Ibanez MOStortion MT10

[col]

I might have missed something but what are CR1 and CR2?

Col

[RLBJR65]

Not quite the same tone stack as my Peavy SS but very close. http://aronnelson.com/gallery/Richard-Boop-RLBJR65/PeavySSToneStack

STM hope you don't mind I hacked up your schematic! It was so close and I'm being lazy today

Oh, just noticed while previewing that the mid and treb pots in mine are linear not audio.

[Inmorjamn]

Old thread post   by new member.

The replacement mosfet chip for the Mostortion on Mouser is currently unavailable.

I looked up a replacement by Texas Instrument TLC2262CP
There are several versions.
I have the TLC2262CP in the cart but I would like to know if this version will be a good substitute?

This is my first pedal build but not my first time building electronics from a schematic.

[idy]

CA3260 is a chip I love, but not available easily. What makes it *special*, they say is MOSFET input, CMOS output. I think the single opamp package still available, would have to build a daughter board and adaptor...

2262 is a good try at subbing.

I would advise you to put a socket in (you were going to use a socket, weren't you?) and try the 2262 and anything else you want to try. Maybe you are willing to pay, what are 3260s now, like $10 a piece, just to find out.

Any dual opamp will work...

[Inmorjamn]

idy, thanks for the reply. I am doing a Aion board, I think it's called. Sourcing most of the parts at Mouser.
I would pay for that chip if I coup find one.
The BOM has a number for the socket.

[Mark Hammer]

I won't say, and couldn't say, the 3260 is irrelevant.  But, with the clipping diodes in the feedback loop of that first op-amp, the chip is not being pushed past its headroom limitations, making 95% or more of the clipping coming from the diodes, rather than the chip.  The chief characteristics of the MT10 come from use of a 2+2 diode complement (just like a Timmy) and the very effective 3-band EQ.  Could there be nuances between different chips one hears under certain conditions?  I suppose.  But audible differences between a 3260, 3240, or even 4558, will likely be the sort of thing that an audience wouldn't hear, and the player themselves wouldn't hear, once the volume gets turned up.  For purposes of authenticity, score yourself a certified CA3260.  But my guess is that you'd likely be almost as pleased with the pedal, using any of a host of other chips.  Your call.

[GGBB]

I cloned the MT10 and have tried both the TLC2272 and the CA3260 reissue. I heard differences but they are on the subtle side. The 3260 sounded slightly thicker/woolier through the midrange and bass with a slightly tamer top end in comparison to the 2272, with the 2272 giving a slightly brighter impression overall. I also tried a TL082 which sounded close to the 2272. Not an exhaustive test - just 15 minutes swapping back and forth and trying different gain levels ~10:00, ~2:00 and dimed. Gain setting didn't change what seemed different between chips. If my clone sounds like the original (no basis to judge that) then any of those chips would also be close to original in sound IMO. I don't think you'd be missing out by not having the 3260 (unless the reissue chip is different than the original), so maybe the key to its sound is the circuit not the chip. Of course, that's a slap in the face to all the internet hype about the original chip, so I surely must be out of my mind  .

[Mark Hammer]

IF it was the case that the clipping diodes were going to ground from the chip's output, and constraining the output if that stage, rather than in the feedback loop and constraining the voltage gain of the chip, I'd expect the specific chip to make an audible difference, and maybe even an easily audible one, since that first stage  has a potential gain of about 250x.  That's easily enough to turn pretty much any guitar input signal into something that greatly exceeds the chip's maximum voltage swing.  In which case part of what you'd be hearing is the signal bashing its head against the headroom limits.  In contrast, the diodes in the feedback loop constrain the maximum amplified signal voltage to around +/-1200mv, well below the chip's seeming +/-4V maximum voltage swing.

[Inmorjamn]

All comments considered , thanks for the comments and insights.
I thought it was worth signing up here to get some feedback. And it was  worth my time. I appreciate the response.

GGBB, I will try the 2272. So I can go forward with the order. I had no idea the original chip  was obsolete until I tried to find one.
In the original post I did not include the board I am using from Aion.
 https://aionfx.com/project/quantum-mosfet-distortion/

[Mark Hammer]

You'll like it, once you have it built.  It's deserving of the warm reception it receives.

I had ordered some CA3260 chips through AliExpress a couple years ago.  Only one of the 5 actually worked.  Was it actually a 3260?  Who knows.

[bean]

You'll like it, once you have it built.  It's deserving of the warm reception it receives.

I had ordered some CA3260 chips through AliExpress a couple years ago.  Only one of the 5 actually worked.  Was it actually a 3260?  Who knows.

I've had good luck with UTSource for them.

[Inmorjamn]

You'll like it, once you have it built.  It's deserving of the warm reception it receives.

I had ordered some CA3260 chips through AliExpress a couple years ago.  Only one of the 5 actually worked.  Was it actually a 3260?  Who knows.

I've had good luck with UTSource for them.

Wow, UTSource?
You can buy them used and I don't mind that or the price even. Shipping to USA west coast. $27? I don't think it's worth it.

[Inmorjamn]

 

[GGBB]

Newark still has them: https://www.newark.com/renesas/ca3260ez/op-amp-4mhz-10v-us-dip-8/dp/57K3027

Also Futurlec but I'm not as confident that theirs are real.

[Inmorjamn]

Newark still has them: https://www.newark.com/renesas/ca3260ez/op-amp-4mhz-10v-us-dip-8/dp/57K3027

Also Futurlec but I'm not as confident that theirs are real.

Thanks GGBB
I doubt I will notice much difference but now I will have options.

[bean]

Wow, UTSource?
You can buy them used and I don't mind that or the price even. Shipping to USA west coast. $27? I don't think it's worth it.

There's a USPS option that is $7. At least for me in middle TN.

[Inmorjamn]

Wow, UTSource?
You can buy them used and I don't mind that or the price even. Shipping to USA west coast. $27? I don't think it's worth it.

There's a USPS option that is $7. At least for me in middle TN.

I didn't see that option. If I did it would have been done.

There is some new Opamp from Mouser but I have no idea if it would work.
28 pages of info.

[Ben N]

Newark still has them: https://www.newark.com/renesas/ca3260ez/op-amp-4mhz-10v-us-dip-8/dp/57K3027

As of this post, they have 37 in stock, but if you order 500+, they will halve the price per unit! 

[Inmorjamn]

Newark still has them: https://www.newark.com/renesas/ca3260ez/op-amp-4mhz-10v-us-dip-8/dp/57K3027

As of this post, they have 37 in stock, but if you order 500+, they will halve the price per unit! 

I got 2 of them from Newark.
Thank you.