Ambika SVF Resonance lost


Today is not my day, one of my SVF card has no more resonance… (it works fine since yesterday…) do you what IC is risponsible of resonance?


I hav swaped all the IC to an other card, and the problem is gone to the other card.
so it is a IC… Is it normal that a IC have a life duration of 2 weeks?

Were some ICs getting hot when you’ve touched them ?

I’m not an electronic design specialist but, after having a look at the SVF voicecard schematic, it seems that the resonance of the SVF filter is built with the TL074 and the V2164D. May be check them first ? By the way, the 4052N is switching the filter’s types (LP, BP & HP).

Hédi K.

I had a problem with the 4052 on one of my SVF-Voicecards.
My 4052 was only suited for +/- 5v. Check the datasheet of the part you bought.

@ macMO > I had the same problem with all my 6 SVF voicecards. More informations in this topic .

Hédi K.

I see. olivier mentioned your problem in my thread. I’m glad i was not the first with this problem ^^.

Can you try the ICs one by one to find one which one caused the problem?

That what i was doing, but I put IC1 in the wrong side… and it burn in 3 sec…the card was still make a sound but I get it off.

do you think something else could burn in the card, can I try to but an other TL072P to continue investigations?

or do I need to get a new craddle (it doesn’t look too damaged)

I don’t think the socket has been damaged. Try with a new chip. As long as you don’t inverse the position of the chip, nothing wrong can happen…

If I put a working chip, there is no sound at all but with the burned one, I have sound (I can use different waves form)…

Is it possible something else have burnt?

I don’t think so… Have you tried tracing the signal chain?

I don’t know exactly how to do that, is there a explanation somewhere? (is it possible without oscilloscope?)

Not sure if there’s any tutorial or post about this, but you don’t need an oscilloscope, just a piece of cable to “probe” the signal at various places in the circuit and connect this to an amp/soundcard.

Ok will try to get some informations. One last question for the moment : what is your point on the fact that with a burned chip it makes some sound and with a new chip it doesn’t?

Without any measurement, audio recordings, etc. there’s not much I can tell. I think you have to do a bit of work to understand how the circuit works - or at least what are its elements - so that you can provide more accurate diagnostic information.

Ok, I am starting to understand, one other thing, in SVF schematic what are mux A & B ?

These are digital signals which control the 4052 multiplexer (= MUX). When both are 00, the output X0 of the multiplexer (LP) is selected. When A is 0 and B is 1, output X1 of the multiplexer is selected (HP) and so on…