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Author Topic: Are older toroidal amps better for subs generally?  (Read 13449 times)

Richard Stringer

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Are older toroidal amps better for subs generally?
« on: September 22, 2011, 12:50:29 pm »

I've always kind of wondered why toroidal transformer amplifiers are generall better for subs than switch mode power sply amps, and I kno, or rather think, that amplifiers like say the Crown XTI series aren't great on subs because their power supply isn't big enough and can't extract enough power out the wall to cope with the sheer power thats needed for running subs with styles of music that have sustained basslines. Am I right?

A Peavey tech guy told me that generally a lot of switch mode amps are rated in peak power and not continuous average power because the switch mode amplifier in general isn't capable of extracting as much power as toroidal amps, and so rate their switch mode amps in peak ratings because if they rated the actual continuous average power the power output figures, meaning specs, would look pretty shite compared to old school toroidal amplifiers like the Crest CA18, Crown MA5002, Crest 9001 etc..I was also told that older amplifiers have either bigger power caps or more of them so to store enough power ready for when it's needed.

What's your thoughts guys on why in general, toreoidal amps are better for sub than switch mode amps?
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Bob Leonard

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Re: Are older toroidal amps better for subs generally?
« Reply #1 on: September 22, 2011, 01:20:23 pm »

Richard,
It's not the toroid alone that will determine an amps capability. There are far more people on this site more qualified to discuss the subject than I, however, any amplifier will only be as good as the design of it's power supply regardless of type. Big iron is the way I go, but let's not fool ourselves either. You may have a point with entry level amplifiers, but I would say that if Lab Gruppen said they could get 1000 watts out of a battery you could bet your pay check on it.
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Ivan Beaver

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Re: Are older toroidal amps better for subs generally?
« Reply #2 on: September 22, 2011, 01:58:43 pm »

As Bob said, there is a lot more to it than just the transformer or the filter caps.

You cannot compare an entry level cheap amp (such as the XTI) to a Crown MA5000 or Crest 9001.

That would be like comparing a Chevette to a Corvette and trying to determine if the carb is the difference in performance.
 
There is A LOT more to it than that.

If you really want to compare-start with amps that are in the same price/wattage range and see what you end up with.

Switch mode power supplies recharge the caps faster than analog supplies do, so they can get away with smaller caps.

Yes most of the "big dog" amplifiers cannot sustain there rated output for real long.  You cannot put out any more power than you draw from the wall.  But that is "over time".  Large peaks are available with the "switching amps" that are not available with basic transformer amps (toroidal or regular).

There are advantages and disadvantages to each type-"better" means different thing to different people.

As was said many years ago (long before the big dog amps of today) it was said by one of the audio giants  "What we really need is a 100 watt amp that can pass 10,000 watt peaks".  20dB of headroom if you don't want to do the math.

Now that is for "normal" music.

If you are looking for something to be able to sustain long bass notes- you HAVE to do the following first.  Determine how long is "long"? 1 second-10 seconds-1 minute?  How much power do you really want to send to your loudspeakers (what is the point of power compression on your loudspeakers), how much money do you have?

Then you can start your search.


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John Roberts {JR}

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Re: Are older toroidal amps better for subs generally?
« Reply #3 on: September 22, 2011, 02:08:16 pm »

I've always kind of wondered why toroidal transformer amplifiers are generall better for subs than switch mode power sply amps, and I kno, or rather think, that amplifiers like say the Crown XTI series aren't great on subs because their power supply isn't big enough and can't extract enough power out the wall to cope with the sheer power thats needed for running subs with styles of music that have sustained basslines. Am I right?
Well PS matters but older or type of transformer used has little to do with it. FWIW switching PS often use torroidal transformers too. just tiny ones.
Quote


A Peavey tech guy told me that generally a lot of switch mode amps are rated in peak power and not continuous average power because the switch mode amplifier in general isn't capable of extracting as much power as toroidal amps, and so rate their switch mode amps in peak ratings because if they rated the actual continuous average power the power output figures, meaning specs, would look pretty shite compared to old school toroidal amplifiers like the Crest CA18, Crown MA5002, Crest 9001 etc..I was also told that older amplifiers have either bigger power caps or more of them so to store enough power ready for when it's needed.
Nah... and this is a pretty old story, there are slightly different design trade offs wrt reservoir caps on the mains side of a switching supply. Back decades ago appropriate HV capacitors were harder to source, expensive and large. Some early designs wimped out on mains caps and the reputation has stuck with all of them.

Modern amps keep getting better as all technology gets better, but there is no reason why any technology properly executed will ever behave differently than any other technology. If a technology is better or worse at some single aspect, the design engineer just needs to make adjustments for that technology. Properly executed is the magic phrase, and there are numerous examples of amps using all technologies that perform better or worse than typical.
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What's your thoughts guys on why in general, toreoidal amps are better for sub than switch mode amps?[/font][/size]

I don't have any thoughts on why, because I don't believe they are better. There are only better and worse individual design executions.

JR

PS: be careful about listening to Peavey guys, especially ex-Peavey guys..  8)
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Peter PAPP

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Re: Are older toroidal amps better for subs generally?
« Reply #4 on: September 22, 2011, 04:04:00 pm »

I've always kind of wondered why toroidal transformer amplifiers are generall better for subs than switch mode power sply amps, and I kno, or rather think, that amplifiers like say the Crown XTI series aren't great on subs because their power supply isn't big enough and can't extract enough power out the wall to cope with the sheer power thats needed for running subs with styles of music that have sustained basslines. Am I right?

A Peavey tech guy told me that generally a lot of switch mode amps are rated in peak power and not continuous average power because the switch mode amplifier in general isn't capable of extracting as much power as toroidal amps, and so rate their switch mode amps in peak ratings because if they rated the actual continuous average power the power output figures, meaning specs, would look pretty shite compared to old school toroidal amplifiers like the Crest CA18, Crown MA5002, Crest 9001 etc..I was also told that older amplifiers have either bigger power caps or more of them so to store enough power ready for when it's needed.

What's your thoughts guys on why in general, toreoidal amps are better for sub than switch mode amps?


Operational parameters of toroidal amps varies by the power line changes while most of the quality amps with regulated switchmode PSU are virtually independent from line.
Some of people like DJs better prefer fat "floating" bass which effect created by undamped resonating membranes of speakers or even amps clipping hard.
Many circuitry of conventional linear AB,H,TD class amplifiers have lower control of voice coil movements close to the rail Voltages. When the amp loses control of speaker at high levels cycle by cycle it could create extra bass sensation with freely resonating speakers.
Of course what you hear is NOT the original sound rather than something is "added"...
From the professional's view this effect is not good because when lots of speakers used in parallel freely resonating membranes without control mean random phase radiators which usually cancels each other. So bigger systems needs the tightest possible control of voice coils in the right phase otherwise the common output suffers.
The best amplifiers do not use the maximum range of rail Voltages, it means even at the peaks the load can be damped and the output impedance does not drop by pushing the rails higher.
The price of this solution is you need to have at least several tens of Volts above the actual output range. Most of the conventional amps can not work this way due to the unaffordable extra losses... some of the switching amps have this feature and gives tight, very precise phase controled low range for those who like it.

Péter
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Richard Stringer

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Re: Are older toroidal amps better for subs generally?
« Reply #5 on: September 23, 2011, 04:05:59 am »

Thanks guys, that explains a lot to me, trying to understand it is hard but i'm learning about voltage slowly. I really apreciate you helping me on this matter.

Ivan,
I wasn't comparing cheaper amps with more expensive amps so much, but more comparing the switch moce supply to the toroidal supply in general.
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Ivan Beaver

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Re: Are older toroidal amps better for subs generally?
« Reply #6 on: September 23, 2011, 08:43:27 am »

Thanks guys, that explains a lot to me, trying to understand it is hard but i'm learning about voltage slowly. I really apreciate you helping me on this matter.

Ivan,
I wasn't comparing cheaper amps with more expensive amps so much, but more comparing the switch moce supply to the toroidal supply in general.

If you compare the itech amps to the older "better" amps, it would be a better comparison, than using the XTI's.

Cheap amps will have less performance-no matter what the design.

I know many people think that they are getting the Itech performance for an XTI price.  They are not the same quality/performance etc.
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Richard Stringer

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Re: Are older toroidal amps better for subs generally?
« Reply #7 on: September 23, 2011, 10:06:30 am »

If you compare the itech amps to the older "better" amps, it would be a better comparison, than using the XTI's.

Cheap amps will have less performance-no matter what the design.

I know many people think that they are getting the Itech performance for an XTI price.  They are not the same quality/performance etc.

Oh yeah I definately know that, i've heard the XTI series amps on subs a few times and not once have I been impressed. I heard a QSC RMX5050 though I was more impressed with it.
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Ivan Beaver

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Re: Are older toroidal amps better for subs generally?
« Reply #8 on: September 23, 2011, 11:03:47 am »

Oh yeah I definately know that, i've heard the XTI series amps on subs a few times and not once have I been impressed. I heard a QSC RMX5050 though I was more impressed with it.
Just to be clear-I said what I did, because in  your origional post you compared a XTI to much better quality amps.

Had you compared a Lab Gruppen to those amps-your opinion would probably be different-or any other good quality "switcher".

But comparing a cheap entry level amp of one type of design to a much better quality amp of a different design is not exactly comparing.

For example, it could be completely turned around if you said "Why are the switching amps (like a Lab Gruppen-QSCV PL3 series-Itechs etc) so much better sounding than a standard transformer (toroidal or otherwise) like the Samson whatever #?"

Well, when you compare a good amp to a cheap amp-that is what you get.
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John Roberts {JR}

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Re: Are older toroidal amps better for subs generally?
« Reply #9 on: September 23, 2011, 11:31:25 am »

Operational parameters of toroidal amps varies by the power line changes while most of the quality amps with regulated switchmode PSU are virtually independent from line.
Many switching power supplies used in power amplifiers are not regulated. They simply chop the mains voltage at a high frequency so they can use a small transformers, and those supply voltages will sag when the mains voltage sags. 

Most PFC (power factor corrected) amps OTOH are regulated, so they hold voltage and in addition to that, enjoy the extra benefit of spreading the current draw out over the entire mains waveform so literally can pull more power from a given distribution.
Quote
Some of people like DJs better prefer fat "floating" bass which effect created by undamped resonating membranes of speakers or even amps clipping hard.
Many circuitry of conventional linear AB,H,TD class amplifiers have lower control of voice coil movements close to the rail Voltages. When the amp loses control of speaker at high levels cycle by cycle it could create extra bass sensation with freely resonating speakers.
I am not familiar with this mechanism or what DJs prefer. Rumor is they like loud and don't mind clipping to get there. Most amps have clamp diodes across the power devices so even if clipping, back EMF from the loudspeaker can't swing more than a diode drop above the rail voltage and will see a low impedance at that point. 
Quote

Of course what you hear is NOT the original sound rather than something is "added"...
From the professional's view this effect is not good because when lots of speakers used in parallel freely resonating membranes without control mean random phase radiators which usually cancels each other. So bigger systems needs the tightest possible control of voice coils in the right phase otherwise the common output suffers.
again I am not familiar with this phenomenon.
Quote
The best amplifiers do not use the maximum range of rail Voltages, it means even at the peaks the load can be damped and the output impedance does not drop by pushing the rails higher.
Many analog amps use anti-sat diodes to prevent the output power devices from hard saturation. This is to speed up recovery time after clipping events (saturated power devices, stick to the rails and take more time to come out of clipping). So these will sound slightly cleaner and better able to ignore brief transients that clip. But clipping alters the signal output, so never clipping is always better.
Quote

The price of this solution is you need to have at least several tens of Volts above the actual output range. Most of the conventional amps can not work this way due to the unaffordable extra losses... some of the switching amps have this feature and gives tight, very precise phase controled low range for those who like it.

Péter

It is very impractical and generates way too much waste heat to have and not use, tens of volts of power supply rails.  By switching amps are you speaking of class D amps with switching output stages or linear amps with switching power supplies? Class D amps use saturated output devices so all of their PS voltage is always used, switching supply amps come in many flavors. 

Oversized amps that never clip can sound good, because they never clip.

JR
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Re: Are older toroidal amps better for subs generally?
« Reply #9 on: September 23, 2011, 11:31:25 am »


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