Sherwood is very bright

[slowpogo]

I built the Sherwood and it seems to work great, except I have to turn Treble all the way down, and Bass up a decent amount, to approximate a "transparent" tone. I owned a real Westwood and it definitely wasn't like that with my gear, so something is up. Sounds really good though apart from this issue.

All my values are correct afaik. Anything I should check, or any simple mods to tame the brightness?

 

[slowpogo]

Never mind, found some old threads on this issue. My bad

Sherwood EQ

I'd like to play around with some mods to the EQ section of the Sherwood, but I'm not sure what's going on there. Could anyone point me to someplace that explains that particular circuit and how to calculate the affected frequencies?

forum.pedalpcb.com

Sherwood Drive - How to add more low end?

I built a Sherwood Drive a few months back and found the overall tone to be kind of shrill and treble-heavy. No matter how I adjust the bass and treble knobs, I can't dial the treble-heavy tone out of the pedal. I tried a couple different OpAmps but that really only changed the granularity or...

forum.pedalpcb.com

 

[Robert]

That Treble pot connection has haunted me for years...

I'd like to think I would have double (or triple) checked that VREF connection on lug 1, because it's not the typical arrangement and certainly would have caught my eye..... but.... the doubt just bugs the hell out of me.

There's only one way to know for sure... Anyone have an original Westwood? (Incoming)
If not I'll just have to pick up another one. (I did)

 

[jesuscrisp]

The "gyrators" on that one generally just look all wrong.

 

[slowpogo]

For what it's worth, all the other versions I can find also seem to connect Treble 1 to VREF. Of course, hard to know if they were traced independently, or just copied yours

https://pcbguitarmania.com/wp-content/uploads/2020/11/Forestal-Device-Building-docs.pdf

Earthquaker Devices Westwood Overdrive

dirtboxlayouts.blogspot.com

Earthquaker Devices Westwood

For the blog's 600th layout, here's a new one that didn't take long to get traced. Here's EQD's newest offering, the Westwood Translucent Dr...

effectslayouts.blogspot.com

 

[Robert]

... let's find out, shall we?

 

[jesuscrisp]

That Treble pot connection has haunted me for years...

I'd like to think I would have double (or triple) checked that VREF connection on lug 1, because it's not the typical arrangement and certainly would have caught my eye..... but.... the doubt just bugs the hell out of me.

There's only one way to know for sure... Anyone have an original Westwood? (Incoming)
If not I'll just have to pick up another one. (I did)

So it's actually correct?

 

[Robert]

So it's actually correct?

This wasn't a simple open and shut case, unfortunately.

This is a newer revision of the pedal and there are some changes compared to the older through-hole version.

The Treble/Bass pots are connected as we suspected they should be, but there are enough changes that I can't definitively say that the Sherwood was incorrect. I have an updated prototype on the way.

 

[jesuscrisp]

Huh... That's... Something.

The "gyrators" on that one always made my brain hurt and everyone who I know built a clone complained about it's brightness.
Curious to see the new version!

 

[Feral Feline]

+1 Curious to see the new version, and wondering whether I'll want/be-able-to mod my existing as-yet-unbuilt Sherwood to the new spec.

 

[slowpogo]

+1 Curious to see the new version, and wondering whether I'll want/be-able-to mod my existing as-yet-unbuilt Sherwood to the new spec.

Same, having just built the Sherwood I'm hoping it's a situation where we can just cut some traces and run jumpers

 

[jesuscrisp]

Same, having just built the Sherwood I'm hoping it's a situation where we can just cut some traces and run jumpers

You COULD try to disconnect lug 1 of the treble pot from the PCB and run a wire to lug 1 of the bass pot, that probably does a lot already. Otherwise try adding a small-ish value cap in parallel to R17 (graft it onto the same pads, gives you a lowpass filter in conjunction with R9 to tame the treble before the gyrator stage).

There is a whole lot of questionable design decisions, including the topology of the gyrators, which look all wrong to me, but I don't know if I'm Chuck D. Bones enough to make a thread about what to change to have it make sense.

 

[slowpogo]

You COULD try to disconnect lug 1 of the treble pot from the PCB and run a wire to lug 1 of the bass pot, that probably does a lot already.

I finally tried this and it does the trick. But be warned, R13 connects to VREF through the Treble 1 pad. Which means if you entirely unsolder the Treble 1 leg, you will need to run a wire from R13 to R16 to restore VREF connectivity.

(I learned this because I initially thought I could get away with just scraping the visible trace between Treble 1 and R16, however, after this Treble 1 was still connected to R13/VREF through a hidden trace)

After I did that, it works exactly as I remember, Treble at noon is indeed neutral.