My SSS is too clean for me. Ideas? Add the FET input?

[bcmatt]

My SSS based mostly on the MHartman layout is my amp that gets played the least. I think I just need it to thicken up a bit and get it a little dirtier.
I revisited it a couple years ago and tweaked the filters.
I've been going for some better sustain out of this...I just think it's quite sterile unless doing mid boost, PAB, and cranking the volume to at least 8 or 9.
The preamp just seems so weak through most of the volume sweep.
I'm thinking adding the JFET boost might help... Not sure what modern and acquirable JFET could qualify.
Should I ditch the Local NFB?
Should I start going with higher plate resisters on some of the preamp stages (with corresponding larger cathode resisters) that I see on some ODS's?

[martin manning]

I think adding the FET boost is a good place to start.it can add its own distortion as well as drive the first tube stage harder.

[desertmouth90]

My SSS based mostly on the MHartman layout is my amp that gets played the least. I think I just need it to thicken up a bit and get it a little dirtier.
I revisited it a couple years ago and tweaked the filters.
I've been going for some better sustain out of this...I just think it's quite sterile unless doing mid boost, PAB, and cranking the volume to at least 8 or 9.
The preamp just seems so weak through most of the volume sweep.
I'm thinking adding the JFET boost might help... Not sure what modern and acquirable JFET could qualify.
Should I ditch the Local NFB?
Should I start going with higher plate resisters on some of the preamp stages (with corresponding larger cathode resisters) that I see on some ODS's?

Got any pics of the internals?

Why dont you add drive pedals in front?

[bcmatt]

I think adding the FET boost is a good place to start.it can add its own distortion as well as drive the first tube stage harder.

Thanks Martin. I'll give it a try. I just found your post about pre-biasing it with 9v batteries. That should be very helpful. I've never tried the FET before, but does it seem worth it to put the 10k pot on the front panel, or do people find a setting they like and usually leave it there... Therefore best kept internal on a trimpot?

[martin manning]

Later SSS had the FET gain on the front panel, and I think that is a good way to go. Take a look at the Dumble Block Diagram for the SSS here: https://ampgarage.com/forum/viewtopic.p ... 88#p482188

[bcmatt]

Got any pics of the internals?

Yes, its adapted from the chassis and head cab of an old Traynor YGL-3a. The original build documented here several years ago:
https://ampgarage.com/forum/viewtopic.php?f=4&t=28747

20260609_083333.jpg

20260609_083325.jpg

Why dont you add drive pedals in front?

Well, I am basically forced to all the time... even for a clean tone. Without a pedal, it feels like playing into a clean amp with the guitar volume on 3. Then, basically any pedal set to sound alright ends up being quite a bit louder than the sound of the amp with the pedal turned off. I don't feel like any decent amp should require an "always-on" pedal. Although, ironically, I bought a "Notadumble" pedal when they first came out, thinking it would be a quick way to try a dumble-lator in the loop of this amp. They mixed up the circuits, and it turns out that the pedal is actually the FET input circuit anyways. I have used it a bit, and it is an improvement, but maybe not enough on it's own. That's why I think I will also remove the LNFB circuit as well since some SSS circuits don't use it and clamping down on the gain is the opposite of what I need.... And I need that spot for my FET input... or perhaps the FET will always be in and I will use the input spot for the FET Gain control. Maybe I will try to get a push-pull pot for that.

[GAStan]

I'm not familiar with the MHartman layout so this may or may not apply: my SSS is based on s/n 002, which uses a 5751 for V1. Would a 12ax7 here wake it up?

The FET definitely makes a difference! I can't recall which JFET I use, but I found several threads here on TAG discussing a few different options. I feel that getting it properly biased is as, if not more, important than the exact JFET used. Martin has an EXCELLENT write-up on how to bias these in the files section.

[didit]

Hello Matt --

A few years ago I did a small PCB that captured the FET module for ODS etc with an embedded relay. Before finishing up my testing of the project I was obliged to pack my workshop. It happens that I'm in-process unpacking, and could readily spare a PCB plus a FET or two. It's been my plan all along to share board design for others, once it's verified as correct. I've confidence that you'd be up to helping with some final testing etc.

PM me if this seems of interest and we can discuss details, and arrange logistics to get it your hands.

Best ..

[bcmatt]

I'm not familiar with the MHartman layout so this may or may not apply: my SSS is based on s/n 002, which uses a 5751 for V1. Would a 12ax7 here wake it up?

It already uses all 12ax7s.
I did a bunch of work on this amp just over 2 years ago trying to "get more out of it" and realize that I still have basically the same complaints, so whatever I did wasn't enough... but I did list the changes I had made in one of my last posts there:
https://ampgarage.com/forum/viewtopic.p ... 4&start=30
I also realize that I actually had reinstalled the LNFB at that time because I was hoping it would add a bit of compression.

The FET definitely makes a difference! I can't recall which JFET I use, but I found several threads here on TAG discussing a few different options. I feel that getting it properly biased is as, if not more, important than the exact JFET used. Martin has an EXCELLENT write-up on how to bias these in the files section.

Thanks! I just noticed that thread this morning and plan to use it extensively for getting the FET circuit dialed in. I ordered some of these JFETs with the hope that they will do the trick:
https://www.amazon.ca/dp/B0DCJX8YYX?ref ... asin_title

[bcmatt]

Hello Matt --

A few years ago I did a small PCB that captured the FET module for ODS etc with an embedded relay. Before finishing up my testing of the project I was obliged to pack my workshop. It happens that I'm in-process unpacking, and could readily spare a PCB plus a FET or two. It's been my plan all along to share board design for others, once it's verified as correct. I've confidence that you'd be up to helping with some final testing etc.

PM me if this seems of interest and we can discuss details, and arrange logistics to get it your hands.

Best ..

Cool. I sent you a PM. I'd be happy to try it out.

[bcmatt]

Perhaps this is more appriate as a separate thread, but: Does anyone use a Dumbleator with their SSS?

I know Bonamassa talks about Dumbleators as the key ingredient to bring an ODS alive, but what is the consensus on the SSS?
If it seems worth it, I could maneuver around the whole layout to make use of another 12ax7 hole in the chassis... It would turn it into a much more extensive/invasive mod process, but it could be done if it would bring the right thing to this amp. As it is right now, the amp is way too clean to ever bother even using the current passive FX loop.

[Guy77]

Perhaps this is more appriate as a separate thread, but: Does anyone use a Dumbleator with their SSS?

I know Bonamassa talks about Dumbleators as the key ingredient to bring an ODS alive, but what is the consensus on the SSS?
If it seems worth it, I could maneuver around the whole layout to make use of another 12ax7 hole in the chassis... It would turn it into a much more extensive/invasive mod process, but it could be done if it would bring the right thing to this amp. As it is right now, the amp is way too clean to ever bother even using the current passive FX loop.

A Dumbleator would be a great idea. It can fatten your tone and provide more drive for your clean preamp.
Best part is you can pickup an external one and not have to touch anything in your amp.

It fattened up the tone on one of my D style amps years ago in a good way.

Also if your tone stack capacitor coming out of V1b is a .02 uf you could try increasing it to .05uf.

Cheers
Guy

[award70]

It seems like there might be something wrong with the circuit. With the PAB (do sss have a PAB?) on and the volume at 8 to 9 this amp should punch you in face. What speaker are you using?

[bcmatt]

It seems like there might be something wrong with the circuit. With the PAB (do sss have a PAB?) on and the volume at 8 to 9 this amp should punch you in face. What speaker are you using?

Mine has a PAB. It can get loud very easily. the volume is plenty too much, but it takes everything to max to get any decent grind.
I usually will use it with a 4x12 of Creambacks and ET65s or a 4x12 of Creambacks and Vintage 30s.

[Roe]

... need it to thicken up a bit and get it a little dirtier

lower voltage, decrease NFB (or even filtering), change tubes