2 Ohm Capable Lightweight Heads

[Wild Rice Chris]

The Acoustic Image Clarus Series 4 head is 650 watts and 2 ohms. The Genzler Magellan 800 is 2.67 ohms, but Jeff himself said in a post here on TB that it will handle 2 ohms.

IIRC, that was 2 ohms with Genzler cabinets.

 

[Chewy_B_i_T_s]

The Yamaha BBT 500H isn't pocket size but it's still pretty lightweight. I really like mine. It can handle 2 ohms but I've read some stories of it getting quite warm. I've also read that the fan kicks on at a very high set point, causing some to wonder if the fan on their unit even works, so I guess it was engineered to handle the heat?

 

[RColie]

IIRC, that was 2 ohms with Genzler cabinets.

That is correct.

 

[logdrum]

Acoustic Image

 

[Lowbrow]

Yamaha BBT500H

 

[basscooker]

Yeah, just giving the little guys a shout out. I couldn't find a way to view the manual, so maybe not a contender for this thread, but it does appear to be a nice unit. I beat up the ad copy a bit in the thread, but there is a good reputation behind the builder, and they have a member here. Says 1000 watts at 2 ohm. I'm curious as to the caveats.

@Andrea Lo

 

[burgerdj]

What do you consider light? Many of the 90s-era Eden heads are 2ohm rated and clock in around 12-15 lbs.

 

[Jackcrow]

Even though I love my Quilter, this is a pet peeve of mine that's not exclusive to Quilter.

To me, if the amp could drive a 2 ohm load, they wouldn't put 'minimum 4 ohm load' right on the amp. If it can do 2 ohms, they should say it can do 2 ohms and not 'you should be able to do 2 ohms maybe'.

I guess what I'm saying is...I wouldn't trust an amp at 2 ohms unless it's stated on the amp or in the manual that it's designed for 2 ohm operation.

Yeah the Quilter was my first choice but I ruled it out because it said 4 ohm minimum. I didn’t see the other info on the website about running at 2 ohms. Interesting, but it doesn’t really sound like they are fully confident in it at 2 ohms.

 

[Lowbrow]

Even though I love my Quilter, this is a pet peeve of mine that's not exclusive to Quilter.

To me, if the amp could drive a 2 ohm load, they wouldn't put 'minimum 4 ohm load' right on the amp. If it can do 2 ohms, they should say it can do 2 ohms and not 'you should be able to do 2 ohms maybe'.

I guess what I'm saying is...I wouldn't trust an amp at 2 ohms unless it's stated on the amp or in the manual that it's designed for 2 ohm operation.

This used to drive me nuts about the Mesa Walkabout ... many TB posts stating that the amp is in fact 2-ohms stable, but no direct corroboration from manufacturer.

 

[Bringindafunk]

While not 2 ohm rated, the Genz Benz ShuttleMax 12 has two 600 watt power amps so you get the same end result of being able to run a pair of 4 ohm cabs with a bonus of 1200 watts of beautiful, beautiful power.

 

[logdrum]

The 2 Ohm maybe statements may work if you are playing low to mid volume. I damaged by EA doubler because I attended a loud music jam and played very loud for about an hour. Once I got home, I just got a ticking sound out of the master. EA fixed it for free even though they did state 2ohm, low volume only which I disregarded.

EA does make 2 ohm capable amps and they are very nice. Lee Sklar uses them. Well the sad news is they closed shop.

The old SWR lead sleds are 2ohm (but not stated in the amp) capable but they are not class D. Mine (the original Bass 350) is still ticking at my buddy/band mates place and he has friends and band mates that play loud on it with 2 4 ohm 2X10's on a regular basis. It does get hot -- enough to fry an egg. Carvin B and BX series are all 2ohm capable.

 

[OakCityBassist]

The GK Fusion S and Legacy heads do anything from 2-8 Ohms.

I happen to have a Fusion S for sale

 

[logdrum]

IIRC, that was 2 ohms with Genzler cabinets.

I really do not get this. I think TC says that also about one of their amps that only works with TC cabs. An ohm is an ohm and there should not be a Genzler or TC ohm.There must be a reason why.

They (Genzler) do make good products and staying in their ecosystem is not a bad idea.

 

[noahw1]

Genzler 2.75 but will go to a solid 2 using their cabs.

 

[agedhorse]

The old SWR lead sleds are 2ohm (but not stated in the amp) capable but they are not class D. Mine (the original Bass 350) is still ticking at my buddy/band mates place and he has friends and band mates that play loud on it with 2 4 ohm 2X10's on a regular basis. It does get hot -- enough to fry an egg. Carvin B and BX series are all 2ohm capable.

While some earlier models did state that they could drive 2 ohms, most did not and could not safely (even if they stated so). Bridged, 4 ohms was the minimum load on later models and 8 ohms was MUCH safer on earlier models. Fender addressed much of this in the later ones (made in Corona, CA) in order to meet 60065 safety standards.

I really do not get this. I think TC says that also about one of their amps that only works with TC cabs. An ohm is an ohm and there should not be a Genzler or TC ohm.There must be a reason why.

They (Genzler) do make good products and staying in their ecosystem is not a bad idea.

No, it's nowhere near as simple as this.

A cabinet has a nominal impedance which combines the minimum impedance along with the amount of area contained under the curve that is sub-nominal. Most engineering based designers also weight the frequency spectrum with the area under the curve because some areas contain more energy which increases the stress on amplifiers.

Non-engineering based speaker designers (especially DIY/hobby builders and smaller companies that do not understand the engineering behind amplifiers) often become very liberal with how much (and how large) sub-nominal impedance are, ignoring generally accepted engineering principles. From an amp designer's perspective, these speakers are called "amp killers" because (as an example) a 4 ohm 410 may drop down to 3 ohms over as much as an octave and if this is in a high energy area (say 35Hz to 500Hz) it could become a very real problem to the amp.

Amp designers do address this within reason, but the example above would require that the amp can actually drive 1.5 ohms which becomes more challenging. This example may seem extreme, but I have seen much worse. For a 25% drop in impedance, there is a corresponding 25% increase in current at the rated voltage. 800 watts into 4 ohms would be 14 amps RMS or 20 amps peak. The same signal driving a 3 ohm load (using the example above) would be 17.5 amps RMS or 25 amps peak.

Jeff is fully aware of this issue of this possibility other manufacturer's cabinets. We studied this in excruciating detail while were developing the GBE models (GBE-400/600/750/1200). We respect the concept of nominal impedance, which means that the Genzler (and Subway for that matter) cabinets do not place an unreasonable or unknown/unexpected stress on an amp. This is why the Genzler amp can drive 4 of the Genzler cabinets, this area of sub-nominal concern doesn't exist. The same can not be said for other manufacturer's cabinets... I have seen 4 ohm cabinets drop to 2.5 ohms in some areas, that's asking a lot of an amp to drive. This is also why good amp designers put so much effort into effective protection circuits (though no protection circuit is perfect).

 

[Lowbrow]

The Yamaha BBT 500H isn't pocket size but it's still pretty lightweight. I really like mine. It can handle 2 ohms but I've read some stories of it getting quite warm. I've also read that the fan kicks on at a very high set point, causing some to wonder if the fan on their unit even works, so I guess it was engineered to handle the heat?

... something I wish I knew earlier on before I pulled the fan out of mine thinking it must have been broken.

 

[fishdude101101]

Sell all of those cabs and get yourself two Subway cabs and call it a day.

This. I had a brief love affair with an ampeg 810 a month or two ago. Even posted a thread about. I played it on a few gigs as provided backline. Sometimes it was great sometimes not....but my subway 115 is the best sounding bass cab I've ever played on. I'll be getting another one soon.

 

[mike buzzetti]

get one of these !!!
https://www.automationdirect.com/ad...Ang6Vq20nzxD63BA-X0aeBC2zWZtFQgRoCi_YQAvD_BwE

 

[Zooberwerx]

While some earlier models did state that they could drive 2 ohms, most did not and could not safely (even if they stated so). Bridged, 4 ohms was the minimum load on later models and 8 ohms was MUCH safer on earlier models. Fender addressed much of this in the later ones (made in Corona, CA) in order to meet 60065 safety standards.


No, it's nowhere near as simple as this.

A cabinet has a nominal impedance which combines the minimum impedance along with the amount of area contained under the curve that is sub-nominal. Most engineering based designers also weight the frequency spectrum with the area under the curve because some areas contain more energy which increases the stress on amplifiers.

Non-engineering based speaker designers (especially DIY/hobby builders and smaller companies that do not understand the engineering behind amplifiers) often become very liberal with how much (and how large) sub-nominal impedance are, ignoring generally accepted engineering principles. From an amp designer's perspective, these speakers are called "amp killers" because (as an example) a 4 ohm 410 may drop down to 3 ohms over as much as an octave and if this is in a high energy area (say 35Hz to 500Hz) it could become a very real problem to the amp.

Amp designers do address this within reason, but the example above would require that the amp can actually drive 1.5 ohms which becomes more challenging. This example may seem extreme, but I have seen much worse. For a 25% drop in impedance, there is a corresponding 25% increase in current at the rated voltage. 800 watts into 4 ohms would be 14 amps RMS or 20 amps peak. The same signal driving a 3 ohm load (using the example above) would be 17.5 amps RMS or 25 amps peak.

Jeff is fully aware of this issue of this possibility other manufacturer's cabinets. We studied this in excruciating detail while were developing the GBE models (GBE-400/600/750/1200). We respect the concept of nominal impedance, which means that the Genzler (and Subway for that matter) cabinets do not place an unreasonable or unknown/unexpected stress on an amp. This is why the Genzler amp can drive 4 of the Genzler cabinets, this area of sub-nominal concern doesn't exist. The same can not be said for other manufacturer's cabinets... I have seen 4 ohm cabinets drop to 2.5 ohms in some areas, that's asking a lot of an amp to drive. This is also why good amp designers put so much effort into effective protection circuits (though no protection circuit is perfect).

I actually understood this.

Riis

 

[Smooth Operator]

Coda – High performance Class G Power Amp | Jad Freer Audio

Lightweight Class G Amp? I didn't know they existed. I will say my GK 1001rbii and Mesa Carbine M6 seem quite a bit louder and hit harder than my Mesa Subway amps despite being lower Wattage RMS.