Can resistor substitute for a speaker to get desired Ohmage

[Emetal]

I tried my amp on friends cab which is 4 Ohms., I REALLY REALLY like the sound, it's much bigger, and has more bass. So just wondering, my cab is 8 Ohms could I use a 4 Ohm resistor in parallel with my cab to get 4 Ohm cab. Will my amp OT notice any difference and how many watts would that 4 Ohms resistor would have to be? (Off course all of this is done by using appropriate designated output jack on the amp. If I use 8 Ohm cab I use 8 Ohms output, 4 Ohm cab = 4 Ohm amp's output jack) EDITED: SORRY I WANTED TO SAY 8 OHM RESISTOR in a parallel with the cab.

[vibratoking]

No, you can't add a 4 Ohm resistor in parallel with your 8 Ohm speaker and end up with a 4 Ohm cab and the good sound you are after....for many reasons.

[xtian]

No, you can't add a 4 Ohm resistor in parallel with your 8 Ohm speaker and end up with a 4 Ohm cab and the good sound you are after....for many reasons.

This was my gut feeling, too, but, aside from reduced power to the speaker, I can't think of why this might damage anything. What are you thinking, Vibratoking?

[Milkmansound]

speaker impedance changes with frequency - a dummy resistor does not. I have never tried it, but my suspicion is that it will not be as effective as simply plugging the 4ohm cabinet into the 8ohm tap of the transformer. You'll lose some power that way, but you also eliminate any risk of starting a fire.

[vibratoking]

4 in parallel with 8 is 2.7 Ohms. As mentioned, the speaker load is reactive, not purely resistive, but the nominal load will be 2.7.

You will waste power in the 4 Ohm resistor. You will have to size it properly, but I wouldn't add it if it were me.

2.7 is low for your transformer taps.

Overall, it's not a good idea on any front.

[Firestorm]

This was a tone question, right? Unless the speakers and cabs are identical except for the impedance, you're chasing the wrong thing. A 4 ohm resistor parallel to an 8 ohm speaker makes a 2.6 ohm cab (sort of), with 2/3 of the output power going to heat up that resistor. The resistor will behave the same way with all frequencies; the speaker won't. So this kind of jerry rig will fundamentally alter the tone. And if the OT isn't really well made, it might commit suicide.

[Emetal]

OK sorry sorry typo, I made a mistake, I meant 8 Ohms resistor in parallel with the cab... I was clumsy did not look what I was typing, was doing something else. So would that work?

[JazzGuitarGimp]

This was a tone question, right? Unless the speakers and cabs are identical except for the impedance, you're chasing the wrong thing.

+1

[Emetal]

Yes identical speakers, V30 Celestions, only his cab adds up to 4 Ohms mine to 8 Ohms... Would not go into details of the cab wood and stuff, simply technically speaking will 8 Ohms in parallel with my cab hurt my amp, will my amp see it as a real 4 Ohm cab, will the sound be close to his 4 Ohms cab?

[Firestorm]

will the sound be close to his 4 Ohms cab?

Not with a parallel resistor, no. You don't have impedance taps on your amp? What kind of cab: 2x12? 4x12? 1x12?

[JazzGuitarGimp]

Assuming your amp is a tube amp, and your intention is to run a 4 ohm load on the amps' 8 ohm output, you could damage the amp. At the very least, it will stress the output tubes and possibly overheat the output transformer. Half of the energy coming out of your amps' output will be diverted to the resistor, which does nothing in and of itself to contribute to the sound, though it may influence what the output stage of the amp is doing. The best way to find out if that is what caused the difference in sound you heard, of course, is to try it and see. You've already run the amp at 4 ohms using the other speaker. If it does sound better, my advice would be (again, assuming an 8 ohm tube amp output) not to use it for anything louder than apartment volume levels for extended periods.

[martin manning]

I believe the speaker load and impedance selector are matched per the first post. There is no reason not to try paralleling an 8 ohm resistor with the 8 ohm speaker and connect it to the 4 ohm tap. The resistor will eat about half if the output power, of course, so the resistor should be rated for at least half of the amp's output power.

[alvarezh]

Get one of these:

http://taweber.powweb.com/store/zmatch.htm

It will alter the tone a bit as you are passing the signal through an additional transformer, but you wont hurt anything.

All the best.

[Emetal]

Tubed amp. Using appropriate output jacks off course... 4 ohm amp's output for 4 Oms cab. 8 for 8 off course.

[JazzGuitarGimp]

My feeling is there is something else going on beyond load impedance. Are the cabs manufactured by the same company, and are they the same model? Do either of them have foam or glass wool batting in them? Are they both closed-back? Ported? Did you try both cabs in the same room, and in the same location in the room?