Proper spring reverb

[Beck]

Time for bringing this one back to life.

We've got the PAIA spring reverb but an IC1 has gone missing. We're in a rush due to two EP's I've recorded that needs finishing very soon and PAIA's office is taking a break + plus shipping from the US is slow and cost money.

This leads us to the question of which IC1's can be used from Ebay? A link will be recieved with gratitude. Getting a bit desperate, please help.

The original IC was the RC4136

The only direct replacement that is a little easier to find and a bit better performance is the TL075. Both these ICs are rare and discontinued.

Here's some TL075 in UK.

TL075 Integrated Circuit x 1 Pieces | eBay

http://www.ebay.com/itm/TL075-TEXAS...al_Components_Supplies_ET&hash=item4ad032d5bb

Other than that you would have to get an adapter and use more common quad op amps. The RC4136 is configured all wrong.

 

[ecc83]

I thought the PAIA was a kit and the chip wasn't included in the set for some reason, but I could be wrong.
The RC4136 does seem to have a vastly different pinout than the TL084 or LM348 chips, the diagram online for the PAIA seemed to be using the 4136 pinout, so I'm not convinced a TL would work, e.g. it seemed to need the outputs on 3,4 10 and 12, as opposed to 1,2,3 and 4 like the others.

This is assuming I had the right schematic, of course:
PAiA Corporation: Hot Springs Reverb Schematics

Sorry! These old eyes did not see the different pinout on a poor schematic. RS seem to have the original chip?..Buy Operational Amplifiers RC4136N, Quad Operational Amplifier 3MHz, 14-Pin PDIP Texas Instruments RC4136N online from RS for next day delivery.

Dave.

 

[ecc83]

Did not want to screw up above.
I have also found a thread regarding the 4136 in another piece of audio kit where they are slagging it off a bit for having poor performance (about as goo as a 741!) The thread goes on to suggest more modern, higher performance ICs. Do not I urge you try this! The ad hoc "upgrading" of components, especially ACTIVE components can lead to all sorts of problems such as increased power consumption and/or instability.

The fact is that apart from it poor noise performance the venerable 741 is quite a useful audio chip and replacing it with say LM4562s (which are "better" than NE5532s) would probably not make an audible difference in most cases.

Dave.