ta7136 substitution

Some of the System 700 modules use Toshiba TA7136 SIP opamps (datasheet), which are long obsolete and semi-sought after by DIY guitar types because it was used to apparently pleasing effect in a Boss distortion pedal. An eBay seller is trying to get the best part of twenty quid for one.

A while back I bought a bunch from Utsource, and when I eventually got round to making a board to test them I found they were fake…

TA7136 vs fake

…booo.

I made up this adapter for an alternative op amp, ‘cos I don’t think using this particular chip is that important (for now, anyway).

TA7136 to TL071

Here’s a strangely moody photo of the resulting stripboard.

TA7136 > TL071 stripboard adapter

After this I cut one chunk out of one side of the board to indicate pin 1.

I’ve had this working in the 708 noise/ring mod and the 711 output module, and it works fine, although I’ve not had a chance to compare it directly to the 7136.

7 comments

  1. 1st January 2019Arri says:

    Just curious do you think this could be used in a CE1?

  2. 1st January 2019ua726 says:

    Can’t see any electrical reason why it wouldn’t, though it might be a bit tall to fit in the enclosure? Dunno.

  3. 4th January 2019Arri says:

    I’m actually trying to make a clone of one.
    I was just gonna copy the original PCB and populate it.
    My only worry was the fact that pin 1 and 5 aren’t going anywhere.
    Thanks for the reply!

  4. 4th January 2019ua726 says:

    Nice, good luck with the cloning! If you write it up would love to see a link in the comments here.

  5. 11th January 2019Arri says:

    I’ll probaby write it up when I’m done. 🙂
    I’m planning to use it as a test bed of sorts to see if I can get other more common ICs to play nicely with it.
    If I clone it will you strip-board it hahahaha.

  6. 27th January 2019Steve says:

    Also building a CE-1, planning to use this as a low noise alternative to the Ta7136.

    How can i etch this on a pcb to save space?

    Thanks!

  7. 27th January 2019ua726 says:

    CE-1 frenzy! Well, two of you anyway

    There’s someone who has made an adapter board for the 7136-to-other-op-amp, and it’s available on eBay, but they’re in Idaho in the US, and they’re not super cheap.

    Etching your own boards has always been something I’ve avoided ‘cos of having to deal with the chemicals.

    I imagine you could draw out the schematic from the pin-out I’ve posted, do a layout in Kicad/Eagle/something-else (maybe using a surface-mount footprint for the op-amp to save space) and have ten of them made up in China for the same cost as those other boards, although it might take a while with the impending new year holiday. And then you could sell the ones you don’t need to other Boss chorus pedal fetishists.

    I might even have a go at some stage, I’ve got a couple of things built up that could do with this – if I get round to it I’ll post it here. Don’t hold your breath though.

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