Tuesday, March 24, 2015
Catalinbread Sabbra Cadabra
This pedal is inspired by Tommi Iommi's classic combination of Laney Supergroup amps and a Rangemaster treble booster. It's not an emulator like the Supergroup pedal I posted a little while ago. If you look at the schematic it actually looks like 2, AMZ mini booster-type stages at its heart, with a transistor-based input stage. It also has a fixed tone array before what I'm guessing is a JFET-based gain recovery stage at the output. The originals have MPF4393 JFETs, but socket and try others with GSD pinout (J201, 2N5457, etc). The layout below says to use 9v, but it can also be run at 18v. I've drawn it so you can use right angle PCB pots, mounted from the solder-side of the board if you want, and it should all fit nicely in a 1590B.
I just need my A1M pots to arrive to tag this board verified (or no, haha). Can you do a G2D Morpheus layout? I never found one online!
ReplyDeletethis one sounds pretty good, did it with the old layout (pcb), cant get any of my bc182/bc184 to work...finally used a 5088 and made the connection from volume 1 to ground.
ReplyDeleteits getting boxed as soon as i sort out graphics.
Works fine. Used 2N5457 jfets and BC547B NPN which needs to be turned around.
ReplyDeleteSounds good.
BC184 LC has different pinouts to BC184 ,pins need to be twisted round ,I made the mistake of not having them the right way round.
ReplyDeletehas anyone problems like a little gain or fuzz sound? and when changing tha gain from 100% to 50% or below has a cut to the sound like it is being gated very hard? can i have the schematic so i can work this out?? please respond!
ReplyDeleteI haven't built one, but the schematic can be found here:
ReplyDeletehttp://freestompboxes.org/viewtopic.php?f=7&t=25043&p=249151#p249151
Really enjoying this layout! Finished mine about 45 minutes ago and rocked the hell out of this circuit with my Gibson SG with Burst Buckers. Make sure you check your bc184 pinout since I had to cross a leg since mine had the base on the outside.
ReplyDelete-Cody
Sounds awesome, Check pinout on BC184LC as mentioned above.
ReplyDeleteCould not make it work. Tried twice. Totally changed all jfets and the transistor I'm using is 2n3904 rotated 180deg. All I got is a hum. Something strange happened. When I touch the range pot there's another type of noise, like when you touch the tip of cable plugged in the amp. Any thoughts?
ReplyDeleteShort answer: Something's wrong with your build
DeleteLong answer: It's been verified by multiple builders. I can't really diagnose what wrong with your build based on what you've said. Double check all your connections with a DMM and reflow solder joints.
It's working now. I switched the input and output but it sounds awful. Very low gain and some controls like range just don't do nothing when dialed. I will try to bypass the transistor stage.
DeleteI managed to find the transistors MPF4393, but my pedal is very high gain. How can I change to a little less gain?
ReplyDeleteHi all, I didn´t find jfets used on this layout and I try another ones, like BF245, 2n5486, 2sk117 and mpf102... The mpf102 after bias adjusts was the one with less noise, after that I change treble boost circuit trying to be near as rangemaster, however, using a ac127 (germanium) npn transistor and ground on 0v. I had good results, if anyone would like to try these modifications. The scehmatic is here:
ReplyDeletehttps://www.4shared.com/get/bByhZiNOca/black_friday.html
hi, what kind of bias adjusting did you do? i saw this schem you post and has many diferences from the layout in this page.
DeleteI did adjust of bias based on bsiab pedal, because I used the same components and this type of construction avoid noize, my first pedal 100% based on the sabbra cadabra from this page don´t work very well, very loud high frequency noize. another important things to consider is put the circuit inside a metal box and the box on gnd. Regards
DeleteAnyone having a pop issue with this one? I put a pull down resistor at the input, I'm using dpdt millenium bypass, disconnected the led also , didn't do anytbian mich, I also have extra pulldown resistor at the output, maybe I can try 3pdt input grounding?
ReplyDeleteHi, I built this pedal last week and the volume pot is showing a weird behavior, it never mutes the sound, even if turned all the way to the left... Actually, the volume is really loud even with the volume pot on zero. Does anyone know what may be the problem, or can think of a solution? By the way, I used a 2N2222 for Q1 and MPF102s for the Fets. Thanks in advance
ReplyDeleteNevermind, I realized that I used an old pcb layout which didn´t have lug 1 of the volume pot connected to ground. Made the correction and now is working fine.
DeleteSomthing is wrong with mine. sounds very quiet and gated. I followed the traks with a cable conected to the amp, to listen where it starts to go wrong. The treeble booster works fine but after the firs fet, the sound go to shit. And after the other fets its worst. I used mpf102. should i change some resistors to bias them correctly?
ReplyDeleteTry to use my modded circuit, I used mpf102 too, is possible to make my changes using the PCB posted over here.
DeleteWorks pretty good. Didn't have a BC184 so I tried a BC547(with 420hfe because it's what I grabbed and felt that was an appropriate range considering, lol) and it just didn't have enough gain for me so I put in a 2N5088 with about 800hfe and now it's where it needs to be. You really gotta slam the front end with that booster to get that thick furry fuzz tone with it. With the lower gain transistor it made a nice overdrive but it didn't sound like demos of the real deal. With the 2N5088 I feel it's closer to factory. The Naga Viper (which is what the first transistor stage is based on) uses a 2n2222A, which is pretty high gain device, as are the BC184. I would suggest socketing that position so you can tune it to taste, or replace that 47Ω resistor in the upper left area with a 1k~5k trimmer and use a high gain transistor for Q1 and adjust the gain of the booster section via the trimmer to taste. Or put it on the outside, I'm not your dad, do your own thing kids.
ReplyDeleteIs there a schematic for this?
ReplyDeleteReally, really good sounding effect. It sounds really good with the MF4393, and not so precise with any other jfets I tried. You need the correct jfets to have a fully functional and very nice sounding clone .
ReplyDeleteI'll start the building of this pedal, does the bf245 works great? I will use a 2n2222 to substitute the bc184. Thanks
ReplyDeleteThis comment has been removed by the author.
ReplyDelete2n5457 for Q2-6 and BC549C for Q1 was the best matching, i've tried 2n2222 and 2n3904, but it doesn't sounded good, replaced for BC549C and WOW, what a sound, pure sabbath.
ReplyDeleteAll working excepy for range..... no change at all... I've triple checked every component. Any suggestions?
ReplyDeleteSame. I switched the bc184 with a 3904 and now the rage pot does something. Try a bunch of 184 or replacements.
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