JPTR FX Jive Reel Saturator
- Thread starter Boba7
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jesuscrisp
Active member
Since finally my account is ripe enough to post in the request forum, here's the Jive gutshots of 2 Jives, 1 that I had myself, the other I've seen on Reverb.
It's literally a value for value clone of the Zvex SHO, adding hard clipping diodes after the output cap and also adding a master volume knob. The diodes seem to change a lot or are subjective to manufacturing mistakes, the ones for the current version you can look up on their site. Previous descriptions on the site included Russian germanium (?) diodes IIRC, which you see in both of these but in different positions. Toggles are on/on SPDT although the one I bought used had on/off/on toggles for some odd reason (resulting in two diode-off positions).
If this becomes a PCB I suggest adding a power filter cap which the original doesn't have and maybe skip the 100K pulldown resistor at the output as it really does nothing but drop the value and change the taper of the volume pot slightly.
It's literally a value for value clone of the Zvex SHO, adding hard clipping diodes after the output cap and also adding a master volume knob. The diodes seem to change a lot or are subjective to manufacturing mistakes, the ones for the current version you can look up on their site. Previous descriptions on the site included Russian germanium (?) diodes IIRC, which you see in both of these but in different positions. Toggles are on/on SPDT although the one I bought used had on/off/on toggles for some odd reason (resulting in two diode-off positions).
If this becomes a PCB I suggest adding a power filter cap which the original doesn't have and maybe skip the 100K pulldown resistor at the output as it really does nothing but drop the value and change the taper of the volume pot slightly.
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Devoureddeth
Active member
I imagine it is based off this https://www.diyrecordingequipment.com/products/15ips-tape-saturation-colour-mkii
jesuscrisp
Active member
Not at all, it's far lazier, see my post above.
Devoureddeth
Active member
I missed the picture, I would rather the synth rack version as a pedal. It needs some modifications but I think it could be an interesting pedal.
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Are you certain it’s hard clipping diodes? Having played one for a year or so, it *sounds* like soft clipping, even with all 3 engaged.
jesuscrisp
Active member
They all connected to ground. The mosfet doesn't seem to produce a lot of harsh harmonics in this context, which is probably why it sounds "soft". Also I'm almost sure that to make it soft clipping it would need another cap in series with the diodes like in a big muff gain stage, which it didn't.
I do keep the gain (which is what I assume controls the mosfet?) low, around 10 o’clock, so that would explain things further.
So you’re saying that even though it’s a hard clipping setup, bring in parallel means the clipping will be minimized?
No, it seems to me he's saying all three pair of diodes (each on a toggleswitch) are parallel, so when you activate the pair with the smallest threshold, it won't make any difference if then you toggle on/off the other two switches.
It doest make sense to have three switches when you could just use one on-off-on switch.
That’s interesting because when I bought mine the copy said that the 3 diode options could be mixed and matched, but now on Reverb it says ‘Each option overrides the one above it so when the bottom diode switch is engaged, you are at the most extreme setting’ which matches what you’re saying. Also when I got mine it said there was a symmetrical and asymmetrical germanium diode plus a silicon- now all 3 are listed as silicon. Plus mine is SMD while the ones above are thru hole. Puzzling. I’ll play around with the switches later today and see if when the bottom is engaged the other 2 make a difference.
jesuscrisp
Active member
The gain control is the standard SHO boost control and yes it crackles. Then it has a voltage divider volume pot at the output too, so you can run the mosfet hotter than with a normal SHO without blasting your head off. Basically with the gain you control how much volume you're driving into the diodes but also at high gain settings the mosfet itself will clip. In general it sounds rather soft and doesn't produce all that much top end harmonic content.
The toggles are parallel and to some degree they could be mixed, but in general if you have 2 diodes in parallel in the same direction, the one with the lower forward voltage cancels out the other. (Quite a cool fact actually for making something like a rat with 3 clipping options, as you can do it with a simple on-off-on toggle, LEDs being always on and putting silicone or germanium in parallel.)
As for the differences in models: It's not the first and only time they change some models, but also their QC is off every now and then, which may be why the through hole versions seem to have their diodes in different positions. Also they may have reworked the Jive because the diodes they used aren't available anymore in large quantities or as SMD equivalents or just to cut cost and maximize profit.
It has supposedly gotten better in terms of QC with pretty much anything they do as preassembled SMD boards, but of the 2 JPTR pedals I picked up so far, both had issues. The Jive I got obviously had the wrong switches in and looked like it was soldered by an intern. And an earlier run Warlow I picked up had 2 broken germanium diodes, making the pedal sound awful, but not in a doom/shoegaze way, just straight up wrong. The newer ones are SMD with 2 internal switches, there's no more germanium diodes and also no more OPA2134 ICs that were pushed heavily in the marketing.
The toggles are parallel and to some degree they could be mixed, but in general if you have 2 diodes in parallel in the same direction, the one with the lower forward voltage cancels out the other. (Quite a cool fact actually for making something like a rat with 3 clipping options, as you can do it with a simple on-off-on toggle, LEDs being always on and putting silicone or germanium in parallel.)
As for the differences in models: It's not the first and only time they change some models, but also their QC is off every now and then, which may be why the through hole versions seem to have their diodes in different positions. Also they may have reworked the Jive because the diodes they used aren't available anymore in large quantities or as SMD equivalents or just to cut cost and maximize profit.
It has supposedly gotten better in terms of QC with pretty much anything they do as preassembled SMD boards, but of the 2 JPTR pedals I picked up so far, both had issues. The Jive I got obviously had the wrong switches in and looked like it was soldered by an intern. And an earlier run Warlow I picked up had 2 broken germanium diodes, making the pedal sound awful, but not in a doom/shoegaze way, just straight up wrong. The newer ones are SMD with 2 internal switches, there's no more germanium diodes and also no more OPA2134 ICs that were pushed heavily in the marketing.
I had QC issues with mine too: all the Jives released around last Christmas had a faulty component so that they only worked with gain maxed (which wasn’t the actual max gain available on a regular unit so it was still useful to me). They sent out replacements to everyone and mine works well but the DC jack keeps loosening. Also kind of weird: they refused to take back the faulty ones, saying that this would contribute to the egregious ecological effects of shipping; but a. it’s not like a pedal gets shipped by itself and b. having all these faulty pedals sitting around seems like more of a waste.
I tried to contact them for clarity re: all these diode and SMD vs thru hole questions but a week later they still haven’t responded.
As for the diode switching question: yes, engaging a lower switch overrides any above. If the bottom is on then the top 2 have no effect, or not noticeable anyway. Can’t believe I didn’t notice that before.
@George67: It's exactly like Boba and Jesus said (sounds like a nerds dream team right there 
). The signal will only be clipped to ground through the diodes with the lowest vf.
There was never an ability to mix & match and the claim that it would be is just marketing - and obviously a lie. Which is not really surprising given that they also claim the pedal is based on an Akai GX210D. For comparisons here is the schematic of that Akai: https://imgv2-1-f.scribdassets.com/img/document/234153186/original/88d8014f3e/1636867583?v=1
It's honestly surprising that they maintain a good reputation with a lot of people due to the ongoing QC problems and misleading marketing... every pedal that passed through my hands made by them was faulty in some or another way. I heard it's gotten better but my interest in finding out about that is nonexistent by now.
). The signal will only be clipped to ground through the diodes with the lowest vf.There was never an ability to mix & match and the claim that it would be is just marketing - and obviously a lie. Which is not really surprising given that they also claim the pedal is based on an Akai GX210D. For comparisons here is the schematic of that Akai: https://imgv2-1-f.scribdassets.com/img/document/234153186/original/88d8014f3e/1636867583?v=1
It's honestly surprising that they maintain a good reputation with a lot of people due to the ongoing QC problems and misleading marketing... every pedal that passed through my hands made by them was faulty in some or another way. I heard it's gotten better but my interest in finding out about that is nonexistent by now.
So, the gain should be a 5k reverse log, correct? This is interesting because my defective unit has a 100k pot in the gain position and a 5k in the volume position. Could this be the "defective component"?
jesuscrisp
Active member
Sounds like it! Is it by any chance also log taper (A100K)? Because then the taper is also completely messed up, but even if it was linear, it would match what you're describing. Shouldn't have an effect on total gain however.
C5K for volume would mean it will also be quieter than they should be, yet go quite loud rather quickly and plateau almost at some point.
Is your defective unit through hole or SMD now?
C5K for volume would mean it will also be quieter than they should be, yet go quite loud rather quickly and plateau almost at some point.
Is your defective unit through hole or SMD now?
jesuscrisp
Active member
Pretty sure swapping pots would fix it. Can you read the values of the SMD resistors too by any chance?