808 bass drum schematic : explanation

schematicstransfer function

I am curious about this schematic (I would develop a project around this machine)
I was trying to understand how this bass drum work, but sounds complicated for me…

The trigger input is a pulse.

So : I already get some stuff :

I think there is a bridged T network filter around the First OA : C41/C42 + R166 and Q43.
I guess Q43 is for starting oscillator ?

I am actually trying to get the transfert function of this simplified part of the schem :

schematic

simulate this circuit – Schematic created using CircuitLab

I think i can simplified the schem by that, but I can't find the transfert function !
(I don't know exactly how to start…, also because I don't know what s will be the load, after the OA.

Thanks for you re help, have a nice day !
Vivien

tr 808 bass drum schem

Best Answer

I'd download LTSpice and get to grips with how to use it. Once you have got a circuit drawn you can do transient analysis (or AC analysis) and with simple op-amp circuits get really good results.

Yes, there is a steep learning curve but it has to be done if you wish to improve your repertoire - I use a different suite of simulation tools but I've used LTS in the past and basically, I can say, that using a simulator cuts out at least one PCB iteration.

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