Any idea to patch this? or any existing module

[karlderletzte]

Hello,

i read (modularsynthesis.com) about the Buchla 284 Quad VC Envelope Generator Modul, that it is designed this way:

"The 284 is an interesting design. It is comprised of two AR envelope generators operated in a loop fashion. The first envelope generator is for the delay and duration and the second envelope generator is for the CV output.

At the end of attack of the first envelope generator it triggers the second envelope generator and remains in a hold. At the end of attack of the second envelope generator it releases the hold of the first envelope generator (to start the decay) and remains in a hold. At the end of decay of the first envelope generator it releases the hold of the second envelope generator (to start the decay).

Since the second envelope generator has not started the attack, the attack of the first envelope generator creates the delay. Since the second envelope generator holds at the end of the attack, the decay of the first envelope generator creates the duration."

It looks like it could be patched with two EG, but you need some triggers.

i tried it with the Nysthi 208 EG, but gave up.

Perhaps with two venom envelope generator. The modules contains so many possibilities

any ideas?

Karl

[goldtorizo]

Check out this module

Infinite-Noise ADR Envelope

[DaveVenom (Dave Benham)]

I patched up a complete emulation of the Quad VC Envelope Generator. I believe it is faithful to the hardware from a functionality standpoint. I did indeed use two Venom Envelope Factories per EG as you suggested, so the architecture is fairly close to the hardware as well.

Do not use this version 1 patch - it is seriously buggy! Instead use the corrected version 2 or the much simpler version 3 found in later posts. Or use a bare Envelope Factory for one envelope generator as described later in this post.

Buchla 284 Quad VC Envelope Generator.vcv (10.1 KB)

Here is the user interface and patch bay that represents the complete module:

And here is the functional internals that should not be touched:

It was a little tricky to get everything working properly. I had to introduce a sample delay for one of the controlling gates. It also takes some logic to properly block retrigger actions while an envelope is active. I use an AD/ASR to convert the gate into a trigger for when Sustain is off. If Sustain is on I pass the incoming gate directly to the 1st Envelope Factory and I also send -10V CV to the Duration time (1st EG release) to effectively set it to 0 so the Decay stage starts immediately after the gate is released.

But I think there is a much simpler solution that only uses one Envelope Factory per envelope generator. Simply create 4 copies to get full Quad functionality.

Buchla 284 Single VC Envelope Generator.vcv (3.5 KB)

The patch is configured for Sustain OFF, as shown below.

Any control voltage should be patched to the V/Oct input, except the Envelope Factory doesn’t have an attenuverter for that input. You will have to provide your own.

All the controls and ports have been renamed in the tooltips to show what their function is in context of the Buchla 284. Most of the controls are locked so you can’t accidently corrupt the functionality.

To turn sustain ON, simply change the 3rd stage action (the Duration stage) to Sust, and make sure to set the Drift knob to 0, as shown below. In the hardware this knob would be ignored when sustain is enabled, but here it must be manually set to 0.

I recommend saving the Envelope Factory configuration in the patch as a preset so you can conveniently create a Buchla style EG at any time.

[karlderletzte]

Thank you very much. i knew that it must be possible with your modules. Another idea came up to me, is to use a functiongenerator like rampage or any other. but I can’t see that the Buchla Module has slew or any additional features. So a functiongenerator will be a bit over. And I remember that the original has four of them.!

[DaveVenom (Dave Benham)]

Ugh - the complicated quad EG emulation v1 is seriously bugged.

The 4th EG was completely broken, and the retrigger blocking logic did not work properly if the gate is held high while the sustain is off.

A corrected version 2 required significant changes. The logic module was replaced by 4 T type flip flops. In order for looping to work I had to set the Envelope Factories to use fast triggers (1 sample instead of 1 msec). But this then required a 2nd AD/ASR per EG to convert the EOC 1 sample triggers back into 1 msec triggers.

Here is the corrected version 2.

Buchla 284 Quad VC Envelope Generator v2.vcv (10.3 KB)

And here is an image of the functional internals for v2. The UI has not changed.

All in all, I think the single Envelope Factory per envelope generator is a much better solution.

[DaveVenom (Dave Benham)]

I figured out how to create a full quad emulation with a nice UI using only one Envelope Factory per envelope generator. This is by far my favorite version. The only shortcoming I see is that changing the sustain state will instantly terminate any active envelope, which will also terminate looping if you have patched EOC to the gate input. But this seems like a fairly minor issue.

Version 3 should be my last quad emulation version.

Buchla 284 Quad VC Envelope Generator v3.vcv (7.8 KB)

Image of user interface:

Image of functional internals:

[karlderletzte]

Thank you very much for your work. It works, but after reading some other documentation about the 284, i am not sure anymore, if this description (above first entry) is correct. Following the other documentation, the Dual EG 208 from Nysthi is working correct, but only with the correct patching.

Switch trans is on; dur cv is patched with a cv (+/- 5V); dur length is set to “5”, the middle. Now a trigger to gate initiate the envelope. The length can be lengthen or shorten with the cv from dur in. The other documentation contains nothing about a delay. I am puzzled. Perhaps someone knows the hardware functionality correctly or owns a module.

Thanks for all the ideas,

i will test and read.

Karl

[karlderletzte]

After some testing and patching i created a patch to simulate the module as far as i understand. And with the help of the wonderful new envelope generators from @Infinite-Noise . thank you!

here is a screenshot. Trigger in is A.trigger from left EG, Output is Env from the right EG. And it has inverted EG. What is your opinion?

Karl

[Infinite-Noise (Pelle Liljendal)]

Just a small heads up: In the next version I’ve changed the scaling of the time knobs. On load of a patch saved with a previous version the knobs will automatic rescale so it loads with the same time as dialed in previously. However when using an external tool like the PatchMaster I suspect you’d have to tweek the knob position dialed in by the PatchMaster to achieve the same time-settings.

[karlderletzte]

Ok thank you. i will test it with the new version.

[karlderletzte]

hello, a question: how can i patch your Envelope Generators to loop. If EG2 ends, it should trigger EG1 again. But because a patched trigger input disables phase, how could i use the phase input? or any other idea?

Buchla284_Emulation_Test.vcvs (10.5 KB)

[karlderletzte]

A small additional info. If i only use the trigger inputs i managed it to loop, but then the feature (sustain) does not work. This means, that EG1 stays in hold after EndofAttack with the level of Attack. And if trigger input goes low, it goes to the delay phase. I think the problem is, that phase and trigger inputs are not working together. Is it correct? Any ideas?

[Infinite-Noise (Pelle Liljendal)]

I’m not entirely sure what you are trying to achieve. However you should either use the Phase input or the A.trig/DR.trig inputs. If you only use the the Phase input (e.g. in gate mode) “it works as a normal envelope”:

• Envelope going high: will kick start the Attack phase of the envelope, and then sustain (hold A.level)
• Envelope going low: will kick start delay (if D.time > 0), then release, and then idle (hold R.level)

If you instead use the A.trig and the DR.trig inputs you can input an A.trig to kick start Attack/Hold at A.level, and input a DR.trig to kick start delay (D.time > 0), then release and then idle (hold at R.level).

Hence when using the A.time/DR.trig the only real sustain is to wait firing the DR.time trigger. You can however fake a fixed length sustain, by connecting the EOA (End Of Attack) into DR.trig and dial in a non-zero Delay. When EOA triggers DR.trig the delay will begin, where it will wait D.time while the envelope is hold at A.level (fake sustain) and once D.time have elapsed the release will kick in.

[karlderletzte]

Thank you for the suggestions. Yes i tested the delay, but do not find a solution to let it delay as long as i want, e.g a voltage is high on the input. Can i use an unlimited delay?

[karlderletzte]

@Infinite-Noise

Hence when using the A.time/DR.trig the only real sustrain is to wait fireing the DR.time trigger.

but how can i use this, if i use the phase, too?

[karlderletzte]

a little description. the buchla module can use three modes: freerun, oneshot, sustain.

Freerun means looping one envelope.

Oneshot means one trigger, one envelope.

Sustain means one trigger starts the attack phase. After finish the voltage hold until a trigger starts a decay phase.

[Infinite-Noise (Pelle Liljendal)]

As the documentation says: “You should EITHER use the Phase input or the dedicated trig inputs.”. It’s never been designed for using both at the same time.

From your description, if Freerun and Oneshop is with a fixed sustain time, then ADR Envelope can do it … as a fixed sustain can be dialed in as a delay.

To do the Oneshot (from a trigger) you pass your trigger into A.trig, connect EOA to DR.Trig and dial in a D.time (your faked sustain). If you connect EOR into A.trig you will basically have your Freerun as it will keep triggering itself and have the envelope running forever - until you brake the connection between EOR and A.trig … however it can only be done with a fixed length “gate” … again it will be the delay (D.time) that is faking the sustain.

[karlderletzte]

Thank you for the clarification.

[DaveVenom (Dave Benham)]

All my 284 emulations in this thread are flawed. I have learned that the 284 does support retrigger during the decay stage, which is very different than my emulations here.

I have started a new thread where I emulate both the 284 and its successor, the 281.

Emulating Buchla 284 and 281 envelope generators

This is a continuation of discussion and efforts from the following threads: AI led me astray in my prior attempts to emulate the Buchla Quad Voltage Controlled Envelope Generator model 284. I mistakenly thought the 284 could not be retriggered, but I have learned that it can be retriggered during the decay phase. This of course has a major impact on construction of an emulator, and on the resulting functionality. I have scoured YouTube videos, and writings from experienced Buchla users, e…

[jaibhimadevi]

Ouch.

Can you imagine how much would have to be re-written, if the old Carlin joke came true?

"Mathematicians have announced the discovery of a new number; the number is called ‘bleen’, and is located between six and seven"