Schematic for the MXR Dynacomp Rev. F?

[Paul Marossy]

Anyone have a schematic for the MXR Dynacomp Rev. F?

Rev F uses an LM13700 dual OTA instead of the CA3080. I'm wondering what changes may have been done to the the circuit with that change. Rev F seems to be sound just a little diffenent than the Rev E version.

[Nocaster Cat]

I've heard that the LM13600 is a couple of 3080's in a single package, could be wrong though.

[Mark Hammer]

You're close.  It contains two transconductance amplifiers (which the 3080 is) but is a slightly different design internally, and has better specs.  A bit like saying a TL072 is a pair of 741s: they're both op-amps, true, but not quite the same performance as op-amps.

The 3080 has ceased production, AFAIK, so as the supply dwindles down, many manufacturers have switched to the LM13600 and LM13700.  The same is true of the CA3094 (also a single OTA, but with an added output stage).

[Paul Marossy]

So what do they do with the 2nd stage? Just leave it unconnected? I guess I could look at it and figure it out.

[Nocaster Cat]

So what do they do with the 2nd stage? Just leave it unconnected? I guess I could look at it and figure it out.

I believe so.

[SISKO]

Something like this? http://tonepad.com/getFileInfo.asp?id=121

[Paul Marossy]

I guess the Rev F version shouldn't sound different than the Rev E version, but they seem a little different to me. 

I modded the Rev E version for someone recently and it seemed to have more "sizzle" with the sensitivity maxxed and it seemed to decay into feedback better than my Rev F that I picked up cheap the other day. That's what made me wonder if a CA3080 and 1/2 of an LM13700 are really the same thing. They seem slightly different to me...