stereo/mono cabinet

[bobsixpax]

I need help if anyone can tell me where to get a wiring diagram. It is for two (whatever) inch 4 ohm guitar speakers in one cabinet. I need an 8 ohm mono load and 4 ohm stereo load. I need this to be with just one stereo jack and no switch. First, can this be done? second, will it work at higher power like 200 watts? third, if it can't be done is three jacks and a switch the only way? cornfuz'd

[mikebw]

Provided Link: http://www.bcae1.com/spkrmlti.htm


Check out this website- <A HREF="http://www.bcae1.com/spkrmlti.htm">http://www.bcae1.com/spkrmlti.htm</A>

If you have two 4-ohm speakers you can achieve a total 8 ohm impedance by wiring them together in series as shown.

From the website link below:
[In series] "If both of the speakers have an impedance of 4 ohms, the total impedance will be 8 ohms. In a series connection, you simply add the individual impedances. If there were three 4 ohm speakers in series, the total impedance will be 12 ohms. "

It will not be possible to get a total 4-ohm system using two 4-ohm speakers. If you want to use each speaker separately for stereo operation, each one would function as a 4-ohm load.

How many watts your system will work with depends on your amplifier and your speakers particular ratings. If your amp can provide 200 watts at 4 ohms, and your speakers are wired to provide at least that much impedance (and are also rated to handle that much power) then everything is fine.
You can run into problems when the amplifier cannot provide adequate power into low-impedances (less than 4 for example) and when your speakers cannot handle a large amount of power, measured in watts. You would need to lookup the ratings for each device to determine this.

In regards to the input jack(s), if you want to be able to operate these two speakers in stereo, you will have to wire them in parallel. (if they were in series both channels would play through both speakers, negating the stereo effect). So you would need a stereo plug and a stereo jack, wire one + lead to one speaker, the other + lead to the other speaker, and then wire the - lead from both back to the tip of the jack.
This gives you 2 independent 4-ohm loads.

Now you also want to be able to use that in mono, without a switch or separate jack? Let's see- you can insert a mono plug into a stereo jack, the - (GND) tip will match up either way, but the two + connections will be touching the same + lead from the plug. Since the two 4-ohm speakers are already wired in parallel your system load with a mono signal becomes 2 ohms. If your amp can handle that then great, but most cannot.

***I am just speculating here***
I'm pretty sure you will have to have a 2-way switch in order to achieve your impedance and multiphonic goals. If I have thought this out correctly, you would wire the switch in between the two speakers as to create a connection from - on one to the + on the other for Mono operation, and for stereo this link would be broken, and instead the signal would be returned to -.

Maybe this page can answer your questions better-
<A HREF="http://colomar.com/Shavano/2x12wiring.html">http://colomar.com/Shavano/2x12wiring.html</A>

> I need help if anyone can tell me where to
> get a wiring diagram. It is for two
> (whatever) inch 4 ohm guitar speakers in one
> cabinet. I need an 8 ohm mono load and 4 ohm
> stereo load. I need this to be with just one
> stereo jack and no switch. First, can this
> be done? second, will it work at higher
> power like 200 watts? third, if it can't be
> done is three jacks and a switch the only
> way? cornfuz'd

[mikebw]

A Dual-Pole, Dual-Throw (2 position) switch.

From the website (http://colomar.com/Shavano/2x12wiring.html):

The Right channel jack is completely disconnected when in Mono Mode. Do Not alter this configuration (you risk doing serious damage to your power amps if wired differently).

Mouser Electronics Sells 1/4 inch phone jacks that have a built in DPDT switch - the switch contacts are electrically isolated from the 1/4 inch Jack connection (they have to be in order for you to wire this correctly) - Marshall used this type of Jack/Switch to automatically set the speaker selection mode. They are expensive and prone to failure over time, however, using them often simplifies set-up of your rig. If you decide to use these, the Mono/Stereo switch functionality would be associated with the Right channel, where when nothing is plugged into the Right channel, the cabinet is operating in Mono Mode.

WARNING: Never run a Tube Type power amp to the Right channel if the switch is set to Mono mode - it will damage the output transformer.

NOTE: If you want Tweeters or Piezos in this configuration, you will need 2 of them, 1 per Woofer. This is because the speakers can be operated as seperate channels, using 2 completely different power amplifiers. The Tweeters or Piezos will be wired in parallel with the Woofers. The same arrangement as the above Dual Impedance systems.

WARNING: The Left and Right jacks cannot be mounted on the same metal plate (serious damage to some power amps will occur if you do this). Use a seperate jack plate for each channel, mounted on a non-conductive surface