SSS002 build happiness

[talbany]

Thanks Erwin
The Reverb controls are on the back and filters are where the Drive and OD levels were..Reverb driver is in the middle of the chassis down on the input side to help with noise I like your amp better.
BTW..Next time I'll think I'll get a Z mounted power transformer
Tony

[dbharris]

Both clips sound great Erwin and Tony! Thanks for sharing.

-Dan

[rccolgan]

@Richard1001 @erwin_ve (and/or whoever pointed this out originally that I can't seem to comb through and find), I'm sorry I am just coming up to speed on the 100k vs 1M resistor for LNFB (Thank you, @bombacatotal for making sure I see this) I made the updates to my GitHub drawings. I also changed all carbon film resistor values to 4 band color code instead of 5. Lines up nicer to the resistors in your hand now https://github.com/colganr/steel-string ... er/Circuit

[Bombacaototal]

Hi all, I was double checking the 002, as I am planning on doing it, and I think there is a mistake on the filters.

PLease find a "rough" correction (in pink - with erased in black) on the layout and the trace from 001. At least this is my perception...I think the current one is as per Jap Schematic, which looks wrong if you check the other SSS references...

[Bombacaototal]

Additionally, if you look at the 002 gut shot, and where the incoming signal is coming from, you can see that the jap schematic is not correct.

You can also assume where the junction of the .001uF and the 100K are, which would be more in line with the other SSS and my post above

[erwin_ve]

Additionally, if you look at the 002 gut shot, and where the incoming signal is coming from, you can see that the jap schematic is not correct.

You can also assume where the junction of the .001uF and the 100K are, which would be more in line with the other SSS and my post above

Hi Rafael,

I think you're right, I m gonna check this weekend. I ran some simulations on LT spice to see if it alters the frequency response. It does.
Luckily with the pcb you can easily cut the trace as it is on the top layer and hardwire it to the cap.
I'll post my findings.

[martin manning]

What is being proposed as the correct circuit? Just that the 0.001 connects between the 0.01 and the 100k instead of in front of the 0.01?

[erwin_ve]

What is being proposed as the correct circuit? Just that the 0.001 connects between the 0.01 and the 100k instead of in front of the 0.01?

Correct Martin. I talked to Ryan about this for a brief moment. That is the difference between the jap schematic(with lots of errors) and the actual pic were the trace is visible.
Frequency response is mainly a more pronounced mid dip with the correct circuit, depending on the filter setting.
On my pcb thre is a edit possible without lifting the board: red is cut trace, Blue is hardwire.

[martin manning]

I see this change bringing the whole bass side down a bit, a dB or so, something less than half a click on the bass selector? If I had an amp using your board, I don't think I would be too excited about modifying it.

[erwin_ve]

I see this change bringing the whole bass side down a bit, a dB or so, something less than half a click on the bass selector? If I had an amp using your board, I don't think I would be too excited about modifying it.

Just my boards or any? When using a eyeletboard and having the wire under the board that would freak me out; lift the whole board,including all tube pin wiring.

[martin manning]

Maybe I wasn't clear... I think the difference is small enough to ignore, so no need for any surgery.

[erwin_ve]

Maybe I wasn't clear... I think the difference is small enough to ignore, so no need for any surgery.

Did you use LT spice for simulations? Several frequency plots were around 3dB difference, but I'm a novice at LT spice.

[martin manning]

Yes. Looks like the effect is a little stronger if I go back to the original component values instead of using the ones in my revised filter circuit. If you try the mod, I'm interested in what you hear.

[rccolgan]

kind of related, I think Rafael's fix would also need to be applied to the Hartman SSS?

Screen Shot 2021-04-29 at 5.29.39 PM.png

I'm going to try to rework my thru-hole SSS #002 tomorrow if my stay-at-home-astronaut job allows. I can't wait to report back findings! I am attaching my proposed modifications to the thru-hole version for those playing at home. I don't have to lift the board!!! (I think?)

Screen Shot 2021-04-29 at 5.36.22 PM.png

[Bombacaototal]

Hi all, I spotted a couple more mistakes. The cathode cap on the mixer circuit is reversed on Ryans layout. It should be 1uF on the dry path and 5uF on the wet. This is as per Jap schematic and in line with all other SSS amps which always have a fatter/more low end on the reverb side

Second is the LNFB on the reverb driver, the 2.2M should come before the 10K, like other SSS amps and as per Jap Schematic

Both will yied in sonic differences