Err... is this a good idea????

[richntiff]

Ok - I found a cable on Ebay and here is the description:

Connects from one amp to two speakers.

This cable is wired in series, and provides many advantages over a parallel cable or standard connections available from speaker and amp jacks alone. Amps and speakers with multiple jacks only provide a parallel wired connection. This series cable will allow your amp to run safer, and turn up more, making the volume more manageable. Amps are not damaged by a larger ohm load, in fact, they are damaged by impedances that are too low.

FIND THE TONE YOU WANT AT A LOWER VOLUME!!

When plugged into two speakers the impedances are added together like this.

4 ohm speaker cabinet + 4 ohm speaker cabinet = 8 ohm load to your amp

or 8+8=16 / 16+16=32

I'm FAR from an expert on amps/ohms/etc - but something about this doesn't seem correct - what says the TB pros about a cable that is wired in series to supposedly be able to run, say, two 4 ohm cabs at 4ohms apiece, 8ohm load to the amp?? Basically the cable is one 1/4" jack with two sets of cable/1/4" jacks - plug the one jack into the amp and one of each of the other jacks into each cab. Seems to me to be a recipe to melt or blow something....

[Primakurtz]

Fear not - series cables and boxes are real, and useful. Rarely for bass, but often useful for guitar tube amps. Two 8 ohm cabs in series equals 16 ohms, which makes many tube amps happy... Whereas 4 ohms makes them very sad.

[B-string]

Originally Posted by Primakurtz

Fear not - series cables and boxes are real, and useful. Rarely for bass, but often useful for guitar tube amps. Two 8 ohm cabs in series equals 16 ohms, which makes many tube amps happy... Whereas 4 ohms makes them very sad.

That is actually backwards. Does hold true for SS amps though.

[Primakurtz]

Sorry if I wasn't clear. Many Marshall heads, for example can run at 8 or 16 ohms, but not 4, or much less 2. SS heads are different kettle of worms.

[richntiff]

Wow thanks! That's good to know. The gears started turning when I saw it - I have a 4 ohm cab and am thinking about adding another (identical) 4 ohm cab to it. The resulting 2 ohm load had me needing to get a 2 ohm capable head right away - I could put that purchase off for awhile though...

[B-string]

Buy 2 cables and three matching cabs. You'll be back to a 4 ohm load and enough speaker area to crack plaster

[SurferJoe46]

Don't bother with those cables.

You'll accidentally plug them into something that doesn't like it. Someday. Accidentally.

Do this instead:::



I had to do that for an old Peavey PA that required 16Ω and all I could find was a pair of 8Ω cabs - so I build this parallel/series box. Cheap.

[tjh]

Originally Posted by B-string

Buy 2 cables and three matching cabs. You'll be back to a 4 ohm load and enough speaker area to crack plaster

... just to clarify .. buy 3 MORE matching cabs (so you have 4 total) ... we are saying the same thing, just clearing up for others than the OP

[Munjibunga]

Originally Posted by richntiff

Wow thanks! That's good to know. The gears started turning when I saw it - I have a 4 ohm cab and am thinking about adding another (identical) 4 ohm cab to it. The resulting 2 ohm load had me needing to get a 2 ohm capable head right away - I could put that purchase off for awhile though...

The only thing is, let's say your (solid state) amp is rated at 500 watts at 4 ohms. When you connect two 4-ohm cabinets to it with a series cable, you're presenting an 8-ohm load to the amp, and it will put out only about 300 watts max. But it will still be louder, in general, than one 4-ohm cab getting all 500 watts.

I've made a couple series cables myself. Here's a couple pics of one, plus a free schematic. For Speakon^® connectors, tip = pin 1+ and ring = pin 1-. Make sure you use Elite cable, too.

[B-string]

Originally Posted by tjh

... just to clarify .. buy 3 MORE matching cabs (so you have 4 total) ... we are saying the same thing, just clearing up for others than the OP

Yep, four 4 ohm cabs + two serial speaker cables = a 4 ohm load and lots of speaker area

[richntiff]

LOL - I think I will stick to two cabs. I understand the reduced wattage at 8 vs 4 ohms too - I still think a more powerful head is in my future (GAS...) but this could be an interim fix. Thanks everyone!!

[Arjank]

I would only run cabinets in series if they are totally the same, else the power distribution is f.....up

[sokolasty]

Originally Posted by Primakurtz

Sorry if I wasn't clear. Many Marshall heads, for example can run at 8 or 16 ohms, but not 4, or much less 2. SS heads are different kettle of worms.

As far as I know, tube amps can work with proper load, i. e. 2 or 4 (Ampeg SVT 2 pro) and you need to select correct load with a switch. Tube amps cannot work with any other load as indicated. You cannot attach a 8ohm cabinet to SVT 2 pro, at least according to manual.

Solid state can work with any load which is not lower as minimum, most commonly 2 or 4. If the minimum load is 4, you can attach 32ohm cabinet (i. e. headphones), 5,33 or 16 or 10 or whatever you want as long as it is not less as 4.

[JimmyM]

You CAN attach an 8 ohm cab to an SVT tube amp and I have done so without incident (only on rentals), but if you're going to be pushing any real volume with one, you can cause early wear and tear on the tubes and output transformer and possibly cause something catastrophic. It works for me because nobody ever lets me crank (nor do I want to), but it's not recommended by any means and will void your warranty if something bad happens.

[Mr. Foxen]

Don't fuss about losing watts, they don't matter nearly as much as people make out.

[Munjibunga]

Originally Posted by SurferJoe46

Don't bother with those cables. You'll accidentally plug them into something that doesn't like it. Someday. Accidentally.

Dunno about that. Someone would have to be awful slow to miss the markings on this one.

Originally Posted by Munjibunga

[richntiff]

I like that cable - I will probably build one just like it, but with 1/4' instead of speakon for the amp side - that will make it even tougher to mess up! Plus, I don't have so much gear that the opportunity will even be there :-)

[Pilgrim]

BEAUTIFUL work, Munji!

[Munjibunga]

Originally Posted by richntiff

I like that cable - I will probably build one just like it, but with 1/4' instead of speakon for the amp side - that will make it even tougher to mess up! Plus, I don't have so much gear that the opportunity will even be there :-)

Here's a picture of the quarter-inch version. I recommend color-coding with shrink tubing. BTW, these are not going to pull apart at the grafts. The cable will break first.

[Munjibunga]

Originally Posted by Pilgrim

BEAUTIFUL work, Munji!

Thanks. I love to solder.