Jen - KPS900 Phase Shifter

ChuckNorris1982 · Post by **ChuckNorris1982** » 23 Jan 2008, 09:07

Someone over at HCFX posted these pics of this pedal. Wouldn't mind building one up, anyone fancy tracing/making a schem/perf layout for it?

Dirk_Hendrik · Post by **Dirk_Hendrik** » 23 Jan 2008, 11:46

How bout you?

ChuckNorris1982 · Post by **ChuckNorris1982** » 23 Jan 2008, 11:47

I don't have the know-how mate. Thought someone else might like to, as it'd be an interesting build for more than just myself.

Post by **modman** » 24 Jan 2008, 14:05

ChuckNorris1982 wrote:I don't have the know-how mate.

http://www.phpbbserver.com/freestompbox ... stompboxes

I believe there are various pitch shifter projects around. Isn't there a Maestro Phase Shifter at GGG?

Why are you so interested in this particular unit?

ChuckNorris1982 · Post by **ChuckNorris1982** » 24 Jan 2008, 14:39

Cheers for the link. I'm particularly interested in this unit because I love phasers, but am not really too keen on MXR types. I haven't tried out a Phase 45, so am going to build one up very soon, and I thought it would be nice to build this one up too to compare.

Anyway, I thought posting the guts of pedals was just the done thing around here?

analogguru · Post by **analogguru** » 24 Jan 2008, 19:04

Sadly the guts are not so sharp as desired. Do you own the unit or have access to ? If yes, what is written on the chips ?

analogguru

R.G. · Post by **R.G.** » 24 Jan 2008, 22:19

Two ICs, no transistors or LDRs?

Probably a single notch OTA variant. Half a Small Stone, perhaps?

analogguru · Post by **analogguru** » 24 Jan 2008, 23:41

I would assume a quad fet in a chip.... like in the orange Ross Phaser: AM9709CN

analogguru

R.G. · Post by **R.G.** » 25 Jan 2008, 03:34

analogguru wrote:I would assume a quad fet in a chip.... like in the orange Ross Phaser: AM9709CN

analogguru

Could be. That would still make it a single notch, as a quad opamp in the other IC would be just enough to use two of the JFETs for one notch.

HEAD · Post by **HEAD** » 20 Oct 2010, 12:18

Hi,

sorry for necro-posting, but does somebody ever come up with a schematic for this? Looks like the most simple commercial phaser I've ever seen. Though it might not be the most impressive sounding but for educational purposes it would be nice to see how it works.
Thanks in advance!

Helge

Dirk_Hendrik · Post by **Dirk_Hendrik** » 20 Oct 2010, 20:01

Nope. Not me.

But thanks for the "necro-posting" term. Never heard that one but do like!

borislavgajic · Post by **borislavgajic** » 21 Oct 2010, 09:02

what about this?
http://2562175720203886435-a-1802744773 ... edirects=0

http://www.pedalarea.com/images/jen_kps_900_04.jpg

Boris

mictester · Post by **mictester** » 21 Oct 2010, 11:40

borislavgajic wrote:what about this?
http://2562175720203886435-a-1802744773 ... edirects=0

http://www.pedalarea.com/images/jen_kps_900_04.jpg

Boris

Please note - the LM324 isn't quite a direct replacement for the MC3403. Same pinout, different specification. The 3403 is quieter and wider bandwidth, as I remember.

HEAD · Post by **HEAD** » 22 Oct 2010, 11:26

Thanks!

Still need to understand how phaser with inverters do work.

analogguru · Post by **analogguru** » 22 Oct 2010, 12:47

HEAD wrote:Thanks! Still need to understand how phaser with inverters do work.

Forget it....
The schematic is wrong, the chip is a 4007, the diode is a zener diode 4,7V and at a wrong place.....and some other mistakes.

analogguru

HEAD · Post by **HEAD** » 22 Oct 2010, 13:23

... that is probably why it did look so weird to me at first glance. My first impression was like "eeek, somethings missing here or something is wrong." But as I'm still a noob I thought it was due to my limited knowledge - hey, and I did proof that one more time to be true.

Dirk_Hendrik · Post by **Dirk_Hendrik** » 22 Oct 2010, 17:25

I do like the idea of using a 4007 for the FET's. They are ultra cheap and since made from the same batch op silicon on the same wafer one could, for the experiment, assume the characteriststics of the FET's are pretty much similar. That means
no matching of Fet's!

But on the matter of matching FET's
A wile ago I was in that process for a repair and was convinced my test setup was faulty. All measured the same within a 1% tolerance range. Untill I took another from the "desoldered sometime, someplace, somewhere in time" bin. Totally different. Conclusion; when all come from the same batch chances are very good they all have the same characteristic.

HEAD · Post by **HEAD** » 22 Oct 2010, 17:40

Me too. That's why I'm so interested in this phaser as it seems to be the most simple commercial phaser to uses CMOS, which are indeed quiet cheap and easily available. So it might be a good start to get into that topic. I know about the Bad Stone which uses almost the same technique as far as I understand, but it's still a bit over my head.

Helge

borislavgajic · Post by **borislavgajic** » 22 Oct 2010, 19:54

analogguru wrote:
HEAD wrote:Thanks! Still need to understand how phaser with inverters do work.
Forget it....
The schematic is wrong, the chip is a 4007, the diode is a zener diode 4,7V and at a wrong place.....and some other mistakes.

analogguru

is there a chance to see corrected schematic please?
I am going to make PCB layout then........

thanks

Boris

HEAD · Post by **HEAD** » 23 Oct 2010, 11:29

... otherwise we'll have to wait until mictester comes up with his pwm controlled cmos phaser.

Jen - KPS900 Phase Shifter [schematic]