#1
And no not the kind that goes with erectile disfunction. Basically my amp head is like 80 watts at 8 ohms, but is 120 watts at 4 ohms. The only output jacks for my cab are 8 ohms coming from the head, and my cab is loaded with 8 ohm speakers. How do I get it to 4 ohms so I can get 120 watts out of it?
#2
Buy a 4 ohm cab, or put 4 ohm speakers in your cab. I'm not sure this will actually get you more volume. What are you doing that 80W into a 4x12 isn't enough volume anyway?
Dunlop Straps™
The best sounding straps on the market


Quote by steven seagull
Justice is this, justice is that...justice is 9 minutes long and recorded in a cupboard full of fluffy pillows
#3
Power = (Current^2)*(Impedance) = (Volt^2)/(Impedance). Power is in watts, Current in amps, Impedance is in ohms and volts is usually 120 V RMS if you live in the US but you have to take in to account if there is a step down transformer, then you need to know the turns ratio for the inductors and M (the magnetic couple coefficient).

That's the engineering answer.
Schecter C-1 Elite
Gretsch 5120
Fender Ultra-Chorus Amp
#4
Quote by Missingno476
Buy a 4 ohm cab, or put 4 ohm speakers in your cab. I'm not sure this will actually get you more volume. What are you doing that 80W into a 4x12 isn't enough volume anyway?

Its 80 watts solid state, and Im gigging with the amp. I need all 120 watts if possible. But I dont have a 4 ohm output on my head. Is it bridge-able or something?
#5
generally you don't... buy 4ohm cabinet.
My Rig:

+Epiphone AJ100 acoustic
+Fender 60th. Anniversary Stratocaster
+Vox AD30VT
+Vox V847a Wah


look all i wanted was for someone to give me advice on what to do not to slag me off ok

Want advice? Suck yourself off.
#6
Are you sure you got the model number right? I couldn't find the RG100ES on the Randall website. It looks like all the RG series amps, though, have both 4 ohm and 8 ohm speaker jacks.
Hi, I'm Peter
#7
It's probably the same jack. I have a Randall RH150G3 and it has two jacks, but they're only if you wanted to do stereo. The total impedance from the speakers still has to be 4 or 8 ohms. You can use one or both jacks.

If you rig up your cab for 4 ohm and plug it into your head you should be fine, and you'll get your 120w.
#8
Quote by Dirk Gently
Are you sure you got the model number right? I couldn't find the RG100ES on the Randall website. It looks like all the RG series amps, though, have both 4 ohm and 8 ohm speaker jacks.


Yeah the model number is right. I wasnt sure about it either, but I emailed the Randall company and got them to give me the owners manual for it. Its a late 80's- mid 90's amp. Its actually really cool.
#9
with 4 8 ohm speakers, they are probably in series-parallel wiring to get an 8 ohm cab. at least, thats how i would do it. now, i cant think of any possibly way to get four 8 ohm speakers to be arranged to get a 4 ohm load.
#10
Quote by LuthierofTexas
And no not the kind that goes with erectile disfunction. Basically my amp head is like 80 watts at 8 ohms, but is 120 watts at 4 ohms. The only output jacks for my cab are 8 ohms coming from the head, and my cab is loaded with 8 ohm speakers. How do I get it to 4 ohms so I can get 120 watts out of it?
You don't. With 4 8-ohm speakers, your choices are 32 ohms, 8 ohms, and 2 ohms.

You could even wire it for 4.8 ohms,
but that's such a horrible idea that I won't even suggest it.
The power would be unevenly distributed between the speakers.
Meadows
Quote by Jackal58
I release my inner liberal every morning when I take a shit.
Quote by SK8RDUDE411
I wont be like those jerks who dedicate their beliefs to logic and reaosn.
#11
Quote by SomeoneYouKnew
You don't. With 4 8-ohm speakers, your choices are 32 ohms, 8 ohms, and 2 ohms.

You could even wire it for 4.8 ohms,
but that's such a horrible idea that I won't even suggest it.
The power would be unevenly distributed between the speakers.


Ha!

Yeah, I was doing the math in my head and didn't see it working out. The good news is that I don't think it will make a great deal of difference volume-wise between the 4 and 8 ohm settings.

I'd suggest LoT find himself a 4 ohm cab and test out the theory. If the speakers in that 4x12 are rated high enough that two of them can handle 120W, you could disconnect two of them and run the other two at 4ohms for a test run.
You Don't Need a halfstack.

You Don't Need 100W.

Quote by jj1565
i love you slats.
#12
Quote by jof1029
with 4 8 ohm speakers, they are probably in series-parallel wiring to get an 8 ohm cab. at least, thats how i would do it. now, i cant think of any possibly way to get four 8 ohm speakers to be arranged to get a 4 ohm load.

Well, if he hooked up 2 8 ohm cabs and the internal wiring to the speaker outputs is parallel, each cab would be treated as 4 ohms. Am I doing that correctly?
Hi, I'm Peter
#13
Quote by Dirk Gently
Well, if he hooked up 2 8 ohm cabs and the internal wiring to the speaker outputs is parallel, each cab would be treated as 4 ohms. Am I doing that correctly?


If he daisy-chained a second 8 ohm cab in parallel, the total load would be 4 ohms.
You Don't Need a halfstack.

You Don't Need 100W.

Quote by jj1565
i love you slats.
#15
^ Cheap, no. Easy, yes.


@ Peter, yes you are.
Meadows
Quote by Jackal58
I release my inner liberal every morning when I take a shit.
Quote by SK8RDUDE411
I wont be like those jerks who dedicate their beliefs to logic and reaosn.