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MOSFET Amplifier?
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ape3435 View Drop Down
Young Croc
Young Croc


Joined: 23 August 2009
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Points: 552 		Post Options Post Options   Thanks (0) Thanks(0)   Quote ape3435 Quote  Post ReplyReply Direct Link To This Post Posted: 05 May 2016 at 12:20pm
Originally posted by Earplug Earplug wrote:

Originally posted by csg csg wrote:

i disagree, and constantly run SMPS amplifiers on generator supplies.

modern smps units tend to be autoranging and non sensitive to frequency. Linear supplies are never autoranging and dislike frequency fluctuations. Good amps are usually PFC'd too which helps on generator supplies too.

off course i am assuming the use of good quality equipment.


Ok, maybe I was unlucky, but I had problems (several times) with both QSC Powerlight and Powersoft Digam - neither cheap amps - and that has made me wary. I sold those amps and now only have a couple of Crest Pro´s with SMPS, but still tend to use toroidals if I know there´s going to be a generator at a gig, as I´ve never had any problem with those.


 
Have to agree with you Earplugs, I once used a Macrotech 5000i on a float and the genie kept shutting down, I used the same genie another time with el cheapo Samson amp and there was absolutely no problem.
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ape3435 View Drop Down
Young Croc
Young Croc


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Points: 552 		Post Options Post Options   Thanks (0) Thanks(0)   Quote ape3435 Quote  Post ReplyReply Direct Link To This Post Posted: 05 May 2016 at 12:22pm
Originally posted by odc04r odc04r wrote:

A massive part of these experiences is the genkit itself. Are we talking a little Honda fluctuating all over the place or a small portacabin sized professional beast? Results will change again.
 
I think the point is that despite the type of genie, the torroidals seem to continue working but the smps won't.
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Old Croc
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Points: 7216 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Earplug Quote  Post ReplyReply Direct Link To This Post Posted: 05 May 2016 at 12:29pm
"A massive part of these experiences is the genkit itself. Are we talking a little Honda fluctuating all over the place or a small portacabin sized professional beast? Results will change again."


Yes - obviously depends on the generator - but I`ve had a couple big units (30/50kVA) giving problems as well. A lot of these gennies get thrashed on building sites and then sent straight out to festivals with no proper maintainance or checks done on them. There`s one big hire company here that`s notorious for this, but people still use them as there`s not a lot of choice. The only solution is to always hire an extra in case one goes down. Not good.




Edited by Earplug - 05 May 2016 at 5:47pm
Earplugs Are For Wimps!
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Old Croc
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Points: 6086 		Post Options Post Options   Thanks (0) Thanks(0)   Quote csg Quote  Post ReplyReply Direct Link To This Post Posted: 05 May 2016 at 12:42pm
Off course it depends on both the amps and generator but in the 20 years ive been using Labs and the last few using Powersoft i have never had an issue with SMPS amps of generators.

The last racks of linear psu amps we had were crest P8001/9001's which were fairly good on gensets and electrovoice P3000/2000 which were much more sensitive to voltage and particularly frequency fluctuations. Buss fuses seemed to be prone to going when the supply was not ideal.

One site we regularly supply has a house supply fed from large gensets ( around 1/2 MW) which suffers from low line voltage with 170V or so being quite common when the site is very busy and demand high on their rather under spec'd distribution infrastructure. The Labs we run on that site simply get on with it with no drop in power, or any other issues. I cant see a linear amp doing that.

Off course my own views are formed by my own experience, but sweeping statements saying that you need to use linear psu amps on gensets are not really true..
“The fact is this is about identifying what we do best and finding more ways of doing less of it better”
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Points: 11155 		Post Options Post Options   Thanks (0) Thanks(0)   Quote jbl_man Quote  Post ReplyReply Direct Link To This Post Posted: 05 May 2016 at 2:16pm
"A massive part of these experiences is the genkit itself. Are we talking a little Honda fluctuating all over the place or a small portacabin sized professional beast? Results will change again."

Let's hook a Behringer iNuke up to a little 1.5kva Honda with a lawnmower engine and see how long it lasts. LOL

I think under those circumstances i would rather have an old PPX or HH.

But it is an interesting subject this. Amazing those Lab amps will run perfectly at just 170v Chris,wonder how low it has to drop before they stall?
Be seeing you.
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odc04r View Drop Down
Old Croc
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Don't forget bridged into a piece of copper piping.
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Old Croc
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Points: 7216 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Earplug Quote  Post ReplyReply Direct Link To This Post Posted: 05 May 2016 at 5:57pm
"...but in the 20 years ive been using Labs and the last few using Powersoft i have never had an issue with SMPS amps of generators."

"Off course my own views are formed by my own experience, but sweeping statements saying that you need to use linear psu amps on gensets are not really true.."

Likewise. We all learn from our experiences - especially the bad type. Maybe Labs and the newer Powersofts are more tolerant/better made, who knows, but it does seem that if you have a choice between a 'budget' linear and a 'budget' SMPS, linear is the way to go...
Earplugs Are For Wimps!
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csg View Drop Down
Old Croc
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Points: 6086 		Post Options Post Options   Thanks (0) Thanks(0)   Quote csg Quote  Post ReplyReply Direct Link To This Post Posted: 05 May 2016 at 7:32pm
you have a choice between a 'budget' linear and a 'budget' SMPS, linear is the way to go...

ill agree with you there...

Amazing those Lab amps will run perfectly at just 170v Chris,wonder how low it has to drop before they stall? 

Well Ian, the Labs will operate between 70 and 265V, and our newer generation Powersoft amps operate anywhere between 85-440V. Neutral-live, phase-phase, they don't really care.
“The fact is this is about identifying what we do best and finding more ways of doing less of it better”
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Young Croc
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Points: 552 		Post Options Post Options   Thanks (0) Thanks(0)   Quote ape3435 Quote  Post ReplyReply Direct Link To This Post Posted: 05 May 2016 at 8:40pm
I'm not sure if a Crown Macrotech 5000i is a budget amplifier but the Samson definitely is and like I said earlier it kept the genie running but the macro would cause the genie to shut down (quite a few times too).
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