phasers with transistors

[BMS1971]

Hello all
I used to own a EHX bad stone witch had only transistors (8?) and no IC. Sold it long ago....
It kept me wondering if they was a schematic of it somewhere and if other phasers where made like this with transistors and not ICs.
Cheers
Benoit

[OC26]

Quick reply: Univibe

[aionios]

The original Bad Stone used JFETs, not transistors. Many phasers like the Phase 90 and Boss PH-1 use the same method.

The only phaser I’m aware of that uses actual BJT transistors is the Pearl PH-44.

[bumblebee]

Korg Nu Vibe has about 28 transistors in it…could be FETS, I have no idea. Has some ICs in it but I’m not sure what they’re using them for. Some are for switching and slider pots wave shape formation, I know this much.

Sounds brilliant BTW. I bought the pedal when I found a new one far cheaper than retail.

I haven’t even opened mine to take a peak yet….been planing to just couldn’t be fckd.

Also, the only bad stone phaser schematics I have use ICs.

[bumblebee]

[Lani]

Wow.... This would be a chore to clone.

https://www.synthxl.com/wp-content/uplo ... Manual.pdf

[JiM]

OFF-TOPIC

The original Bad Stone used JFETs, not transistors.

Just an off-topic remark : JFETs are transistors, that's what the T means.
It's not the first time i see people refer to only BJT as transistors, and it feels weird.

BTW, in the Bad Stone the 4009 is used as a MOS transistor array, half of the inverter gates are shorted. It's a nice way to have matching FETs.

[aionios]

OFF-TOPIC

The original Bad Stone used JFETs, not transistors.

Just an off-topic remark : JFETs are transistors, that's what the T means.
It's not the first time i see people refer to only BJT as transistors, and it feels weird.

Correct... but in practice, both in the DIY community and broader electronics field, 99% of the time you hear "transistor" it refers to BJT, and it's generally safe to assume this is the case. JFETs are always called JFETs and MOSFETs are always called MOSFETs, even though the "T" in both stands for transistor.

So if it feels weird, that means you're part of the 1% and you should give in and join us over here in the 99%

[aionios]

Also, the only bad stone phaser schematics I have use ICs.

The first version (most mummy face models) used JFETs and ran at 18V:
https://sites.google.com/a/davidmorrin. ... /bad-stone

Some very late mummy face models did use CMOS (e.g. the one here: http://www.home-wrecker.com/badstone.html) but they're pretty rare. It seems to have been right before the transition to the 3-knob V2, which all used CMOS.

[bumblebee]

Wow.... This would be a chore to clone.

https://www.synthxl.com/wp-content/uplo ... Manual.pdf

And I thank you very much for the schematic!

[JiM]

OFF-TOPIC

Correct... but in practice, both in the DIY community and broader electronics field, 99% of the time you hear "transistor" it refers to BJT, and it's generally safe to assume this is the case. JFETs are always called JFETs and MOSFETs are always called MOSFETs, even though the "T" in both stands for transistor.

Ideed, but you took it the other way around, implying that JFETs are NOT transistors, which is plain wrong.
Anyway, nothing of importance, case closed.

[BMS1971]

Thanks everyone for your help
Ben