JHS Pedals Overdrive Preamp

[jeffwhitfield]

I highly doubt this is a complex circuit so shouldn’t take long to trace. It’s a precursor to the DOD 250. Very interested in seeing what this circuit looks like. Sounds interesting.

JHS Pedals, Kansas City USA— Overdrive Preamp

www.jhspedals.info

 

[music6000]

Yep, Should read M1 = 1N4001, as drawn in my corrected Layout.

 

[music6000]

All the traditional (?) schematics have 4148. According to the live video he did after the release, he used 4001. I don’t know why, voodoo maybe?

He couldn't lie straight in bed!

 

[Robert]

According to the live video he did after the release, he claimed he used 4001. I don’t know why, voodoo maybe?

Maybe in the through-hole version, but T4 is the SMD code for 1N4148.

 

[Robert]

Why is there only one silicon diode visible in the big box "throwback" version? ...

 

[Coda]

Why is there only one silicon diode visible in the big box "throwback" version? ...

Because the whole pedal is a Red Herring. It does nothing, but the player expects it to, and hears what they think they should be hearing. Its the REAL Placebo Pedal...

 

[jeffwhitfield]

R2/R4 would make VREF around 0.09V, that can't be right.


BTW those T4 diodes are 1N4148, S7 is BAT42.

I'll look again. In fact, I'll post some good shots of the board so that we can all look at the resistor codes.

 

[jimilee]

Maybe in the through-hole version, but T4 is the SMD code for 1N4148.


View attachment 23773

Oh, I believe you, that’s where the he claimed part comes in. You definitely know more than I do about the smd stuff.

 

[jimilee]

Because the whole pedal is a Red Herring. It does nothing, but the player expects it to, and hears what they think they should be hearing. Its the REAL Placebo Pedal...

But but but, why would he lie about pedals he is selling way over priced pedals???

 

[Coda]

But but but, why would he lie about pedals he is selling way over priced pedals???

Because the whole thing is one giant, well-organized hipster troll effort...

 

[jeffwhitfield]

Here's some pics of the board. First one is an overview so you can follow along. Then there's three of each section that should be good enough for everyone to read the codes off the resistors and whatnot.

 

[phi1]

Why is there only one silicon diode visible in the big box "throwback" version? ...

Looks like The throwback version doesn’t have the diode sw, so apparently only GE mode. The 1 si is probably for polarity protection.

 

[jeffwhitfield]

R2/R4 would make VREF around 0.09V, that can't be right.


BTW those T4 diodes are 1N4148, S7 is BAT42.

Yeah, definitely got the values wrong. They're both 1M.

 

[Robert]

Yeah, definitely got the values wrong. They're both 1M.

Yep, easy to do and it makes more sense that way.

 

[Robert]

Looks like The throwback version doesn’t have the diode sw

Ahh, completely overlooked that.

 

[jeffwhitfield]

Looks like The throwback version doesn’t have the diode sw, so apparently only GE mode. The 1 si is probably for polarity protection.

Yep, it's likely a 1N5817. Typical for that.

 

[jeffwhitfield]

Fixed values of R2 and R4. Gonna just start linking the doc via Dropbox so I don't have to keep reposting it.

Dropbox

www.dropbox.com

In case you're wondering, JAC stands for "Just Another Clone".

 

[jesuscrisp]

Kinda weird question, but... Have you played it so far?

Curious about the taper of the gain pot, as with lin tapers for both volume and gain most of the distortion would likely be after 3 o'clock and the volume will give you a false sense of loudness. Also, do you have any other DOD250 or Dist+ for comparison?

 

[music6000]

Kinda weird question, but... Have you played it so far?

Curious about the taper of the gain pot, as with lin tapers for both volume and gain most of the distortion would likely be after 3 o'clock and the volume will give you a false sense of loudness. Also, do you have any other DOD250 or Dist+ for comparison?

Curious to hear how much Gain with a B250K?
DOD 250 uses 500K, Distortion + uses 1M!
Every modder seems to use a C taper!

 

[jeffwhitfield]

Kinda weird question, but... Have you played it so far?

Curious about the taper of the gain pot, as with lin tapers for both volume and gain most of the distortion would likely be after 3 o'clock and the volume will give you a false sense of loudness. Also, do you have any other DOD250 or Dist+ for comparison?

I built the AionFX version a while back. Also built an Irrlicht (EQD White Light) which is based on the Distortion+. Between the two, I preferred the Errlicht.

I did breadboard a stock 250 last week so I'll be able to compare for sure. Once I nail down this new-old one, I'll likely re-breadboard it and compare.

 

[jeffwhitfield]

Curious to hear how much Gain with a B250K?
DOD 250 uses 500K, Distortion + uses 1M!
Every modder seems to use a C taper!

It's noticeably less gain than my Irrlicht which uses a 1M. Guess they decided later on to add a bit more gain to the circuit prior to release?