Expansion Cabinet assist

5:25 and 5:50's

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Whale
Bottle Rocket
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Joined: Mon Jun 19, 2017 2:42 pm

Expansion Cabinet assist

Post by Whale » Mon Jun 19, 2017 2:53 pm

I read up on the Express manual and scoured the search results, but I haven't found a definitive answer. I was wondering if someone on the board can help me out.

I have an Express 5:50 Plus combo (1x12). I want to run a 4 ohm expansion cabinet (two 8 ohm speakers running in parallel) along with the 8 ohm combo speaker.

When I hook up the 4 ohm expansion cabinet to either of the 4 ohm speaker jacks along with the combo speaker the tone becomes noticeably darker and bass-ier. From what I've read, this is due to the amp running cooler and not pushing as hard.

"Mis-matching - When running a higher resistance (for example: 8 ohm output into 16 ohm cabinet), a slightly different feel and response may be noticed. A slight mismatch can provide a darker smoother tone with a little less output and attack. This response is a result of the amplifier running a bit cooler. "



Is it possible to connect both a 4 ohm and an 8 ohm load onto the amp at the same time while avoiding the issue of the darker tone?

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Authorized Boogie
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Re: Expansion Cabinet assist

Post by Authorized Boogie » Mon Jun 19, 2017 6:49 pm

Whale wrote:I read up on the Express manual and scoured the search results, but I haven't found a definitive answer. I was wondering if someone on the board can help me out.

I have an Express 5:50 Plus combo (1x12). I want to run a 4 ohm expansion cabinet (two 8 ohm speakers running in parallel) along with the 8 ohm combo speaker.

When I hook up the 4 ohm expansion cabinet to either of the 4 ohm speaker jacks along with the combo speaker the tone becomes noticeably darker and bass-ier. From what I've read, this is due to the amp running cooler and not pushing as hard.

"Mis-matching - When running a higher resistance (for example: 8 ohm output into 16 ohm cabinet), a slightly different feel and response may be noticed. A slight mismatch can provide a darker smoother tone with a little less output and attack. This response is a result of the amplifier running a bit cooler. "



Is it possible to connect both a 4 ohm and an 8 ohm load onto the amp at the same time while avoiding the issue of the darker tone?
You are dropping the amp below the recommended 4 ohm load, and risk damaging your output tubes, followed by output transformer damage. 2.66 ohms is not appropriate for the amp...
MESA/Boogie - Product Specialist/Customer Service - http://www.mesaboogie.com/support/index.html

Krek13
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Joined: Tue Aug 30, 2011 4:35 pm

Re: Expansion Cabinet assist

Post by Krek13 » Thu Jun 22, 2017 8:25 am

LOL you will destroy your amp, don't do that...the two "4 ohm" outputs are for connecting two 8 ohm cabinets/speakers at the same time, for example in stereo setup with two 8 ohm cabs...

If you have two 8 ohm speakers in your cabinet you should wire them separately, each speaker to it's own input jack, and connect them with 2 cables into those two "4 ohm" outputs on the amp...that's how I'm using it because I had two 8 ohm speakers before I bought the mesa...

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