Herbert Ohm question

[BigR]

I Was thinking of hooking up both my Marshall and Bogner 4x12s to my Herbert, and have a question regarding doing it safely. The Bogner is 8ohm, the Marshall 16ohm, so when running both the load on the amp should be 10.67ohm, if I'm figuring it correctly (the resistance of both cabs multiplied, divided by the sum of both cabs). The Mesa Dual Recto manual shows this configuration, with the 8ohm cab hooked up to the 4ohm output, and the 16ohm cab to the 8 ohm output. Would this be the correct and safe way to run both cabs with the Herbert? I assume it would, but before I risk frying the OT on my Herbert, I figured I'd better ask, just in case the info in the Mesa manual isn't applicable to a Diezel.

 

[thegame]

No ! I'm sorry but your math is WAY off Running 16 & 8 ohm cabs at the same time yields 5.3333 ohms. Therefore plug EACH cab into the 4 ohm jacks on the Herbert. This is safe but the 8 ohm cab will be louder.

 

[King Crimson]

Never mix ohms when conecting cabs. You won't be getting the best quality sound and it may in the end hurt a component or worse.

 

[supersonic]

Plug your 16ohm cab to the 8ohm speaker out and your 8ohm cab to the 4ohm speaker out. That's what I do, unless that's wrong?

 

[BigR]

No ! I'm sorry but your math is WAY off Running 16 & 8 ohm cabs at the same time yields 5.3333 ohms. Therefore plug EACH cab into the 4 ohm jacks on the Herbert. This is safe but the 8 ohm cab will be louder.

You're right, my figure was exactly twice what it should have been Dunno how I did that. Had the formula right in front of me too Hit a wrong button on calculator, I guess. Glad I didn't hook anything up without double checking my numbers. Would the 8ohm cab be significantly louder? I was mainly curious to see how the cabs sound together side by side at home, so it may not be worth the trouble if the 8ohm cab will drown out the 16ohm.

Plug your 16ohm cab to the 8ohm speaker out and your 8ohm cab to the 4ohm speaker out. That's what I do, unless that's wrong?

Thats what I was thinking, since the exact same mismatch (16 & 8 ohm cab) is shown in the Mesa DR manual, unless maybe I misread it.

 

[thegame]

The 8 ohm cab will be significantly louder yes. It'll get 2/3 the power the amp is dishing out. In order to compare them, make a stack and put the 16 ohm one on top. That'll balance the volume your ears are getting at least. Running both cabs using 4 ohm outputs is perfectly safe. I would not recommend using multiple ohm jacks simultaneously on any amp.

No ! I'm sorry but your math is WAY off Running 16 & 8 ohm cabs at the same time yields 5.3333 ohms. Therefore plug EACH cab into the 4 ohm jacks on the Herbert. This is safe but the 8 ohm cab will be louder.

You're right, my figure was exactly twice what it should have been Dunno how I did that. Had the formula right in front of me too Hit a wrong button on calculator, I guess. Glad I didn't hook anything up without double checking my numbers. Would the 8ohm cab be significantly louder? I was mainly curious to see how the cabs sound together side by side at home, so it may not be worth the trouble if the 8ohm cab will drown out the 16ohm.

Plug your 16ohm cab to the 8ohm speaker out and your 8ohm cab to the 4ohm speaker out. That's what I do, unless that's wrong?

Thats what I was thinking, since the exact same mismatch (16 & 8 ohm cab) is shown in the Mesa DR manual, unless maybe I misread it.

 

[King Crimson]

Plug your 16ohm cab to the 8ohm speaker out and your 8ohm cab to the 4ohm speaker out. That's what I do, unless that's wrong?

You're actually almost spot-on-the-money there, sup. The only thing that you would need (based on the math) is to round it out with an extra 24ohm cab there, and then you could force your amp to run in tri-stereo, like a 3.14159265358979323846 trinity sound theatre, unless you wanted to take a chain saw and cut the 16ohm cab in two, then you wouldn't need the extra 4.759ohm draw from the amps plate voltage to top it off. Having said that, it would be ideal to just keep the Pignose on site as a backup, in the event of a cable miss-fire, which might cause your strings to inflate, resulting in your pickups levitating thus defeating all gravitational pull, what-so-ever, but this would make down-tuning to 8 octaves down in D root more feasible and practical in this case. I seem to recall that the total energy emitted from your now highly inflated strings is directly proportional to its mass and to the amount of its velocity times itself, but not to exceed the speed of light; otherwise you will be watching the 81’ movie Scanners in the morning – since you will have gone back in time. However, your only listening audience will be very young sperm whales off shore at this juncture. Therefore, the casters mounted to the cab would not be disturbed while drinking ice cold bong water during the break whilst the rest of the knuckle-dragging crew with over sized suits purchased from big-and-tall buckled up for the new water slide event as they exit the van down by the river.

David