Providence Stampede OD SOV-2

Olof · Post by **Olof** » 20 Mar 2012, 10:40

Hi, I’m Olof.
I noticed someone mentioning Providence Stamped OD Sov-2 in the request section. I had a chance to borrow a SOV-2 from a friend. I took it apart and traced it. I’ve attached the circuit trace, a couple of pictures and a bill of materials.
I have NOT verified the trace by building the unit, but the traced circuit looks possible. Hope this is OK.
Sov-2 is assembled on two PCB’s. This is a +/-15V circuit. 9V is dropped to 5V on the SUB PCB by a TA78L005 3-pin regulator and then stepped up to +/-15V with a muRata NMA0515SC DC-converter. There are two 4558 opamps and one pair of clipper diodes which are unidentical. I could not see any codes on diodes even with a 7x loop.

-Olof

v0d00blues79 · Post by **v0d00blues79** » 22 Mar 2012, 03:51

The small one with the blue band looks like a 1S1588 diode. I've never seen anything like the other one.

Thanks,

Andy

mictester · Post by **mictester** » 22 Mar 2012, 06:10

So....

It's a Tubescreamer with op-amp input and output buffers (instead of transistors), mechanical switching, a bipolar supply rail (derived in a somewhat inefficient way - there's a lot of battery energy wasted in the drop to 5V and then some more in the SMPSU module) - and slightly dissimilar clipping diodes to give slightly asymmetrical clipping.

The two advantages of the 30V supply are that you can get a very big output voltage swing if you want, and you're unlikely to get the op-amps themselves to clip (which usually sounds really nasty). The disadvantages are high battery consumption, increased complexity and component cost, and the risk of introducing the high frequency switching artefacts from the SMPSU on to the output - these may be ultrasonic, but may well play havoc with subsequent BBD-based or digital effects with high frequency clocks!

Dingleberry · Post by **Dingleberry** » 22 Mar 2012, 10:01

I think the diode is 1N4249 or similar rectifier. I have got a bunch of similar looking diodes. Some of them has 1N4249 stamped on them and some without any markings. 1N4249 is basically a 1N4007 substitute.
-T

gilmour_pugliese · Post by **gilmour_pugliese** » 22 Mar 2012, 11:38

mictester wrote:bipolar supply rail (derived in a somewhat inefficient way - there's a lot of battery energy wasted in the drop to 5V and then some more in the SMPSU module)

In fact the pedal draws approx. 90mA...

gilmour_pugliese · Post by **gilmour_pugliese** » 22 Mar 2012, 11:44

Olof wrote:This is a +/-15V circuit. 9V is dropped to 5V on the SUB PCB by a TA78L005 3-pin regulator and then stepped up to +/-15V with a muRata NMA0515SC DC-converter.

There's a cheaper way to obtain a +/-15V from a single 9V supply? Maybe using LT1044 or LT1054?

mmolteratx · Post by **mmolteratx** » 22 Mar 2012, 19:00

mictester wrote:So....

It's a Tubescreamer with op-amp input and output buffers (instead of transistors), mechanical switching, a bipolar supply rail (derived in a somewhat inefficient way - there's a lot of battery energy wasted in the drop to 5V and then some more in the SMPSU module) - and slightly dissimilar clipping diodes to give slightly asymmetrical clipping.

The two advantages of the 30V supply are that you can get a very big output voltage swing if you want, and you're unlikely to get the op-amps themselves to clip (which usually sounds really nasty). The disadvantages are high battery consumption, increased complexity and component cost, and the risk of introducing the high frequency switching artefacts from the SMPSU on to the output - these may be ultrasonic, but may well play havoc with subsequent BBD-based or digital effects with high frequency clocks!

I had one for a while and ya, there are some odd design choices for sure but it sounds pretty good and I never had issues with any of my BBD or digital gear after it (and I run a lot

). I always wondered why the current draw was so high and now it's very obvious...

Sari · Post by **Sari** » 23 Mar 2012, 07:55

gilmour_pugliese wrote:
Olof wrote:This is a +/-15V circuit. 9V is dropped to 5V on the SUB PCB by a TA78L005 3-pin regulator and then stepped up to +/-15V with a muRata NMA0515SC DC-converter.
There's a cheaper way to obtain a +/-15V from a single 9V supply? Maybe using LT1044 or LT1054?

Actually there is!

Check the data sheet - there is a schematic for a +18/-18 (or 9, which you could make into 18 at a cost of a bit more ripple) IIRC

Danch · Post by **Danch** » 10 May 2012, 09:10

Layout and pcb,
7660S, 1054 or 1044 are used to convert voltage, clipping diodes are your choice.
Follow the schematic for connections.

jfk1063 · Post by **jfk1063** » 28 Jun 2012, 11:21

Cool! Did anyone made this and verify it? Looks like a great pedal.
Thanks! John

Danch · Post by **Danch** » 11 Jul 2012, 08:15

It is verified by me, otherwise I would not post it.

jfk1063 · Post by **jfk1063** » 26 Aug 2012, 14:47

It works and is a pretty great pedal!

It took some time to make the board without making a pcb, but it worked out fine. I still have to experiment with the clipping diodes and maybe potvalues.
Thanks guys!

roseblood11 · Post by **roseblood11** » 27 Aug 2012, 20:28

May I suggest this?
viewtopic.php?f=13&t=16890&hilit=rose+screamer

A very similar approach as the Stampede OD, but much more tonal possibilities with just a few more parts.

I'm working on a new version at the moment (see attachment), it will have a few changes:
-Jfets oder Mosfets for soft clipping
-different tone control (J. Ormans "AMZ tone 4" instead of standard TS)
-three position bass switch
-more pre gain for the "no diodes, just opamp clipping" mode (switchable extra resistor (R14) in the feedback loop of the first opamp - try it, 100k is just a guess)

jfk1063 · Post by **jfk1063** » 28 Aug 2012, 07:57

roseblood11 wrote:May I suggest this?
viewtopic.php?f=13&t=16890&hilit=rose+screamer

A very similar approach as the Stampede OD, but much more tonal possibilities with just a few more parts.

I'm working on a new version at the moment (see attachment), it will have a few changes:
-Jfets oder Mosfets for soft clipping
-different tone control (J. Ormans "AMZ tone 4" instead of standard TS)
-three position bass switch
-more pre gain for the "no diodes, just opamp clipping" mode (switchable extra resistor (R14) in the feedback loop of the first opamp - try it, 100k is just a guess)

Wow, looks nice! I will have a look.
So far I did:
- gain pot to 500K
- inputcap to 50nf
- clipping diodes: pair of 1n4148's and a 1n4007
- opamps to tl072
I still want to look at the tonecontrol. I now have a 5K pot and this works better, but I'm gonna try a 20K W taper to maybe get a better evenly sweep. I will also check AMZ tone 4 control.
Thanks!

distortion_gfx1 · Post by **distortion_gfx1** » 28 Mar 2013, 14:15

jfk1063 wrote:It works and is a pretty great pedal!
It took some time to make the board without making a pcb, but it worked out fine. I still have to experiment with the clipping diodes and maybe potvalues.
Thanks guys!

Do you have some sound clips?

cdeschenes · Post by **cdeschenes** » 29 Mar 2013, 04:47

Can someone help with the pads for the pots on the PCB transfer above. Im a bit lost.

Intripped · Post by **Intripped** » 29 Mar 2013, 05:25

connections for drive pot:
pad for pin2 (and pin3) comes from R13 in the layout, you see it at the bottom, close to the output pad
pad for pin1 is just above C23

tone pot connections are easy to find

connections for level pot: they are marked with VR2 and VR3 in the layout - connect them to pin2 and to pin3 respectively
pin1 has to be connected to ground, there isn't a pad for this on the PCB - you could run a wire from pin1 to the ground of the output jack, for example

jfk1063 · Post by **jfk1063** » 29 Mar 2013, 13:36

distortion_gfx1 wrote:
jfk1063 wrote:It works and is a pretty great pedal!
It took some time to make the board without making a pcb, but it worked out fine. I still have to experiment with the clipping diodes and maybe potvalues.
Thanks guys!
Do you have some sound clips?

Hi,
I used it at my cd-releaseparty. Check out my latest vids at: https://www.youtube.com/user/JohnFKlaver for the sound.
But a few months ago I changed it with a Madbean Kingslayer and a Centaur (all DIY). This SOV sounds great but the tonecontrol needs work to be evenly and the bass is a bit muddy. Maybe I will work on it later.

cdeschenes · Post by **cdeschenes** » 30 Mar 2013, 17:40

Intripped wrote:connections for drive pot:
pad for pin2 (and pin3) comes from R13 in the layout, you see it at the bottom, close to the output pad
pad for pin1 is just above C23

tone pot connections are easy to find

connections for level pot: they are marked with VR2 and VR3 in the layout - connect them to pin2 and to pin3 respectively
pin1 has to be connected to ground, there isn't a pad for this on the PCB - you could run a wire from pin1 to the ground of the output jack, for example

Thanks so much. Makes sense now.

lovetone · Post by **lovetone** » 10 Jun 2013, 22:42

Has any one tried the Free The Tone MS SOV Special Matt Schofield Special?

i was wondering what the new input section is all about?

Providence Stampede OD SOV-2 [traced]