BE100 HBE Mode Tone

Dave,
Love the BE100. LOVE. I live in the BE mode, and rarely use the HBE. Sometimes when I hit the HBE I want to fiddle with the tone - backing off the treble a bit (I am an Eric Johnson/Allan Holdsworth type - don't roll your eyes!).

This has replaced my Bogner Ecstasy as my main session amp.

What would be the easiest way to add some level of tone control just to the HBE channel?

Thanks,
Ron
PS Just turned on a buddy to the Smallbox combo for gigging and he is ecstatic.

I'm sure Dave will reply but thinking thru that circuit, possibly adding a larger plate bypass cap would knock off some top end just in the HBE mode...

mixn4him":3jvm87mn said:

I'm sure Dave will reply but thinking thru that circuit, possibly adding a larger plate bypass cap would knock off some top end just in the HBE mode...

Click to expand...

Sure, but I would like a small tone knob. Or a micro 3-way (like the bright switch on the clean channel).

Rdodson":2mh09yrl said:

mixn4him":2mh09yrl said:

I'm sure Dave will reply but thinking thru that circuit, possibly adding a larger plate bypass cap would knock off some top end just in the HBE mode...

Click to expand...

Sure, but I would like a small tone knob. Or a micro 3-way (like the bright switch on the clean channel).

Click to expand...

Is this unlike the structure switch that now comes on a BE100?

Rdodson":31iur5mn said:

mixn4him":31iur5mn said:

I'm sure Dave will reply but thinking thru that circuit, possibly adding a larger plate bypass cap would knock off some top end just in the HBE mode...

Click to expand...

Sure, but I would like a small tone knob. Or a micro 3-way (like the bright switch on the clean channel).

Click to expand...

I wouldn't mess with a pot or switch with the plate bypass cap. Too much DC voltage there.

Coming off the plate of the HBE triode, the signal passes through a coupling cap, and then goes through a 1 Meg / 68k to ground voltage divider before hitting the relay for BE/HBE mode.
I would suggest using a switch to add a cap ( or caps ) bypassing the 68k to ground at the voltage divider. The cap to ground will dump high end.
I have no idea what values would give you the desired result, but I would probably start with 500pf and .001uf with center off ( stock ) on a micro switch, and then adjust to taste.
A cap / pot arrangement could also easily be rigged up here to provide a variable high cut, but I like the simplicity of a switch personally. I would be constantly futzing with a pot...
And a switch takes up much less front panel real estate.

fusedbrain":1iwepvz0 said:

Coming off the plate of the HBE triode, the signal passes through a coupling cap, and then goes through a 1 Meg / 68k to ground voltage divider before hitting the relay for BE/HBE mode.
I would suggest using a switch to add a cap ( or caps ) bypassing the 68k to ground at the voltage divider. The cap to ground will dump high end.
I have no idea what values would give you the desired result, but I would probably start with 500pf and .001uf with center off ( stock ) on a micro switch, and then adjust to taste.
A cap / pot arrangement could also easily be rigged up here to provide a variable high cut, but I like the simplicity of a switch personally. I would be constantly futzing with a pot...
And a switch takes up much less front panel real estate.

Click to expand...

I was going to suggest the same thing.

A Low Pass Filter after the coupling cap, so cap to ground bypassing the 68k divider. Given the low value resistor, 500pf cap will provide a 4.7khz roll off and 1nf cap will provide a 2.3khz roll off. You may want to go higher for the desired effect, but it would be easy to experiment.

For me, I actually like the extra brightness of the HBE, but find it absolutely needs a seperate gain control (hence the Deluxe models).

I would like to see if the HBE mode could have it own separate GAIN knob from the BE. It would be cool to be able to have individual gain controls for each mode.

Fret-Shredder":w9ao4b35 said:

I would like to see if the HBE mode could have it own separate GAIN knob from the BE. It would be cool to be able to have individual gain controls for each mode.

Click to expand...

That’s the BE100 Deluxe

kdmay":3tqvc5nm said:

Fret-Shredder":3tqvc5nm said:

I would like to see if the HBE mode could have it own separate GAIN knob from the BE. It would be cool to be able to have individual gain controls for each mode.

Click to expand...

That’s the BE100 Deluxe

Click to expand...

I might ask Dave if he can add that to my BE100

Fret-Shredder":2czyzs0p said:

kdmay":2czyzs0p said:

Fret-Shredder":2czyzs0p said:

I would like to see if the HBE mode could have it own separate GAIN knob from the BE. It would be cool to be able to have individual gain controls for each mode.

Click to expand...

That’s the BE100 Deluxe

Click to expand...

I might ask Dave if he can add that to my BE100

Click to expand...

It’s a very simple mod

kdmay":20iiq3j4 said:

Fret-Shredder":20iiq3j4 said:

kdmay":20iiq3j4 said:

Fret-Shredder":20iiq3j4 said:

I would like to see if the HBE mode could have it own separate GAIN knob from the BE. It would be cool to be able to have individual gain controls for each mode.

Click to expand...

That’s the BE100 Deluxe

Click to expand...

I might ask Dave if he can add that to my BE100

Click to expand...

It’s a very simple mod

Click to expand...

any idea on how its done?

donho":1e8t5duh said:

kdmay":1e8t5duh said:

Fret-Shredder":1e8t5duh said:

kdmay":1e8t5duh said:

Fret-Shredder":1e8t5duh said:

I would like to see if the HBE mode could have it own separate GAIN knob from the BE. It would be cool to be able to have individual gain controls for each mode.

Click to expand...

That’s the BE100 Deluxe

Click to expand...

I might ask Dave if he can add that to my BE100

Click to expand...

It’s a very simple mod

Click to expand...

any idea on how its done?

Click to expand...

Add a relay, another gain pot (after some chassis drilling) and toggle the pot wipers with the relay. Standard process. There will be a slight change in tone, as the 2 pots in parallel provide a different load to the previous gain stage, but nothing worth worrying about. Talk to Dave, he can and has done this on many amps.