Catalinbread - SFT  [traced]

General documentation, gut shot, schematic links, ongoing circuit tracing, deep thoughts ... all about boutique stompboxes.
User avatar
deltafred
Opamp Operator
Information
Posts: 1654
Joined: 06 Apr 2010, 16:16
Location: England
Has thanked: 813 times
Been thanked: 306 times

Post by deltafred »

mothercruncher wrote:Hmm, just got back from hols and had a good session with this tonight- did anyone have an issue with HUGE volume with the vero layout for this?

The volume pot is basically barely doing anything and, stock, it's (probably rightly) running so much louder than when in bypass :hmmm:
It sounds like you could have no ground connection to the volume pot, either a faulty pot or bad soldered joint ( but looking at you photos I would very much doubt a bad joint).

Really neat build, love it. I would also like to thank Mike for his vero layout and all the guys involved in tracing it.

I have built 3 so far and none have had volume issues, one was very unstable and gated but that turned out to be me missing a track cut. :roll:
Politics is the art of so plucking the goose as to obtain the most feathers with the least squawking. - R.G. 2011
Jeez, she's an ugly bastard, she makes my socks hurt. I hope it's no ones missus here. - Ice-9 2012

User avatar
ShortScaleMike
Resistor Ronker
Information
Posts: 387
Joined: 12 Feb 2008, 14:36
my favorite amplifier: Marshall JCM800
Location: London, UK
Has thanked: 16 times
Been thanked: 93 times
Contact:

Post by ShortScaleMike »

mothercruncher wrote:Many thanks to Mike for the ver0 layout and rcubed and the original tracers who put the hard yards in. :applause:
No worries, beautiful build.

User avatar
mothercruncher
Information
Posts: 4
Joined: 30 Oct 2008, 15:42

Post by mothercruncher »

Argh, how embarrassing- I should have spotted that one- nothing was getting bled through to ground. That pot was the one component I recycled for the project too, that'll teach me.
Thanks for the spot DF :applause:

User avatar
deltafred
Opamp Operator
Information
Posts: 1654
Joined: 06 Apr 2010, 16:16
Location: England
Has thanked: 813 times
Been thanked: 306 times

Post by deltafred »

mothercruncher, glad to be of help.

If I have a problem with something electronic I usually phone a good friend of mine and talk through it. Usually it hits me as I am having to think it through to explain it to him (he is also a retired EE). When you have built something you usually imagine the worst.
Politics is the art of so plucking the goose as to obtain the most feathers with the least squawking. - R.G. 2011
Jeez, she's an ugly bastard, she makes my socks hurt. I hope it's no ones missus here. - Ice-9 2012

User avatar
neoflox
Breadboard Brother
Information
Posts: 77
Joined: 09 Feb 2010, 17:48
Has thanked: 6 times
Been thanked: 2 times

Post by neoflox »

Hi,
did anyone ever compared an original SFT with a cloned one? I did back when the first verified layouts came out and I remember it sounding significantly different. Less overall gain, shitty sound with lowered gain. If someone is certain to know a equally sounding layout, please tell which one it is ;)
Cheers

User avatar
DWBH
Cap Cooler
Information
Posts: 498
Joined: 24 Aug 2007, 16:26
Location: portugal
Has thanked: 12 times
Been thanked: 3 times

Post by DWBH »

Image

Here's one I built for my bassist friend of mine.
Regarding the weird connection on the pot, you're all talking about that connection between lug2 and the resistor to ground right? What's the catch? Should it be eliminated?

Haven't tried it with bass, only with guitar, and although I thought it would be more gainy, it's very amp-like, almost tweed-ish.

User avatar
deltafred
Opamp Operator
Information
Posts: 1654
Joined: 06 Apr 2010, 16:16
Location: England
Has thanked: 813 times
Been thanked: 306 times

Post by deltafred »

DWBH wrote:Here's one I built for my bassist friend of mine.
Regarding the weird connection on the pot, you're all talking about that connection between lug2 and the resistor to ground right? What's the catch? Should it be eliminated?

Haven't tried it with bass, only with guitar, and although I thought it would be more gainy, it's very amp-like, almost tweed-ish.
It's a while ago so I had to go look at the schematic to see what what was going on around the gain pot and realise that I have wired mine incorrectly and that was probably causing the high gain with the gain pot right down. I should think that if you wire it as the schematic (and not incorrectly as I did) then it should be fine.

I have used mine on both guitar and bass, I built it for bass but sounds nice with guitar.

It is supposed to sound like an Ampeg SVT bass amp, with a similar sound when you overdrive it. Having only ever played bass through an Ampeg rig once I cannot say how true this is. We were the support band and the Ampeg rig belonged to the headline band so I didn't want to mess with it. I just plugged in and it sounded ok as he had it set so played it like that.
Politics is the art of so plucking the goose as to obtain the most feathers with the least squawking. - R.G. 2011
Jeez, she's an ugly bastard, she makes my socks hurt. I hope it's no ones missus here. - Ice-9 2012

User avatar
Sonofthebeach
Information
Posts: 8
Joined: 31 Dec 2012, 10:39
Has thanked: 1 time

Post by Sonofthebeach »

I built this one yesterday and am not sure that it works right cause the pedal behaves not "normal" compared to other overdrives.

Only with gain maxed the pedal has a good sound. low gain settings let the overall volume drop. With low gain settings the volume has to be cranked but when I crank the gain the volume gets way too loud. But with the volume on half or below there is less gain...

I used a madbean faultline pcb. I already put a linear volume gain pot in....

When comparing to youtube demos I notice that the original units do not seem to have those problems.

Has anyone an idea whats going on?

User avatar
greenskull
Resistor Ronker
Information
Posts: 253
Joined: 03 Jul 2007, 22:47
Has thanked: 33 times
Been thanked: 8 times

Post by greenskull »

Sorry to say I built the Faultline years ago and was disappointed I couldn't really match the demo of the real thing. Seemed like not enough gain from what I remember.
fuck smooth tone, fuck eric johnson - Seiche

User avatar
tapion
Information
Posts: 2
Joined: 06 Jul 2016, 06:57
Been thanked: 2 times

Post by tapion »

Hey there,

i'm still having problems getting my build (tagboardeffects vero) to work (using J111s as Q1-Q6 until the replacements arrive...)
Does anyone have important bias points i could measure in the meantime?

Well at least the case is finished ;)
Attachments
IMG-20160708-WA0001.jpg

User avatar
tapion
Information
Posts: 2
Joined: 06 Jul 2016, 06:57
Been thanked: 2 times

Post by tapion »

Small update: in the meantime my build works with 2n5457s, but has incredible amounts of gain and oscillations in one switch setting, maybe the PN4393s will fix this...

User avatar
Stymie13
Information
Posts: 7
Joined: 19 Sep 2014, 01:26
Been thanked: 9 times

Post by Stymie13 »

I know this is an old one but I'm not able to get this one working properly. All component values, locations, tracks, cuts, links, wiring, etc. has been double, triple, and quadruple checked. The tone controls work as do gain and volume but the sound is terrible. Anyone who has a properly working SFT II version, please post your FET drain voltage readings. With J201, 5457, 5485, and MPF4393s the voltages were very similar:

Q1 .58-1.08
Q2 9.4
Q3 2.5-3.5
Q4 9.4
Q5 5.16-5.45
Q6 9.4

User avatar
Stymie13
Information
Posts: 7
Joined: 19 Sep 2014, 01:26
Been thanked: 9 times

Post by Stymie13 »

Found an incorrect resistor biasing Q1 and swapped it out. Working properly after correcting a switch wiring issue also.

Q1 4.8
Q2 9.4
Q3 4.1
Q4 9.4
Q5 5.2
Q6 9.4

User avatar
rankotomic70
Information
Posts: 2
Joined: 28 Dec 2015, 11:50
Been thanked: 1 time

Post by rankotomic70 »

I built ver. I using Ampegulator PCB (schematics is the same), but I have some high frequency hiss (about 8kHz) when running charge pump switched to 18V. Does anyone else has the same problem with 18V charge pump? Any hints?

User avatar
rankotomic70
Information
Posts: 2
Joined: 28 Dec 2015, 11:50
Been thanked: 1 time

Post by rankotomic70 »

Now I have checked - hiss is at 10kHz, and it is due to the fact that I have used TLC7660A instead of TLC7660S (which I couldn't buy here). S version of that IC has frequency boost at pin 1, while A doesn't have that, and it's internal working frequency is 10kHz. I will try to filter it out using a 10n capacitor between +18V and ground, but for all of you who want to build this (or any other pedal) using charge pump - DO NOT use TLC7660A, use TLC7660S only!

User avatar
Jiomy
Information
Posts: 1
Joined: 03 Aug 2016, 13:44
Has thanked: 1 time

Post by Jiomy »

Hello , i recently finished my SFT Build and the stoner mode is way too loud for switching it live , so i would like to ask if anyone here can point me to the right direction to make it usable for live situations to work the stoner mode as a little gain boost. My first thought was maybe lowering the value of the electro that the switch enables. You see i am not a so much of a fun of how the stoner mode sounds on my keyboards (organ), so maybe i have to add/remove something else from another place in the circuit to get what i want. Any pros here that can give me a tip about that?
:thumbsup

User avatar
etta place
Information
Posts: 1
Joined: 19 Jun 2014, 13:37
Has thanked: 75 times
Been thanked: 1 time

Post by etta place »

maybe put a 2 to 10K trimmer in series with the electro,and adjust it to taste.
or,use a standard pot,adjust,measure and replace it with a fixed resistor
η πεσ στο στελιο να σου δωσει το τηλεφωνο μου :lol:

User avatar
n4m3less
Information
Posts: 6
Joined: 10 Apr 2016, 23:00
Location: Italy
Has thanked: 3 times

Post by n4m3less »

Blend wrote:If I connect the capacitor 22uF, the problem arises, but with the complete switch as in the original I do not hear any crackling noise, other mod that suggest you do in the 1st SFT is to replace R5 22k with 10k. :wink:
Hi! i have made the mods recommended by Blend...one question: the 47pf add on q8, what does?what kind of changes in the sound?
thanks

P.S: to my ears the first version with these mods sounds better than the last version.Someone Confirmation?

User avatar
elbeeuk
Information
Posts: 16
Joined: 11 Jan 2010, 20:13
Been thanked: 2 times

Post by elbeeuk »

Hi all,
I'm hoping someone can help point me in the right direction with debugging this build.
I've built it all and the circuit lets the signal through when engaged but the gain is weaker than demos. The layout I used is over at http://tagboardeffects.blogspot.co.uk/2 ... ft-ii.html
The main problem I'm having though is that I get a weird squeal when stoner is engaged. Here's a quick vid to explain better in terms of pots involved:
https://photos.app.goo.gl/1Bwv7Qc03aNyy5g03

Can anyone think where to start with debugging? I've built 4 other pedals without issues, this is the first that's giving me bother.

DPDT switch is wired lkike this:
https://photos.app.goo.gl/d839CmHh40PKJbrE2

Solder on the veroboard looks like this:
https://photos.app.goo.gl/Vqg7srdPfQ6kB6a03
https://photos.app.goo.gl/YRxqSaZpcJJ4YAnO2
https://photos.app.goo.gl/O91edceJB54DqYpu1

Give me a shout if you need other info that might help.

Cheers
Elbee

User avatar
icziko
Information
Posts: 8
Joined: 27 Jan 2016, 20:22
Has thanked: 5 times

Post by icziko »

Add 1M resistor between Q1 gate and GND. This is missing component on schematics.
This is on pedalpcb schematics https://www.pedalpcb.com/docs/SOFTii.pdf
With this pedal works consistently, there is no need to "reset" it after each 10 seconds, tone is not dark anymore and different transistors can be used. I tried 2SK170, BF256B, J201 and 2N5457 and they were all consistent.

Post Reply