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Discussion in 'Amp Central Station' started by Bikerider20, Oct 23, 2021.
To your ears what fender blackface amp has the tightest bass when played clean and overdriven?
Generally the cleanest/tightest will be the circuit with the smallest coupling cap in the position shown in red on the 5F6A schematic below. (The Blackface versions do not vary in the topology in this part of the circuit so the 5F6A schematic can be used as a demonstration.) The value shown is .02uF. Some of the Blackface schematics go as low as 500pF for this coupling cap. The next determining factor would be the speaker as long as the same power tube type is considered.
Running a large capacitance in the first stage of filtering firms up the low end, ime. In this respect, the Ultralinear Fenders yield the tightest low end. The Ultralinear amps run almost three times the amount of capacitance in that first stage compared to the BF and earlier SF amps. Fwiw, most if not all of the high dollar amps that do high gain run a large capacitance in that first stage in addition to considering coupling caps and preamp tone structures so as to keep the low end articulate when the signal is overdrive. example…
Boogies do the same…Dumbles…Trainwrecks…
As for a Fender with a BF that does cleans and high gain with tight bass, the Pro Sonic is the best, imho. It runs large capacitance in the first stage. https://schematicheaven.net/fenderamps/prosonic.pdf
The Pro .Sonic also displays another aspect of how choices can affect the low end..especially when in overdrive. There are three modes of rectification and biasing choices. The cathode biased/tube rectifier is the loosest in overdrive. The tube rectified/fixed biased has a more control…it is stiffer. The solid state rectified with fixed bias mode has the stiffest response.
If we are strictly in the blackface years the Bandmaster AA763, AB763 and the Bassman AA765 would be my bet.
Good luck with getting the Twin into overdrive.
The Pro Sonic is an amp starting production in 1996.
Yes….none of the amps that I mention were built from the fall of 1963 through March, 1967. In that era, the Showman/Dual showman is the king big clean….or the Normal channel of the TR. I modified a Normal channel in a 964 Dual showman. It has the biggest, tightest low end in overdrive that I have experienced in a BF amp. I have recapped an AB165 BF Bassman that has three gain stages and used 2 x 220mfds in series for the first stage. That amp will hit your chest like a truck…and has that good overdrive that distinguishes that amp from all other BF Fenders….none other will overdrive like an AB165 Bassman, ime. The big first stage makes it punch and stay articulate in the low end.
What’s the image?
The image is of a Twin Reverb.
A Twin or a Super will have bass punch without flub. That is how I would define tight.
Agreed, but the OP also asked about overdriven. Maybe overdrive with a pedal but it will be loud making a twin overdrive.
It's been awhile since I played in front of a crowd of 10,000 or more.
Iron is a factor too, but a flubby speaker can ruin everything. An EV or JBL K series will give you what it receives.
That 1964 Dual Showman I mentioned above was put into a Pro Sonic 2 x 10 cab loaded with two EVI Force speakers.