Running Mesa/Boogie Bass 400 at 2 ohms

[HeavyAxe]

Hey! I have a Mesa/Boogie Bass 400. It is an earlier model and does not have 2 ohm taps. Only 4 and 8, three of each. I've heard of some people running the 400 at 2 ohms despite the lack of 2 ohm taps. I'm just curious to hear if anyone has done this. Results? Sound? If it has worked, how would you connect two 4 ohm cabs?
Thanks

 

[Chris 'Wighat' Jordan]

Exactly which cabs are you considering doing this with?

 

[HeavyAxe]

Exactly which cabs are you considering doing this with?

Well, currently I only have a Mesa/Boogie Diesel 2x15 with EV's. The cab is rated at 4 ohms. I'd probably be looking into two 4 ohm 4x10s if I was going to run it at 2 ohms, likely Traynor or some other brand I could get 4 ohm 4x10s from.

 

[HeavyAxe]

Unless I found a second 4 ohm Diesel 2x15 that is.

 

[Chris 'Wighat' Jordan]

Opinions vary on how big a deal running a tube amp into an improper impedance is. I won't do it with any of mine. And I don't see why you need to:

If your looking to buy a couple of 410's, why not just get 8 ohm models? Or a 4 ohm 810? Or use a series speaker cable with two 4 ohm cabinets (like another Diesel 215) so you can use your Mesa's 8 ohm tap.

 

[HeavyAxe]

Opinions vary on how big a deal running a tube amp into an improper impedance is. I won't do it with any of mine. And I don't see why you need to:

If your looking to buy a couple of 410's, why not just get 8 ohm models? Or a 4 ohm 810? Or use a series speaker cable with two 4 ohm cabinets (like another Diesel 215) so you can use your Mesa's 8 ohm tap.

It's just that I have other heads that would benefit from two 4 ohm cabs but I'm not made of money so I can't buy multiple rigs. I'm just curious if 2 ohm operation would possibly work.

 

[Shaunpski]

I'd suggest just calling Mesa. I have a 28 year old Mesa guitar combo and have talked to their techs as well as sent mine back for work/updating. Customer service was outstanding at every turn. I'm sure they will not lead you astray. Good luck!

 

[Chris 'Wighat' Jordan]

It's just that I have other heads that would benefit from two 4 ohm cabs but I'm not made of money so I can't buy multiple rigs. I'm just curious if 2 ohm operation would possibly work.

Yeah, so here's the way to go: get a second Diesel 215 (or whatever two 4-ohm cabs you like). Use the series cable with the Mesa 400 and just run the cabs parallel (regular cords) with your 2-ohm-capable amps.

 

[Mickeyb48]

If the amp isn't designed for the two ohm load, you can easily go into thermal overloads, causing distortion, and possible shut downs until it cools off. Most professional Sound touring companies run at 4 or 8 ohm loads that was designed for their particular amps. If your looking for more power, go for another amp, and speaker cabinet, by adding another 215 on a two ohm load you may only notice a gain of 3db.

 

[Ender_rpm]

Hey! I have a Mesa/Boogie Bass 400. It is an earlier model and does not have 2 ohm taps. Only 4 and 8, three of each. I've heard of some people running the 400 at 2 ohms despite the lack of 2 ohm taps. I'm just curious to hear if anyone has done this. Results? Sound? If it has worked, how would you connect two 4 ohm cabs?
Thanks

If it has 3x 4 ohm taps, it seems like it is in fact built to run at 2ohms (using 2x4ohm taps simultaneously) or lower.

But after reading the 400+ manual, I am not so sure.

Try the guy in this thread to get the manual?

Mesa Boogie 400 (NOT 400+) - anybody got a manual? | TalkBass.com

 

[jeff62]

I had a later model 400 (non-plus) that had 2-ohm taps, separate from the 4 and 8-ohm taps. If yours doesn't specifically have 2-ohm taps my advice would be to avoid it for all the obvious reasons already stated.

 

[BassmanPaul]

If the amp isn't designed for the two ohm load, you can easily go into thermal overloads, causing distortion, and possible shut downs until it cools off.

The OP isn't running a SS amplifier. Running a 2Ω load isn't advisable BUT if you must, run it from the 4Ω tap. You'll stress your tubes more shortening their life span but nothing should blow.

 

[Chef]

http://www.mesaboogie.com/media/User Manuals/Bass 400 Plus.pdf

 

[HeavyAxe]

Sounds like I should just find a power/slave amp to run a second 4 ohm can with.

 

[Chris 'Wighat' Jordan]

If it has 3x 4 ohm taps, it seems like it is in fact built to run at 2ohms (using 2x4ohm taps simultaneously) or lower.

This is incorrect and not how tube amps work.

 

[Chris 'Wighat' Jordan]

Sounds like I should just find a power/slave amp to run a second 4 ohm can with.

Why? And lose the all-tube tone and feel that is the very reason to use this amp to begin with? The series cable is such a simple solution....is that suggestion falling on deaf ears?

 

[Ender_rpm]

This is incorrect and not how tube amps work.

I'd amend that to say "not how MESA tube amps work". My EBS works like this, but now that you've pointed it out, my Rectoverb does not.

 

[Omega Monkey]

If it has 3x 4 ohm taps, it seems like it is in fact built to run at 2ohms (using 2x4ohm taps simultaneously) or lower.

I'm not sure, but I imagine that's so you can use up to 3 cabs that combined equate to 4ohms or higher (ie 3 12 or 16ohm cabs, which would be pretty rare in the bass world, but would allow you to run 3 series "chains" of 2 8 ohm cabs in series times 3 for 6 cabs total). NOT 3 times 4 ohm cabs (or chains), which would go way beyond the norms of MI amp design.

 

[Ender_rpm]

I'm not sure, but I imagine that's so you can use up to 3 cabs that combined equate to 4ohms or higher (ie 3 12 or 16ohm cabs, which would be pretty rare in the bass world, but would allow you to run 3 series "chains" of 2 8 ohm cabs in series times 3 for 6 cabs total). NOT 3 times 4 ohm cabs (or chains), which would go way beyond the norms of MI amp design.

yeah, re-reading my amps manual showed me my error

 

[tekhedd]

The normal mesa thing is that the two taps named "4 Ohms" are intended to allow you to plug in two 8 Ohm cabs in parallel. They're weird.