Using a bass cab with a guitar combo?

[lostcontrol_]

I recently upgraded my cab to an Ampeg SVT215e (which, paired up with a Genz Benz GBE750, is _awesome_ btw ), so now my old Fender Rumble 4x10 is just gathering dust.

Our guitar player came up with an idea to use the Rumble as an external cab for his Fender Deluxe Reverb (mostly for laughs and testing, I'd assume ), which is a very nice little combo.

Is it possible to damage either piece of equipment with running the Deluxe Reverb into the Rumble? If not, is it even worth the effort, ie. do we even get the elements moving? Even for laughs?

Specs for the Rumble, a 4x10 500w @ 4 Ohm cab:
http://www.fender.com/products/rumbl...prodNo=2347000

Specs for the Deluxe Reverb, a 22w tube amp:
Fender® Products

Thanks!

[T-Bird]

Hi.

Originally Posted by lostcontrol_

Is it possible to damage either piece of equipment with running the Deluxe Reverb into the Rumble?

As long as the impedances match, no.

Originally Posted by lostcontrol_

If not, is it even worth the effort, ie. do we even get the elements moving? Even for laughs?

It may actually sound pretty good if his preferred tone comes from the amp and he doesn't rely on speaker break-up.

Regards
Sam

[lostcontrol_]

Originally Posted by T-Bird

As long as the impedances match, no.

That's the issue, as the impedances don't match. The DR specs tell that the amp has a power handling of 22 Watts into 8 Ohms. The amp has two speaker outs (Internal/External, wired parallel), the onboard speaker is running at 8 Ohms.

If I'm doing my math correctly, the two cabs have a total parallel impedance of 4 Ohm + 8 Ohm = ~2.6 Ohms.

So far Google has given me some contradicting answers, ranging from "go nuts, it'll sound cool" to "oh my god never do that, especially with a tube amp" to "why bother" :P

Edit: For the record, I don't really care that much if there's damage to the Rumble, it's the $1400 amp I'm worried about

[blackba]

A Deluxe Reverb has an 8ohm output as you know. It can run safely at 4ohms. Under 4ohms is not recommended. If you want to try the 410 cab with the Deluxe Reverb, than disconnect the internal speaker and plug the 410 cab into the main speaker output jack and thus the amp will see 4ohms.

As you probably know as well, don't run the Deluxe Reverb without a speaker load connected.

[T-Bird]

Hi.

Originally Posted by lostcontrol_

That's the issue, as the impedances don't match.

If I'm doing my math correctly, the two cabs have a total parallel impedance of 4 Ohm + 8 Ohm = ~2.6 Ohms.


Edit: For the record, I don't really care that much if there's damage to the Rumble, it's the $1400 amp I'm worried about

In that case, I wouldn't do it.

Originally Posted by blackba

A Deluxe Reverb has an 8ohm output as you know. It can run safely at 4ohms.

As "You have tested it for 4Ohm performance, preferably with the said cab, measured the load curve and the operating parameters"

OR

As "that's what they say in the 'net, and everybody knows a tube amp is fine with 100% impedance mismatch".

Is it really worth risking?

Regards
Sam

[basscooker]

i say don't do it unless you have fender literature saying your amp will be fine at 4 ohms. then, the either/or setup of the combo ala carte OR the 4x10 cab, never both, never neither, might sound pretty badass. lots of old tube guitar amps were 4x10, 4x8, 3x12, etc.22 watts thru 4x10 can be pretty loud if he relies on power tube breakup.

[walterw]

fender tube amps are known for being OK with a little impedance mis-match. you lose power, though, whether going higher or lower than what the output transformer wants to see (8Ω in this case)

by "a little", i mean running a 4Ω total load, so the bass cab by itself only.

that said, it would probably not sound that great. big and bassy, yes, but otherwise...

[lostcontrol_]

Thanks for the replies! I think we might try it with just the bass cab and see how it turns out, depending on the guitar player. I'll post an update on how it went (if we try, that is).

[blackba]

Originally Posted by T-Bird

Hi.



In that case, I wouldn't do it.



As "You have tested it for 4Ohm performance, preferably with the said cab, measured the load curve and the operating parameters"

OR

As "that's what they say in the 'net, and everybody knows a tube amp is fine with 100% impedance mismatch".

Is it really worth risking?

Regards
Sam

Not sure why you are busting my chops here. But, I did run occasionally with the Fender Deluxe Reverb where I had into a 4ohm load with no issues. Its also common knownledge on the web that most fenders can tolerate a 100% missmatch either way, there are some exceptions. Fender did include a extension speaker out jack on their DR and most other Blackface models. This means they expected you to run the DR into 8 or 4ohms.

You are correct that there is a risk in miss matching impedance with the output transformer.

I have tried my guitar amps into bass cabs before and not liked the results.