Age old Impedence ?

[kmcguitars]

This has had me wondering for years! And noboby has ever had a straight or
logical answer for me. :smack: Take your basic BF/SF Fender amp 64' to 81'.
(My princeton for example) I have a jack for a 8 ohm speaker and another
for a 8 ohm ext. cab. So if I add another 8 ohm speaker I'll be running a
4 ohm Load. Yes? The OT has no tap for a 4 ohm load. Yes? Doing such
a thing would stress my OT? Yes/no? If yes ... Why did fender design
it like this knowing it would cause a Impedence mismatch? Seems nobody
has complained in 40 years. :laugh2:

 

[Warheart]

Re: Age old Impedence ?

hmmm well if your princeton is anything llike the 5150 combo, heres how it works:
the internal speakers of the 5150 are at 16 ohms, and there is a jack for a 16ohm extension cab. the way it works is that, when you plug a 16 ohm cab(or any ohm cab) in the extension, the head automatically switches to an 8 ohm load(16 & 16 paralled = 8). Therefore you can run the amp 3 ways, in your case:
1. internal speakers at 8 ohms, or a cabinet at 8 ohms plugged into the internal jack,
2. internal speakers at 8 ohms, and an extension cab at 8 ohms, which would make the amp switch to 4 ohms and,
3. only plug a 4 ohm cab into the extension jack, and the amp will switch to 4 anyways.

again, this is the way it works for the 5150 combo, but there are only so many possiblities, so you should check the manual first.

 

[kmcguitars]

Re: Age old Impedence ?

hmmm well if your princeton is anything llike the 5150 combo, .

Nope, Not at all. Your Peavey has to have a multible
tap transformer That internally switches when another jack is pluged in.
This is my point . Even old Marshall's gave you a Impedence selector
switch. Fender gave you the extra AC outlet in the back of the amp
that comes in handy at times. But with Impedence they kinda left ya
hanging. :saeek:

 

[Artie]

Re: Age old Impedence ?

Its also possible that the jack is wired to connect the extension in series rather than parallel.

Deleted the part that might have been a safety concern.