JHS - Bender  [traced]

General documentation, gut shot, schematic links, ongoing circuit tracing, deep thoughts ... all about boutique stompboxes.
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A Paz
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Post by A Paz »

Bender 1.jpeg
Bender 2.jpeg
Bender 3.jpeg
Bender 4.jpeg
JHS Bender Schematic.png
Here is my trace of the JHS Bender. I was interested in the way that he got "germanium sound from silicon transistors" so I thought I would give tracing it a go. I measured all of the resistors in the circuit, and the values seemed to make sense so I didn't cut any traces. I did however, cut all the traces around the capacitors to measure them so I know they are correct.

While tracing, I removed Q2 in order to measure it but dropped it on the carpet and couldn't find it so I attached a socket to the pads and tried various transistors until I found one that I liked. That is why there is a 2N2222A there.

In order to figure out what the other transistors were, I breadboarded the circuit and tried [so many] different transistors until I got to the BC108C. In hindsight I should have started with those. The closest SMD parts that I can find to a BC108C are the BC848 or similar, so that is what I'm guessing JHS uses. I didn't measure the HFE of those, but I doubt that JHS is measuring and batching their transistors for these pedals so I don't think it really matters.

Since I've breadboarded it already, it might be considered Verified, but I would appreciate if someone else could build it too and see what they think. The design is kind of interesting since it kind of looks nothing like a normal tonebender mkIII. Also feel free to redraw the schematic if you want, I realized right now that I drew it kind of weird.

Edit: I didn't realize that the component numbers in the schematic don't match the board. I'll fix that and then re-upload the schematic.
Edit 2: Fixed
Last edited by A Paz on 19 Sep 2023, 02:19, edited 3 times in total.

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VivMeLol
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Post by VivMeLol »

Thanks

Since there are so many Opamp based distortion pedals, it's nice to have a look at the transistor based circuits for a change.

If I have time, I will enter this schematic into SPICE and publish my findings including frequency response, clipping characteristics and wave shapes of each stage

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beniboy87
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Post by beniboy87 »

Looks like the transistors are one of the BC846-BC847-BC848 (based on the K1Q marking): https://www.diodes.com/assets/Datasheets/ds11108.pdf

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287m
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Post by 287m »

Just Hot Silicon Bender?

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Frank_NH
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Post by Frank_NH »

287m wrote: 18 Sep 2023, 11:59 Just Hot Silicon Bender?
Yes.

viewtopic.php?t=7767&hilit=hot+silicon+bender

Image

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andregarcia57
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george giblet
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Post by george giblet »

I found a few things and updated the schematic.

I didn't check the switch wiring to see if the each half of the switch selects the correct components.

After looking at mictester's silicon bender, should the alternative pot wiring be used?
JHS Bender Schematic (paz 2023_09) GG V1.1 fixes.png

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Nocentelli
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Post by Nocentelli »

A Paz wrote: 18 Sep 2023, 02:52 I was interested in the way that he got "germanium sound from silicon transistors"
:hmmm:

george giblet wrote: 19 Sep 2023, 06:55 should the alternative pot wiring be used?
I suspect "mictester's" version should be used, since otherwise the gain pot setting slightly affects the bias. Is it correct that the switch bypasses the hot cake-style tonestack and simultaneously alters the bias point to lower the total output, compensating for the perceived boost from bypassing the lossy tonestack?

Off on a slight tangent, i find it hilarious that josh has yet again just lifted a DIY "design" and stuck it in a box with his name on (fair play if he makes money and just doesn't care) but there's a whole extra level of fun bcos when i posted a Q about "mictester's" hot silicon schematic on the DIYSB forum (quite a few years ago now), people got really cross and insisted someone else had bolted that tonestack onto that TB mk2 and posted a schematic of it and it was outrageous plagiarism, and here's ol josh just knocking out those boxes by the thousand and enjoying his yacht
modman wrote: Let's hope it's not a hit, because soldering up the same pedal everyday, is a sad life. It's that same ole devilish double bind again...

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Manfred
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Post by Manfred »

I owned the original tonebender shown in this video about 50 years ago and sold it a few years later to buy a Fender Blender, which I sold as well.
That was a mistake from today's perspective, but who knew then that these devices will be sought after. :(

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george giblet
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Post by george giblet »

Nocentelli wrote: 19 Sep 2023, 17:54 I suspect "mictester's" version should be used, since otherwise the gain pot setting slightly affects the bias. Is it correct that the switch bypasses the hot cake-style tonestack and simultaneously alters the bias point to lower the total output, compensating for the perceived boost from bypassing the lossy tonestack?
From the PCB it seems likely to me but I'm always reluctant to call a best guess reality.
Off on a slight tangent, i find it hilarious that josh has yet again just lifted a DIY "design" and stuck it in a box with his name on (fair play if he makes money and just doesn't care) but there's a whole extra level of fun bcos when i posted a Q about "mictester's" hot silicon schematic on the DIYSB forum (quite a few years ago now), people got really cross and insisted someone else had bolted that tonestack onto that TB mk2 and posted a schematic of it and it was outrageous plagiarism, and here's ol josh just knocking out those boxes by the thousand and enjoying his yacht
I like Josh's attitude towards things.

The JHS website says it's a 1973 MKIII Tonebender (3-knob, Silver/Orange box) replica. I haven't checked it against any obscure versions in my stash but that doesn't seem 100% correct to me. The common circuit would be Darlington+reverse diode circuit.

EDIT: this MK2 is more like it,
https://1.bp.blogspot.com/-zWNYzS5xIYQ/ ... er_MK2.jpg

I did some digging and mictesters version is preceded by Doug Hammond' "Hot Silicon" 2003. Some of Doug's designs changed over time but he kept the same name and didn't always assign a version or date.
dh_hot_silicon.gif
Which points to one of Gus's circuit and Aron Nelson's Hot Fuzz 2000,
hfuzz1.jpg
I owned the original tonebender shown in this video about 50 years ago and sold it a few years later to buy a Fender Blender, which I sold as well.
That was a mistake from today's perspective, but who knew then that these devices will be sought after. :(
Happens to everyone. You can't have too much regrets in the guitar and pedal business, otherwise you would jump out of a window.

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Post by Nocentelli »

george giblet wrote: 21 Sep 2023, 22:16
I like Josh's attitude towards things.

The JHS website says it's a 1973 MKIII Tonebender

the video of the whole range has him saying he spent ages trying and tinkering to get the Ge sound out of Si and after endless testing, it turns out that these two decades old schems had it exactly right back then - who knew? i like the fact he's doing cool retro pedals with a nice sounding circuit inside, but i find the endless bs about the origins of his pedal-guru creations is a bit much
hot mess.png
george giblet wrote: 21 Sep 2023, 22:16
I owned the original tonebender shown in this video about 50 years ago and sold it a few years later to buy a Fender Blender, which I sold as well.
That was a mistake from today's perspective, but who knew then that these devices will be sought after. :(
Happens to everyone. You can't have too much regrets in the guitar and pedal business, otherwise you would jump out of a window.
yep
modman wrote: Let's hope it's not a hit, because soldering up the same pedal everyday, is a sad life. It's that same ole devilish double bind again...

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Post by Manfred »

Happens to everyone. You can't have too much regrets in the guitar and pedal business, otherwise you would jump out of a window.
Well said!

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Post by A Paz »

Nocentelli wrote: 23 Sep 2023, 11:22
the video of the whole range has him saying he spent ages trying and tinkering to get the Ge sound out of Si and after endless testing, it turns out that these two decades old schems had it exactly right back then - who knew? i like the fact he's doing cool retro pedals with a nice sounding circuit inside, but i find the endless bs about the origins of his pedal-guru creations is a bit much

Yeah that's what made me buy this in the first place. I was excited because I thought it was gonna be a super cool and original circuit. I should have read the JHS on the front and known that he had just ripped off and is profiting from someone else's idea. I feel dumb. Fool me twice. . .

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Post by jalmonsalmon »

Nocentelli wrote: 23 Sep 2023, 11:22
The video of the whole range has him saying he spent ages trying and tinkering to get the Ge sound out of Si and after endless testing, it turns out that these two decades old schems had it exactly right back then - who knew? i like the fact he's doing cool retro pedals with a nice sounding circuit inside, but i find the endless bs about the origins of his pedal-guru creations is a bit much

hot mess.png
This one looks familiar :roll:
I built this a long time ago when he sold them as a Hot Chilicon on an etched board.
I noticed he change the name to SRIRACHA FUZZ.
No mention of Gus's schematic but it's a hot silicon fuzz as you can see.
If any of y'all decide to make a JHS - Bender, socket those trannies and experiment!
Hot silicon fuzz is an awesome pedal!
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