Analog heat envelope follower

Hi everyone, thinking about buying this box soon. The only reason I doubt is because the control input accepts cv signals but not audio, is at right? What happens if you plug an audio signal into the control input? Will it generate any control signal? If not, is there any way you can convert audio to cv?
I would like to have a drum track trigger the cutoff frequency of a pad, for example.

Thanks a lot for your help, I cannot find this answer online,

The envelope follower ‘follows’ the audio input level and can have the filter cutoff as destination. On top of that, the cv input can also be directed to the filter cutoff


Ok. So my question is:

How can you have an external audio signal (not the input one) control the cutoff?
This is a typical function in the envelope follower-filter-distortion boxes so I am surprised it is not included.
If you plug audio into the control input will it trigger the filter with it?


If don’t try it I’ll do!

you can have a gate signal as a trigger in the control input.

The other day I “made” like this a hybrid synth using a Digitone, a Analog Heat and a keystep sending MIDI notes to DT and gate to AH.


Possible to hear it? :slight_smile:

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Sure I’ll a make a video tomorrow. Sorry, too tired right now :slight_smile:


Just tried…and yes you can!
Don’t ask me why, but it worked using only jacks tips, (2 jacks, tips linked with alligator) with expression pedal input.

Totally empirical, but I could modulate filter with FILTER FREQ dest, and trigger lfo / env with TRIG LEVEL dest.

A bit weird results, but there are definitely possibilities. :loopy:

@qlamerand j’aurai bien testé ton joystick dans la foulée, mais je le retrouve plus ! Un grand rangement s’impose.

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So yes. Not interested in anymore ?

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Hi sezare56, I would love if you could expand on your cable (and overall) setup to use the expression input for audio and routing that to envelope follower. I have just got the heat and wish to route a drum break to the envelope follower to effect the filter on a sustained chord. Thanks.


Sorry, I can’t elaborate, I don’t have AH anymore. May buy it again, but not a priority, hoping accurate midi trigger of envelopes / lfos will exist one day!

Do you have gear sending CV?

Hi, thanks for the response.
I do have some cv gear but I’m looking to use audio to trigger the envelope follower on the heat. But not the audio from the heats Imputs, a separate audio Imput into the expression Imput. Did you have to make a specific cable to preform this function?

Yes I think I understood.

That’s what I used.

@qlamerand told me about an kind of audio to CV adaptator IIRC…

An audio to +5V trigger gates : Bastl Klik.
But it seems to be discontinued.

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So, is it actually safe to plug a line level or Eurorack level audio output into the control voltage input of the heat? I understand that it would be a bit messy, but now I want to try. Just don’t want to cause damage.

Also, not to get off subject; but if it works for Heat, shouldn’t it work for Analog RYTM MkII and Analog Four MkII as well?