Fender Bassman 500 speaker question??

[Paul O'Bryan]

I'm looking at a Fender Bassman 500 head.Obviously a reissue of
an old Bassman with 2 tubes and modern technology for the rest. My question is,
on the 2 speaker output panel it says , parallel speaker outputs 4 ohm minimum total.
Does this mean that I can run 2 x 4 ohm speaker cabs from this head ??

[Fred]

Two 4 ohm cabinets in parallel will be a 2 ohm load. So, no, not a good a idea.

[Paul O'Bryan]

That's what I thought Fred, but apparently you can run 2 x 4 ohm cabs
from the all tube vintage Bassman heads so I just thought they may have made these
reissues the same

[J Fletcher]

From the owner's manual .

"The power rating of the external cabinets should meet or exceed the rating listed on the amplifier.
The MINIMUM impedance of all
connected speaker cabinets is 4Ω ."

[Paul O'Bryan]

So that means It can be done does it J ?

[J Fletcher]

You can only use one 4 ohm cabinet at a time . Total speaker impedance should not be less than 4 ohms . Two 4 ohm speakers connected would be 2 ohms . You could connect them in series though , for an 8 ohm load , which would be safe , though you wouldn't get the full power output this way . Probably wouldn't notice the missing power .

[Paul O'Bryan]

Yeah okay just use one of the speaker outputs and run two speakers.
Thanks J

[Fred]

Yeah okay just use one of the speaker outputs and run two speakers.
Thanks J

Just make sure the speakers are connected in series for 8 ohms. If you run them in parallel into a single output jack it’s the same as using both jacks. In other words the two output jacks are already wired in parallel. Electrically they are the same output.

[Godfrey Arthur]

Unless you're planning on putting a cabinet on two ends of a stage, you would be better off just using one cabinet @ 4 ohms.

Are the two cabinets set up to run "SERIES" into each other? If not you'll be getting the same connection as connecting two 4 ohm speakers to the back of your 500 head.

Here's a simple diagram.

[Paul O'Bryan]

I have two separate speaker cabs with a 4 ohm 15"
speaker in each. So I was hoping to plug one into the right and one into the left
output on the 500

[Fred]

There's only one output with two jacks connected to it.

[Godfrey Arthur]

I have two separate speaker cabs with a 4 ohm 15"
speaker in each. So I was hoping to plug one into the right and one into the left
output on the 500

Not going to happen as per the minimum requirements of the amp. Running 2x4 ohm speakers in parallel will create a TWO OHM LOAD. Amp will be on speed at that impedance.

Also with more than one speaker you'll get "bouncing" reflections, and unless the two cabs are equidistant from your ears (like headphones) you won't hear the two cabs as one pulsing unit. If the two 15's" are not matched you're looking at different sonics from each jumping all over the place. It will be a see-saw effect, certain frequencies coming out of one on a single note of your guitar and not in the other, to be critical.

That's why I asked if you really need two cabs or are you thinking that two cabs means twice the volume?

It doesn't work that way.

You will notice more volume out of single 15 at 4 ohms assuming that the single 15 can handle that much wattage which is 500 watts into 4 ohms or 350 watts into 8 ohms.

Photo below is from the Fender 500 factory manual.


The only way to properly use two cabs is that your 15's are 8 ohms each then you'll get FOUR out of two EIGHTS in parallel as the amp speaker outs are wired.

IMO you'll get better power/sonics out of a single 4 ohm 15. Choose which cab sounds best to you out of the pair. This way the amp provides the power and response.

Also do take note of the IMPORTANT NOTE speaker specs as the 500 has a bridged mode and can use Speakon type speaker connectors in addition to the usual 1/4" phone plug.



Speakon speaker connectors

[Paul O'Bryan]

I have learnt a lot from every reply.
That's what I love about this forum is that there is so much knowledge out there
and that you only have to ask!
Appreciate it guys,
Thank you