Fuchs casinoline boost... Not PAB?

[Bigwan]

Stumbled on this the other day while investigating low watt power sections. The fuchs 4 aces has a boost that doesn't work like the standard Dumble pab in that the tone stack is still connected. Anyone care to suggest how it's being done? My first thought was switching cathode bypass cap values...

[ampdoc1]

I don't know what Andy is doing, but PAB isn't all or nothing. I've used various tail resistors in some dumble type amps (~70k works well), and even better is a pot, so you can choose the amount of boost you want.

a'doc.

[Bigwan]

Yeah, I know the PAB is good for some people, but one guy that played the d'lite I built wasn't so keen on loosing the stack. Funny you mention the tail resistor - just after I posted this I was looking at a Bluesmaster schematic and noted a switched 72k tail resistor used there. The pot idea is a good one though.

[M Fowler]

I personally don't find any need for a PAB with my style of playing and the amp get's way to bright for my taste with PAB engaged. I would rather build the Dlite or ODS without that option.

[tictac]

This is the way I do my mid-boost; you can dial in mild-boost all the way up to boogie-ville with this circuit... Only need 1/2 a relay to implement too...

TT

[heisthl]

This is the way I do my mid-boost; you can dial in mild-boost all the way up to boogie-ville with this circuit... Only need 1/2 a relay to implement too...

TT

Genius

[ChrisM]

This is the way I do my mid-boost; you can dial in mild-boost all the way up to boogie-ville with this circuit... Only need 1/2 a relay to implement too...

TT

Love this!
How noticeable is the pot when the mid boost is active?

[tictac]

How noticeable is the pot when the mid boost is active?

Not sure exactly what you're asking, the pot is actually a 1M trim pot inside the amp; it's a set it and forget it control but you could put it on the outside of the amp...

I've A/B'd the preamp with and without the mid-boost connected and couldn't detect any audible change in the un-boosted tone of the preamp. The 260k / 1M combo doesn't seem to load the preamp down...

TT