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

[bcmatt]

I don't know if this is ADHD or what, but I have so many side projects going on at once... I built a pine-caster in spare time over the last few weeks. I wanted to move my Palm Bender over to something that I could keep in open tuning (not that I've tuned it that way yet)
It's taken since time with all the making of the body from a pine shelf I took off the wall in our new house, to shaping a nut out of a much too large bone blank, to trying my hand at winding my own pickups...

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It's absorbed too much time that I need for getting the FET added to this amp.
Thanks Didit for the boards! I should be about to take this now.

[bcmatt]

Spent a bunch of time today trying to prep this amp for the FET. I had to make some room. I ended up removing all of the LNFB circuits throughout. I also swapped the second stage cathode to 1k/.68uF like #005

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I'm still not sure how I will mount the FET board, but I swapped out the bright switch to be the FET in/out switch.

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[martin manning]

I'm thinking here:

[bcmatt]

I'm thinking here:

Space-wise it makes sense... But I'm unsure how to mount it. That side wall is also right against the cabinet. This chassis is also very difficult to drill, so it's always tempting to look for pre-existing holes. Is there a mounting method I'm not thinking of that could work?

Although, now that I think about it.. a screw head on the outside of the chassis should just create a little dent into the inside of the cabinet wood when the side cabinet screws are re-tightened... So that could actually work. I was originally assuming it would have to be screws that go through the whole side cab wall.

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[martin manning]

Drill and countersink for flat head screws, with nuts on the inside? Anything protruding on the outside might make sliding the chassis in and out difficult.

[didit]

It’s small and weighs almost nothing. Bit unclear to me what you plan to put into that front panel open hole, but suggest you explore fastening a tiny bracket within that assembly and float the board horizontally above the main fibreboard.

edit to add a detail:this approach would provide a sufficient space for the classic Dumble PCB board, which is a debuggged and documented solution.


Best .. Ian

ps: relieved to see Canada Post delivered.

[dbharris]

You could use something like this if you didn't want to drill a hole. But I would cut off the adhesive part and use rtv to secure it to the chassis.

https://www.amplifiedparts.com/products ... ve-backing

-Dan

[bcmatt]

It’s small and weighs almost nothing. Bit unclear to me what you plan to put into that front panel open hole, but suggest you explore fastening a tiny bracket within that assembly and float the board horizontally above the main fibreboard.

edit to add a detail:this approach would provide a sufficient space for the classic Dumble PCB board, which is a debuggged and documented solution.


Best .. Ian

ps: relieved to see Canada Post delivered.

Hey Ian,
I'll think a bit about the floating horizontal approach using the green board as well...
The chassis hole I cleared out is where I'm planning to put the FET gain control, instead of as a trim-pot on the board.

[bcmatt]

This FET circuit seems to help in a HUGE way!
I populated the PCB from Didit and did the single 9V battery test with the 8.2K resister option. I figure I'm trying to get a bit of compression wherever I can. It is still boosting the signal to the first preamp tube very easily. I dialed it in for about 3.2V to be the 1/3 of the 9.6V battery measurement.

It definitely gets this amp into a useable area for me where it will sound fuller and get closer to the breakup point where it finally gets some compression. I could crank it for full distortion even, but that's not my goal. I just want to get some sustain and compression out of this. It's a much better starting point now that could still take some drives in front of it, but I now consider this a very useable clean tone that will compress a bit when digging in.

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I still want to recheck the voltages now that it's in... and I'm also interested in some form of Dumbleator eventually out of curiosity for this amp... but I'm thinking I may try to build something in pedal form using a subminiature tube... after I build my Hot Cat Preamp pedal using some subminiatures.

[martin manning]

Great! People used to regularly say the FET input didn't sound good, but the problem was generally it wasn't getting biased in the right place.

[didit]

Excellent news for a somewhat nervous PCB CAD jockey ..

[bcmatt]

I'm current it of province on holidays, but I picked this up on my travels that I'm eager to try with my SSS for a 1x12 option:

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I hear alot of love and hate for these so I'm not sure where I will land... But I think it's rather different from my usual choices...