Friedman BE-OD Pedal  [traced]

General documentation, gut shot, schematic links, ongoing circuit tracing, deep thoughts ... all about boutique stompboxes.

Re: Friedman BE-OD Pedal

Postby bmxguitarsbmx » 06 Aug 2017, 00:45

If you look at my last posted schematic, you will see all bias points are active (connected to the bias buffer). There is not necessarily anything wrong with how Friedman/Bugg did it. Lots of bias supplies are just resistive dividers with capacitive filtering to create a stable reference voltage.

The reason to avoid doing resistive divider R/C filtered bias supplies is that assymetrical clipping of some circuits will integrate with a long time constant of their high output impedance and cause slow bias shifts. A single clean stage is less of a problem and symmetrical clipping is less of a problem. That being said, bias shifts could be the feature. Who knows in this zany world of stompboxes. If it sounds good, it is good ;)

For this message the author bmxguitarsbmx has received thanks:
bugg (06 Aug 2017, 01:40)
bmxguitarsbmx
Breadboard Brother
 
Posts: 135
Joined: 25 Mar 2010, 22:15
Has thanked: 236 times
Have thanks: 71 times

Re: Friedman BE-OD Pedal

Postby bmxguitarsbmx » 06 Aug 2017, 00:53

Belanger88 wrote:... can someone explain the point of the 2 LED'S going to Vref rather then ground? I read Bajaman explain it a little earlier in the post but I can't seem to find it now
[ Image ]



The LED's you refer to are clipping diodes connected directly to the output of an op-amp. The output should exist at roughly 4.5V with no signal present. If you connect the LED's to ground, you will have current flowing through one of these LED's at all time. ~4.5V->0V. This is not what we want. We want the LED to conduct when the signal passes above the forward conduction voltage of the LED, and so the LED will be connected to a voltage that is at the same potential as the op-amp output. 4.5V.

You could block this 4.5V bias voltage at the output of the op-amp and then connect your LED's to ground. Totally fair. In both cases, the LED's don't conduct until there is signal present as both sides of the LED's arre at he same potential. Hope that is helpful :)

For this message the author bmxguitarsbmx has received thanks: 2
bajaman (06 Aug 2017, 06:48), Belanger88 (06 Aug 2017, 03:23)
bmxguitarsbmx
Breadboard Brother
 
Posts: 135
Joined: 25 Mar 2010, 22:15
Has thanked: 236 times
Have thanks: 71 times

Re: Friedman BE-OD Pedal

Postby bugg » 06 Aug 2017, 01:47

bajaman wrote:I received the pcb I ordered from bugg in the mail yesterday but it is too wide to fit in a 1590B style case, so i will probably shelve it - unless someone wants to buy it from me :wink:
I did criticize bugg for perhaps using the wrong schematic - my sincere apologies for this mistake of mine bugg :oops:


No apologies necessary! Like I said, I think my response came across the wrong way... not to mention I'm a bit frustrated with myself for not being able to offer more help to rmroza and alltrax.
I appreciate all of your input in this thread, don't ever hesitate to call me out on something. :mrgreen:

I do apologize for not being clearer that this PCB was intended for a 125B with top-mounted jacks, I have since updated the page on my site to make this more obvious.

I'm working up a new build doc, would appreciate any feedback/criticism.
http://www.pedalpcb.com/files/docs/ThermionicDistortion.pdf
bugg
Breadboard Brother
 
Posts: 94
Joined: 11 Feb 2013, 04:10
Has thanked: 30 times
Have thanks: 214 times

Re: Friedman BE-OD Pedal

Postby jalmonsalmon » 06 Aug 2017, 02:12

bmxguitarsbmx wrote:
jalmonsalmon wrote:
http://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=4c463742d1

Best of the best components for this build imho :mrgreen:

of course does not include the common stuff you need to make a pedal :secret:


This has 1/4 watt resistors spec'd, no?


Koa Spear 1/4 watt metal film resistors for the most part and Yageo 1/6 watt metal film resistors for the values that Koa does not have.
I made a PCB that fits inside a 1590b as well and I like those tiny 1/4 watt resistors Koa has.
I can post another mouser list that has 1/8 watt resistors if anyone wants :P

For this message the author jalmonsalmon has received thanks:
bmxguitarsbmx (06 Aug 2017, 03:28)
User avatar
jalmonsalmon
Solder Soldier
 
Posts: 192
Joined: 14 Sep 2012, 23:49
Has thanked: 66 times
Have thanks: 23 times

Re: Friedman BE-OD Pedal

Postby toneman » 06 Aug 2017, 02:46

The New PDF:Aug5, 2017
the bad:
C13 wasn't on first pdf; now, C5 is not on schematic.
turned C5 into C13. C5 is gone(?)

C5 is 100p; C13 is 100n---BIG difference!

C13 is now listed as 100p, should be 100n;
it's a bypass cap for C25, Vref voltage dividor.
that makes 6 100n caps
still only 1 100p cap

the good:
pot names are on the pcb! YAY!
diodes are now labeled except for LEDs
trimmer part# is specified: 3362P(?) mouse# would be more helpfull

suggestions:
wiring diagram? doesn't look like same pcb(?)
Leave pots off diagram. Better labeling for input power and ground.
specify the part number(mouser) for the pots since they must be exact to fly off the pcb
include diode/transistor substitutions as suggested in 24 page discussion
include forum suggestion for C12 substitution: 120p to 470p to reduce noise.
I didn't note the 1/8w resistors until i received pcb-I'm using 1/4w standing up like Boss and Ibanez.
Add pot names to BOM(page 3) like on page 1and maybe mouser#.
Add release date to pdf.
Tone-to-the-Bone

For this message the author toneman has received thanks: 2
bugg (06 Aug 2017, 04:02), ozzy666 (06 Aug 2017, 22:07)
User avatar
toneman
Resistor Ronker
 
Posts: 273
Joined: 17 Jul 2007, 14:05
Location: sacatomatoes, Kali4nia
Has thanked: 87 times
Have thanks: 19 times

Re: Friedman BE-OD Pedal

Postby jalmonsalmon » 06 Aug 2017, 02:47

bugg wrote:
bajaman wrote:I received the pcb I ordered from bugg in the mail yesterday but it is too wide to fit in a 1590B style case, so i will probably shelve it - unless someone wants to buy it from me :wink:
I did criticize bugg for perhaps using the wrong schematic - my sincere apologies for this mistake of mine bugg :oops:


No apologies necessary! Like I said, I think my response came across the wrong way... not to mention I'm a bit frustrated with myself for not being able to offer more help to rmroza and alltrax.
I appreciate all of your input in this thread, don't ever hesitate to call me out on something. :mrgreen:

I do apologize for not being clearer that this PCB was intended for a 125B with top-mounted jacks, I have since updated the page on my site to make this more obvious.

I'm working up a new build doc, would appreciate any feedback/criticism.
http://www.pedalpcb.com/files/docs/ThermionicDistortion.pdf

Here you go BUGG... you can link that to your BOM for a Mouser order with all the common passives you need... 1/8 watt resistors in lots of 10... CHEAPER that way LOL
http://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=4aa527362b

For this message the author jalmonsalmon has received thanks: 3
bmxguitarsbmx (06 Aug 2017, 03:30), bugg (06 Aug 2017, 04:47), J0K3RX (06 Aug 2017, 16:06)
User avatar
jalmonsalmon
Solder Soldier
 
Posts: 192
Joined: 14 Sep 2012, 23:49
Has thanked: 66 times
Have thanks: 23 times

Re: Friedman BE-OD Pedal

Postby Belanger88 » 06 Aug 2017, 03:28

That makes perfect sense now! Thank you very much for taking the time to explain that to me! :oops:




bmxguitarsbmx wrote:
Belanger88 wrote:... can someone explain the point of the 2 LED'S going to Vref rather then ground? I read Bajaman explain it a little earlier in the post but I can't seem to find it now
[ Image ]



The LED's you refer to are clipping diodes connected directly to the output of an op-amp. The output should exist at roughly 4.5V with no signal present. If you connect the LED's to ground, you will have current flowing through one of these LED's at all time. ~4.5V->0V. This is not what we want. We want the LED to conduct when the signal passes above the forward conduction voltage of the LED, and so the LED will be connected to a voltage that is at the same potential as the op-amp output. 4.5V.

You could block this 4.5V bias voltage at the output of the op-amp and then connect your LED's to ground. Totally fair. In both cases, the LED's don't conduct until there is signal present as both sides of the LED's arre at he same potential. Hope that is helpful :)
Success is no accident. It is hard work, perseverance, learning, studying, sacrifice and most of all, love of what you are doing or learning to do.
Belanger88
Breadboard Brother
 
Posts: 75
Joined: 15 Jul 2016, 23:28
Location: Canada
Has thanked: 104 times
Have thanks: 31 times

Re: Friedman BE-OD Pedal

Postby bmxguitarsbmx » 06 Aug 2017, 03:29

jalmonsalmon wrote:... I like those tiny 1/4 watt resistors Koa has.
I can post another mouser list that has 1/8 watt resistors if anyone wants :P


My bad! I didn't realize these were small enough to fit. Thank you jalmonsalmon :)
bmxguitarsbmx
Breadboard Brother
 
Posts: 135
Joined: 25 Mar 2010, 22:15
Has thanked: 236 times
Have thanks: 71 times

Re: Friedman BE-OD Pedal

Postby alltrax » 06 Aug 2017, 08:23

Tayda pcb angled pots do also fit very well on bugg's pcb
alltrax
Breadboard Brother
 
Posts: 54
Joined: 28 Mar 2013, 09:29
Location: Bordeaux, France
Has thanked: 15 times
Have thanks: 16 times

Re: Friedman BE-OD Pedal

Postby andlord » 06 Aug 2017, 09:06

alltrax wrote:Tayda pcb angled pots do also fit very well on bugg's pcb


Too bad they don't have them in anti-log :(
andlord
 
Posts: 36
Joined: 25 Jun 2017, 08:31
Has thanked: 4 times
Have thanks: 4 times

Re: Friedman BE-OD Pedal

Postby bugg » 06 Aug 2017, 12:26

The ones Tayda didn't have I bought from Mammoth.
bugg
Breadboard Brother
 
Posts: 94
Joined: 11 Feb 2013, 04:10
Has thanked: 30 times
Have thanks: 214 times

Re: Friedman BE-OD Pedal

Postby Jonotron » 06 Aug 2017, 15:11

Built up the latest vero layout with socketed diodes and it's not behaving itself. Sounds terrible with gain at 0 and starts oscillating as soon as it's increased. I removed the diodes (4148) and it sounds great, tone controls work well. I would be grateful for any suggestions to the cause of this.. many thanks!
Jonotron
 
Posts: 12
Joined: 03 Aug 2013, 10:33
Has thanked: 1 time
Have thanks: 0 time

Re: Friedman BE-OD Pedal

Postby Jan1966 » 06 Aug 2017, 18:32

Jonotron wrote:Built up the latest vero layout with socketed diodes and it's not behaving itself. Sounds terrible with gain at 0 and starts oscillating as soon as it's increased. I removed the diodes (4148) and it sounds great, tone controls work well. I would be grateful for any suggestions to the cause of this.. many thanks!


Its a mystery. The origional pedal oscillates if you turn the trimmer up. Its a noisy pedal. This circuit hasn't been 100 percent verified but its getting close.
Jan1966
Breadboard Brother
 
Posts: 52
Joined: 15 Dec 2014, 20:17
Has thanked: 11 times
Have thanks: 15 times

Re: Friedman BE-OD Pedal

Postby Jonotron » 06 Aug 2017, 19:51

Jan1966 wrote:
Jonotron wrote:Built up the latest vero layout with socketed diodes and it's not behaving itself. Sounds terrible with gain at 0 and starts oscillating as soon as it's increased. I removed the diodes (4148) and it sounds great, tone controls work well. I would be grateful for any suggestions to the cause of this.. many thanks!


Its a mystery. The origional pedal oscillates if you turn the trimmer up. Its a noisy pedal. This circuit hasn't been 100 percent verified but its getting close.


The build sounds good without the diodes installed, and the tone controls are cool. No issues with squealing and the gain control has a bit of range. Nice fizz free decay and the trimmer seems to work fine. Plug the diodes in and it goes into theremin mode! Totally unusable on any setting Definitely botched something here..
IC voltages are...
Here's the pin voltages on the ics
TL072
1. 4.34
2. 4.34
3. 2.92
4. 0
5. 4.31
6. 4.34
7. 4.34
8. 8.76

TL074
1. 4.31
2. 4.34
3. 4.21
4. 8.69
5. 4.34
6. 4.44
7. 4.75
8. 3.97
9. 4.48
10. 4.34
11. 0
12. 3.56
13. 3.89
14. 3.89

Will be eternally grateful if someone can shed some light here!
Jonotron
 
Posts: 12
Joined: 03 Aug 2013, 10:33
Has thanked: 1 time
Have thanks: 0 time

Re: Friedman BE-OD Pedal

Postby toneman » 06 Aug 2017, 20:28

did u increase the value of C12 as mentioned earlier??
Tone-to-the-Bone
User avatar
toneman
Resistor Ronker
 
Posts: 273
Joined: 17 Jul 2007, 14:05
Location: sacatomatoes, Kali4nia
Has thanked: 87 times
Have thanks: 19 times

Re: Friedman BE-OD Pedal

Postby Jonotron » 06 Aug 2017, 20:48

toneman wrote:did u increase the value of C12 as mentioned earlier??

I did thanks, in a roundabout way.. paralleled another 120p cap as I had no 470ps. I'll try a bigger cap like 1nf but I'm convinced there is some other issue here as several people have reported success with this layout.
Jonotron
 
Posts: 12
Joined: 03 Aug 2013, 10:33
Has thanked: 1 time
Have thanks: 0 time

Re: Friedman BE-OD Pedal

Postby psychepool » 07 Aug 2017, 05:15

I ordered ZTX951 and BAV99 to try the bajaman recommendations and received them today.
Let me talk about the feeling that I tried.


As bajaman says, the ZTX951 reduces noise and suppresses much of the oscillation.
And had more bass.
But it was very regrettable that the Marshall vibe was disappearing.
When I used the 1N4148, I had a distinctive sticky feeling.
The ZTX951 is a bit stiff, hard and dry, so I didn't like the lack of the somewhat savage feeling that I expected when I made a marshall pedal like BE-OD.

BAV99 had trouble to apply it because it is SMD element, it was very small and I did not have special equipment.
(The only thing I have is a 25W 0.5R tip.)
I burned two of them with the soldering iron and managed to succeed.
In conclusion, they were not much different from the 1N4148.
It is not accurate because I didn't test it by switching it, but it seems to be the same.
Sounds were similar and noise and dscillation were similar.

In fact, I would like to put the 4148, which can be installed safely on a universal board.
The board is too small, so it is not easy to revert back and I think I will just install BAV99.


The oscillation was somewhat improved by placing a buffer at the front.
I have a demeter mid boost clone and put it off the front, and a lot of oscillation disappeared.
I need to get a simpler circuit and try it with a low-noise opamp.


Conclusion: Personally, 4148 seems to give me the expected sound.



Below is my board layout. I worked it with bugg's Thermionic schematic.
It is a complicated layout because it designed to put in 1590A case.
Noise and oscillation may be caused by this overcrowded layout.
It was aim to make small and it seems to be result that it is not bad for use personally.
Friedman BE OD 4.jpg



Below is a simple buffer that I've applied. Quite the suppression of the Oscillation. Now the trimmer can be left until about 10 o'clock.
opamp buffer.jpg
You do not have the required permissions to view the files attached to this post.

For this message the author psychepool has received thanks: 2
modman (16 Nov 2017, 01:34), ozzy666 (07 Aug 2017, 14:01)
psychepool
 
Posts: 34
Joined: 04 Jan 2012, 06:51
Has thanked: 1 time
Have thanks: 18 times

Re: Friedman BE-OD Pedal

Postby alltrax » 07 Aug 2017, 08:47

I had exactly the same feeling with the ZTX, you loose the spirit of the pedal.
Regarding the oscillations, the C12 mod worked well with the circuit unboxed, but they came back once boxed in a 1590B enclosure.
A klon buffer in front (I have one always on at the input of my pedalboard) removes them all
I'll maybe try to shield the input on the pedal

I'd like to see a pic of your 1590A unit once done :thumbsup
alltrax
Breadboard Brother
 
Posts: 54
Joined: 28 Mar 2013, 09:29
Location: Bordeaux, France
Has thanked: 15 times
Have thanks: 16 times

Re: Friedman BE-OD Pedal

Postby rmroza » 07 Aug 2017, 12:52

Today's the day I'll try and spend more time with the pedal. I'm on vaca...if you can call it that, but have sick as FUCK since last Monday and ER yesterday for Z-pak as not going away!!

alltrax, thanks for the clips of your vero build! At 1:29-1:30 between setting 2 and 3 there seems to be quite a bit of noise! At least your pedal seems to be working. I'm currently at a loss but will go over everything and triple check today.

For Groovenut, I probably did not reply back because I don't remember seeing your post! I can't tell by the photos I posted the orientation, so will look directly and with magnifying glass, but I did respond back that I did review components for polarity, values and placement and there were no issues no did anyone else say anything, so I think it may be correct...but I'll triple check. The LED pair DOES light up, so would that not be the case if reversed?!?? I'll check and report back out.

I'd like to verify traces also (maybe something wrong with the PCB), but the Buggs boards are dark and a lot of silkcreen (which cannot be removed due to a conformal coating on top of that. It would be nice to have both sides trace clean so could check point to point for continuity especially before assembly, but we'll have to cross that bridge when we get to it.

Thanks bugg for the layout explanation of what to do about the 470k resistor to tight pot pin 1, but also that, that is not baseline and just an improvement idea. Have to see how that fares well with a working unit.

bajaman "rmroza is having problems with his build and they seem to point to a bias problem in the input stage - my suggestion to connect the 470k to vref was an attempt to help" - I'll check this out today if I don't find anything else and see if any difference.

"ZTX, you loose the spirit of the pedal"

That's what I was afraid of! This is a theory v. reality thing. In the end, your ears are the prime requisite. If it sounds good, it's good. But a good experiment nevertheless.

I'll have to check about this 470p cap thing and posting about some component missing or something. I wasn't following that late last night.

Looks like more clones for sale again!! lol Not sure why anyone would pay $170 when you can get a used real thing for $150, but whateva...maybe if it was absolutely dead quiet, had the same tone or better, and had improvements...mid control, etc. Good Luck. - https://reverb.com/item/6224475-exodus-effects-friedman-be-od-clone
rmroza
Breadboard Brother
 
Posts: 101
Joined: 27 Apr 2010, 14:48
Has thanked: 4 times
Have thanks: 44 times

Re: Friedman BE-OD Pedal

Postby bool » 07 Aug 2017, 13:03

... Conclusion: Personally, 4148 seems to give me the expected sound. ...


That wouldn't be surprising, because electrically they seem to be fairly close to the original SMD part.

Also juction capacitance; 1pF @ BAV99 vs 2pF @ 1N4148 yields a cca 1pF vs cca 2pF total capacitance diff. for the 4 in-circuit diodes. Close enough imho.

What would be interesting would be to try to swap the 4 diodes for a B-E junction of MPSA06 transistor that's used in the tube amp. (so 4x MPSA06s)

(But I'm not the one to go and try that.)
bool
Breadboard Brother
 
Posts: 75
Joined: 01 Feb 2008, 02:06
Has thanked: 0 time
Have thanks: 11 times

PreviousNext

Return to Boutique Stompboxes dissected...

Who is online

Users browsing this forum: 7on1, Faber, floris, jamesmafyew, jetofuj, Svullgo, vinzz115 and 28 guests

cron