freestompboxes.org

I have an EVH 117 flanger in for repair. I can take some pictures if someone is interested. It uses a (weird) v3204 dunlop branded BBD device..

Pictures are ALWAYS welcome!

Can NEVER have enough pics! Please do

yes pictures please make sure you take both component and track side so if one of wants to have a go at tracing it we can get a schematic together cheers

I would imagine this pedal like a lot of the newer MXR stuff is pretty mutch all SMD, I would love to see a couple of pics of the pcb.

2 Quick pictures so you can see the pcb. I will make larger/better ones for tracing purpose.

Does anyone have some info on the v3204 IC? Could it be a rebranded v3205?
This specific pedal sometimes starts to make a huge amount of random weird noise like self oscillation, so knowing what BBD is in there may be interesting to know.

Rebranded v3205? No...

It's just a specially for MXR made MN3204, it's 512 stages.

So I guess this hasn't got a direct replacement?

Coolcat0078 wrote:So I guess this hasn't got a direct replacement?

Not unless you ask MXR for one.

The oscillation issues will be feedback or clock adjustments probably, you should probably ask MXR which trim controls which parameter and what the set up procedure is if you're going down that route.

there are ideas that makes sa572?

Sa572 is a compander, one half compress the signal befor the digital portion and the other half expand the signal after that.

Yes, but why is it needed in the flanger circuit?
It is used in analogue delays, in the original scheme with sad1024 it was not used.
http://rudn.nodevice.com/preview/big/373/373202-1.jpg

POTL wrote:Yes, but why is it needed in the flanger circuit?
It is used in analogue delays, in the original scheme with sad1024 it was not used.
http://rudn.nodevice.com/preview/big/373/373202-1.jpg

My guess would be to simply lower noise in a BBD based circuit, same as it does in a delay.

Ice-9 wrote:

POTL wrote:Yes, but why is it needed in the flanger circuit?
It is used in analogue delays, in the original scheme with sad1024 it was not used.
http://rudn.nodevice.com/preview/big/373/373202-1.jpg

My guess would be to simply lower noise in a BBD based circuit, same as it does in a delay.

I concur, the circuit is obviously quite different to the original, this uses a 512 stage BBD but the original used the SAD1024 in series mode so 1024 stage BBD... maybe rather than get two types of BBDs they just increased the delay length from half the stages and then needed to cut the noise down that introduced. Who knows without a schematic and/or clock readings though.

Scruffie wrote:

Ice-9 wrote:

POTL wrote:Yes, but why is it needed in the flanger circuit?
It is used in analogue delays, in the original scheme with sad1024 it was not used.
http://rudn.nodevice.com/preview/big/373/373202-1.jpg

My guess would be to simply lower noise in a BBD based circuit, same as it does in a delay.

I concur, the circuit is obviously quite different to the original, this uses a 512 stage BBD but the original used the SAD1024 in series mode so 1024 stage BBD... maybe rather than get two types of BBDs they just increased the delay length from half the stages and then needed to cut the noise down that introduced. Who knows without a schematic and/or clock readings though.

It seems even more strange why use the rare component mn3204 and expensive sa572 if you could just set nm3207 or nm3007 and get a 1024 stage BBD

They use the 3204 in the micro flanger and I haven't checked but I think possibly the choruses too. It's not rare for them as it's made especially for them.

Probably use the 572 in their delays, cheaper to have a lot of one part produced than less of two separate parts.

Could be other design reasons though, as I said, can't say without a schematic and/or clock readings but I doubt they made an accounting mistake.