2 vintage cabs on an Ampeg SVT-300

jacksunn · #1 04-08-2011, 03:55 AM

hi people, just joined talkbass today 'cause we have a serious question we hope you can help us out with.
Can anyone tell us how they used to hook up two vintage ampeg 810's with only one input to a 70's SVT-300 with only one output. The ext. speaker-out overrides the main as soon as you use it, so we are very curious.

Also, if anyone can help us to find a manual for the 70's svt-300 amp, your very welcome.
have pictures if needed.

thanx

kosmicwizard · #2 04-08-2011, 04:16 AM

To the best of my knowledge the SVT 300 didn't exist until the 1990's, SLM brought Ampeg back from the grave and created a rack mountable SVT called the SVT II without the pre-amp (I.E. only the power section) this amp is called the SVT 300.

Pictures always help us understand what you are talking about, so posting them would be a good idea, but since I have a SVT II, a 8x10E from 2006 and a 2x15 (with only one input jack) from 2000 sitting right beside me I will tell you how I hook it all up. My SVT II has a bent 1/4 inch output jack so since only one works I hook up a speaker cable from it to the 8x10 that has 3 1/4 inch input jacks and 2 speakon jacks. Then I run a 1/4 cable from the 1/4 input beside the one that has the speaker cable in it already and then put the other end in the 2x15. If each of your cabs only has one input and your power amp only has one output I can't see any way that you would be able to run that power amp at 2 Ohms. All the best! Cheers.

duderasta · #3 04-08-2011, 04:22 AM

make a y-cable?

coreyfyfe · #4 04-08-2011, 05:30 AM

using the extension shouldn't shut off the main out on a vintage SVT. The way the extensions were wired was such that if you plug into that ext. speaker jack you're essentially activating the 2 ohm tap, but you have to have something plugged into the main out as well or it doesn't work. Plug one cab into each and you should be good to go. If that doesn't work, something is up with the wiring in your amp.

jacksunn · #5 04-08-2011, 03:38 PM

Ok, here are some pic's. and sorry it's a 70's SVT head, maybe even from '69, instead of a SVT-300.

jacksunn · #6 04-08-2011, 03:54 PM

Quote:

Originally Posted by coreyfyfe

using the extension shouldn't shut off the main out on a vintage SVT. The way the extensions were wired was such that if you plug into that ext. speaker jack you're essentially activating the 2 ohm tap, but you have to have something plugged into the main out as well or it doesn't work. Plug one cab into each and you should be good to go. If that doesn't work, something is up with the wiring in your amp.

we hooked up two 810's (4ohms each) last week and the one on the main speaker-out just didn't work. Had a technician check out the wiring and found out that it did switch of the main-out. He advised us to find the right manual to begin with.
so if anyone can help us with that, we'll be one step closer.

coreyfyfe · #7 04-08-2011, 05:50 PM

This is the best I know of for a manual for a vintage SVT. It covers all 70s ampeg bass amps. There is a section that mentions the extension speaker output but there isn't much there. Pretty much says what I said, you should be able to just plug the two cabs in and go, that's how it's designed to work anyways.