HEY you speaker-wiring Gurus!!!!

[midnite_man]

Hi Guys and Gals!!!
I just scored a really nice 2 X 12 cabinet from Forum-Brother ericmeyer4, loaded with Celestion V30 8 ohm speakers. Currently they are wired in a "parallel series" configuration for a 4 ohm load. Since I'm not totally versed on "parallel" and "series" configurations, I was hoping someone here could assist me in what I need to do to rewire them in series for 8 ohms? Maybe you have or could throw together an easy diagram to follow and use?
The reason I'm switching 'em back to 8 ohms is due to having another 1 X 12 cab with an 8 ohm speaker that I may use with the 2 X 12 cab from Eric.
I'll be using them mainly with a newly acquired Marshall JCM2000 DSL50 amp, but may be inclined to use the 2 X 12 with my Fender Blues DeVille now and then as well. So going with the 8 ohm wiring would keep everything consistent.
I'd appreciate any thoughts!

....Bob

[aleclee]

Re: HEY you speaker-wiring Gurus!!!!

2x12 or 4x12?

A 2 speaker cab can't be wired series/parallel, it's either series or parallel. You can't rewire a 4 ohm mono cab in 8 ohms mono. Avatar Speakers has a nice page on wiring cabs.

[midnite_man]

Re: HEY you speaker-wiring Gurus!!!!

Okay....I used the link aleclee posted (thanks, 'bro!), and at this moment the 2 - 8 ohm 12" speakers are parallel wired from the jack-socket. This is how it's wired:

Now, does this mean the speakers have to be powered off of a 16 ohm lead from the amp, or a 4 ohm lead? I know the Marshall DSL50 I just bought has output jacks for 4, 8, and 16 ohm impedences
Could I run this cab w/speakers wired this way from my aux. jack in my Blues DeVille 2 X 12 combo without any problems? That'd give me 60 watts powering 4 - 12" speakers. ....Bob

[That90'sGuy]

Re: HEY you speaker-wiring Gurus!!!!

Two 8 ohm speakers wired in parallel, will yield a total output of 4 ohms. If you were to keep the cab this way, you would plug a speaker cable from the 4 ohm cab out to the 4 ohm input on the amp.

As for the Blues Devil, I wouldn't mess with it. I have a 2x12 cab myself, but my stock Fender Vibrolux Reverb sounds great and I'm not sure exactly what it could handle for an extension cabinet, so the safest bet would be to do nothing at all, I don't think you'd be missing much anyways (Fender + V30s? nah )

The idea behind ohms is pretty easy. With a series configuration, you have to go through one load to another before returning to the "source" (aka the output jack) and those loads have resistance, therefore more ohms. Parallel wiring allows two separate routes for the flow of electrons, so there is less resistance.

[midnite_man]

Re: HEY you speaker-wiring Gurus!!!!

Two 8 ohm speakers wired in parallel, will yield a total output of 4 ohms. If you were to keep the cab this way, you would plug a speaker cable from the 4 ohm cab out to the 4 ohm input on the amp.

As for the Blues Devil, I wouldn't mess with it. I have a 2x12 cab myself, but my stock Fender Vibrolux Reverb sounds great and I'm not sure exactly what it could handle for an extension cabinet, so the safest bet would be to do nothing at all, I don't think you'd be missing much anyways (Fender + V30s? nah )

The idea behind ohms is pretty easy. With a series configuration, you have to go through one load to another before returning to the "source" (aka the output jack) and those loads have resistance, therefore more ohms. Parallel wiring allows two separate routes for the flow of electrons, so there is less resistance.

Thanks for that explanation, Chris! That's easy enough for me to understand. If I switched the wiring to series-type, would the 8 ohm speakers have to be driven by a 8 or 16 ohm source? If I leave the wiring as is in the cabinet, I'll just plug in a cable from the cabinet to the 4 ohm speaker output on the DSL50 amp. With less resistance, would that also mean less line noise?
....Bob

[brandobean]

Re: HEY you speaker-wiring Gurus!!!!

You can wire it for series parallel.

I did it with a Carling DPDT Switch. I use it to switch between 4 and 16 Ohms so I can either use 1 2x12 or 2 2x12 cabinets.

I wired it just like the Seymour Duncan Humbucker Series/Parallel switch diagram posted on this site.

Just imagine the + and - wires as the input current to a pickup or in this case, the switch. Just omit the volume and tone knobs.

I was told that the switch does not need to be heavey duty (in my case I opted for the $15 switch because I am a snob).

Often high power amplifiers (home audio) have fused speakers. I was told that this small fuse (looks like a hair in that tube) does not inhibit the sound of the speaker. I cannot vouch for this. I am a bit bewildered by it because I spent all that $$$ on heavy AWG wire.

Post here if you need more help. I will check back. I have done it and it works!

brando

[brandobean]

Re: HEY you speaker-wiring Gurus!!!!

PS. You can also wire the cab with switched jacks (but I recommend against this because you could ground the amps output if someone were to plug into both jacks at once).

That is why I went with the Carling switch.

brando

[flank]

Re: HEY you speaker-wiring Gurus!!!!

you have a 4 ohm load now... wiring them in series would give you 16

[midnite_man]

Re: HEY you speaker-wiring Gurus!!!!

If I was to run the speakers, wired as is, as exterior speakers from my Fender Deluxe Reverb amp which puts out an 8 ohm load to a single 12" speaker in it's cab, would that cause any problems? I would think that if I had the 2 X 12 cab speakers wired in series with a 16 ohm resistance, trying to push an 8 ohm load through them might possibly damage either the speakers or the amp?
Is there something I'm not getting here? Would it be better to unplug the speaker from the amp in the DR and just use the 2 X 12 cab with that amp. I'd like to hear how well 22 watts can drive two 12" speakers, or even three.
Thanks for replying....I just don't want to blow anything up because of ignorance.
....Bob

[brandobean]

Re: HEY you speaker-wiring Gurus!!!!

Is the deville solid state or tube?

If it is tube, insist that you have the correct load or risk blowing an expensive output transformer.

For tube you can go higher in ohmage and the volume of the sound decreases (or the head room will). However you should NEVER go below the recommended ohmage.

For Solid State the rules tend to be less strict, but as a general and safe rule, never UNDER load your amp.

Overloading could make things hot too, but use your brain. If stuff starts getting hot or the Ohms start to exceed 16 Ohms.... it could be an expensive lesson.

brando

[philthis]

Re: HEY you speaker-wiring Gurus!!!!

here is a thought. I got a couple of ADA 2/12 cabs with celestion 30's in each cab. it has a vintage and bright switch on the back of each cab. switched to vintage-makes the speakers clip alot harder-great for 6L6 amps that have alot of gain but need more clip. the bright accents the gain and is slightly louder-great for EL34 amps that have great clip but could use more gain. Ime not sure how to wire this but some where sombody knows and its well worth the effort for the sound and versitility. now those 2 2/12 cabs are all I use. they just sound that good and versitility is awsome.