Pedals with interesting ICs?

[skeletonghost]

Hey everyone, I'm interested to find out what you think are some of the more unique pedal designs that use strange ICs or have some interesting non-standard designs. The other day I learned about the Catalinbread hyperpak that uses a complementary CMOS transistor chip (CD4007). A bit more common but Red Llama's, hot tubes, and runoffgrove's 22/7 use hex invertering buffer for linear amplification.

Has anyone ever seen a design that uses a transistor array like the ULN2003 for example? Recently I also found resistor bank in a 16p DIP package at a local surplus (are there diode DIPs?). I've never seen a pedal design with something like that.

It made me wonder about other unique circuit designs that don't utilize op-amps or standard transistors. Any ideas?  

[nocentelli]

There's a tonebender MKII made with a 3046 npn array, and I believe the original Way Huge Swollen pickle fuzz is a BMP utilising an array chip.

[Feral Feline]

Yeah, MPQ3904 was used in the Pickle, 2n3904 transistors are the equivalent, so I've read.

FuzzDog's clone can be used with the chip or discrete transistors.

Kit Rae's site mentioned NTE2321 as well.


The thing about using the chip vs separate transistors is that the chip is purportedly already matched up.


Using discrete, you'd want to match all four transistors' hfe.


Just regurgitating what I've read.

[lasermonkey]

The Pearl PH-03 Phaser used the 4069 hex inverter to provide a set of matched FETs for the phase-shifting. I think the EHX Bad Stone used a similar approach. Quite ingenious, really.

[nocentelli]

Feral Feline wrote

Yeah, MPQ3904 was used in the Pickle, 2n3904 transistors are the equivalent, so I've read.

The thing about using the chip vs separate transistors is that the chip is purportedly already matched up.

Using discrete, you'd want to match all four transinm stors' hfe.

Just regurgitating what I've read.

Definitely useful for FETS when used as resistive elements, but you don't need to match the trannies in a BMP