Blackout Effectors - Whetstone Phaser [guts]

culturejam · Post by **culturejam** » 09 Nov 2009, 21:51

Got this in the mail today. Sweet. I'll take more shots later. I want to play this bad boy!!

This is an OTA-based phaser. Looks like Blackout used a pair of dual OTA chips - NE5517N, as well as a single OTA - CA3049e.

One of the transistors is 2n7000 (probably polarity protection?), and there are three 2n5087 and one 2n5088.

This thing rules.

chicago_mike · Post by **chicago_mike** » 09 Nov 2009, 21:52

ahh... 2 OTA's

the NE5517 is a LM13600 / LM13700

culturejam · Post by **culturejam** » 09 Nov 2009, 22:01

I just took a look at the Small Stone schematic, and just based on the number of OTAs and the transistor part numbers, it seems that the Whetstone is a super-tricked out Small Stone.

I don't recall anyone using dual OTAs in the past, however. That's pretty cool.

Mouser has the NE5517 for about $1.50 each, which is cheaper than tracking down CA3080s:

http://www.mouser.com/ProductDetail/ON- ... gq8POgo%3d

rocklander · Post by **rocklander** » 09 Nov 2009, 22:53

that is seriously cool dood.. watching to see how this develops

allmonochrome · Post by **allmonochrome** » 09 Nov 2009, 23:32

culturejam wrote:I just took a look at the Small Stone schematic, and just based on the number of OTAs and the transistor part numbers, it seems that the Whetstone is a super-tricked out Small Stone.

based on the "ultimate small stone" at the bottom of this link, i'd say that's a good guess: http://blackouteffectors.com/site/?page_id=313

invalidcd · Post by **invalidcd** » 09 Nov 2009, 23:44

Maybe a 12 stage phaser moog/small stone

whatever kind of phaser it is based off of im sure it sounds 80 times better , it looks cool as shit. And the build quality is fantastic.

culturejam · Post by **culturejam** » 09 Nov 2009, 23:49

invalidcd wrote:Maybe a 12 stage phaser moog/small stone

The web site and even the silk screen on the pedal says it's 4-stage. There is a 4-stage / 2-stage switch, which is a really great option.

This thing is easily the most versatile modulation pedal I've ever used. I'm very impressed so far. There are some crazy sounds in there (ring mod mode, for one), but you can also get very classic phase tones. It's a keeper. And I rarely say that.

And yes the build quality is pretty good. I see a resistor or two that aren't totally flat with the board, but other than that, it's quite well done.

Here's the Pro Guitar Shop demo video:
http://www.google.com/url?sa=t&source=w ... SD5Ih0ZAPw

And I've attached the instruction PDF from Blackout Effectors.

culturejam · Post by **culturejam** » 10 Nov 2009, 00:56

Hmmm. Now that I've had a better look at the Small Stone schematic, there seem to be quite a few differences. For starters, each phase stage on the Small stone has two PNP trannies. The Whetstone definitely doesn't have enough of them to be exactly the same.

The similarities are 4 phase stages and an LFO, all built on OTAs.

I'll have to get some shots of the the other side and suss it out.

soulsonic · Post by **soulsonic** » 10 Nov 2009, 02:40

culturejam wrote:Hmmm. Now that I've had a better look at the Small Stone schematic, there seem to be quite a few differences. For starters, each phase stage on the Small stone has two PNP trannies. The Whetstone definitely doesn't have enough of them to be exactly the same.

The similarities are 4 phase stages and an LFO, all built on OTAs.

I'll have to get some shots of the the other side and suss it out.

The transistors in the Small Stone schematics that immediately follow the OTAs are the output buffers that are on the same chip as the OTA. The OTAs used in the Whetstone has these as well. It's probably nothing more than a tweaked Small Stone.

culturejam · Post by **culturejam** » 10 Nov 2009, 02:47

soulsonic wrote:The transistors in the Small Stone schematics that immediately follow the OTAs are the output buffers that are on the same chip as the OTA. The OTAs used in the Whetstone has these as well. It's probably nothing more than a tweaked Small Stone.

I was looking at the Tonepad schematic, and the corresponding layout calls for 14 BJTs. Is Tonepad double-dipping on the buffers?

DimebuGG · Post by **DimebuGG** » 10 Nov 2009, 03:20

Single OTA's like CA3080, 3094, etc doesn't have output buffers and so BJT's in darlington config are called in.

uncleboko · Post by **uncleboko** » 10 Nov 2009, 10:52

DimebuGG wrote:Single OTA's like CA3080, 3094, etc doesn't have output buffers and so BJT's in darlington config are called in.

The CA3094 does have an output darlington.

noise31 · Post by **noise31** » 10 Nov 2009, 12:51

this pedal sound good,

jupagblkxten · Post by **jupagblkxten** » 10 Nov 2009, 14:16

thanks for the pics; been interested in this box for a while, even more so now that i picked up a russian small stone on the cheap. i'm guessing the lfo is a near copy of the one in the stone; the width switch being one half of the color switch. feedback arrangement is probably a lot like what had been presented in mods throughout the net. asym switch looks like its switches in some "univibed" interstage caps. i'm curious as to the implementation of the rate switch (looks like there are some extra electrolytics around that 3094) and the depth control. thanks again for the pics and looking forward to the next batch.

jupagblkxten · Post by **jupagblkxten** » 10 Nov 2009, 15:09

after reading the attached literature, it seems that "depth" is a bit of a misnomer for that control and i incorrectly assumed it's function.

culturejam · Post by **culturejam** » 10 Nov 2009, 16:05

uncleboko wrote:
DimebuGG wrote:Single OTA's like CA3080, 3094, etc doesn't have output buffers and so BJT's in darlington config are called in.
The CA3094 does have an output darlington.

That's what I thought.

I'm thinking a fun side project would be a simple two-stage OTA phaser, using the chips and arrangement in the Whetstone. If you can make the OTAs work without all the extra BJTs, that really makes the layout efficient.

culturejam · Post by **culturejam** » 11 Nov 2009, 06:04

Well, the NE5517 data sheet explains quite a bit.

Attached is an excerpt that is particularly relevant.

culturejam · Post by **culturejam** » 11 Nov 2009, 14:53

Got another shot of the top side, and some photos of the bottom of the board.

I'll have to say I'm pretty impressed with the build quality.

jupagblkxten · Post by **jupagblkxten** » 12 Nov 2009, 14:02

after looking at the new pics, i can confirm that the lfo is a copy of that in the small stone and the rate switch selects between C12, C20 and C21. any chance you could post their values? i'm guessing that C12 is the 33u.

it also appears that the feedback control is not as i assumed. the pot replaces the 270k resistor in the feedback loop.

Reginald · Post by **Reginald** » 26 Nov 2009, 23:02

It's not much, but it's a start:

Blackout Effectors Whetstone Phaser

R1 - 4k7
R2 - 470k
R3 - 2M2 ?
R4 - 470k
R5 - 27k
R6 - 3k3
R7 - 27k
R8 - 27k
R9 - 27k
R10 - 27k
R11 - 1k ?
R12 - 10k
R13 - 1k ?
R14 - 10k
R15 - 22k
R16 - 1k
R17 - 10k
R18 - 1k
R19 - 10k
R20 - 4k7
R21 - 30k
R22 - 27k
R23 - 27k
R24 - 27k
R25 - 30k
R26 - 10k
R27 - 1k ?
R28 - 7k5
R29 - 27k
R30 - 4k7
R31 - 4k7
R32 - 2M2
R33 - 1k ?
R34 - 27k
R35 - 10k
R36 - 10k
R37 - 1k8
R38 - 10k
R39 - 470k
R40 - ???
R41 - ???
R42 - 15k4
R43 - 15k4
R44 - 10k

If someone can look this over it would be great. Most of it should be right, but I couldn't see everything. I'd like to see this project make some progress.

Blackout Effectors - Whetstone Phaser [guts] [traced]