Double Bass Focus Head at 2 ohms

[Alain Bass]

Does anyone has tried to run the old Focus head (the 600 W one) at 2 ohms?
Does it work? Any problems, observations?
I am expecting to buy 2 Wizzys and want to know if I could run them together.
Thanks' for the answer.
Alain

 

[robgrow]

Does anyone has tried to run the old Focus head (the 600 W one) at 2 ohms?
Does it work? Any problems, observations?
I am expecting to buy 2 Wizzys and want to know if I could run them together.
Thanks' for the answer.
Alain

Alain, It's never wise to run an amplifier with a load lower than the manufacturer's minimum rated impedance. If you do so, it's very likely you will damage the amp. Minimum load impedance ratings are specified for good reasons.

 

[mchildree]

FYI - the EA iAMP 800 (and the 500, I think) will run at 2 ohms safely. I use my 800 with a pair of Wizzys, and it's a fantastic little rig.

 

[Alain Bass]

Minimum load impedance ratings are specified for good reasons.

Yes, and a Focus at 4 ohms works properly …… but
I asked the same question to Rick Jones from AI
and he told me to make a loud test at 2 ohms.
it should work with most 2 ohms cabs.
If it doesn't work, the amp will quickly cut without damage.

I believe Rick, but as I didn’t yet buy my 2 Wizzys, I cannot make the test, and I just wanted to have some inputs from folks who experiments that.

here is Rick 'S answer:
The Focus SA will operate with most 2 ohm loads. To check, connect
your 2 ohm speaker load and run the amp at the highest volume you
expect to play. If there are no problems then you should be ok. If
the amp cuts out when you hit the loudest notes, then the current
protection circuit is cutting in to protect the amp from outputting
too much current. Since the impedance rating of speakers is
nominal, so 2 ohm loads can be much lower than 2 ohms and cause
problems with the amp.

There is no risk. The amp has built in overcurrent and thermal protection that will save the amp if things go wrong.
When you run the 2 ohm test, give it a hard workout to make sure it will be ok.
We have a 2 ohm test bed here that we regularly put our amps through. The guy running the test has to wear ear protection.
Rick

Any answer will be welcome
Alain

 

[Alain Bass]

FYI - the EA iAMP 800 (and the 500, I think) will run at 2 ohms safely.

The EA IAMP 800 is probably a wonderfull amp, but I like the weight of my Focus = 5 pounds. I like to travel light.
Thank's mchildree for your answer
Alain

 

[mchildree]

Depending on your time frame requirements, you might keep an ear out for news from EA. The news has slipped out that they will be releasing a sub-5 lb head soon as well.

 

[Alain Bass]

Yes mchildree, and I can tell you I keep my two ears and my two eyes on EA news ……… and find the time to be long, ……waiting, waiting …………… especialy those new Wizzys, it's those one I want to buy, but I will try to keep my Focus Head, cause it works fine, and try not to spend too much bucks.

 

[Alain Bass]

Minimum load impedance ratings are specified for good reasons.

Robgrow
Comming back to your answer, EA can probably guarantee their Focus at 4 ohms, and not at 2, but it's interesting to know if it's possible or not.
The only problem I can have is that, during a gig …… the amp cuts …… and this is a bad punishment.
Alain

 

[LowNote]

Alain,

I have routinely run my Focus Series II amp head with a two ohm load with no troubles whatsoever. I have used two four-ohm Schroeder Mini12+ cabinets and two of the AI ContraEx cabinets at different times. I have also done this in the U.S. on 110 volt current and in the U.K. on 240 volt current, again with no troubles. I wouldn't worry about it.

Erik Hansen

 

[::::BASSIST::::]

I have two wizzys and a Focus SA II (600w lowest recc. 4 ohms). I have tried running both wizzys and the focus sa. I cranked the output / level knob of the focus to maximum and lowered the preamp so as to fully punish the focus. My question was the same as yours and I wanted to make sure the sucka would hold up. Well, I played it that way for two hrs without a break and it did not shut down. It did get pretty bloody warm though. One tip you could try is getting a fan and blowing air across the amp to help keep it cool.

Keep in mind that wizzys are actually less than 4 ohms each. If I remember correctly its 3.87ohms. This means that you are pushing the Focus below 2ohms (even if marginally).

My conclusion is that yes you can do it, but I am still a little squeemish about running the amp like that at a gig in case it cuts out.

I would love to hear from others such as LowNote who have tried it without a problem.

 

[bribass]

I have two wizzys and a Focus SA II (600w lowest recc. 4 ohms). I have tried running both wizzys and the focus sa. I cranked the output / level knob of the focus to maximum and lowered the preamp so as to fully punish the focus. My question was the same as yours and I wanted to make sure the sucka would hold up. Well, I played it that way for two hrs without a break and it did not shut down. It did get pretty bloody warm though. One tip you could try is getting a fan and blowing air across the amp to help keep it cool.

Keep in mind that wizzys are actually less than 4 ohms each. If I remember correctly its 3.87ohms. This means that you are pushing the Focus below 2ohms (even if marginally).

My conclusion is that yes you can do it, but I am still a little squeemish about running the amp like that at a gig in case it cuts out.

I would love to hear from others such as LowNote who have tried it without a problem.

AI heads can run warm if the power source is a bit questionable. Read this thread. http://www.talkbass.com/forum/showthread.php?t=226837

You may need a Uninterupted Power Source/ surge protector outlet strip in some questionable power situations.

My Focus has run warm or cool as a cucumber depending on the juice (old build., boat gigs, generators, versus new build or conditioned power supply etc.)

BG