Tiny Timmy. A new distortion with vocal octave-up effect

[anotherjim]

This design shrinks the diode options of a Timmy that concentrates on sludgy heavy distortion and adds an interesting side effect with an almost vocal/sing-song octave up that has a clicky kind of rhythm of its own.
The opamp used is expensive and hard to find except as engineering samples but is a new Burr-Brown design that includes a low-noise CMOS soft-clipping output stage that should revolutionise instrument electronics.

Sound demo clip...
https://soundcloud.com/ashdalestudio/tinytimmy

Enjoy

[composition4]

I actually have a bunch of OPA4121 (the CN version not AM) lying around... Breadboarded this minus the Selenium plate rectifiers and I'm very impressed

[Invertiguy]

Got any info on that opamp? I can't seem to find any data on it anywhere and Google turns up nothing.

(assuming this isn't related to the current date, of course  )

[iainpunk]

The opamp used is expensive and hard to find except as engineering samples but is a new Burr-Brown design that includes a low-noise CMOS soft-clipping output stage that should revolutionise instrument electronics.

you know the CA3130 also have extremely low noise, and soft clipping CMOS output stages
similar GBP as well, a bit faster slew rate, and only one opamp per dip 8 instead of 2 opamps...
i build it with those and selenium rectefiers out of  car battery chargers, and i can only get it to squeal? any pointers?

cheers

[Marcos - Munky]

an interesting side effect with an almost vocal/sing-song octave up that has a clicky kind of rhythm of its own.

Very interesting, indeed.

[duck_arse]

excellent timing, Jim, and an E2 range design to boot. won't those rectifiers be affected by the moon to some extent?

also, yer missing the biasing section.

[iainpunk]

also, yer missing the biasing section.

i just used a 7905 to create 5v, and a 4148 to take off a further 0.6v for a nice 4.4v.

cheers

[EBK]

Have you tried using a really long wire for the feedback path and zigzagging it through the rectifier plates?  It would probably allow you to make C3 smaller to save some space, making this design even more tiny!

Excellent demo, by the way.   

[anotherjim]

Ah, no bias network needed. It basically floats toward a rail and then jerks itself off toward the opposite rail according to the rectifier via that very loose 10M coupling.
Mind you, I can't see much use for the thing unless you're a fan of The Darkness.

[Nasse]

You think 3130 could substitute for opa with that biasing of to bipolar suply? And believe i have 3140 in junk box, would it better put lower noise spec One in first or second position. Or put them in sockets. Sounds good, but I was waiting more BGs style voicing, but was more on Barry White setting (trough mobile speakers so dont trust me)

[anotherjim]

Device noise isn't really a concern, so long as it's got a high input impedance (gigohms) it's worth a shot. You've only got until 1 minute to midnight to do it. It may already be too late for some.
Also, B2 may be a bridge rectifier too far.

[GGBB]

[anotherjim]

The important part number is more like 4-1-21 or 1-4-21 according to regional preferences.

[KarenColumbo]

There must be some sort of mistake. I had no bridge rectifier at hand, so I used a precision full wave rectifier. But now I have 18 V instead of the promised 9 V.

[anotherjim]

Sorry, Andreas, there is no place for anything with "precision", real or imaginary, in this circuit. You could try x4 of the leakiest and oddest Ge diodes you have to make a bridge. Really, the more mismatched the better!

[antonis]

I believe there should be some vintage Triumph, Norton or BSA hanging around into garages in Vienna, Andreas.. 
(ultimate source for Selenium rectifiers..)

[iainpunk]

You think 3130 could substitute for opa with that biasing of to bipolar suply? And believe i have 3140 in junk box, would it better put lower noise spec One in first or second position. Or put them in sockets. Sounds good, but I was waiting more BGs style voicing, but was more on Barry White setting (trough mobile speakers so dont trust me)

the 3130 and 3140 have different output stages, the 3130 has cmos inverting output stage and the 3140 has a bipolar transistor output stage which is unity gain. very different clipping characteristics between them. here is the transfer curve from the output stage when used open loop


edited bc. shouldn't post serious stuff in joke threads, sorry

[aron]

I built mine during my lunch hour but I get octave down only. Luckily I put the Tycobrahe octavia back end on it and got normal pitches. That fixed it fast.

[Nasse]

Did fall in sleep in studio sofa before magig moment so this is day late dollar short. Did not notice that selenium bridge text until late. I had idea to use plate amplifier instead of plate rectifier, And i have two Selenium titanium drivers which are 100 Watts and said to be super clean. Tlc271 might be useful op amps for somethin

[KarenColumbo]

Sorry, Andreas, there is no place for anything with "precision", real or imaginary, in this circuit. You could try x4 of the leakiest and oddest Ge diodes you have to make a bridge. Really, the more mismatched the better!

Sorry mate, just wanted in on the joke