suggestion for replacing/upgrading 4136 quad discrete op amps?

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capacitor

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Apr 25, 2017
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195
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Denver, Colorado
Just a simple old school 70's project.

I get to debug a Tapco 4400 spring reverb with a silent channel. I'm good with what I need to do, and it should be pretty straightforward :)

While I'm in there, I figured i would first replace the electrolytics like one should. Everything looks good in terms of traces, components and wiring, and it hasn't been abused. Both tanks are good. Pretty cool unit!

My question surrounds replacing the opamps. I would like to swap in some better op amps, if it isn't a stupid thing to do. I mean a 4400 isn't exactly a Gary Wright approved Minimoog, correct? Haha! Anyways.

The seven 4136 quad 741-type op amp ICs run off of +-18vdc. From what I can gather, the 4400/4400a is not known to be super quiet, and if it could be improved upon with an op amp upgrade, that would rock.

Thanks in advance for any help. I'm somewhat inexperienced but careful and methodical.
 

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So the 4136 are dead? Or still working?

Doesn't the 4136 have a pinout different from most other quads? Would need some kind of adapter. Also better check periphery requirements, cos might need to be adapted too.

Is it worth it? Maybe the 4136 are where the 'mojo' happens.
 
The 4136 was an inexpensive quad op amp with decent noise and gain bandwidth but it had a unique footprint,

there are adapters to accept 2x smd dual op amps RC4136 Upgrade Adapter - 060601 - Cimarron Technology

rc4136-upgrade-adapter-browndog-060601-100x100.jpg

Nothing special about the 4136 other than good for the money.

JR
 
Thanks and I was thinking the same about mojo and peripherals. I haven't debugged the non-working channel just yet, but the other channel works/sounds like it should.

I'm thinking I'll just debug it and keep it stock. The adapter pcb looks good to go, but if I did all the op amps that would add up, and it's a color piece anyways :)
 

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