Friedman BE-OD Pedal  [traced]

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Re: Friedman BE-OD Pedal

Postby Chromaticdeth19XX » 07 Sep 2016, 04:40

...Like the AMZ Presence and Tone Control mods for the Big Muff Pi. The bands have a mid push but you can mess with the pots to attenuate or boost the lower or upper frequencies, that mid hump is still there though similar to a marshall tonestack. Which would also make sense why they are less useful at doing anything in the high gain circuit here, you dial a sweet spot that doesn't sound like a tin can nor a wet blanket over your speakers and leave it alone as the gain gets cranked up.

The more I listen to it the more it reminds me of my friend's old Zoom Hyper Lead pedal.
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Re: Friedman BE-OD Pedal

Postby bmxguitarsbmx » 07 Sep 2016, 07:17

The actual be-100 cleans up with volume. Not many pedals seem to do that.

Pete Thorn's video shows a ton of knob turning. I also wouldn't be surprised if there is a gyrator in there for that resonant bass response:
https://www.youtube.com/watch?v=NVotKbmlDic

I'm guessing its similar to the lovepedal superlead.

here's Fred Briggs blog post on the lovepedal superlead (similar to the marshall guv'ner) with scheme :) .
http://revolutiondeux.blogspot.com/2012 ... rlead.html

here's a good demo of the lovepedal. the demo dude rolls his volume back at the end and it cleans up. Tones are similar. Add a gyrator tuned to 100Hz mt-2 style and it might nail it:
https://www.youtube.com/watch?v=TwaPs8no3I8
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Re: Friedman BE-OD Pedal

Postby J0K3RX » 07 Sep 2016, 07:18

It's not a kin to the Shredmaster or Guv'nor, no ground-shunted clippers. The "Tight" control is not like the Tight Metal/Rock, actually looks like it may be useful... :wink: The treble and bass controls are probably the least exciting but seem effective.. The presence control was not what I expected. The SOT-23 series pair diode clipping is different... soon! :wink:
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Re: Friedman BE-OD Pedal

Postby MoonWatcher » 07 Sep 2016, 21:33

bmxguitarsbmx wrote:Pete Thorn's video shows a ton of knob turning. I also wouldn't be surprised if there is a gyrator in there for that resonant bass response:
https://www.youtube.com/watch?v=NVotKbmlDic

If there's anything active for the bass, it actually sounds kind of fixed. The bass response doesn't seem to completely drop off as the knob is rolled down.

It almost sounds like the pot itself is panning between two different lowpass filters. Treble almost seems to do something similar. Looking at the cap values on the pcb, I don't think the treble and bass are Baxandall, although there are pairs of resistors that would kind of support that.

...And anti-log taper for the bass would explain why it's so subtle through a lot of its sweep, even compared to a linear-taper pot.
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Re: Friedman BE-OD Pedal

Postby MoonWatcher » 07 Sep 2016, 21:45

bmxguitarsbmx wrote:here's Fred Briggs blog post on the lovepedal superlead (similar to the marshall guv'ner) with scheme :) .
http://revolutiondeux.blogspot.com/2012 ... rlead.html

here's a good demo of the lovepedal. the demo dude rolls his volume back at the end and it cleans up. Tones are similar. Add a gyrator tuned to 100Hz mt-2 style and it might nail it:
https://www.youtube.com/watch?v=TwaPs8no3I8

Well, the Superlead cleans up because there's really only two lowpass filters (besides the tone control). The first has a center frequency of 970 hz, and the second has a center frequency of 1k6 hz. You'd have to really cut the tone knob back to kill the top end.

The Superlead sounds a lot buzzier to me - it sounds like a Guv'nor with the tone controls ripped out. Not a bad sound per se, but the Friedman pedal doesn't sound similar to what I think I hear from the derived-from-Marshall pedals.
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Re: Friedman BE-OD Pedal

Postby MoonWatcher » 07 Sep 2016, 21:54

J0K3RX wrote:...no ground-shunted clippers.

...The SOT-23 series pair diode clipping is different...

Interesting...

Any chance the diodes are in the negative feedback loop of an op amp stage that's got the signal going thru the inverting input? That's actually pretty similar to hard clipping. The Runoffgroove.com Thunderbird uses something similar for "Marshall phase inverter clipping," according to them. And the 6k8 resistor in series with the diodes of the Marshall Bluesbreaker are what make it sound much more like an OD than a distortion...
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Re: Friedman BE-OD Pedal

Postby J0K3RX » 11 Sep 2016, 11:38

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..

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Re: Friedman BE-OD Pedal

Postby rbird » 11 Sep 2016, 14:23

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?
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Re: Friedman BE-OD Pedal

Postby J0K3RX » 11 Sep 2016, 17:20

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?


:slap: Yes and Yes... The curse of copy/paste strikes again :lol:
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Re: Friedman BE-OD Pedal

Postby J0K3RX » 11 Sep 2016, 19:51

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..
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Re: Friedman BE-OD Pedal

Postby FiveseveN » 11 Sep 2016, 23:51

The Tight control won't do anything as drawn, but grounding (tying to Vr) the pot's pin 1 does the trick:
Image
Probably missed a trace.
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Re: Friedman BE-OD Pedal

Postby bmxguitarsbmx » 12 Sep 2016, 08:18

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.
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Re: Friedman BE-OD Pedal

Postby bmxguitarsbmx » 12 Sep 2016, 09:53

All ops should bias up. presence is dubious at best
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Re: Friedman BE-OD Pedal

Postby J0K3RX » 12 Sep 2016, 16:43

Was thinking this was a noninverting "single supply" design with some other stuff going on..?
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Re: Friedman BE-OD Pedal

Postby MoonWatcher » 12 Sep 2016, 21:46

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.
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Re: Friedman BE-OD Pedal

Postby bmxguitarsbmx » 12 Sep 2016, 23:16

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.
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Re: Friedman BE-OD Pedal

Postby Chromaticdeth19XX » 13 Sep 2016, 05:24

The topology around the Gain pot (U1B) and the cascading stage proceeding it (U2A) look surprisingly similar to the Ibanez Super Metal. Barring the extra two diodes around U2A.
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Re: Friedman BE-OD Pedal

Postby brejna » 17 Sep 2016, 09:38

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
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Re: Friedman BE-OD Pedal

Postby J0K3RX » 17 Sep 2016, 14:26

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.
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Re: Friedman BE-OD Pedal

Postby bmxguitarsbmx » 18 Sep 2016, 00:19

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!
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