Monday, June 20, 2016
Catalinbread SFT
Here's a really versatile overdrive from Catalinbread. The SFT is based on Ampeg amps from the 70s, using JFETs to simulate tubes (like many of Catalinbread's other overdrives). The Stones/Stoner switch allows you to go from verge of breakup tones to near fuzz tones with the flip of a switch. This can be run off 18 volts and this gives extra headroom, so it may not be a bad idea to include a charge pump in your build. This layout reflects the newest version of the SFT, and the schematic can be found here.
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18v really brings this one alive
ReplyDeleteHello,
ReplyDeletePlease make PCB for Catalinbread DLS MKIII
reg
Martin
The 33k resistor should be 2k2
ReplyDeleteUpdated
DeleteVerified! I went with J201 for the trannies, a single 2n4393 costs like four pounds here. Also tried with 2n5458 but those made the breakup nasty and sputtery and a bit gated. Now it is really gainy, wonder how it sounds with a set of 2n5457. I wired the switch as the tagboardfx-layout suggests: lug 2 & 3 goes to bottom, and lug 5 & 6 to the top holes.
ReplyDeleteThanks for the layout!
I got my 2n4393s on Aliexpress for less. Didnt use them in my build yet, so i dont know how they compare to j201.
DeleteThe tagboardfx uses a differend numbering for the switch imho.
Cool, thanks! Is there any tranny/combination that you prefer?
ReplyDeleteHello I had a problem with mine on the stones mode i have a really low gain and volume and when i switch to stoner everything seems like the video. I cheked every value and everything seems correct , the trannies i used are KS4393 which only have different layout from the stock ones. Is there a way i can boost the stones mode a little bit? Thanks in advance
ReplyDeleteHello. If a want only use the stoner mode, should put some jumper in the place of swithches? Thanks
ReplyDeleteJust jump the Sw2-3 pads and leave the Sw4-5 pads open. You can also omit the 470k and 4.7n right by the Sw4-5 pads.
DeleteNooby cuestión, but thankss
DeleteHi there
DeleteMay I ask a similar question please? If I like to go Stones mode only, how should I jump? Jump sw3 and 4?
For Stones only, jump pads sw4-5 and leave sw2-3 open. Then you can omit the 22uF cap in the top right of the board as well.
Delete
ReplyDeleteDo you think i can build it with the transistor replacement mpf4393 by mpf102?
Compare the datasheets, but I think that should work. Worth socketing and experimenting with at least. J201 will work here and I would guess 2N5457s would too.
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ReplyDeleteI see in the picture Sw2 and Sw3.. And Sw4 and Sw5.
ReplyDeleteAnd i See that in the original Pedal has only 1 Stoner Button
How is it? Shoud i Jumper one of the two Sw?
Sory for my english
Those are the pin numbers for a double pole double throw (DPDT) switch. 4 and 5 are connected for "Stones" and 2 and 3 for "Stoner". All unconnected is closer to the "Stoner" side, but slightly less gain and volume. The switch is not necessary for the circuit to work.
DeleteVerified!! Sounds huge and has a wonderful ampeg character. The fuzz side is a beast. Used 2N5457. Will try another one with J201, but I think it will be almost the same. Thanks again for your work here!!
ReplyDeletePic here:
http://www.studionegro.tv/ftp/diy/sft2.jpg
I'm pretty sure the 470K on the input is on the wrong side of the 100nF cap at the input. (R1 and C1 on the schematic that comes up when you search for it). It will work, but if you boost the signal going into the pedal up above 2VAC it will throw Q1 out of whack and be a sputtering fuzz mess until the voltage settles back down. I just added an additional 470K on the solder side of the board because it's a PITA to pull out and monkey around with, and that solved my problem I was having with it. Cheers.
ReplyDeleteHi! I know it's been a while, but can you explain me better where did you solder that aditional 470k res? Just after the Input, before splits into cap and the other res? I've been experiencing the same problem, mostly in Stoner mode, and with all transistors (2N5457, J201 & BF245A). Thanks in advance. Regards
DeleteHi, I saw a Ampeg based kit called Ampegulator (fuzzdog pedal parts) using a charge pump to provide 18V DC by using an external switch, is it what does the stones/stoner control of the SFT v2 ?
ReplyDeleteThe switch on the SFT v2 changes some component values in the circuit. The Ampegulator just adds a switchable charge pump, giving you the option to run at 9v or 18v.
DeleteOK so thé ampegulator is a kind of sft v1....!?
DeleteAs far as I know, yes.
DeleteThanks for answering, what about the 18v on the present layout ? is a mod needed to use it with 18V (add of a charge pump pcb) ? regards
DeletePS: does the layout takes in account revisions suggested by the comments about JFETs or component values ?
You can add a charge pump board to your build. As long as your components are rated high enough you shouldn't have any problems. (Really it's electrolytic caps you have to worry about. I generally don't buy any rated at less than 35v)
DeleteIt's been a while since I worked on this layout, but it is verified and follows the schematic linked in the description.
Ok thanks !
DeleteI may be wrong but I think the transfer layout has not been inverted ?
ReplyDeleteFor the typical tone transfer method it doesn't need to be inverted. If you're using the photo resist method you can invert it before printing, but since you're likely to be printing on transparency you can just flip the print out over and be fine.
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ReplyDeleteWhat's the dpdt Pinot for the stones/stoner switch?
Delete1-2
3-4
5-6
Or
1-4
2-5
3-6
Nevermind, found it on fsb
DeleteBtw some put put a 1Mohm between the gate of Q1 and ground to stabilize bias of Q1 and have some good result if other jfets are used . And even with some brand of MPF4393. For info on this , stoner mode oscillation problem and later catalinbread values for some resistors, google Aion Artemis mk.II v1.1 pdf and you'll find what you're looking for.
DeleteThis one really works great with 18V! 9V is kinda... meh.
ReplyDeletePutting the Stones/Stoner Mode on a Footswitch makes it great to perform with.
I advise to put a 1M Resistor from Q1 G to GND to bias it correctly. Without this i had weird drop outs/shorts. And the Polarity Protection is wrong in this Layout :P
If I remember correctly, Catalinbread's polarity protection method was the diode from 9v to ground. If you're referencing PPCB's schematic, that method is just what Robert has standardized for his PCBs. Both methods are valid.
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Deleteyou are right i had a brainfart...
DeleteThe missing 1M resistor at Q1 has been added to the layout.
ReplyDelete