Adsr

[N-Brock]

I have wanted to have ADSR filter for some time now but I was wondering if anyone here had advice or experience regarding this subject before I get started.
For those of us who don't know, an overview of function and theory is here: ADSR envelope - Wikipedia, the free encyclopedia
As a gained interest about this, I wondered how hard it might be to make one of these. A google search later and I came up with this site. Synth Schematics --::-- Envelope Generator ADSR
The second schematic has my preference as it looks simpler and is recommended on the above page.
Does anyone know what model transistor should be used in the first part of the circuit, or if it even matters?
Also, I've heard that certain diodes can greatly impact sound characteristics, is it a good idea to make the diode selectable with a rotary switch of some kind or am I reading too far into that?

Thanks,
Nelson

[N-Brock]

Alright, never mind. I remain interested but just found some more information that might keep me from trying this. It would be appreciated if a mod could delete this thread as it is not of much use.
Thanks

[PauSim]

You want to build something like a Moogerfooger to process guitars and other audio sources? Then you should instead use an envelope follower circuit to translate the audio signal amplitude into a control voltage that will modulate the filter cutoff frequency. An ADSR generates control voltages but it still needs to be triggered externally.

Regarding the sound of diodes, the germanium types are prefered in the old ring modulators. Since an ADSR doesn´t generate or process audio directly, it doesn´t call for any "better" than a common diode such as 1N4148.

You´ll find lots of schematics and good advice at the DIY section of the Electro-music forum.

[MaxPlankton]

Originally Posted by PauSim

. Since an ADSR doesn´t generate or process audio directly, it doesn´t call for any "better" than a common diode such as 1N4148.

An ADSR can become an oscillator if triggered at a fast freq from an LFO, for example
The shape of the ADSR then determines the timbre of the sound, rather than the shape and decay etc.

If you're looking to construct any modular synth circuits, have a look for some Serge circuits,
he had some more interesting and versatile designs than most of the other early synths

Cheers

[PauSim]

Originally Posted by MaxPlankton

If you're looking to construct any modular synth circuits, have a look for some Serge circuits,
he had some more interesting and versatile designs than most of the other early synths

Cheers

And Buchla

[MaxPlankton]

Yeah PauSim...Buchla's are very interesting synths...but I've never seen circuits
Mebbe they're out there...I know guys have copied the Serge.
I used to have a massive synth collection...embarrassingly massive..heh
Now all I have is a 28 module Digisound (UK) system
They came out around '83 and one of the UK mags had a series on building the kits
it was a bit too late for modular analogs...but they're great...based on the
Aries system..and uses Curtis chips...sounds like a modular Prophet 5

Cheers

[PauSim]

I know about those synths Early Prophets used SSMs. I´m a synth freak myself. I own a few vintage ones and started to build an eurorack modular recently. Hope it´ll be finished some day, as pro and consumer audio are distinct worlds and I can´t think about both at the same time...

Here you´ll find some Buchla schematics http://www.simple-answer.com/DIY.htm
In the diy section of the Electro-music forum there are groupbuys for pcbs.

[PauSim]

Sorry, correct link is DIY

[MaxPlankton]

Hoy PauSim...thanks for that link..but i keep getting a 404 error...and can't find it on the main page
I'm gonna get my tech to add a few more modules to my Digisound,
so maybe some Buchla circuits might be fun
(although I suspect his V/Octave system was 'non-standard'..heh)
I'm actually a bluegrass-ragtime style guitarist but think that analog synths are the best toy ever invented...
and more fun than a barrel'o'monkeys
I had a synth playing girlfriend in the early eighties that got me interested
When midi came out everybody was dumping analog...cheap
So I collected a warehouse full of analog during the digital craze
The plan was to have a mega synth studio like Hans Zimmer etc
Unfortunately, a prolonged family court case meant I had to dump most of it,
but that's the way it goes, and in a way, having that stuff saved my ***.

I'll keep you updated on the Digisound project...I've gotta build a new cabinet for it...
try to match it to the Roland 184 Four-voice CV keyboard
(which I'd originally kept for a project consisting of four Prophet Pro 1 panels mounted
in a cabinet...sorta like an Oberhiem 4-voice type setup)

Yeah...SSM's on the early Prophet's series 1 & 2 I think
Roland did the same on the Super Jupiter...switched to Curtis chips after a while

Don't forget to show us the Eurorack when it's finished...
I don't know much about 'em, but I'm out of touch with the synth scene

Cheers