Using Multiple Cabs

[Jerry1996x]

Is there a way to use multiple cabs in your standard Preamp+Mac+Cabs setup? Im probably not going to need to, but I just picked up a vintage Bag End cab and was wondering if it was possible, and if so how to set it up.

[mijknahs]

Is there a way to use multiple cabs in your standard Preamp+Mac+Cabs setup? Im probably not going to need to, but I just picked up a vintage Bag End cab and was wondering if it was possible, and if so how to set it up.

Of course it's possible. As long as you can run speaker wires to the Mac you can do it. Or you can run speaker wires from one cab to the other. Just be aware of the ohms.

[Jerry1996x]

How do you do it? If you can only use 1 channel on the Mac, how do you hook up 2 cabs to 1 channel?

[strumminsix]

How do you do it? If you can only use 1 channel on the Mac, how do you hook up 2 cabs to 1 channel?

You'll benefit by googling different ways to hook up speakers, cabinets, how to measure ohms, etc.

In short:
amp expects a load - example is say 4 ohms
speakers have load - most common are 8 or 16
cabinets and load have no direct linkage, it's only the speakers
you wire in parallel load decreases (2 8 ohm speakers = 4 ohms)
you wire in series , load increases ( 2 8 ohm speakers = 16 ohms)

so, if your amp wants 4 ohms you can supply 1 cabinet with 2 8 ohm speakers in parallel or 2 cabinets with 2 16 ohm speakers in it each in parallel in the cab then in parallel to the amp.

[Jerry1996x]

Right, I get that, but im not sure how you would physically hook up 2 cabs to a Mcintosh.

[mijknahs]

Right, I get that, but im not sure how you would physically hook up 2 cabs to a Mcintosh.

It depends on what kind of speaker connections you have or want to use. Let's say you just want to use the screw terminals with the bare wire speaker connectors. You just put the positive wires together and the negative wires together from both speaker cabinets (that would be parallel) and just hook them up to the one channel of the Mac. I suppose that would be a 2 ohm load if both cabinets were 4 ohm each.

There are many ways of connecting the wires to the Mac. I actually modified a couple of my Macs with banana plug inputs (like the WOS Macs) but I had to drill into the chassis. I also have used the bare wires screwed down onto the terminals and also used the right angle banana plug connectors that screw onto the terminals. Like these:


You can double these up so that one is above and one is below on the same terminal screw.

Or you can connect the speaker cabinets together at the cabinet (like when there is a speaker jack plate with 2 jacks) before you connect them to the Mac.

[JonnyBoy]

You can tie multiple speaker wires to one terminal as long as the ohms are correct. Strummin shows how to calculate it there. I did like Jim and tied the 4 ohm tap of a mono mac (1 terminal), to a double female terminal in parallel so I could plug in two speakers into one terminal strip without having speaker wires touching. You really don't want your speaker wires to touch if you can help it! That can short your amp. If you plan on hooking up speakers like that do it as clean as you can at the terminal, IMO. It would work the same to tie all the speaker wires together first then run a single pos/neg wire to the terminal. But, Before you do that, you have to research how to calculate your ohms! the great thing about a mac is you have a 4/ 8 / 16 tap. you shouldn't run the 16 tap for one cab then run the 4 tap for another cab at the same time/same terminal (mc50/mc100), you gotta add your speakers and choose one to pull from. BUT you can run 2 separate cabs with 2 different ohms on a stereo amp with two separate terminals (MC250/mc2100). Hope that didn't confuse you more...Good luck dude!

[Jerry1996x]

Thanks for all the info guys! I think i get what youre sayin. I will use this info wisely, and try not to blow out the windows of my house

[TRG]

You can double these up so that one is above and one is below on the same terminal screw.

I never even thought of that...good to know!

[jenkins]

That's a cool trick mjnaks, double bananna clip adapters one facing up, one facing down.

I have a Q for the OP, Are you against using both channels of your mac forr some reason?
So far for my guitar I've only used one channel, but I'm also only usiing one cab. I've always thought that if I had the need to run multiple cabs I would just use the other channel on the mac to power the second cab. Is there some sort of good reason I wouldn't want to run it that way?
I have a single 1/4" cable to double 1/4" cable that I've still never even used for guitar, but why not run outt of the preamp out tap into the splitting cable into both sides of the mac?
When you split a cable like that do you lose power?

Are there spllitting speaker cables? I have a bannana clip to 1/4" cable that I run from my right angle bannana clip adapters on the back of my mac to my cab (1x12), If this cable was splt to go to two seperate cabs would the power be split between the two cabs as well? That's what I always thought but I really don't know. That's why I figured it would be a better idea to split the preamp out cable into both sides of the mac to run double cabs.

[Rick Turner]

re. speaker connectors for MacIntosh tube amps, for the GD, we used to replace the terminal blocks with an array of banana jacks with one set per channel set in an arc with black for ground as the center and then three colors...I think it was blue, green, and red set for 4, 8, and 16 Ohms. Very convenient for adapting for different impedance loads or number of speaker cabinets, easy to flip phase (equally easy to get wrong if you didn't pay attention...), and even easy to jury rig for weird setups. Yeah, you have to drill the chassis, but those things aren't sacred.