4 ohm amp in 8 ohm speaker?

[BuddyGuit]

I have a '57 Fender Champ which according to the Fender Amp Field Guide uses a 4 ohm speaker. I'd like to use my DRRI as a cab for the Champ not using the Champ speaker but the Deluxe speaker. The Deluxe speaker is 8 ohms. Will I hurt the Champ if I do this?

[SatelliteAmps]

Nope. Do it all the time. Most Fenders can handle 100 percent mismatches. Enjoy.

[BuddyGuit]

Adam

Thanks for the response. Good news for me. I would hate to have crooked my Champ!

Buddy

[Nolatone Ampworks]

I've always heard that you can feed a HIGHER impedence load, but don't do a lower one. You'll read all sorts of opinions on this. Or friends at Mercury Magnetics say higher is fine. I'd consider that pretty reliable :-)

[mooreamps]

I don't even think running with a lower impedance speaker is really going to hurt it that much. Maybe run the O/T a little warm, depending on just how loud you are playing, but certainly not enough ; IMO ; to burn something up.

[shally]

I've always heard that you can feed a HIGHER impedence load, but don't do a lower one. You'll read all sorts of opinions on this. Or friends at Mercury Magnetics say higher is fine. I'd consider that pretty reliable :-)


same basic thing i was told by my amp guru, jim N, at little dawg amps..

i trust his opinion completely..

[MikeNiteRail]

I have a Vibro Champ...Is there a way I could run the amp's 4ohm speaker with a 4ohm 2x10 cab at the same time??? I suppose it would be an 8ohm load. Is there something I can plug the 2x10 and 1x8 cab into to make one input for the amp?

Or would I have to mod the amp? If so, what would I do and how easy would it be to return to stock in the future?

[Adwex]

I have a Vibro Champ...Is there a way I could run the amp's 4ohm speaker with a 4ohm 2x10 cab at the same time??? I suppose it would be an 8ohm load. Is there something I can plug the 2x10 and 1x8 cab into to make one input for the amp?

Or would I have to mod the amp? If so, what would I do and how easy would it be to return to stock in the future?
Two 4 ohm speakers will be an 8 ohm load only if they are wired in series. If they are wired in parallel, you got a 2 ohm load.

[MikeNiteRail]

I would use a cab wired for 4ohm in series with the 4ohm VC speaker....however, I need something that let's me plug the two together in series and then into the amp. Thoughts? Ideas?

I suppose I could use a different transformer, but that'd mean modding the amp.

[MikeNiteRail]

Could the input of the vibrato pedal be modded to take an extension speaker in series???

[SatelliteAmps]

Yes it could be wired that way.

[RedMan]

It will sound really different with the impedance mismatch. You may or may not like it.

[TopBooster]

I've always heard that you can feed a HIGHER impedence load, but don't do a lower one. You'll read all sorts of opinions on this. Or friends at Mercury Magnetics say higher is fine. I'd consider that pretty reliable :-)

It's not a matter of opinion. With tube amplifiers, it's a fact that feeding a higher load than expected is WORSE for the OT than running a lower load than expected (by the OT). I don't have the time to cover it now, but do a search on "flyback voltages." I remember reading a good post from John Phillips discussing the matter in detail.

Could the input of the vibrato pedal be modded to take an extension speaker in series???

I think you should wire it in parallel, so your load decreases when you add the external cab.

[adamzappa]

Running a Champ into an 8 ohm speaker wont hurt the amp. You will lose power though, 3.5 watts is a bit short to start with so you decide. Running an amp into a speaker load smaller than what the amp wants to see will hurt your amp. Power tubes will wear out and you could burn out your output transformer.

[TopBooster]

Running an amp into a speaker load smaller than what the amp wants to see will hurt your amp.

You don't specify what type of amp in this blanket statement. If you mean a tube amp, you have it wrong. I suggest you do a search for "flyback voltage" as well. This topic has been covered so many times. Power tubes do indeed wear out more quickly when running a lower impedance load than expected by the OT, but it's when running higher impedances than expected by the OT that you put the OT's insulation at risk.

[BuddyGuit]

All I want to do is drive an Eminence Canibus Rex (8 ohms) housed in a Fender Deluxe Reissue with my '57 narrow panel Fender Champ (w/o using the Champ speaker). SatelliteAmp says it'll work fine. You other guys are over my head :confused:

I'm a professional musician who doesn't know the ins and outs of amp workings. You guys are speaking a language I don't understand ...... kinda wish I did but .... :o

[TopBooster]

You should be fine as Satellite said. ±100% mismatch is usually OK. I was just being picky about some statements I read in this thread... It's when you go outside of the ±100% window that you can run into the trouble I was talking about.

[SatelliteAmps]

People worry about this with good reason. Some amps are very susceptible to overheating output transformers. Your Champ will be fine. I've got a number of small Fender amps that are running 8 ohm speakers in similar situations. One of my favorite vintage style Jensens only came in 8 ohms. It sounds amazing. I've got a 1962 Tweed Champ with this mismatch. It's had the same tubes for almost 8 years now. It's been on over a dozen records, it's been run for 12 hours at a time for days on end. It still sound amazing.

While flyback voltages are a real possibility, they are a rarity and have generally been overhyped on the internet. That doesn't mean it can't happen, just that it really only happens in a few amps, and within certain scenarios. For instance, some British amps are notorious for popping output transformers.

You can wire the jack to have a parallel or series output, whichever serves your purpose best.

[booj]

Awesome setup! How about a switchable connector box? I can build you a box which will allow you to run both speakers in series, as well as either speaker. If that interests you, you're welcome to email me.

[SatelliteAmps]

Be careful if you are hot switching speaker loads. If you are talking about wiring an A/B Both box to act as a speaker switcher, there will be a moment of time when there is no load on the amplifier. That could cause damage to an output transformer pretty easily.

Or are you talking about some other kind of switchable box?