Friedman BE-OD Pedal

J0K3RX · Post by **J0K3RX** » 16 Jul 2016, 16:30

Admin edit November 16th 2017

This thread has gone on to be +33 pages, almost 600 posts and 70.000 views. We should give out awards to builders, or rather: to marketing departments. This looks like the hype of the year. The thread used to be longer even; I have cut out all the banter, speculation, but kept to the rule that any discussion on the circuit should stay. Took me a day or three to wade through this... I might still split off all Build reports, which would cut down the thread to 11 pages.

Tracing a circuit is real work: once decent gut shot are published, the board sides can be superimposed in a graphic program to see which components are linked by which traces.
Speculation --we had 2 pages of that after the gut shots-- is a waste of time as long as there is tracing to be done.
You are tracing a particular unit. Remember that the same pedal from the same factory may have different board, different values, different brand components.
Ok, there is some discussion to read through, but this discussion is what lends the resulting schematic more credibility than any schematic on the web.

Definite schematics
http://www.pedalpcb.com/docs/Thermionic ... ion.v2.pdf
Schematic v13 by Bajaman viewtopic.php?f=7&t=27775&p=264870#p264870
Schematic with Bajaman clipping solution: viewtopic.php?f=7&t=27775&start=280#p265006

Project Files by Bugg
http://www.pedalpcb.com/product/thermionic-distortion/
http://www.pedalpcb.com/docs/Thermionic ... ion.v2.pdf
BOM at Mouser for Buggboard viewtopic.php?f=7&t=27775&start=420#p265446 [change resistors to 1/8W to fit!]

Gut shots
First set of gut shots posted: viewtopic.php?f=7&t=27775#p260343
Second set of gutshots posted: viewtopic.php?f=7&t=27775&p=260729#p260618
Third set of gut shots: viewtopic.php?f=7&t=27775&start=140#p264396

Component Values listed
Values by Pakrat: viewtopic.php?f=7&t=27775&start=60#p264101
Values by Pakrat according to pcb numbering viewtopic.php?f=7&t=27775&start=60#p264115

Schematic
Schematic is sent to member anonymously: viewtopic.php?f=7&t=27775&start=20#p260437
Schematic v1 published: viewtopic.php?f=7&t=27775&p=260449#p260444
Schematic v2 published: viewtopic.php?f=7&t=27775&p=260449#p260449
Schematic v3 viewtopic.php?f=7&t=27775&p=260449#p260465
Schematic v4 published viewtopic.php?f=7&t=27775&start=20#p260729
Schematic v5 viewtopic.php?f=7&t=27775&p=260729#p260737
Schematic v6 viewtopic.php?f=7&t=27775&p=263527#p263527
Schematic v7 viewtopic.php?f=7&t=27775&start=40#p264106
Schematic v8 viewtopic.php?f=7&t=27775&p=264122#p264122
Schematic v9 viewtopic.php?f=7&t=27775&start=60#p264143
Schematic v10 viewtopic.php?f=7&t=27775&p=264170#p264170
Schematic v11 viewtopic.php?f=7&t=27775&p=264184#p264184
Schematic v12 viewtopic.php?f=7&p=264231#p264231

Bajaman Weedman Bee ODD viewtopic.php?f=7&t=27775&start=160#p264510
Schematic still wrong? viewtopic.php?f=7&t=27775&start=200#p264862
Schematic v13 by Bajaman viewtopic.php?f=7&t=27775&p=264870#p264870
Schematic with Bajaman clipping solution: viewtopic.php?f=7&t=27775&start=280#p265006

Layout
Destro updated vero layout: viewtopic.php?f=7&t=27775&start=140#p264396
Destro's perfboard layout [uncorrected] viewtopic.php?f=7&t=27775&start=60#p264148
Perfboard layout by Psychepool viewtopic.php?f=7&t=27775&p=265467#p265475
PCB Layout by Frabbio [verified] viewtopic.php?f=7&t=27775&p=266107#p266395
PCB Layout by JohnK viewtopic.php?f=7&t=27775&p=267026#p267026

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Um.... F%#K!!! I want, I want, I want!!!

Played through the clean channel on the Friedman Buxom Betty amp!

mkedude · Post by **mkedude** » 02 Sep 2016, 20:12

https://s14.postimg.org/wlrca26ul/IMG_4269.jpg
https://s14.postimg.org/ithis65gt/IMG_4270.jpg
https://s14.postimg.org/rpsaw3w31/IMG_4273.jpg
https://s14.postimg.org/64n88hzcd/IMG_4274.jpg
https://s14.postimg.org/g386uz8rx/IMG_4301.jpg
https://s14.postimg.org/bvdem87cd/IMG_4308.jpg

J0K3RX · Post by **J0K3RX** » 03 Sep 2016, 15:40

The 2 back to back SOT23 packages are dual common cathode diodes I think.. Maybe BAV99 or something in that series? SMD LED's are being used for clipping, be nice to know what color they are? Just about 100% sure that all 3 opamps are TL072.. Looks very traceable! Need some more shots from the lower part of the board where the jacks are.. Mainly just the solder side of the jacks since that appears to be where the traces should be.. The jack side of the board looks like it's mainly the ground plane. The SMD caps will be a guessing game unless somebody get's brave and removes or isolates them somehow and gets measurements.. Probably can guesstimate them if needed.

Maybe get a Mod to move this topic into the "Boutique Stompboxes Dissected" area?

J0K3RX · Post by **J0K3RX** » 11 Sep 2016, 10:38

A very cool person who asked to remain anonymous traced the BE100 and sent me the schematic that he drew on a piece of paper. I just copied it into Diptrace and here it is..

rbird · Post by **rbird** » 11 Sep 2016, 13:23

J0K3RX wrote:A very cool person who asked to remain anonymous traced the BE100 and sent me the schematic that he drew on a piece of paper. I just copied it into Diptrace and here it is..

Thanks to you and your very cool friend.

There are a couple things that got my attention.

D1 appears to be backwards (unless it's some sort of Zener)
Should the 2nd Gain pot (just before IC3.1) be Treble?

J0K3RX · Post by **J0K3RX** » 11 Sep 2016, 16:20

rbird wrote:
J0K3RX wrote:A very cool person who asked to remain anonymous traced the BE100 and sent me the schematic that he drew on a piece of paper. I just copied it into Diptrace and here it is..
Thanks to you and your very cool friend.

There are a couple things that got my attention.

D1 appears to be backwards (unless it's some sort of Zener)
Should the 2nd Gain pot (just before IC3.1) be Treble?

Yes and Yes... The curse of copy/paste strikes again

J0K3RX · Post by **J0K3RX** » 11 Sep 2016, 18:51

Ok, here it is again with corrections. You will see a few caps with no values because they were SMD caps and I am guessing he didn't want to remove them especially since it was not his pedal.. Probably mostly in the pF range so take a guess or throw it into Spice and mess around with the values..

FiveseveN · Post by **FiveseveN** » 11 Sep 2016, 22:51

The Tight control won't do anything as drawn, but grounding (tying to Vr) the pot's pin 1 does the trick:

Probably missed a trace.

bmxguitarsbmx · Post by **bmxguitarsbmx** » 12 Sep 2016, 07:18

I'm seeing a few things:

1) IC1.2 signal on pin 6 will be the same as on pin7(high impedance), so there will be no gain from gain control.

2)IC2.1 cannot be directly connected to IC3.2 pin6, as IC3.2 needs to control its inputs. Needs a resistor between the two, probably that 10k.

3) Out from IC3.2 should probably come from pin7 of IC3.2 as opposed to the wiper of the gain trim.

4) IC3.1 doesn't appear to have a DC path to ground or a reference voltage, so it will not be biased up. IC2.1's bias voltage also seems to be ambiguous.

bmxguitarsbmx · Post by **bmxguitarsbmx** » 12 Sep 2016, 08:53

All ops should bias up. presence is dubious at best

J0K3RX · Post by **J0K3RX** » 12 Sep 2016, 15:43

Was thinking this was a noninverting "single supply" design with some other stuff going on..?

MoonWatcher · Post by **MoonWatcher** » 12 Sep 2016, 20:46

bmxguitarsbmx wrote:All ops should bias up. presence is dubious at best

Assuming the schematic is now more close to what's actually going on than not, some of the familiarity in the sounds seems kind of apparent.

The tightness control does appear to be similar to what Amptweaker is doing - a highpass filter that's also a gain dump. Corner frequency goes up as gain goes down.

U2A looks to be a variation of IC1B in a Marshall Bluesbreaker - inverting input means more like hard clipping, but R15 basically serves the same function as the 6K8 in the Bluesbreaker. Even the highpass filter at U2A's input is the same corner frequency as a Bluesbreaker (or Guv'nor).

The bass control is an adjustable bridged-T. It actually does look to be like a cousin of the Shredmaster's contour control. The Amptweaker pedals also use a bridged-T variation at the thrash switch.

I'm wondering if the presence and treble are possibly closer to how it's done with runoffgroove's Thunderbird? The treble control in the BE-OD is actually 100k-linear, right?

I'm not familiar with the BAT54, but it looks to have similar characteristics to other Schottky-types, and the forward voltage looks similar to some germanium-types.

bmxguitarsbmx · Post by **bmxguitarsbmx** » 12 Sep 2016, 22:16

MoonWatcher wrote: The tightness control does appear to be similar to what Amptweaker is doing - a highpass filter that's also a gain dump. Corner frequency goes up as gain goes down.

it's not a gain dump. The Op amp has zero output impedance, so the "tight control" has no resistance to divide the signal with. Tight control only divides the signal with the complex impedance of the capacitor. If it was a stage with output impedance, you would be correct.

MoonWatcher wrote: U2A looks to be a variation of IC1B in a Marshall Bluesbreaker - inverting input means more like hard clipping, but R15 basically serves the same function as the 6K8 in the Bluesbreaker. Even the highpass filter at U2A's input is the same corner frequency as a Bluesbreaker (or Guv'nor).

Interesting possibility!

MoonWatcher wrote: The bass control is an adjustable bridged-T. It actually does look to be like a cousin of the Shredmaster's contour control. The Amptweaker pedals also use a bridged-T variation at the thrash switch.

The contour is a passive midscoop. In the feedback loop, it is a active midboost. I did scale the 3.3k values to 33k to get them into the bass region.

MoonWatcher wrote: I'm wondering if the presence and treble are possibly closer to how it's done with runoffgroove's Thunderbird? The treble control in the BE-OD is actually 100k-linear, right?

Great catch on the 100k! Thanks. That makes more sense now. I did the presence and treble like the presence and tone from the MI crunchbox. Maybe someone could comment if it appears they react similar.

MoonWatcher wrote: I'm not familiar with the BAT54, but it looks to have similar characteristics to other Schottky-types, and the forward voltage looks similar to some germanium-types.

I just threw the bat54 in there because I didn't feeling drafting the BAV?? part Jok3rx put in.

brejna · Post by **brejna** » 17 Sep 2016, 08:38

I did layout based on this schematic. Here is how it looks, if this is final word on the schematic, I can share it..

Cheers

J0K3RX · Post by **J0K3RX** » 17 Sep 2016, 13:26

brejna wrote:I did layout based on this schematic. Here is how it looks, if this is final word on the schematic, I can share it..

Cheers

Good luck with that... I have been using the pictures along with the schematic I was sent to try to get a more accurate trace but it's slow going and there is gonna have to be some guesswork... If I had this pedal in hand it would be 100% traced no questions asked. It looks so easy and it's mainly all on one side except for the ground plane. You have to really use a meter to test the connections because there are a lot of via hole that wormhole out to the other side from underneath the IC's or some random open spot on the board.

I don't doubt that the schematic bmxguitarsbmx created will work but, it's a lot of corrections and guesswork based on a schematic that was wrong to begin with so... ? who knows?? Ya never know, it may sound better than the BE100, give it a try and let us know.

I myself am not satisfied until it's traced and verified.. and I have been meticulously going over the traces and I think it's pretty safe to say there are some inaccuracies.

bmxguitarsbmx · Post by **bmxguitarsbmx** » 17 Sep 2016, 23:19

That's awesome Brejna!
Jok3rx is totally correct. I'm just making educated guesses. I'll breadboard my circuit on sunday, let you know what happens.

If you haven't routed yet, maybe hold off. Your work should still be very useful!
Cheers!

brejna · Post by **brejna** » 18 Sep 2016, 09:03

I already finished routing, but it shouldn't be problem to make changes to layout if you trace it guys. I'll follow topic regulary..
Thanks for your effort
Brane

MoonWatcher · Post by **MoonWatcher** » 18 Sep 2016, 14:05

J0K3RX wrote:I don't doubt that the schematic bmxguitarsbmx created will work but, it's a lot of corrections and guesswork based on a schematic that was wrong to begin with so... ? who knows?? Ya never know, it may sound better than the BE100, give it a try and let us know.

I myself am not satisfied until it's traced and verified.. and I have been meticulously going over the traces and I think it's pretty safe to say there are some inaccuracies.

Whether or not it would sound better than the BE100, it would most likely sound different.

I can't speak for others, but I personally get bummed out when I build something, and it doesn't sound like the original.

I think just some good old patience would really pay off - it's a simple circuit, so if we wait until someone (else) gets one (and posts more pics), an accurate trace should go really fast.

rbird · Post by **rbird** » 18 Sep 2016, 18:45

MoonWatcher wrote:I think just some good old patience would really pay off - it's a simple circuit, so if we wait until someone (else) gets one (and posts more pics), an accurate trace should go really fast.

Just waiting on payday (unless someone beats me to it).....

J0K3RX · Post by **J0K3RX** » 18 Sep 2016, 23:10

ok, here's some of the pics that mkedude posted that I have been working on. I brightened them a little so I could see the traces better. Download the originals and brighten them a little if you want to check the traces without my silly ass artwork obstructing the image... The black pcb makes it a real bitch and the fact that there is only really 5 usable pics to work with etc.. If you lighten the photos and really zoom in on them you can see a lot of the traces or at least a faint outline of them. The via holes are tricky.. On the smd side you don't see a lot of them but on the opposite side you can pretty well see all of them so if you see one on the through hole/cap side of the board then there has to be a matching one on the smd side. Some of them come through under the TL072's or under stickers so you have to compare both sides really well... I'm still trying to piece it together so you may find some stuff that I missed. Still missing a lot of the grounds Should be able to put together a fairly accurate schematic with what we have so far, throw in a little educated guesswork and Shazam!

https://www.dropbox.com/sh/adl2ow5whhue ... -J2ga?dl=0

Friedman BE-OD Pedal [traced]