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 bancika » 20 Jul 2017, 12:57

It would be great if MJE253 can be used as a replacement, I was able to track down those here in Serbia. Although they are much bigger, but maybe easier to install because of through hole package.

ZXTP25040DFH are not easy to find.

Cheers
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
bancika
Resistor Ronker
 
Posts: 273
Joined: 02 Jan 2008, 03:24
Has thanked: 15 times
Have thanks: 79 times

Re: Friedman BE-OD Pedal

Postby bool » 20 Jul 2017, 12:59

@bajamon: are you absolutely totally sure you applied the "DIY-er correct" methodology in simulations? Perhaps I'm mistaking, but (to me) it seems that you are comparing TWO pn drops (i.e. 4x1N4148 scenario) versus ONE pn drop (fat transistor b-e junction).

My ghetto solution (but I could be totally wrong) would be to just go and use two 1N400x in existing layouts (or shoehorn SM400x's there) to get somehow closer to a B-E drop.

1N4148's have cca. 2pF junction capacitance; 1N400x's have ccca 10-times more than that which is probably closer to a fat PNP b-e junction cap. Which could bring the upper mids more in line (40pF nfb capacitance versus 2pF with 4x1N4148).
bool
Breadboard Brother
 
Posts: 74
Joined: 01 Feb 2008, 02:06
Has thanked: 0 time
Have thanks: 11 times

Re: Friedman BE-OD Pedal

Postby bajaman » 21 Jul 2017, 00:19

@bajamon: are you absolutely totally sure you applied the "DIY-er correct" methodology in simulations? Perhaps I'm mistaking, but (to me) it seems that you are comparing TWO pn drops (i.e. 4x1N4148 scenario) versus ONE pn drop (fat transistor b-e junction).

My ghetto solution (but I could be totally wrong) would be to just go and use two 1N400x in existing layouts (or shoehorn SM400x's there) to get somehow closer to a B-E drop.

1N4148's have cca. 2pF junction capacitance; 1N400x's have ccca 10-times more than that which is probably closer to a fat PNP b-e junction cap. Which could bring the upper mids more in line (40pF nfb capacitance versus 2pF with 4x1N4148).


Hello bool
Yes, I did compare 4 x 1N4148, 2 x red leds, 2 x 5.6v zeners, 2 x BAV99, 2 x BAT85S, 2 x MPSA56, 2 x MPSA92, 2 x 2N5087, 2 x BC557, 2 x ZXTP25015DFH, 2 x ZXTP25012DFH, 2 x ZXTP25020DFH, a2 x ZTX915, 2 x MJE253, 2 x MJE15029, 2 x MJE15031, 2 x MJE15033 and many more devices.
I cannot comment on how these devices sound or how they actually clip in practical terms, but running several AC sweep simulations made it very clear that the FREQUENCY RESPONSE CHARACTERISTICSare very different between these devices. Interestingly the ZXTP250***FH series all give almost identical frequency responses and the closest through hole components I could find to these frequency responses were the MJE253 and MJE15029 devices - the MJE15031 and MJE15033 devices were not the same by the way :!:

I tried juggling resistor values as you suggested in the hopes of alighning the frequency responses using small signal diodes etc., but this had very minimal effect on the response curves.

Interesting to me was the so called through hole equivalent Zetex E line device - the ZTX951 which considerably flattened the mid range hump around 1.5KHz, reducing the level by nearly 10dB at this frequency centre while still retaining the same output level at frequencies below 150Hz, and reducing the 10KHz response by only 4db or thereabouts. I am looking forward to trying these devices perhaps with a small toggle switch for a flat or boosted mid range response option. i cannot recall finding any other pnp device that simulates like the ZTX951 and the spice model came directly from Zetex too.

All my simulations with any of the diode clippers moved the mid hump from 1.5KHz to 2KHz and raised the level by 4.5db at this frequency and a massive 10dB at 10KHz. Again, frequencies below 300Hz are largely unaffected.

cheers
bajaman
be kind to all animals - especially human beings

For this message the author bajaman has received thanks: 3
Belanger88 (04 Aug 2017, 05:44), Ice-9 (21 Jul 2017, 21:06), ozzy666 (21 Jul 2017, 23:25)
User avatar
bajaman
Old Solderhand
 
Posts: 4103
Joined: 26 Jun 2007, 22:18
Location: New Brighton, Christchurch, NZ
Has thanked: 346 times
Have thanks: 822 times

Re: Friedman BE-OD Pedal

Postby Intripped » 21 Jul 2017, 00:45

great work banjoman!

For this message the author Intripped has received thanks:
toneman (21 Jul 2017, 07:47)
Intripped
Cap Cooler
 
Posts: 454
Joined: 25 Aug 2009, 02:03
Has thanked: 509 times
Have thanks: 207 times

Re: Friedman BE-OD Pedal

Postby bajaman » 21 Jul 2017, 07:10

GRRRRRR :evil:
be kind to all animals - especially human beings

For this message the author bajaman has received thanks:
Intripped (21 Jul 2017, 16:13)
User avatar
bajaman
Old Solderhand
 
Posts: 4103
Joined: 26 Jun 2007, 22:18
Location: New Brighton, Christchurch, NZ
Has thanked: 346 times
Have thanks: 822 times

Re: Friedman BE-OD Pedal

Postby toneman » 21 Jul 2017, 08:06

and a massive 10dB at 10KHz. Again, frequencies below 300Hz are largely unaffected.

Is there any "music" above 10K? :?

the topology seems to be:
input buff-> into screamer(modified)->into inverting screamer(modified-)->into inverting GAIN stage-> then "presence" filter-> into a Rat-> thenfinal tone control -> output volume

the "presence" control is actually a high-cut---nothing to do with mids.. :cry:
my first "mod" will be a mid parametric with boost/cut :wink: maybe TWO parametrics(???) :shock:
but.....WHERE to put the new filter(s) :scratch:
i wonder if this is what the Dirty Shirly is :wink:
maybe THAT's what buggs NEXT pedal will be???

GRRRRReat comeback B-man :lol:
nighty nite
8)
Tone-to-the-Bone
User avatar
toneman
Resistor Ronker
 
Posts: 270
Joined: 17 Jul 2007, 14:05
Location: sacatomatoes, Kali4nia
Has thanked: 85 times
Have thanks: 19 times

Re: Friedman BE-OD Pedal

Postby bancika » 21 Jul 2017, 09:13

what I'm puzzled with is how you're getting those huge differences with only 10mV at the input. That's like 1/10th the output of an average pickup or even less. Is the circuit even clipping at those levels? Or those differences are there even with the un-clipped signal?

Cheers
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
bancika
Resistor Ronker
 
Posts: 273
Joined: 02 Jan 2008, 03:24
Has thanked: 15 times
Have thanks: 79 times

Re: Friedman BE-OD Pedal

Postby bajaman » 21 Jul 2017, 11:13

what I'm puzzled with is how you're getting those huge differences with only 10mV at the input. That's like 1/10th the output of an average pickup or even less. Is the circuit even clipping at those levels? Or those differences are there even with the un-clipped signal?


Hi bancika
Yes - a very low input level because this is a very high gain pedal :wink:
The circuit is certainly clipping even at these low levels but not as much as with a guitar level of course.
If the sims are correct the it certainly shows the added fizz that diodes bring to the party compared to the medium power (4A 15v) pnp devices that appear to be used in the friedman pedal :hmmm:
cheers
bajaman
be kind to all animals - especially human beings
User avatar
bajaman
Old Solderhand
 
Posts: 4103
Joined: 26 Jun 2007, 22:18
Location: New Brighton, Christchurch, NZ
Has thanked: 346 times
Have thanks: 822 times

Re: Friedman BE-OD Pedal

Postby bugg » 21 Jul 2017, 11:35

toneman wrote:maybe THAT's what buggs NEXT pedal will be???


Close but not quite..... This one is much warmer than the BEOD. :mrgreen:
bugg
Breadboard Brother
 
Posts: 76
Joined: 11 Feb 2013, 04:10
Has thanked: 26 times
Have thanks: 137 times

Re: Friedman BE-OD Pedal

Postby bool » 21 Jul 2017, 12:45

@baja: "....I cannot comment on how these devices sound or how they actually clip in practical terms, but running several AC sweep simulations made it very clear that the FREQUENCY RESPONSE CHARACTERISTICSare very different between these devices. ..."

That's precisely what I was getting at. Device-in-use junction capacitance in general would be IMHO the major contributing factor to this stage freq. response.

For this message the author bool has received thanks:
bajaman (21 Jul 2017, 13:41)
bool
Breadboard Brother
 
Posts: 74
Joined: 01 Feb 2008, 02:06
Has thanked: 0 time
Have thanks: 11 times

Re: Friedman BE-OD Pedal

Postby J0K3RX » 21 Jul 2017, 15:35

bajaman wrote:bugg - The more I try and figure this out the more I realise that your schematic is correct except for those smd clipping devices - i did a search for the BAV99 which someone mentioned were the correct diodes but the Vishay datasheet gives JE for the type marking so surely they cannot be correct.
The Zetex datasheet for the ZXTP25015DFH on the other hand gives 1A7 for the type marking, which is the same as the board pictures.
Using diodes for clippers accentuates the upper midrange compared to the pnp transistors which would tend to make it a bit more fizzy sounding perhaps :hmmm:
Still waiting on the transistors to arrive so will just have to be a bit more patient.
cheers
bajaman


Yeah, I think it was me that pointed to the BAV99 but, I took a little closer look and now appears to be wrong..

I was thinking the manufacturing site placeholder was before, not after the A7
You do not have the required permissions to view the files attached to this post.

For this message the author J0K3RX has received thanks:
bajaman (21 Jul 2017, 23:15)
User avatar
J0K3RX
Degoop Doctor
 
Posts: 971
Joined: 29 Jun 2011, 02:25
Location: US Florida
Has thanked: 292 times
Have thanks: 459 times

Re: Friedman BE-OD Pedal

Postby bajaman » 21 Jul 2017, 23:13

I am now confident that bugg's board will work fine with the right clipping devices :oops: - it should just sound a bit "fizzier" when using 4 clipping diodes of any sort. It will be very easy to modify with some mini toggle switches to perhaps choose between different devices in this position. :D

IMG_4301.jpg


I looked again very closely at this picture, and there it ism - the connection from pin 7 of the opamp to the junction of C13 and pin 3 of the presence control - partially obscured and hidden under the IC2 screenprinting :wink:
You do not have the required permissions to view the files attached to this post.
be kind to all animals - especially human beings

For this message the author bajaman has received thanks: 2
bugg (21 Jul 2017, 23:53), ozzy666 (21 Jul 2017, 23:38)
User avatar
bajaman
Old Solderhand
 
Posts: 4103
Joined: 26 Jun 2007, 22:18
Location: New Brighton, Christchurch, NZ
Has thanked: 346 times
Have thanks: 822 times

Re: Friedman BE-OD Pedal

Postby bugg » 22 Jul 2017, 00:00

Good find! I have the original pedal sitting in front of me, so lets move on to the mystery diodes.

The pinout (going by measuring forward voltage drops with the diode function of my Fluke DMM) matches that of the BAV99 dual diode not the ZXTP25015DFH (or any other BJT, there is no "Base" lead)

Using these datasheets for reference:
BAV99 - https://www.diodes.com/assets/Datasheets/ds12007.pdf
ZXTP25015DFH - https://www.diodes.com/assets/Datasheets/ZXTP25015DFH.pdf

I'll pull the pots in the morning and go over the trace again, let me know if there's anything in particular you'd like me to check out.

For this message the author bugg has received thanks: 9
bancika (22 Jul 2017, 07:29), bmxguitarsbmx (22 Jul 2017, 06:26), caspercody (22 Jul 2017, 02:13), emilpaulsrud (22 Jul 2017, 05:44), Groovenut (22 Jul 2017, 03:44), ilshat (22 Jul 2017, 15:40), J0K3RX (22 Jul 2017, 03:14), jalmonsalmon (22 Jul 2017, 04:56), ozzy666 (22 Jul 2017, 14:08)
bugg
Breadboard Brother
 
Posts: 76
Joined: 11 Feb 2013, 04:10
Has thanked: 26 times
Have thanks: 137 times

Re: Friedman BE-OD Pedal

Postby rmroza » 22 Jul 2017, 02:12


For this message the author rmroza has received thanks:
bugg (22 Jul 2017, 02:17)
rmroza
Breadboard Brother
 
Posts: 99
Joined: 27 Apr 2010, 14:48
Has thanked: 4 times
Have thanks: 38 times

Re: Friedman BE-OD Pedal

Postby jalmonsalmon » 22 Jul 2017, 04:57

bugg wrote:Good find! I have the original pedal sitting in front of me, so lets move on to the mystery diodes.

The pinout (going by measuring forward voltage drops with the diode function of my Fluke DMM) matches that of the BAV99 dual diode not the ZXTP25015DFH (or any other BJT, there is no "Base" lead)

Using these datasheets for reference:
BAV99 - https://www.diodes.com/assets/Datasheets/ds12007.pdf
ZXTP25015DFH - https://www.diodes.com/assets/Datasheets/ZXTP25015DFH.pdf

I'll pull the pots in the morning and go over the trace again, let me know if there's anything in particular you'd like me to check out.


https://www.arrow.com/en/products/bav99/fairchild-semiconductor
User avatar
jalmonsalmon
Solder Soldier
 
Posts: 190
Joined: 14 Sep 2012, 23:49
Has thanked: 64 times
Have thanks: 22 times

Re: Friedman BE-OD Pedal

Postby bajaman » 22 Jul 2017, 05:59

The pinout (going by measuring forward voltage drops with the diode function of my Fluke DMM) matches that of the BAV99 dual diode not the ZXTP25015DFH (or any other BJT, there is no "Base" lead)

Hello bugg - well that is peculiar because the code marking for the BAV99 is 7E according to that datasheet and 1A7 on the ZXTP25015DFH datasheet.
This picture clearly shows the 1A7 code marking on the two mystery components, but i am not arguing with your measurements :wink:
IMG_4301.jpg


I received my ZTX951 devices so thought i would compare them to the 4 x 1N4148 diodes (which simulate almost identically to the BAV99 pairs).
WOW - what a difference - no more squeal even when the treble, gain, and presence are maxed out :thumbsup
As for the sound - i know when i like what i am hearing because it usually takes me about an hour before I stop doodling :wink:
Touch sensitivity is astonishing now and the gain has a very useable range from blues to full on chugga chug chug. I swapped back in the 4 x 1N4148s and the gain, noise level and that annoying squeal all came back and it sounded very fizzy - took me less than 60 seconds to pull them and fit the back to back ZTX951 devices :lol:
This pedal has so much bass i had to wind the bass control almost off and run the tight around halfway even with a single coil strat bridge pickup - not complaining because with the bass on full and tight on full, there is that metal chugga chug chug sound that that Swedish guy likes demoing :lol:
With the gain on 0 i was able to get some lovely touch sensitive blues sounds and with the gain on 10% i could play Neil Young's Cinnamon Girl riff very convincingly - one of the most amp like pedals I have had the pleasure to play - cleans up nicely by rolling back the guitar volume too!

Hopefully my ZTXP25015DFH parts will arrive soon and i will let you know how they sound, in the meantimei may just have found the Holy Grail of dirt boxes by accident with these ZTX951 devices.
Well worth trying them in place of the 4 x 1N4148 diodes.
cheers
bajaman

ps: I am going back out to the workshop for more doodling now :lol:

pps: I had not noticed Jalmonsalmon's post with the Fairchild BAV99 datasheet which clearly shows the code 1A7 - how odd :hmmm:
Bloody smd codes - one datasheet says 7E and another 1A7 :roll:
Anyway someone said earlier in this thread that their original pedal squealed with gain treble and presence on full. All i can say is try the ZTXP915 pairs and no more squeal even boxed up :idea:
You do not have the required permissions to view the files attached to this post.
be kind to all animals - especially human beings

For this message the author bajaman has received thanks:
bmxguitarsbmx (22 Jul 2017, 06:07)
User avatar
bajaman
Old Solderhand
 
Posts: 4103
Joined: 26 Jun 2007, 22:18
Location: New Brighton, Christchurch, NZ
Has thanked: 346 times
Have thanks: 822 times

Re: Friedman BE-OD Pedal

Postby rmroza » 22 Jul 2017, 10:00

"in the meantimei may just have found the Holy Grail of dirt boxes by accident with these ZTX951 devices."

Aren't you gladwe didn't rest with "it's done"? Good stuff continuing.

It will be interesting to know the differences in tone between the 4148s, BAV99, ZXTP250's,ZXTP951's, etc...and which one is best (noise floor and tone)

For this message the author rmroza has received thanks:
bajaman (22 Jul 2017, 11:42)
rmroza
Breadboard Brother
 
Posts: 99
Joined: 27 Apr 2010, 14:48
Has thanked: 4 times
Have thanks: 38 times

Re: Friedman BE-OD Pedal

Postby alkuz1961 » 22 Jul 2017, 11:34

I'm sorry, but I can clearly see that this is not a 1A7. It's just a symbol, like an upside-down "i"
Image

For this message the author alkuz1961 has received thanks:
modman (16 Nov 2017, 01:06)
alkuz1961
 
Posts: 4
Joined: 14 Jun 2011, 20:59
Has thanked: 0 time
Have thanks: 2 times

Re: Friedman BE-OD Pedal

Postby bajaman » 22 Jul 2017, 11:50

It will be interesting to know the differences in tone between the 4148s, BAV99, ZXTP250's,ZXTP951's, etc...and which one is best (noise floor and tone)

I know the difference between the ZTX951 and the 1N4148 - flatter frequency response = thicker tone and no midrange hump for the ZTX951 and much lower noise floor AND complete absence of any squeal.
Personally, i don't care whether BAV99 (or the 1N4148 equivalents) are the correct parts to use - I will keep using the ZTX951 pair because i believe it is far superior soundwise.
Try them and see what you think!
cheers
bajaman

ps: don't tell Friedman :lol:
be kind to all animals - especially human beings

For this message the author bajaman has received thanks:
bmxguitarsbmx (22 Jul 2017, 20:40)
User avatar
bajaman
Old Solderhand
 
Posts: 4103
Joined: 26 Jun 2007, 22:18
Location: New Brighton, Christchurch, NZ
Has thanked: 346 times
Have thanks: 822 times

Re: Friedman BE-OD Pedal

Postby bugg » 22 Jul 2017, 11:57

bajaman wrote:Hello bugg - well that is peculiar because the code marking for the BAV99 is 7E according to that datasheet and 1A7 on the ZXTP25015DFH datasheet.
This picture clearly shows the 1A7 code marking on the two mystery components, but i am not arguing with your measurements :wink:

Just to clarify, I can't confirm that the component is a BAV99, but it is a dual diode, definitely not an NPN or PNP transistor.

bajaman wrote:Personally, i don't care whether BAV99 (or the 1N4148 equivalents) are the correct parts to use - I will keep using the ZTX951 pair because i believe it is far superior soundwise.

That's all that really matters, right?

alkuz1961 wrote:I'm sorry, but I can clearly see that this is not a 1A7. It's just a symbol, like an upside-down "i"

Yep, you're correct. I noticed that in mine as well.

For this message the author bugg has received thanks:
bajaman (22 Jul 2017, 12:49)
bugg
Breadboard Brother
 
Posts: 76
Joined: 11 Feb 2013, 04:10
Has thanked: 26 times
Have thanks: 137 times

PreviousNext

Return to Boutique Stompboxes dissected...

Who is online

Users browsing this forum: No registered users and 13 guests

cron