JAM Pedals - Rattler  [traced]

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

any body play or have one of these ? curious to find out what mods might have been done to original rat, maybe a refinement of the ruetz mod, which is ok but seems to take off a little too much distortion and makes it less "forward" overall.

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Dingleberry
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Post by Dingleberry »

Don't have access to one, but from th gutshots I found I drew this schematic.
Basically it's vintage rat with mostly cc-resistors and 100kC filter pot.
Power supply resistor was hard to determine from the gutshots. Looks like it could be 110R, but not sure. In the other picture one band behind the wire looks like red...
Anything from 47R (the stock RAT value) to, say 120R will work as the current consumption is so low that there is hardly any voltage drop across that resistor.
Also the clipping diode section is assymmetrical in the stock rattler and could be wired couple of ways.
Try and see how it sounds best to you. Rattler + uses stock rat clipper and metal can LM308AH ic.
Have fun!

-T
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Rattler not verified
Rattler not verified
Simplify before you amplify.

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Post by Cub »

Hi everybody !

I've been feeling Ratty lately and the Jam Rattler caught my eye. The Jam Rattler Classic vs Rattler Plus video had some nice gutshots from both pedals, so I took some stills and attached them here.

In the Plus, the anode of the 1N4148 sits where the anode of the LED in the Classic goes, while keeping the kathode in the same place. This must mean that in the Classic, there is a 1N4148 and a LED in series going antiparallel with a single 1N4148.
Now, that's what I call asymmetrical ! I would have thought it would be two 1N4148 diodes in series antiparallel with an LED, the same recipe as the "Burn" mode on the three way clipping switch of the Proco Solo.

But Back to the Jam pedal. The switch on the Plus appears to be a simple SPST on-off switch, wired somewhere between the opamp and the RC networks. Since there are no additional components, my best guess would be a Ruetz switch to take the 47r resistor and 2.2µF cap out of the circuit.


Also, I found a video in which Joe of Gray Bench takes apart a newer model with a red PCB. I took some stills again and and attached those here as well. Compared to the older boards, there's one extra metalfilm resistor on this new one. I'll try and have a good look this weekend to see what it could be doing on there.
Here's the link if you want to see the whole video for yourself. Jam Pedals Rattler Teardown! Modern Rat Clone with Vintage Flair!


Lastly, there's one more video I'd like to share with you good people. The Ultimate RAT Pedal Blindfold Challenge - 7 Pedals - £40 - £200 Shootout! of Andertons got me interested in the Rattler. No gutshots, but it's always nice to hear pedals compared on a level playing field.

.
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Jam Pedals - Rattler Classic (old version) top
Jam Pedals - Rattler Classic (old version) top
Jam Pedals - Rattler Plus (old version) top
Jam Pedals - Rattler Plus (old version) top
Jam Pedals - Rattler (new version) top
Jam Pedals - Rattler (new version) top
Jam Pedals - Rattler (new version) bottom
Jam Pedals - Rattler (new version) bottom
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Post by Cub »

Dingleberry wrote: 26 Feb 2015, 09:24 Power supply resistor was hard to determine from the gutshots. Looks like it could be 110R, but not sure. In the other picture one band behind the wire looks like red...
Anything from 47R (the stock RAT value) to, say 120R will work as the current consumption is so low that there is hardly any voltage drop across that resistor.
Could that mysterious power supply resistor is 3.3r then ? I see orange, orange, black and silver bands on all three boards for that one.
It seems a bit on the low side, though.
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Post by Intripped »

At least in the second pic the band looks gold, so 33 Ω, that is a more conventional value.

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Post by Cub »

Intripped wrote: 04 Jan 2023, 10:24 At least in the second pic the band looks gold, so 33 Ω, that is a more conventional value.
Good eye, that must be it !
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