Thursday 26 April 2012

Ibanez OD850 - V3

Requested.  This is a slightly modified Triangle clone that some others may also be interested in.  The original used buffered bypass and FET switching but this has removed those components and is designed to be used with external mechanical bypass switching of some description such as a 3PDT stomp switch.

The scheme that I did this from noted 2SC1815's as the transistors, but I've got a batch of these and based on those I would imagine most people would be disappointed with their performance in this.  The datasheet lists them as 70 - 700 hfe, but mine are all on the low side, and nowhere near the 600 - 650 hfe you'd ideally want for a Triangle clone.  I'd suggest using a 2N5088/5089 or maybe a BC550C (transistors rotated 180 degrees to that shown in the layout) which should get you in the right ball park for gain.  As such the transistors shown in this have a CBE pinout, but if you want to use the 2SC1815 which are BCE, you will need to insulate the legs and twist round the base and collector.

The original schematic also showed the Tone pot to have a W taper, but these aren't very common so I'd suggest using a linear pot as in most Muffs.


2 comments:

  1. Verified. (as my effort for today :))

    Guess what? I tried on a couple of different transistor options. And once again. The lower you go, the better it sounds. 2N5088 and 2N5089 were quite boring - just what you would expect from japanese triangle rebuild. Basically, it was just cleaner than original. With 2N2222 i got nice lively color to the sound, but i guess i've done too many muff variants with BC109C and 2N2222, so i sticked BC549s in, measured around 360 hfe. These sound also pretty good.

    Controls work perfectly with ones Mark has mentioned.

    And one more thing. I omitted that power filtering - by leaving out the 100uF cap and that link on the right, next to Q2. In these kind of designs, that filter shouldn't affect the circuit in any negative way, so i might put it back on once i start boxing this.
    +m

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