SSS002 build happiness

[Richard1001]

So i had a day off today and decided to leave LT spice and breadboard the filters to find out more about the sound of different wirings. With an output buffer with flat frequency responce i wired it to the effectloop of an other amp. (ODS clone) I recorded the different wirings to analyse later.

What i noticed was that the 0.01 and 0.001 caps in series sound smoother than in parallel, but there is less mid. It sounds good but a little bit scooped.
When i leave the caps in series but wire the 470k resistor to the junction of both caps (the other side of the 0.001 cap) the mid frequency's return while the smoothness stays. Without the 470k resistor the mid is also back, but the highs are somewhat harsh.

I also bypassed the inductor to see what the effect would be. I could not hear any difference for the bass response but when removed (shorted) the highs also get some kind of ice picky harshness. (All sound tests are with overdrive)

Looking back at the spectrum of the recorded tracks it occured to me that in the end, the guitarspeaker is what makes the filters / amp work and sound like they do. Sure the output of the filters show a much higher level of high frequency's than low frequency. This may appear unbalanced, but when it goes through the guitar speaker, this brings the balance back. This is the 2400p cap selected with overdrive engaged and the bass filter up 3 clicks:

1620936758295-533993394.jpg

The only thing i now wonder is if perhaps the japanese schematic has the 470k resistor drawn wrong too. Could it be attached to the input side of the 0.001 cap instead?
It would be more consistent with the way the Ceriatone SSS is wired. I mean: If the 470k was suppose to be wired to the output of the 0.001 cap, why leave it in when that cap is no longer there?

Japanese schematic:

20210512_183934.jpg

Alternative wiring of the 470k resistor:

20210512_183940.jpg

Ceriatone wiring:

20210512_183945.jpg

Do any of you have any thoughts on this?
(Or perhaps a higher resolution gutshot photo? )

[martin manning]

I also bypassed the inductor to see what the effect would be. I could not hear any difference for the bass response but when removed (shorted) the highs also get some kind of ice picky harshness. (All sound tests are with overdrive)

Here's a plot showing the effect of a 300mH, 400Ω DCR inductor (Triad SP-118) in the filter circuit (input caps in series), with low and high switches at mid position (high cap is 1n). The Green trace shows the result with the inductor out of the circuit, which is a ~2dB reduction at very high frequencies, and no significant effect In the audible range. (edit: over-simplified sanity check comment deleted. No change to the result below.) L and C can produce a resonance peak, but nothing shows up here.

[Richard1001]

Thanks Martin, this is realy helpfull!

[martin manning]

Sure. Just remember, "All models are wrong, some are useful."

[Max]

Japanese schematic:

20210512_183934.jpg

Original Japanese schematic:

SSS002japschem.png

Why is the 6PS-S10 not in the same position in the two drawings?

Best regards,

Max

[Richard1001]

Japanese schematic:


20210512_183934.jpg

Original Japanese schematic:


SSS002japschem.png


Why is the 6PS-S10 not in the same position in the two drawings?

Best regards,

Max

Because the gutshot picture seems to show the 0.001 cap is in series with the 0.01 cap. This suggests a mistake in the Japanse schematic. (Like there are Many) So i wanted to see what the difference in tone would be and how the wiring of the 470k would affect the tone.

[Max]

I understand. Thanks for the explanation.

[Richard1001]

After exploring all possibilities and based on the gutshotpicture i do believe both caps on the input of the filter should be in parallel. I can even see the trace going under the kathode resistor and cap.

Further i did see an eylet / solderingpoint on the driverboard next to the 270 ohm resistor. I marked the spot on the gutshotpicture. There even looks to be a wire connected, although the picture is to blurry to realy tell. But there is something soldered there.

So i took out the unusable 1nF brightcap and made the mid accent switch with 1uF over the 270 ohm resistor. (After comparing different values)
It sounds very nice and i think this is how it was wired. With a orange 1uF electrolytic mounted on the switch. (And if not, this is how it should have been wired imo. )

SSS002 v1b wiring and mid accent.png

[erwin_ve]

Further i did see an eylet / solderingpoint on the driverboard next to the 270 ohm resistor. I marked the spot on the gutshotpicture. There even looks to be a wire connected, although the picture is to blurry to realy tell. But there is something soldered there.

So i took out the unusable 1nF brightcap and made the mid accent switch with 1uF over the 270 ohm resistor. (After comparing different values)
It sounds very nice and i think this is how it was wired. With a orange 1uF electrolytic mounted on the switch. (And if not, this is how it should have been wired imo. )
SSS002 v1b wiring and mid accent.png

So a presence cap wired like a 3rd gen with a accent switch? I like that. I will do that in my amp

[timrobertson100]

I’m not enjoying that bright switch, so will do too. Did you use the preamp ground for the other side of the cap please?

[Richard1001]

It depends on the way you wired your grounds. I have the driver board grounded at the effect return so i wired the caps ground there also.

[rccolgan]

Further i did see an eylet / solderingpoint on the driverboard next to the 270 ohm resistor. I marked the spot on the gutshotpicture. There even looks to be a wire connected, although the picture is to blurry to realy tell. But there is something soldered there.

So i took out the unusable 1nF brightcap and made the mid accent switch with 1uF over the 270 ohm resistor. (After comparing different values)
It sounds very nice and i think this is how it was wired. With a orange 1uF electrolytic mounted on the switch. (And if not, this is how it should have been wired imo. )
SSS002 v1b wiring and mid accent.png

So a presence cap wired like a 3rd gen with a accent switch? I like that. I will do that in my amp

This makes a lot of sense now. I never, ever bonded with the mid accent. So hissy and crude the way it was per the schematic. My only concern is how a tech can mistaken a .001uf orange drop with a 1uf electrolytic? I guess they are both orange and roughly the same size... ? I will update the drawings and try out my own. I believe Dumbleland is likely the same here

[rccolgan]

Latest diagram with these revisions uploaded here. (Static links and will always be the latest revisions as I make changes which is cool)

PDF: https://github.com/colganr/steel-string ... Layout.pdf

PNG: https://github.com/colganr/steel-string ... Layout.png

[erwin_ve]

Wired the "mid" slide switch as Richard did: Much better and very useable. Switching the slider in the "on" position result in more high and mid. I can see on a low volume stage this is very useable.
Thanks Richard!

[rccolgan]

Wired the "mid" slide switch as Richard did: Much better and very useable. Switching the slider in the "on" position result in more high and mid. I can see on a low volume stage this is very useable.
Thanks Richard!

Same here. Very nice. I found it worked really well with the jazz (mic) and darker tones from the high cut filter. I used 1uf value