Bright Cap

[Structo]

Anybody ever put a bright cap on the OD volume pot?
I want to brighten it just a bit.

I'm making a list of things to try next time I pull my chassis out and was thinking about this.
I have a 120pf bright cap on the first volume pot but I only like that on clean.

I also have a bright cap on the Master Volume that I might experiment with the value. I think I have a 47pf there now.

I was thinking about trying a 15pf or so on the OD volume pot.
Maybe more since I generally have that at noon or a little past.

Going to try a switched pot for the presence pot as well so I can turn off the NFB.

Anybody have any other mods that work well for them.

This would pertain to the non-HRM ODS amps (100w).

Currently my amp is pretty much to #183 specs, except I have a 6L6 power amp.

[noworrybeefcurry]

I have put a bright cap on the OD volume pot and it seems to work very well, i wouldnt go to big at first though. It is a noticeable difference.

As far as disconnecting the NFB, let us know how that goes. Its something ive been wanting to mess around with.

[Bob-I]

Are you thinking gain pot, or master volume pot?

I like a small cap on the od master, 15 pF is about right. It seems to not only brighten up the od, but it tightens up the bottom end as well. I tried one on the gain pot once and didn't like it. With the gain down below 12:00 is was brittle, above it did almost nothing, I can't remember what value i tried but when i heard it, I just pulled it out.

[gary sanders]

Think Ill try that too.I need an excuse to pull the chassis out of the cab again

[Structo]

Bob, yes I was thinking the OD volume or ratio (master) pot.
Sometimes it's difficult to interpret which control that is, because it has been called so many things.

On my D'lite chassis it is labeled OD Level and on my CE chassis it is called OD Volume.

I think I will start at 15pf and go up.
At the same time I may revisit the 47pf I have on the Master.
I like to run the Preamp Volume and Master Volume at around 1:00 soit may be a futile effort.

Ultimately, a HRM is probably the answer but I am trying to resist that.

It's been a challenge to get this amp tweaked to my likes.
At times aggravating and other times, rewarding.

Without this forum I would never have built the amp in the first place.
So I'm grateful for that.

[vibratoking]

Tom, what exactly are you trying to fix?

I have basically the same architecture that you have. 183 front end with 102/6L6 power section. On mine, the OD has quite a bit of tonal range. I can have plenty of top end with the preamp bright on, no PAB, and no mid boost. It gets progressively darker with mid boost and bright/no bright, no PAB. It is at its brightest with PAB on. I back the guitar volume down with PAB on to balance the volume boost.

BTW, I found the SC mod from bluesdfendermanblues to be very helpful with my Strat. I really like that mod. Gives me back all the Strat sounds, especially the neck position and the in-between quack positions.

I found that I don't like the master bright cap. I also don't like the level of darkness that my Clator brings. I checked the voltages in the Clator, tried different tubes, dropped the 220Kish resistance to 20k. I still find no joy with the Clator. I prefer the amp without it. I know many prefer it.

I tried the LNFB circuit and really found no reason to keep it. It does almost nothing in my amp.

I'd like to hear what you find with the OD bright.

Also, my amp sounds good but it is not what I would call great. It doesn't have the 'magic' that I heard in other D type amps. I have heard amps that have a propensity to feedback in clean and OD mode. Mine does not do that at all.

[Structo]

Heck, I don't know.
Some days it sounds great and other days I feel it lacks articulation in OD.
So I was just trying to put together a list of stuff I want to try next time it's out of the cab.
The OD is just a bit darker than I want right now.

I need to be careful though because if you tweak an amp for low volume bedroom playing it probably won't sound great when cranked up.

It's the old catch 22, where if you get the clean how you want it, then the OD suffers.

By the SC mod from Claus, is that switching the mid cap?
Or bypass cap?
Right now I have a .68uf bypass on CL1 and a 4.7uf on a switch.
So when the switch is off only the .68uf is there, when the switch is thrown it combines the two in parallel for a total of 5.38uf.

Or you can use a larger switch and switch the mid cap as well.

I didn't really care for the OD entrance mod (.05uf or .02uf in series with the 220K then to the 100K trimmer)

I'm trying to keep it simple.

When I first built my D'lator I felt it darkened the tone as well.

What I did was adjust the 220K on the recovery grid. ( the 220K/ 500pf pair)
I went down in resistance to try and preserve the top end.

Then later I did some rewiring and changed out the shielded cable I had in it.
I think the first stuff must have been high capacitance because I was able to go back to the 200K on the recovery grid.