Some Boss clipping diodes

Started by soupbone, May 22, 2014, 03:06:31 AM

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soupbone

I posted this question in a couple other forums,and didn't get a concise answer.I'm trying to figure out the clipping diodes for these Boss Pedals; OS-2,SD-2,SD-2r,DS-2,OD-3,BD-2.Any help with this I would gladly appreciative!

Elijah-Baley

I am not an expert. But I think you need the schematics of those pedals. Perhaps on the web there are some images of the schematic.

For example: I found this: http://forum.cxem.net/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=141578.

Analyzing the schematic you should find the clipping stage. Maybe there's, again, some information on the web.
Is kind of that what you need?  ???
«There is something even higher than the justice which you have been filled with. There is a human impulse known as mercy, a human act known as forgiveness.»
Elijah Baley in Isaac Asimov's The Cave Of Steel

amz-fx

Quote from: soupbone on May 22, 2014, 03:06:31 AM
I posted this question in a couple other forums,and didn't get a concise answer.I'm trying to figure out the clipping diodes for these Boss Pedals; OS-2,SD-2,SD-2r,DS-2,OD-3,BD-2.Any help with this I would gladly appreciative!

The BD-2 is 1SS133 diodes...  which is used for clipping in most Boss pedals.

The SD-2 is a pair of LK28RP red leds followed by a gain stage with 1SS133 diodes in the feedback loop, which makes the choice of red LEDs non-critical.

Don't know about the others.

regards, Jack

Tonemonger

Do You mean what are they ?
I haven't checked out all of those schematics But , Boss pedals usually use Toshiba ISS133.
Ah AMZ just beat me to it.

soupbone

I'm trying to figure out which diodes are the clipping diodes.(not the type of diodes) For experimentation purposes.Thanks for the responses!I guess I should've worded it differently.  :icon_redface:  I can provide schematics if needed.

soupbone

Quote from: Elijah-Baley on May 22, 2014, 04:55:45 AM
I am not an expert. But I think you need the schematics of those pedals. Perhaps on the web there are some images of the schematic.

For example: I found this: http://forum.cxem.net/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=141578.

Analyzing the schematic you should find the clipping stage. Maybe there's, again, some information on the web.
Is kind of that what you need?  ???
Yep!I just can't identify the clipping stages(for modding purposes) My electronics knowledge is decent,but I just need some guidance.Thanks!

soupbone


slacker

Post us some schematics and I'm sure people will point them out.

JustinFun

Bradley speaking, wherever you see diodes set in opposite directions to each other, they're the clipping diodes. They're mostly in the feedback loops of the opamps in boss pedals I think, although there may be some cases where they go from signal path to ground. You can spot feedback loop clipping as it goes from one side of the opamp to the other (the triangles in the schematic).

So wherever you see:

- diode > parallel with diode <
- diode > diode > parallel with diode < diode <
- diode > diode > parallel with diode < (asymmetric clipping)

Those are the the clipping stages

There may be more than one per pedal (the SD2 schematic linked above looks to have 3 - one diodes to ground and two asymmetric clipping in opamp feedback loops)

If you're new to reading schematics, this is a good place to start learning - why not download the schematics for the pedals you list, circle what you think the clipping diodes are and post here for feedback? It's a very friendly learning environment on this forum - unless you're claiming to be the best boutiquer since sliced bread no-one is going to criticise you for not having a particular level of knowledge.

darron

Quote from: soupbone on May 25, 2014, 04:21:34 AM
Yello ? :-\?

In that schematic given as an example they all look like clipping diodes except d12 in the power supply section.

Places where they are in parallel, and connecting to the signal path is a good giveaway.
Blood, Sweat & Flux. Pedals made with lasers and real wires!

JustinFun

Broadly speaking, obs. Autocorrect strikes again...

Quackzed

if the 2 opposite facing diodes go from the front to the back of an opamp (the triangle thing), even if theres lots of other stuff around the op amp too. they're clipping diodes... 'soft clipping' diodes to be more precise...


if the 2 opposite facing diodes are going to ground ,they are clipping diodes...  'hard clipping' diodes to be more precise...



opamps look like 8 pin ic's usually so 2 opposing diodes near the 8 pin chip are clipping diodes. (almost always)
sometimes there are 3 diodes, sometimes 4 but theres always at least one in each direction. so if you see 2 or more diodes together anywhere near an 8 pin chip, they are the clipping diodes...
nothing says forever like a solid block of liquid nails!!!

soupbone

Quote from: JustinFun on May 25, 2014, 08:18:00 AM
Bradley speaking, wherever you see diodes set in opposite directions to each other, they're the clipping diodes. They're mostly in the feedback loops of the opamps in boss pedals I think, although there may be some cases where they go from signal path to ground. You can spot feedback loop clipping as it goes from one side of the opamp to the other (the triangles in the schematic).

So wherever you see:

- diode > parallel with diode <
- diode > diode > parallel with diode < diode <
- diode > diode > parallel with diode < (asymmetric clipping)

Those are the the clipping stages

There may be more than one per pedal (the SD2 schematic linked above looks to have 3 - one diodes to ground and two asymmetric clipping in opamp feedback loops)

If you're new to reading schematics, this is a good place to start learning - why not download the schematics for the pedals you list, circle what you think the clipping diodes are and post here for feedback? It's a very friendly learning environment on this forum - unless you're claiming to be the best boutiquer since sliced bread no-one is going to criticise you for not having a particular level of knowledge.
Cool!I'll pull up some schematics and see if I can point out the clipping diodes with your info.

soupbone

Thanks for the info folks!I'll report back and see I can pick the clippers out.  :icon_mrgreen:

bob barcus

I have a Vox 830 distortion-booster It has both kinds of diodes soft and hard. D1-2 are above IC-A..and D3-4 are going to ground over at IC-B.what would happen if I changed them All to GE 1n34 type I did this to a Boss DS-1 and it softened the distortion.This pedal sounds bright with my 100w Plexi ,but kind of dark with my 63 Bandmaster