
Joined: Fri Sep 18, 2009 3:49 am
Location: Berlin, Germany

Re: Doepfer Dark Energy MK1 envelope question

Post by Navs » Sat Dec 28, 2019 4:02 am

Potentially silly question, but are you sending the DE a trigger or gate from your keyboard? It depends on the envelope design, but a trigger might generate the response you're getting, namely decay but no sustain. You could also test the envelope by triggering it with the DE's LFO. If you use the square-wave, the duty cycle of the square should set/ match the sustain duration. Does that work?

User avatar
nuketifromorbit
Wiggling with Experience
Posts: 291
Joined: Thu Aug 13, 2009 3:47 pm

Re: Doepfer Dark Energy MK1 envelope question

Post by nuketifromorbit » Sat Dec 28, 2019 6:14 pm

Navs wrote:
Sat Dec 28, 2019 4:02 am
Potentially silly question, but are you sending the DE a trigger or gate from your keyboard? It depends on the envelope design, but a trigger might generate the response you're getting, namely decay but no sustain. You could also test the envelope by triggering it with the DE's LFO. If you use the square-wave, the duty cycle of the square should set/ match the sustain duration. Does that work?
No, I've just got a midi keyboard connected to the midi input. Just tried using the onboard lfo as a trigger and the adsr still exhibits the same behavior. I just opened it up to make sure all the internal jumpers are in their appropriate positions, and well they are....

User avatar
Navs
Super Deluxe Wiggler
Posts: 4075
Joined: Fri Sep 18, 2009 3:49 am
Location: Berlin, Germany

Re: Doepfer Dark Energy MK1 envelope question

Post by Navs » Sun Dec 29, 2019 3:44 am

In the meantime I have managed to test this on a DE1 and I can replicate the response you're getting: if the envelope switch is set for 'long/slow' and with some release dialled in, the envelope will decay to zero regardless of the gate duration, and at various sustain levels. This is consistent with envelope designs that have a 'final decay', which is like 'part 2' of the decay. I think some Moog envelopes do this.

That said, I've just read your description here:
To elaborate further, even at max settings the sustain knob seems to only increase the decay time. In other words a held note will still decay into silence even if the sustain knob has been turned all the way clockwise.
... and that sounds like normal behaviour, i.e. when you release the key/gate, the envelope will always decay to silence (be that quickly or slowly). Yes, the sustain level sets the amplitude that the envelope is held at. But it also determines the voltage that the decay decays to and from. It follows that if the envelope is making its final decay from 10V, this will take longer than if it is falling from 1V.

Is that what you're experiencing?

User avatar
nuketifromorbit
Wiggling with Experience
Posts: 291
Joined: Thu Aug 13, 2009 3:47 pm

Re: Doepfer Dark Energy MK1 envelope question

Post by nuketifromorbit » Sun Dec 29, 2019 1:44 pm

Navs wrote:
Sun Dec 29, 2019 3:44 am
In the meantime I have managed to test this on a DE1 and I can replicate the response you're getting: if the envelope switch is set for 'long/slow' and with some release dialled in, the envelope will decay to zero regardless of the gate duration, and at various sustain levels. This is consistent with envelope designs that have a 'final decay', which is like 'part 2' of the decay. I think some Moog envelopes do this.

That said, I've just read your description here:
To elaborate further, even at max settings the sustain knob seems to only increase the decay time. In other words a held note will still decay into silence even if the sustain knob has been turned all the way clockwise.
... and that sounds like normal behaviour, i.e. when you release the key/gate, the envelope will always decay to silence (be that quickly or slowly). Yes, the sustain level sets the amplitude that the envelope is held at. But it also determines the voltage that the decay decays to and from. It follows that if the envelope is making its final decay from 10V, this will take longer than if it is falling from 1V.

Is that what you're experiencing?
No, the issue isn't that the note is decaying after a key is released, but rather that its still decaying when a note is held and the sustain knob is at its max setting. In other words the envelope is behaving more like an ad envelope rather than an adsr.

User avatar
Blairio
Super Deluxe Wiggler
Posts: 1687
Joined: Mon Oct 07, 2013 9:50 pm
Location: Glasgow, Scotland

Re: Doepfer Dark Energy MK1 envelope question

Post by Blairio » Tue Dec 31, 2019 12:32 am

From memory, the Dark Energy MK1 is built around the SEM3394 'synthesiser on a chip'.

I think these chips have been remanufactured, and are not expensive. If you could source one, it may be a simple fix - swap the new in on for the original one. The chip plugs into an 'interference fit' chip holder, rather than being soldered directly onto the circuit board.

Blair

User avatar
Navs
Super Deluxe Wiggler
Posts: 4075
Joined: Fri Sep 18, 2009 3:49 am
Location: Berlin, Germany

Re: Doepfer Dark Energy MK1 envelope question

Post by Navs » Thu Jan 02, 2020 8:21 am

nuketifromorbit wrote:
Sun Dec 29, 2019 1:44 pm
No, the issue isn't that the note is decaying after a key is released, but rather that its still decaying when a note is held and the sustain knob is at its max setting. In other words the envelope is behaving more like an ad envelope rather than an adsr.
I see you've put the DE up for sale - hope we still get to the bottom of this ;)

I've done some more rummaging, based on Blairio's post: the synth part is a CEM chip, yes, but the ADSR must be separate as the CEM only has a VCO/VCF & VCA. (See the block diagramme in Theo Bloderer's write-up here)

I'd guess the envelope is similar or the same as the one in Dieter's A-140 or DIY synth. I can't find any schematics, but if you shoot him a mail (hardware ät doepfer döt de), you'll probably get a reply next week. What I don't understand is the fact that it is triggering but not sustaining - the schematic would tell us more ...

I wonder if it's not something more simple like the normalization on the ext-gate jack. Have you tried wiggling that?

User avatar
Navs
Super Deluxe Wiggler
Posts: 4075
Joined: Fri Sep 18, 2009 3:49 am
Location: Berlin, Germany

Re: Doepfer Dark Energy MK1 envelope question

Post by Navs » Thu Jan 02, 2020 8:43 am

More hints from an old GS thread: are you using an AC-AC adapter and have you tried a reset?

https://www.gearslutz.com/board/electro ... oblem.html

User avatar
Blairio
Super Deluxe Wiggler
Posts: 1687
Joined: Mon Oct 07, 2013 9:50 pm
Location: Glasgow, Scotland

Re: Doepfer Dark Energy MK1 envelope question

Post by Blairio » Thu Jan 02, 2020 9:08 pm

Navs wrote:
Thu Jan 02, 2020 8:21 am
nuketifromorbit wrote:
Sun Dec 29, 2019 1:44 pm
No, the issue isn't that the note is decaying after a key is released, but rather that its still decaying when a note is held and the sustain knob is at its max setting. In other words the envelope is behaving more like an ad envelope rather than an adsr.
I see you've put the DE up for sale - hope we still get to the bottom of this ;)

I've done some more rummaging, based on Blairio's post: the synth part is a CEM chip, yes, but the ADSR must be separate as the CEM only has a VCO/VCF & VCA. (See the block diagramme in Theo Bloderer's write-up here)
Yes, apologies, the chip indeed the CEM 3394. I actually bought a spare chip as soon as I learned that Doepfer were stopping manufacture of the DE MK1, due to supply issues with the CEM 3394. The chip was 'new old stock' and not cheap (around 40 GBP from memory), but by that time I knew my DE MK1 was a keeper, and I considered the expense as insurance.

The Information sheet for the CEM 3394 as provided by On Chip systems states that "Envelope control for both the VCF and the final VCA may be provided either by a hardware envelope generator such as a CEM 3371, or may be accomplished completely through software generators".

I don't think there is a 3371 on the DE MK1, but there are certainly two LM324N Quad Op Amps, which are sometimes used as the basis for ADSR generators.

User avatar
nuketifromorbit
Wiggling with Experience
Posts: 291
Joined: Thu Aug 13, 2009 3:47 pm

Re: Doepfer Dark Energy MK1 envelope question

Post by nuketifromorbit » Thu Jan 02, 2020 11:46 pm

Just tried yet again to do a hard reset and yep the issue is still present. The power supply that I received with this thing was of european origin and had a US style adapter included with it. Of course it caused issues from the get go and caused the DE to sound distorted. I bought a replacement psu on ebay and assumed everything was fine. It wasn't until much later that I realized that the sustain wasn't behaving as it should. Maybe the original psu damaged it in some way? I've also tried using the psu for my darktime to power the DE and the issue is still present.

BarneyRubble
Learning to Wiggle
Posts: 23
Joined: Sun Jul 31, 2016 11:32 am
Location: Scotland

Re: Doepfer Dark Energy MK1 envelope question

Post by BarneyRubble » Fri Jan 03, 2020 6:39 am

I would like to know the answer to this - I have a Doepfer Quad ADSR A-143-2 which exhibits similar behaviour - the Sustain portion decays even though the gate is high.

I also have a Dark Energy Mrk2 but the Sustain portion behaves as expected with a gate the sustain voltage is constant.

This suggests to me that it may be a design thing? I did a search on Muffs and there is some talk about the A-143-2 sustain issue but nothing specific.

User avatar
fumblesmcdrum
Learning to Wiggle
Posts: 20
Joined: Thu Mar 07, 2019 11:15 pm
Location: Salt Lake City

Re: Doepfer Dark Energy MK1 envelope question

Post by fumblesmcdrum » Thu Jan 30, 2020 8:20 pm

Have you taken a look inside to see if someone else has?

User avatar
nuketifromorbit
Wiggling with Experience
Posts: 291
Joined: Thu Aug 13, 2009 3:47 pm

Re: Doepfer Dark Energy MK1 envelope question

Post by nuketifromorbit » Tue Feb 04, 2020 7:57 pm

fumblesmcdrum wrote:
Thu Jan 30, 2020 8:20 pm
Have you taken a look inside to see if someone else has?
Yeah several times, at first to install the glide option, and later to check for any missing jumpers etc after I became aware of the issue. Anyway I just sold it for peanuts. In all honesty though I broke even. I traded a korg odyssey for it plus a dark time and as it turns out my odyssey had a dodgy key that I never noticed. Despite everything I have no ill will towards the wiggler I made the trade with. Some deals are just too good to be true, and it was a case were the both parties exchanged goods with defects that were easy to miss :confused:.

Post Reply

Return to “General Gear”