Author Topic: Schematic for the MXR Dynacomp Rev. F?  (Read 1832 times)

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Paul Marossy

Schematic for the MXR Dynacomp Rev. F?
« on: June 30, 2012, 06:54:44 AM »
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.
_/\_/\_PJM_/\_/\_

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"Tone is in the fingers."

Nocaster Cat

Re: Schematic for the MXR Dynacomp Rev. F?
« Reply #1 on: June 30, 2012, 09:07:37 AM »
I've heard that the LM13600 is a couple of 3080's in a single package, could be wrong though.

Mark Hammer

Re: Schematic for the MXR Dynacomp Rev. F?
« Reply #2 on: June 30, 2012, 09:35:03 AM »
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

Re: Schematic for the MXR Dynacomp Rev. F?
« Reply #3 on: July 01, 2012, 01:06:05 PM »
So what do they do with the 2nd stage? Just leave it unconnected? I guess I could look at it and figure it out.
_/\_/\_PJM_/\_/\_

www.diyguitarist.com
www.soundcloud.com/Paul-Marossy

"Tone is in the fingers."

Nocaster Cat

Re: Schematic for the MXR Dynacomp Rev. F?
« Reply #4 on: July 01, 2012, 02:12:23 PM »
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

Re: Schematic for the MXR Dynacomp Rev. F?
« Reply #5 on: July 01, 2012, 03:02:46 PM »
--Is there any body out there??--

Paul Marossy

Re: Schematic for the MXR Dynacomp Rev. F?
« Reply #6 on: July 02, 2012, 07:12:22 AM »
I guess the Rev F version shouldn't sound different than the Rev E version, but they seem a little different to me.  :icon_confused:

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...
_/\_/\_PJM_/\_/\_

www.diyguitarist.com
www.soundcloud.com/Paul-Marossy

"Tone is in the fingers."