Higher Power Amplification For SDA SRS's
DarqueKnight
Posts: 6,765
A Brief Historical Perspective
From the controversial SDA SRS review in the November 1985 issue of Stereo Review:
"Not surprisingly in view of its large driver complement and rated power-handling of 1,000 watts or more, the Polk SDA-SRS thrives on power levels that would vaporize some lesser designs. We ran out of power from our amplifier (one of the most powerful available for home use) when we attempted to reach the speaker's limits with 1,000 cycle tone bursts. At 100 Hz the amplifier clipped at 1,650 watts into 6 ohms, and at 1,000 Hz it clipped at 765 watts into 20 ohms. Only at 10,000 Hz, where presumably only one driver was in use, did we reach the limits of the speaker and the amplifier at about the same time-1,265 watts into 5 ohms."
Question To Polk's Customer Service Department:
"The SDA SRS 1.2TL is rated for amplifiers up to 1000 watts. Is this a continuous rating or short term? If it is short term, what is the maximum continuous power rating?
Does anyone at Polk know the power amp used for the tests ran by Stereo Review?"
Matthew Polk's Answer:
"We would all like to have a single number that tells us how much power a speaker can safely handle but, like most things, its not that simple. When we rated the SRS 1.2TL for amplifiers up to 1,000 watts we were trying to convey that the speakers would perform better with more powerful amps and also were trying to get away from single number power handling specs which are always misleading. The 1,000 watt rating is most certainly not a continuous power rating. Continuous power handling would depend on whether the driving signal is broad band or a single frequency and would further depend on the specific frequencies being used. Continuous power handling for the 1.2TL at 80Hz, for example, might be very close to 1,000 watts because, at that frequency, all 8 drivers are working together and the system is not limited by mechanical excursion. However, continuous power handling above around 8kHz would be no more than 50 watts because only one tweeter is operating at those frequencies. As a general rule power handling is greater at low frequencies where the voice-coils move enough to help dissipate the heat. At higher frequencies there's no movement and the heat just builds up like the filament of a light bulb.
In addition to these considerations power handling for an SDA product would also depend on whether the stereo signal was mostly in the left or right channel, or mono blended. Power handling would be higher in the midrange for Left or Right only signals.
Stereo Review did test the system with tone bursts. I think that review was done by Julian Hirsch. Julian often used Carver amps but that could not have been the case here because the Carver's were non-common ground and would not have worked with any of the SDA speakers. It's possible that it was a Crown or the hugely powerful NAD 3xxx power amp available at that time.
-msp"
I'm not currently in the market for new monoblocks, but if I were, I wouldn't mind rolling these beasts through my two channel system. There are probably a few tube amps that would work too.;)
The following are, as Rod Serling was fond of saying, submitted for your approval:
Pass Labs x600.5
600 watts/channel 8 ohms.
900 watts/channel 4 ohms.
150 pounds each.
$22,000 per pair new, ~$9500 per pair used.
Figure 1. Pass Labs x600.5.
Figure 2. Pass Labs x600.5.
Figure 3. Pass Labs x600.5.
Figure 4. Pass Labs x600.5.
Figure 5. Pass Labs x600.5.
Pass Labs x1000.5
1000 watts/channel 8 ohms.
2000 watts/channel 4 ohms.
200 pounds each.
$31,000 per pair new, ~$??? per pair used. I have never seen a pair on the used market.
Figure 6. Pass Labs x1000.5.
Figure 7. Pass Labs x1000.5.
Figure 8. Pass Labs x1000.5.
Bryston 28B SST
1000 watts/channel 8 ohms.
1800 watts/channel 4 ohms.
92 pounds each.
$16,000 per pair new, ~$??? per pair used. I have never seen a pair on the used market.
Not as pretty a face as the Pass amps and not as nice a body as the PS Audio, but it has the second best $/watt ratio.
Figure 9. Bryston 28B SST
Figure 10. Bryston 28B SST
Figure 11. Bryston 28B SST
Figure 12. Bryston 28B SST
PS Audio Classic 250
1000 watts/channel 8 ohms bridged mono.
1800 watts/channel 4 ohms bridged mono.
95 pounds each.
$10,000 per pair new, ~$5000 per pair used.
Cute face, gorgeous body and a cost of $10/watt.
The Classic 250 is a 250 watts/channel stereo amplifier that provides 1000 watts/channel in bridged mode. It features a built-in AC power regenerator and has a high degree of immunity to poor wall power quality. It is a complicated design and they were discontinued due to reliability issues. Still, they rarely show up on the used market.
I asked PS Audio if they have plans to produce anything similar to the Classic 250 in the near future. This was their response:
" If we were to produce the C-250 today, its complex design would result in a product that would retail for around $8K to $10K. PS Audio just does not produce products at these prices.
Additionally, the complex design of the C-250 resulted in it being less than entirely reliable, resulting in having to ship a 95 lb amplifier for service occasionally. We use the C-250 as our reference amplifier here, for the development of new products, and hope that in the future we will be able to develop something with performance as good or better, at a reasonable price."
Figure 13. PS Audio Classic 250
Figure 14. PS Audio Classic 250
Figure 15. PS Audio Classic 250
Krell FPB 750 MCx
750 watts/channel 8 ohms.
1500 watts/channel 4 ohms.
140 pounds each.
$29,000 per pair new, ~$13,000 per pair used.
I'm not a big fan of certain aspects of the "Krell sound", but I wouldn't mind if someone would gift me a pair so that:
1. I could say I once owned a pair but traded up.
2. I could sell them and apply the funds toward a pair of the amps previously mentioned.:)
Hey, what's up with that captive power cord?
Figure 16. Krell FPB 750 MCx
Figure 17. Krell FPB 750 MCx
I think I'll commission a machine shop to make a pair of fancy sculpted aluminum faceplates for my JC 1's. That might go a long way toward taking the last little bit of edge off the desire to upgrade.*
*
He's just kidding.
No...I'm not.~DK
From the controversial SDA SRS review in the November 1985 issue of Stereo Review:
"Not surprisingly in view of its large driver complement and rated power-handling of 1,000 watts or more, the Polk SDA-SRS thrives on power levels that would vaporize some lesser designs. We ran out of power from our amplifier (one of the most powerful available for home use) when we attempted to reach the speaker's limits with 1,000 cycle tone bursts. At 100 Hz the amplifier clipped at 1,650 watts into 6 ohms, and at 1,000 Hz it clipped at 765 watts into 20 ohms. Only at 10,000 Hz, where presumably only one driver was in use, did we reach the limits of the speaker and the amplifier at about the same time-1,265 watts into 5 ohms."
Question To Polk's Customer Service Department:
"The SDA SRS 1.2TL is rated for amplifiers up to 1000 watts. Is this a continuous rating or short term? If it is short term, what is the maximum continuous power rating?
Does anyone at Polk know the power amp used for the tests ran by Stereo Review?"
Matthew Polk's Answer:
"We would all like to have a single number that tells us how much power a speaker can safely handle but, like most things, its not that simple. When we rated the SRS 1.2TL for amplifiers up to 1,000 watts we were trying to convey that the speakers would perform better with more powerful amps and also were trying to get away from single number power handling specs which are always misleading. The 1,000 watt rating is most certainly not a continuous power rating. Continuous power handling would depend on whether the driving signal is broad band or a single frequency and would further depend on the specific frequencies being used. Continuous power handling for the 1.2TL at 80Hz, for example, might be very close to 1,000 watts because, at that frequency, all 8 drivers are working together and the system is not limited by mechanical excursion. However, continuous power handling above around 8kHz would be no more than 50 watts because only one tweeter is operating at those frequencies. As a general rule power handling is greater at low frequencies where the voice-coils move enough to help dissipate the heat. At higher frequencies there's no movement and the heat just builds up like the filament of a light bulb.
In addition to these considerations power handling for an SDA product would also depend on whether the stereo signal was mostly in the left or right channel, or mono blended. Power handling would be higher in the midrange for Left or Right only signals.
Stereo Review did test the system with tone bursts. I think that review was done by Julian Hirsch. Julian often used Carver amps but that could not have been the case here because the Carver's were non-common ground and would not have worked with any of the SDA speakers. It's possible that it was a Crown or the hugely powerful NAD 3xxx power amp available at that time.
-msp"
I'm not currently in the market for new monoblocks, but if I were, I wouldn't mind rolling these beasts through my two channel system. There are probably a few tube amps that would work too.;)
The following are, as Rod Serling was fond of saying, submitted for your approval:
Pass Labs x600.5
600 watts/channel 8 ohms.
900 watts/channel 4 ohms.
150 pounds each.
$22,000 per pair new, ~$9500 per pair used.
Figure 1. Pass Labs x600.5.
Figure 2. Pass Labs x600.5.
Figure 3. Pass Labs x600.5.
Figure 4. Pass Labs x600.5.
Figure 5. Pass Labs x600.5.
Pass Labs x1000.5
1000 watts/channel 8 ohms.
2000 watts/channel 4 ohms.
200 pounds each.
$31,000 per pair new, ~$??? per pair used. I have never seen a pair on the used market.
Figure 6. Pass Labs x1000.5.
Figure 7. Pass Labs x1000.5.
Figure 8. Pass Labs x1000.5.
Bryston 28B SST
1000 watts/channel 8 ohms.
1800 watts/channel 4 ohms.
92 pounds each.
$16,000 per pair new, ~$??? per pair used. I have never seen a pair on the used market.
Not as pretty a face as the Pass amps and not as nice a body as the PS Audio, but it has the second best $/watt ratio.
Figure 9. Bryston 28B SST
Figure 10. Bryston 28B SST
Figure 11. Bryston 28B SST
Figure 12. Bryston 28B SST
PS Audio Classic 250
1000 watts/channel 8 ohms bridged mono.
1800 watts/channel 4 ohms bridged mono.
95 pounds each.
$10,000 per pair new, ~$5000 per pair used.
Cute face, gorgeous body and a cost of $10/watt.
The Classic 250 is a 250 watts/channel stereo amplifier that provides 1000 watts/channel in bridged mode. It features a built-in AC power regenerator and has a high degree of immunity to poor wall power quality. It is a complicated design and they were discontinued due to reliability issues. Still, they rarely show up on the used market.
I asked PS Audio if they have plans to produce anything similar to the Classic 250 in the near future. This was their response:
" If we were to produce the C-250 today, its complex design would result in a product that would retail for around $8K to $10K. PS Audio just does not produce products at these prices.
Additionally, the complex design of the C-250 resulted in it being less than entirely reliable, resulting in having to ship a 95 lb amplifier for service occasionally. We use the C-250 as our reference amplifier here, for the development of new products, and hope that in the future we will be able to develop something with performance as good or better, at a reasonable price."
Figure 13. PS Audio Classic 250
Figure 14. PS Audio Classic 250
Figure 15. PS Audio Classic 250
Krell FPB 750 MCx
750 watts/channel 8 ohms.
1500 watts/channel 4 ohms.
140 pounds each.
$29,000 per pair new, ~$13,000 per pair used.
I'm not a big fan of certain aspects of the "Krell sound", but I wouldn't mind if someone would gift me a pair so that:
1. I could say I once owned a pair but traded up.
2. I could sell them and apply the funds toward a pair of the amps previously mentioned.:)
Hey, what's up with that captive power cord?
Figure 16. Krell FPB 750 MCx
Figure 17. Krell FPB 750 MCx
I think I'll commission a machine shop to make a pair of fancy sculpted aluminum faceplates for my JC 1's. That might go a long way toward taking the last little bit of edge off the desire to upgrade.*
*
He's just kidding.No...I'm not.~DK
Proud and loyal citizen of the Digital Domain and Solid State Country!
Post edited by DarqueKnight on
Comments
-
No McInotsh MC2KW monoblocks?
2000WPC into 8 ohms
Over 350 pounds per side, I think
$60,000 per pair -
"He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche
-
I'd choose the Pass pieces every time
"Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul! -
Musical Fidelity kW monoblocks with separate power supplies.
1000 Watts per channel into 8 Ohms (24dBW)
1800 Watts per channel into 4 Ohms
3000 Watts per channel into 2 Ohms
Each block - 95lbs.
Each power supply - 94 lbs.
$28,000 new, $19,000 used
Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
John in MA wrote: »No McInotsh MC2KW monoblocks?Or even MC1.2KW?
I don't find the retro styling aesthetically appealing. Sorry.I'd choose the Pass pieces every time
Pass comes very close to what I would design for myself.:)Musical Fidelity kW monoblocks with separate power supplies.
Those are worth looking into. Plus, they conform to my residential aesthetic.;)Proud and loyal citizen of the Digital Domain and Solid State Country! -
I wish you guys would slow down a bit,,somehow though,,I knew this was coming.
JC approves....he told me so. (F-1 nut) -
Something missing here........ Mark Levinson 336. This will rock your world with the big SDA's. All very nice selections listed however IMHO this amp should be on the list.
Happy Holidays and Merry Christmas to all the Polkies!
Best,
Paul
Main system: Levinson Reference 32 Preamp/30.6 DAC/31.5 Transport/Sony SCD777ES/VPI Aries w/SDS JMW 10.5 arm/Van den Hul Frog/Levinson 33 Monoblocks/33H Monoblocks/Transparent reference XL interconnect & Speaker cable/Nearfield Acoustics Pipedream Reference 18 Line Array.
Bedroom: Levinson 390S/380S/ML3/Sony SCD 777ES/McIntosh MC2000/Infinity IRS-Beta -
What are the requirements for this? Over $10k? I'm sure there is something special about those other amps...
But what about Emotiva's latest offering? The XPA-1 Monoblock at ~$1800 for a pair (new/shipped)
~76lbs each??8 ohms = 500 WRMS
4 ohms = 1000 WRMS
Stable below 4 ohms
Is it even a contender?
____________________
This post is a natural product. The slight variations in spelling and grammar enhance its individual character and beauty and in no way are to be considered flaws or defects.
HT:Onkyo 805, Emotiva XPA-5, Mitsu 52" 1080p DLP / polkaudio RTi12, CSIa6, FXi3, uPro4K
2-chnl : Pio DV-46AV (SACD), Dodd ELP, Emotiva XPA-1s, XPA-2, Odyssey Khartago, LSi9, SDA-SRS 2 :cool:, SB Duet, MSB & Monarchy DACs, Yamaha PX3 TT, SAE Tuner...
Pool: Atrium 60's/45's -
Trying out Different Audio Cables is a Religious Affair. You don't discuss it with anyone. :redface::biggrin:
-
I want a pair of these custom made 1015w RMS tubes! They should push SDAs pretty well :cool:
http://www.chambonino.com/construct/const9.html -
Aragon Palladium, Palladium II, Palladium 1K. Not so high on the watts-per-channel scale as the others; but they oughta be enough--and the price is right considering they're made in the USA, not Communist China.
400 watts @ 8 ohm
600 watts @ 4 ohm
~1000 watts @ 1 ohm
The first 100 watts (Palladium) or 125 watts (PII or P1K) are with the transistors biased into Class A. The power supply is HUGE; they have a bigger transformer than the Bryston 28B SST.
I got my PIIs used for $1700/pair delivered to my home. More usually priced at ~$2000--$2500; although the original Palladiums may be less.
(Don't use 'em with blade/blade SDA speakers...unless you pull the interconnect cable. They're monoblocks, and cannot be made common-ground.)
http://forums.klipsch.com/forums/storage/4/978915/htpallrev.pdf -
I'll throw in the Cary CAD-500 mono's if they are as sweet as my CAD-200.
500W @ 8ohms
1000W @ 4ohms
~$7k new/~$3500 used
WesLink: http://polkarmy.com/forums
Sony 75" Bravia 4K | Polk Audio SDA-SRS's (w/RDO's & Vampire Posts) + SVS PC+ 25-31 | AudioQuest Granite (mids) + BWA Silver (highs) | Cary Audio CAD-200 | Signal Cable Silver Resolution XLR's | Rotel Michi P5 | Signal Cable Silver Resolution XLR's | Cambridge Audio azur 840C--Wadia 170i + iPod jammed w/ lossless audio--Oppo 970 | Pure|AV PF31d
