Friedman BE-OD Pedal  [traced]

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Re: Friedman BE-OD Pedal

Postby rmroza » 30 Jun 2017, 02:25

Ok. Looked at both board. Found some minor things, but still N/G.

The #2 pedal which I had in the pedal sounds good, but has the noise. Flourescent lights off had no impact either
The #1 pedal which was in the enclosure just doesn't put out anything! Likewise, unlike the #2 where both LEDs on the right are on, on this one, only one is on and it is the one on the left of the set on the right.

With the above and both taken out of the box, but different issues, I have to assume it's build issues, but unaware what that may be. I replaced the #1 LED that wasn't on thinking that might help, but that also....nope.

Soo, here are the Hi-Res photos. I don't see any bridges or build problems unless I missed something!

Can't wait for the PC board version but still would like to get these going as I spent a lot of time already in hours and hours populating, building and troubleshooting.

Let me know if you guys see anything out of the ordinary.
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Re: Friedman BE-OD Pedal

Postby jalmonsalmon » 02 Jul 2017, 16:08

bugg wrote:The most recent schematic (as well as the layout/build info) is available at the bottom of this page:
http://www.buggfx.com/product/thermionic-distortion-pcb/

Oh I noticed on the build doc schematic it is missing a 100n cap that should connect to + of that 22uF cap and to ground.
I know the PCB has it so no worries there! :D
I cannot wait to make this one! Low on funds at the moment and Wifey says NO to my pedal building at the moment :slap:
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Re: Friedman BE-OD Pedal

Postby roberttomasz » 04 Jul 2017, 10:27

R6- ? :slap:
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Re: Friedman BE-OD Pedal

Postby bugg » 05 Jul 2017, 15:19

Just got the shipping notification for the PCBs, hopefully they'll be here by the weekend. :D

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Re: Friedman BE-OD Pedal

Postby alltrax » 05 Jul 2017, 16:13

That's good news :thumbsup
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Re: Friedman BE-OD Pedal

Postby screamingdemon » 09 Jul 2017, 13:31

Hello everyone were can I order a pcb i like to build one.
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Re: Friedman BE-OD Pedal

Postby bajaman » 09 Jul 2017, 14:24

Hello everyone were can I order a pcb i like to build one.
http://www.buggfx.com/product/thermionic-distortion-pcb/
on the previous page of this thread :roll:
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Re: Friedman BE-OD Pedal

Postby toneman » 09 Jul 2017, 19:05

hey bugg
ordered 2 pcbs!
gonna get back into building stomps again!
i see interesting mod possibilites already!! :roll:
keep us informed when u ship.
:secret:
8)
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Re: Friedman BE-OD Pedal

Postby bugg » 10 Jul 2017, 20:24

Awesome guys, I appreciate it!

An order of PCBs just came in today so most will be shipping this afternoon when I get home from work, the rest should be on their way in about a week.

Everything should be fairly self explanatory but don't hesitate to shoot me a message if you have any questions or problems.

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Re: Friedman BE-OD Pedal

Postby bancika » 11 Jul 2017, 08:23

Cool, ordered one to Serbia :)
The new version of DIY Layout Creator is out, check it out - https://github.com/bancika/diy-layout-creator
Check out my site with DIY gutars, amps and pedals http://diy-fever.com
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Re: Friedman BE-OD Pedal

Postby rmroza » 11 Jul 2017, 13:42

Ordered on 6/27. Any updates??
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Re: Friedman BE-OD Pedal

Postby alltrax » 11 Jul 2017, 14:40

rmroza wrote:Ordered on 6/27. Any updates??

How about reading 2 posts above ?

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Re: Friedman BE-OD Pedal

Postby bugg » 12 Jul 2017, 02:59

rmroza wrote:Ordered on 6/27. Any updates??


Yep, yours went out today!
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Re: Friedman BE-OD Pedal

Postby BIGSMITTY » 18 Jul 2017, 01:23

Got my board today, looks high quality. Thanks man :applause:
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Re: Friedman BE-OD Pedal

Postby bajaman » 18 Jul 2017, 04:43

although bugg's board is very nice it is however not using THE CORRECT schematic - the presence control connection is wrong for starters. I have built this according to the schematic that bugg uses and the presence is almost none existent - when connected like a previous v1.4 schematic it works but like others i am plagued by high frequency whistle when attempting to increase the gain control past minimum.
Seriously someone should either purchase and post clear pictures of the board under the top row of controls or reverse engineer this pedal properly because as it stands it is a trainwreck :roll:
Surely someone can figure this out instead of just guessing.
I will keep working on this but the pictures posted so far are not the easiest to see the pattern.
cheers
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Re: Friedman BE-OD Pedal

Postby bugg » 18 Jul 2017, 11:22

The presence control works properly on the one I built... Maybe others can chime in when they get theirs assembled.

Oscillations have been confirmed on the original unit with Gain / Trim maxed, I have the trim at just above 50% and there is no oscillation with the gain cranked wide open.
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Re: Friedman BE-OD Pedal

Postby bajaman » 18 Jul 2017, 11:44

Okay folks - I have spent the last few hours running simulations and trying to get to the end of this ridiculous thread.
There has been some great work done by jokerx and others in trying to decipher this mess and one forum member has come very close to the correct scheme. :wink:
One thing that puzzled me with both my simulations and the pedal i built to evaluate bugg's thermionic distortion is those 4 clipping diodes :hmmm:
Bugg suggests using 1N4148 diodes and others have speculated about schottky diodes etc. , but in the simulations these are never driven into clip until well after the following back to back leds are driven into saturation. I looked at the code on the SOT23 devices that Friedman is using - 1A7 and tried to determine exactly what these components are. Mr Friedman has marked the board D5 and D6 which suggests that these are diodes, and yes, they are, BUT not dual diodes as some have speculated. :wink:
They are most likely pnp transistors connected with reversed base emitter junctions - indeed this is the only combination that possibly makes any sense if one examines the way they are connected on the board. :)
ZXTP25015DFH-74334.pdf

Take a look at this pdf - code: 1A7 - a Zetex medium power high current (4A) pnp transistor
I believe these are available from Mouser - the nearest through hole equivalent appears to be the Zetex ZTX951 which is definitely available from Mouser , radiospares, etc.
When running my simulations with the latter (still looking for a spice model for the SOT23 device) I notice far earlier clipping - just after the second gain stage with the back to back leds in the feedback loop begins to clip. I tried simulating with several small signal pnp devices, but only got acceptable results when using 4A devices and the ZTX951 gave by far the best simulated results. i have ordered some and will replace the diodes in my build and report back, in the meantime .....
cheers :thumbsup
bajaman

ps:
Friedman BE OD V1.4-1.pdf

In my humble opinion, this is the most accurate schematic so far - the presence control is connected properly (and it works), you can clearly see the connection of C13 on one of the board photos and this is the same as that. :wink:
One thing puzzling me is why the need to connect the two leds LED3 and LED4 to the bias rail and not to ground :hmmm:
Possibly because they supply the bias voltage to the following gain stage through the treble control - surely C14 should be connected between the output of !C2b and the top of the treble pot , and the leds are connected still to C14, but now feed bias voltage directly to the top of this treble control :?: It seems more logical that way, and certainly explains why the need to connect the leds to v bias rail :wink:
One last thing - R997 and R998 are indeed 33k as has been pointed out previously - this gives a narrow bandpass bass boost centred around 80Hz
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Re: Friedman BE-OD Pedal

Postby bool » 18 Jul 2017, 12:50

Using transistors to clip would make perfect sense since transistors seem to be used as clippers in tube amps as well.
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Re: Friedman BE-OD Pedal

Postby bajaman » 18 Jul 2017, 13:26

Using transistors to clip would make perfect sense since transistors seem to be used as clippers in tube amps as well.

yes - but i was genuinely surprised how different the clipping was with lower current fater devices like the BC557 etc. - even the old BD140 (a relatively slow 1.5A device ) didn't clip as soon as the ZTX devices - quite an eye opener for me :scratch:
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Re: Friedman BE-OD Pedal

Postby bool » 18 Jul 2017, 14:31

Reading on ZTX these seem to be optimised for low saturation voltage switching application, so what you're saying makes perfect sense. (I think MPSA06 are used in tube amps???)

But while you are at simulation, I think you can shoehorn a close-enough characteristic (for DIYers) juggling the resistor values around that stage for users stuck with 1N4148. (or 1N400x which have a bit lower PN-drop).
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