1972 Fender Super 6 Reverb - Volume Question

[Jecarroll7]

Hey Folks, I'm looking at a Fender Super 6 Reverb combo with a master volume (not push pull). My first question is why anyone would want a 6 speaker combo, but that's not the OP. This is a 100 watt silverface amp that uses a balance pot. At the balance point I see ~10ma each or ~40ma total. My question is, this amp doesn't seem very loud for a 100 watt amp. My 50 watt '68 bassman will blow its doors off. It gets loud, but not 100 watts loud. Does anyone have experience with this amp?

[Tom Phillips]

10 ma/tube is a pretty cold bias setting. However, the amp should still be very loud. Certainly louder than your 50W if it is working correctly. I'd suspect it to sound a little lifeless though. Do you have the means to measure output power? You could bias it hotter without ditching the balance pot by changing the values of the voltage divider resistors in the bias supply too. Maybe try 20ma per tube. I also suggest that you check the speaker wiring and phasing in case someone has messed with that. Also try it with another speaker cab .

[ReadyTeddy]

Have you checked output power or tried new output tubes? Old output tubes that have gotten tired won't put out full power. Have you run both amps through the same speaker cab so you know that speaker differences aren't the issue (check impedances first)?

[g1]

My first question is why anyone would want a 6 speaker combo

Because it's easier to move around than this?

[Randall]

Why would anyone want this amp? because it's loud, and someone else moves it around. This is the amp the great blues man Albert Collins used. I know from experience. Like an ice pick in the head, it is so loud. But no one got the best of him in a head cutting session, tell you that. Steven Seagal owns that amp, but don't get me started.

[Leo_Gnardo]

Hey Folks, I'm looking at a Fender Super 6 Reverb combo with a master volume (not push pull). My first question is why anyone would want a 6 speaker combo, but that's not the OP. This is a 100 watt silverface amp that uses a balance pot. At the balance point I see ~10ma each or ~40ma total. My question is, this amp doesn't seem very loud for a 100 watt amp. My 50 watt '68 bassman will blow its doors off. It gets loud, but not 100 watts loud. Does anyone have experience with this amp?

Are all the speakers working? Are they all wired correctly - same polarity? Unless/until your speaker array is correct, the amp won't sound its best. And as others have noted, 10 milliamps per 6L6 is mighty cold biasing. Get that up to 25-30 mA each. What I do is put a trimpot + resistor in place of the bias setting resistor at the balance pot, then you can both bias and balance. The best of all worlds.

It's possible your output tubes are just plain worn out too. Even ones that measure OK, when very played out, will sound dull and uninvolving. That you're only drawing 10 mA per tube, looks good for the worn-out tube theory.

Also, it's possible you have one of those naff-tone output setups the late 60's-early 70's Fender CBS engineers worked out, to try and get their amps sounding "hi-fi." Telltale sign - 150 ohm "ant coffin" resistors from each output tube's cathode to ground. If that's what you have, it would make sense to rework the output department to blackface circuit. At this very moment, I'm taking a break from reworking a Super Reverb that had that dreadful circuit.

[Jecarroll7]

Great comments and will follow-up on all suggestions once I return from traveling. Output tubes are new. I did check all speakers for output (noticed 5 of the original 6 speakers have been replaced at some time in its past) but did not check the harness for wiring correctness. Ant coffin resistors has my curiosity up.