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08-27-2011, 11:28 AM
| | | | My stupid "friend"
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SO I have this ahem......"friend" who played an entire set last night with his gbe 1200 set for a two Ohm load while only running one 4 ohm cab. "He" doesn't need to be told what an idiot he is, he knows. He noticed it at set break and flipped the switch and all seemed fine but I'm....no, HE is wondering if there was potential damage done. He won't let it happen again..
Just plug n play or should I have it inspected? I mean should HE have it inspected? He really loves his gbe and he feels terrible about abusing her. |
08-27-2011, 11:42 AM
| | | | Took me a minute to get the underlying context on this. hah... As for your situation, I have no clue. I do not know much about the topic. I probably wasted your time and your "friends" hopes. |
08-27-2011, 11:52 AM
| | Registered User | | Join Date: Jan 2010 Location: Vancouver | | | I think it should be okay, if the amp doesn't have an output transformer and all. Impedance mismatches are a bigger thing for tube amps. |
08-27-2011, 11:52 AM
|  | Registered User | | Join Date: Aug 2007 Location: Toronto Ontario Canada | | | Nowt wrong with what you did. All that happened was that you didn't get the full power the amp was capable of.
If it had been the other way around, 2Ω load and set to 4Ω you could have had a problem.
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Paul
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08-27-2011, 11:54 AM
|  | Looking for Opportunities to Create Harmony | | Join Date: Sep 2004 Location: Vancouver, BC Canada | | | You could always PM one of the genz benz engineers who post on tb. They'll sort you out 100%
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Stambaugh Shortscale Jazz - GK MB800 - fEARful 15/6
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08-27-2011, 12:09 PM
|  | Registered User | | Join Date: Mar 2008 Location: Kansas City | | Nothing stupid about that at all with this amp - the amp and cab are both perfectly fine. I actually run mine that way on purpose. With the switch in the 2-ohm position, it only puts out ~ 750W into 4 ohms instead of the 1000 it's rated for. I do it because it's easier for me to tap into a bit of that sweet limiter function 
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Brian - Genz Benz Owner's Club #81 - 'Wick Club #221
Warwick Streamer Stage II/Spector NS-5H2-EX :: Genz Benz GBE 1200/SL 900/Mesa M9/Ampeg SVT 7-Pro :: Genz Benz Uber 410/NEOX-212T
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08-27-2011, 12:38 PM
| | | | Good designed SS amps blowing up from some stupid user mistake is very unlikely.
If you had a 2 ohm load, and had it switch to 4 ohm, the the amp protection circuits would still protect it. It would more likely go into thermal shutdowns, but return unharmed. You should run as the manufacturer recommends in the manual, but they are pretty much idiot proof these days.
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"The good thing about science is that it’s true whether or not you believe in it." - Neil DeGrasse Tyson 2011
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08-27-2011, 12:45 PM
| | | | I've known of several guitar players that would drop to 4 ohms on an 8 ohm load and it would give them a little bit of top end roll off not achievable by using the tone controls...
Think someone else said it, not a big deal unless he was running 2 and had it set to 4 |
08-27-2011, 12:47 PM
| | | | You really cannot damage an amplifier running it into a higher impedance. If it was set for 2 ohm you could run it into anything higher. If it was the other was though you could mess up an amp. |
08-27-2011, 01:09 PM
| | Registered User | | Join Date: Feb 2011 Location: Norfolk | | Quote:
Originally Posted by ::::BASSIST::::  You could always PM one of the genz benz engineers who post on tb. They'll sort you out 100% | Not dealt with them before, but wouldn't telling them that void your warranty?
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Originally Posted by capnjim I don't know, but I would like to see it on Youtube. | Mediocre Bassist Club # 709
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08-27-2011, 02:10 PM
| | Development Engineer: Genz Benz | | | | Correct on all counts. Wasn't it you that I suggested this application for? Running with the switch on 2 ohms reduces the power by ~30% in the 8 ohm and 4 ohm mode and shift the limiter thereshold a little so that it has a slightly more agressive overdrive on the power amp.
It's not a good choice running a 2 ohm load with the switch set for 4 ohms because is puts added stress on the output stage, and the amp will deliver ~1500 watts into 2 ohms but it shouldn't damage it but I would expect it to run warmer and with high ambient temperatures or cabinets that have large areas of sub-nominal impedance (<2 ohm), it's possible that the internal protection circuit may activeat. Quote:
Originally Posted by KsPiNeSh Nothing stupid about that at all with this amp - the amp and cab are both perfectly fine. I actually run mine that way on purpose. With the switch in the 2-ohm position, it only puts out ~ 750W into 4 ohms instead of the 1000 it's rated for. I do it because it's easier for me to tap into a bit of that sweet limiter function |
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Engineer: Genz Benz
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08-27-2011, 04:36 PM
| | | cool. Now that I know it wasn't a total bonehead move I can come clean and say it was actually me and not a friend 
thanks for the info fellas! |
08-27-2011, 04:37 PM
| | Banned | | Join Date: Aug 2010 Location: Cohasset, Massachusetts | | Quote:
Originally Posted by BassmanPaul Nowt wrong with what you did. All that happened was that you didn't get the full power the amp was capable of.
If it had been the other way around, 2Ω load and set to 4Ω you could have had a problem. | +1 |
08-27-2011, 05:25 PM
|  | Musician - tech/repair at Nordstrand Guitars
Endorsing artist: Genz Benz - Nordstrand - DR strings | | Join Date: May 2003 Location: Los Angeles/Redlands, CA | | As adgedhorse said (of course he knows something about GB!), a quick look at the manual:
<<POWER FLEX Switch— This switch allows optimum matching of the power supply to the speaker load. Similar in concept to output transformer matching in tube amplifiers. This feature allows the GBE 1200 to drive 2 ohm loads at maximum efficiency compared to more traditional designs. Driving 2 ohm speakers with the switch in the 4-8 ohm position is not recommended as the amp’s monitoring circuitry may reduce the output power to minimize stress on the amplifier. Operating the amplifier with the switch in the 2 ohm position into a 4 or 8 ohm load is not a problem, and may be beneficially used to scale the power of the amp down when playing small clubs that offer limited stage power. An amber “2 ohm” indicator LED is provided on the front panel to confirm that the 2 ohm POWERFLEX mode has been selected.>>
Neat! Genz Benz rocks!
M |
08-27-2011, 05:45 PM
| | | Quote:
Originally Posted by maurilio As adgedhorse said (of course he knows something about GB!), a quick look at the manual:
<<POWER FLEX Switch— This switch allows optimum matching of the power supply to the speaker load. Similar in concept to output transformer matching in tube amplifiers. This feature allows the GBE 1200 to drive 2 ohm loads at maximum efficiency compared to more traditional designs. Driving 2 ohm speakers with the switch in the 4-8 ohm position is not recommended as the amp’s monitoring circuitry may reduce the output power to minimize stress on the amplifier. Operating the amplifier with the switch in the 2 ohm position into a 4 or 8 ohm load is not a problem, and may be beneficially used to scale the power of the amp down when playing small clubs that offer limited stage power. An amber “2 ohm” indicator LED is provided on the front panel to confirm that the 2 ohm POWERFLEX mode has been selected.>>
Neat! Genz Benz rocks!
M |
Thats great to know, I guess I should round up a manual. Seems like running it in 2 ohm mode might be the ticket for some of our smaller venues where the 1200 is mega overkill instead of just normal overkill!! It is a great amp and I tell myself that every time i pack that thing around. There has been more than one occasion that my rig causes circuit breakers to pop at venues with less than ideal power outlets.
Last edited by 1Drop : 08-27-2011 at 05:48 PM.
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08-27-2011, 06:56 PM
| | Musician - tech/repair at Nordstrand Guitars
Endorsing artist: Genz Benz - Nordstrand - DR strings | | Join Date: May 2003 Location: Los Angeles/Redlands, CA | | | |
08-27-2011, 08:06 PM
| | Development Engineer: Genz Benz | | | | Quote:
Originally Posted by maurilio | Thanks for the assist man!
See you at NAMM this year? Bring your bass 
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Engineer: Genz Benz
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08-27-2011, 11:51 PM
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Originally Posted by maurilio | I'm glad I caught you on a good day, Thank you!! |
08-28-2011, 02:59 AM
| | Musician - tech/repair at Nordstrand Guitars
Endorsing artist: Genz Benz - Nordstrand - DR strings | | Join Date: May 2003 Location: Los Angeles/Redlands, CA | | If I was in a good day I would have come over your place and went over all the details, connections and specs…. 
Just messing around! 
Have fun with your GB, these guys are great!
M |
08-28-2011, 03:03 AM
| | Musician - tech/repair at Nordstrand Guitars
Endorsing artist: Genz Benz - Nordstrand - DR strings | | Join Date: May 2003 Location: Los Angeles/Redlands, CA | | Quote:
Originally Posted by agedhorse Thanks for the assist man!
See you at NAMM this year? Bring your bass | Anytime Andy, thank you!
I'm not sure what's up for the new year…. LOTS of stuff cooking in the oven, we'll see!
If I'm there, I'll make sure to stop by and check what's new (since I'm sure you guys are also working on some new dish!)
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