PAB comparisons

[10thTx]

I have used the D'Lite PAB schematic shown. It has a fairly significant
jump in volume and overdrive.

I have used Mat's PAB schematic shown & it has a milder jump in volume and overdrive.

I've realized that Mat's PAB is NOT doing the same thing as the #183 & #124 PAB switch ( which I have drawn withOUT the rock/jazz switch).

Am I thinking thru this correctly??

I am also wondering if 22M pretty well isolates a connection?

I notice on the 124/183 PAB that there is actually 44M to the wiper, but I think that would be about the same as no connection at all functionally?

AND can someone confirm that I have drawn the 124/183 PAB correctly
(without the rock/jazz switch), please?

I am using Mat's PAB in an amp currently and think I might rewire this to the #124 & #183 PAB.

With respect, 10thtx

[greiswig]

Resurrecting this thread...because I'm interested in the feedback, too.

In particular, trying to see if the way the D'Lite does it with half of a relay is about the same as the way #183 does it, which sounds nasal and not all that useful to me.

[Luthierwnc]

I could never get any of the treble-to-bass interrupt circuits to be subtle enough. Now I just tie a switchable resistor at the bottom of the Mid pot. Much easier and I like the sound better. Certainly not HAD approved but ...

YMMV, Skip

[heisthl]

Another method you might like:
Tie the Mid and Bass grounds together and lift by 180k for boost.

[greiswig]

Thanks for the suggestions. I have a Glaswerks Zingaro in the house, and I was surprised at how little I care for the PAB as implemented there (it's not Gary's design, it's Dr. D's). But it's a little trickier to experiment on a PCB-based amp.

[rogb]

Thanks for the interesting comparisons.

I am going to try the #124 configuration on my 86 Special over the holidays and see how it compares. If not enough, I might try the Dlite configuration.

I always felt like I could use a touch more PAB. I will see how it sounds and report back

[talbany]

I don't get it..I have done several different methods upon request for others but for me personally I like the standard break the treble bass connection..It's a tad hot sitting in the studio with the amp in my face but out live and in a band setting works like a champ!!

I am also wondering if 22M pretty well isolates a connection?

Pretty much..



Tony

[vibratoking]

In particular, trying to see if the way the D'Lite does it with half of a relay is about the same as the way #183 does it, which sounds nasal and not all that useful to me.

My 183 does not sound nasal at all, but I have 4.7M resistors instead of 22M. It does have a relatively large volume jump and increase in OD.

Another method you might like:
Tie the Mid and Bass grounds together and lift by 180k for boost.

Henry - stock with no PAB, 183 has the mid pot tied directly to ground and the bass pot connected to ground through a 10k resistor. Do you mean tie the mid and bass pots together and connect that node to ground through the 180k resistor when the relay in one position and restore it back to stock in the other relay position? Can you elaborate on the change in sound? Or I can test it and find out for myself.

[heisthl]

Yes leave the 10k and remove it's ground end connection. Tie that to the mid pots ground and then lift that by 180k (more or less according to the volume jump you want).

[angelodp]

H, in that scenario, what happens to the treble #1 connection that was used in the other PAB connection.

[heisthl]

I guess you could have both boosts - the alternate method does not separate the Bass and Treble, it's just a partial stack lift, if you do a full stack lift I think they call it the "MagaBoost".

[Luthierwnc]

Another advantage of the putting the resistor on the bottom of the stack is that it only uses one half of the relay. I tie the resistor from the Mid Pot #1 lug directly to the buss bar and run another wire to the pole on the relay. The NC throw is grounded. You can use the other half of the relay to open the bright cap connection or lift the ground on a LNFB kill switch.

I think it was on a review of a 2nd gen hybrid that the author said there was a resistor lift on either side of of a DPDT panel switch -- one for the mid pot and the other for the bass. That way you could dial in the frequency of the boost. That amp had a stock PAB on the footswitch. sh

[10thTx]

Just tossing out ideas and options for PAB switching. I use this on my Tweed Overdrive Special. When the PAB is switched on, it switches in a tone control after a CF. It gives the amp a different sound and I use this feature quite a bit.

With respect, 10thtx

[da Geezer]

Just tossing out ideas and options for PAB switching. I use this on my Tweed Overdrive Special. When the PAB is switched on, it switches in a tone control after a CF. It gives the amp a different sound and I use this feature quite a bit.

With respect, 10thtx

That should help smooth out the jump to PAB quite a bit.....I like that idea!

G

[angelodp]

Ok I have the version that you were talking about Henry in my Dlite amp. Real nice. Its in my Redplate so my Dlite is ever migrating towards those values.
I did not throw a resistor on the connection to the relay so its a Major boost, but I am creating a small daughter board with a trimmer to dial that it. Much prefer this PAB/boost to the traditional one that breaks the treble to bass.

Thanks guys