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  • Question about W/P/C

    In the specifications it says that my Marantz PM-KI-Pearl Integrated Amplifier has a rated output of 90 w/p/c into 8 ohms or 140w/p/c into 4 ohms. In Michael Fremer's 2010 review of this IA it says and I quote below:
    Ishiwata claims that the Pearl's power ratings are conservative, and that it delivers a linear 110Wpc into 8 ohms or 180Wpc into 4 ohms.
    Why rate this IA officially at 90w/pc/ when it is clearly capable of more?
    Is there is specific rationale for doing so?

    MF's review
    Dynavector DV20x2L MC cartridge - Genesis G7.1f speakers - Marantz Reference PM-KI-Pearl Int. Amp. - Oracle Audio Paris MkV turntable - Various Morrow & Valab/King cables

  • #2
    Under promise and over deliver.
    Micro Seiki SX-8000 table with flywheel, SME 3012R arm, SME 312S arm, Lyra Etna SL and Dynavector XV-1S cartridges, ARC Ref 3 phono stage, Otari MX-55 tape deck, Ampex 350 repros, Roon Nucleus Plus server, PS Audio DSJ DAC, ARC Ref 6 pre, ARC Ref 75 amp, JBL 4345 speakers, and Def Tech Ref subs.

    Comment


    • Johnny Vinyl
      Johnny Vinyl commented
      Editing a comment
      Pretty standard line, but not sure if that's quite it.

  • #3
    Many companies under rate products that's good
    also some over rate as in same rating but peak and not RMS
    many years ago Amps were made with a peak to peak rating meaning peak from each side of the sign wave so 100 is now 200 but really 100x .707 = 70 RMS
    GLAD it measured more but how good it sounds really matters more lol
    analog stuff.
    otari mtr 10 2 track 1/4 made new by soren
    otari mtr 10 2 track 1/4 1/2 combo made new by soren
    sota sapphire used eminent tech ver 2 arm
    new sota nova table has magnetic levitation platter and full speed control and latest motor same arm as above
    thorens td124 sme ver 2 arm
    thorens td125 sme ver 2 arm
    kenwood direct drive sme ver 2 arm
    phono preamp Ml no 25 all re capped
    speakers cust infinity IRS V , new caps and LPS , magnets etc.
    mark levivson pre no 26 amps no 33
    digital three cust servers , win ser 2016 , AO
    Dacs lampi various

    Comment


    • #4
      You can never have enough power in my opinion however, the first watt is the most important. The perceived power of the amplifier is directly related to the impedance of the loudspeakers. Ultra low impedance dips in the frequency band can suck the power supply dry. The best amps are load invariant, doubling down in power with each doubling of impedance.
      Speakers/Amps: Genesis G2.2 Jr with Powered Servo-Sub Bass, Genesis GR1440 Mono Amps, 5,000 watts total power
      Preamp: SMc Audio VRE-1C Preamp (fully balanced inputs and output)
      Analog 1: VPI Signature 21 Belt-Drive Turntable w/ 10” 3D Printed Fatboy Gimbal Arm and Ortofon MC Windfeld Ti Phono Cartridge driving Lehmann Silver Cube Phono Preamp
      Analog 2: VPI HW-40 Direct-Drive Turntable w/ 12” 3D Printed Fatboy Gimbal Arm and Ortofon MC Anna Diamond Phono Cartridge driving Genesis Gold Phono Preamp
      Analog 3: Studer A810 R2R tape w/ Bridge Console. Using built-in tape preamp
      Digital: Lumin Network Player with Lumin NAS
      Cables: Genesis Advanced Technologies/Absolute Fidelity Interface Interconnects, Speaker, Phono and Power
      A/C Power: Extensive System Upgrades, Sub-panel w/hard-wired power cables, and IsoTek Super Titan Passive Power Conditioning for Amplifiers
      Accessories: Custom Acrylic Equipment Stands, Klaudio Ultrasonic RCM

      Comment


      • tom_hankins
        tom_hankins commented
        Editing a comment
        Damping factor plays a big role too.

    • #5
      Do clads D Amps also have this doubling feature
      my older Aragon's mono amos do my speakrkers dip to just below 2 ohms as well.
      Maybe a post for another thread is pure class a and a/b
      as most have in solid state. I have read that the first few watts on most are class a amd sound better and some claim they can hear when the bios changes to class a/b or b as some call it.
      Shiuid I post another thread on this ?
      analog stuff.
      otari mtr 10 2 track 1/4 made new by soren
      otari mtr 10 2 track 1/4 1/2 combo made new by soren
      sota sapphire used eminent tech ver 2 arm
      new sota nova table has magnetic levitation platter and full speed control and latest motor same arm as above
      thorens td124 sme ver 2 arm
      thorens td125 sme ver 2 arm
      kenwood direct drive sme ver 2 arm
      phono preamp Ml no 25 all re capped
      speakers cust infinity IRS V , new caps and LPS , magnets etc.
      mark levivson pre no 26 amps no 33
      digital three cust servers , win ser 2016 , AO
      Dacs lampi various

      Comment


      • #6
        My class D Merrill Thor Amps are 200 w/p/c at 8 ohms and 400 at 4 ohms.
        Analog: Holbo Turntable, Transfiguration Proteus; Forsell Air Reference, Transfiguration Phoenix S; Rega RP-8, VdH Crimson XGW; VPI Prime Signature, VAS Nova Mono, VAS Nova Signature, Symphonic Line RG-8
        Digital: Mac mini 6,2 with YFS PS-12M LPS; Exogal Comet Plus, Exogal Ion PowerDAC
        Electronics: Aurorasound Vida, Channel D Lino C; Merrill Cara, Gryphon M-100 Mkii (pair)
        Cables: Morrow, Gryphon interconnects; YFS USB cable; Morrow, XLO, Channel D phono cables; Morrow, Gryphon, Goertz speaker cables

        Comment


        • #7
          Originally posted by jonathanb View Post
          My class D Merrill Thor Amps are 200 w/p/c at 8 ohms and 400 at 4 ohms.
          what's the rated output at 2 ohms and do the amps like it
          TURNTABLE TechDAS Airforce III | TONEARM Graham Phantom III | CARTRIDGES ZYX Omega X SB2 + Lyra Etna SL | PHONO STAGE Boulder 1008 | DIGITAL Innuos MiniZen II + M2Tech Young + Palmer PS | LINE STAGE Boulder 810 | AMPLIFIERS Boulder 850 Monos | SPEAKERS Magico A5 | RACK Adona Eris 6DW | CABLES Mogami + Canare

          Comment


          • #8
            I've no idea as 2 ohm spec is not listed but since my speakers are Evolution Acoustic MicroOnes--nominally 6 ohm--I've had no issues.
            Analog: Holbo Turntable, Transfiguration Proteus; Forsell Air Reference, Transfiguration Phoenix S; Rega RP-8, VdH Crimson XGW; VPI Prime Signature, VAS Nova Mono, VAS Nova Signature, Symphonic Line RG-8
            Digital: Mac mini 6,2 with YFS PS-12M LPS; Exogal Comet Plus, Exogal Ion PowerDAC
            Electronics: Aurorasound Vida, Channel D Lino C; Merrill Cara, Gryphon M-100 Mkii (pair)
            Cables: Morrow, Gryphon interconnects; YFS USB cable; Morrow, XLO, Channel D phono cables; Morrow, Gryphon, Goertz speaker cables

            Comment


            • #9
              My Krell KSA-250 that I used to own was good down to .5 ohms.
              Micro Seiki SX-8000 table with flywheel, SME 3012R arm, SME 312S arm, Lyra Etna SL and Dynavector XV-1S cartridges, ARC Ref 3 phono stage, Otari MX-55 tape deck, Ampex 350 repros, Roon Nucleus Plus server, PS Audio DSJ DAC, ARC Ref 6 pre, ARC Ref 75 amp, JBL 4345 speakers, and Def Tech Ref subs.

              Comment


              • #10
                Yes one of things krells did well. I don't remenr what model krells I had years ago they were two large boxes for each c,ahnnel a d meter in the middle black . Truth is I like my cheap Aragone just as much perhaps a bit better on the highend . Low end has its own amps each side
                analog stuff.
                otari mtr 10 2 track 1/4 made new by soren
                otari mtr 10 2 track 1/4 1/2 combo made new by soren
                sota sapphire used eminent tech ver 2 arm
                new sota nova table has magnetic levitation platter and full speed control and latest motor same arm as above
                thorens td124 sme ver 2 arm
                thorens td125 sme ver 2 arm
                kenwood direct drive sme ver 2 arm
                phono preamp Ml no 25 all re capped
                speakers cust infinity IRS V , new caps and LPS , magnets etc.
                mark levivson pre no 26 amps no 33
                digital three cust servers , win ser 2016 , AO
                Dacs lampi various

                Comment


                • #11
                  Originally posted by Joe Pittman View Post
                  You can never have enough power in my opinion however, the first watt is the most important. The perceived power of the amplifier is directly related to the impedance of the loudspeakers. Ultra low impedance dips in the frequency band can suck the power supply dry. The best amps are load invariant, doubling down in power with each doubling of impedance.
                  I agree with the first sentence. The remaining sentences are false.

                  2nd sentence: perceived power has a lot more to do with distortion than the impedance of the speaker! If the amp is making higher ordered harmonic distortion, it will be perceived as louder and therefore more powerful. Its very common for a small amp to sound loud while a much more powerful amp with less distortion does not seem to sound as loud even though its actually louder.

                  3rd: Ultra low impedance likely does not affect the power supply all that much. It affects the output section of the amp quite a lot!

                  4th: this is like saying that only solid state amps are the best, and at the very least the jury is still out on that one. You don't have to know anything technical to understand this, all you have to understand is that tubes (which can't double power like that) are still very much around despite being declared 'obsolete' 70 years ago. If that were really true, tubes would be long-gone. But they are still very much with us and the tubes/transistors debate is older than the Internet. This suggests that the best amplifier (whatever 'best' must mean) could well be a tube amp that does not double power. In fact the doubling power thing is a pretty weak argument- how about how it sounds? That might be more important...

                  Comment


                  • #12
                    Originally posted by atmasphere View Post

                    I agree with the first sentence. The remaining sentences are false.

                    2nd sentence: perceived power has a lot more to do with distortion than the impedance of the speaker! If the amp is making higher ordered harmonic distortion, it will be perceived as louder and therefore more powerful. Its very common for a small amp to sound loud while a much more powerful amp with less distortion does not seem to sound as loud even though its actually louder.

                    3rd: Ultra low impedance likely does not affect the power supply all that much. It affects the output section of the amp quite a lot!

                    4th: this is like saying that only solid state amps are the best, and at the very least the jury is still out on that one. You don't have to know anything technical to understand this, all you have to understand is that tubes (which can't double power like that) are still very much around despite being declared 'obsolete' 70 years ago. If that were really true, tubes would be long-gone. But they are still very much with us and the tubes/transistors debate is older than the Internet. This suggests that the best amplifier (whatever 'best' must mean) could well be a tube amp that does not double power. In fact the doubling power thing is a pretty weak argument- how about how it sounds? That might be more important...
                    How much of why we like tubes is due to the technologies ability to swing voltages?
                    Myles B. Astor, PhD, Administrator
                    Senior Editor, Positive-Feedback.com
                    ________________________________________

                    -Zellaton Plural Evo speakers
                    -Goldmund Telos 300 stereo amp
                    -Goldmund Mimesis 37S Nextgen preamplifier
                    -Doshi EVO and Goldmund PH3.8 phonostage
                    -VPI Vanquish direct-drive turntable
                    -VPI 12-inch 3D Fat Boy dual pivot tonearm, VPI 12-inch 3D Fat Boy gimballed and SAT LM-12 arm
                    -Lyra Atlas SL Lambda, Fuuga Mk. 2, vdh Colibri Master Signature, MutechHayabusa, MOFI Master Tracker, Sumiko Songbird cartridges
                    -Technics RS1506 with Flux Magnetic heads, Doshi V3.0 tape stage (balanced)
                    -Assorted cables including Transparent XL Gen. 6, Skogrand, Viero, Kubala-Sosna, Audience Au24SX, Genesis Advanced Technologies and Ensemble Power Cords
                    -Accessories including Stillpoint Aperture panels, Cathedral Sound panels, Furutech NCF Nano AC receptacles; Silver Circle Tchaik 6 PLC, Symposium ISIS and SRA Craz 3 racks, Audiodharma Cable Cooker, Symposium Ultra and assorted SRA OHIO Class 2.1+ platforms.

                    Comment


                    • #13
                      ^^ I don't think that has much to do with it.

                      As far as I can tell, its all about distortion. All amps distort and if they make higher ordered (and especially odd ordered) harmonics they simply aren't going to sound as pleasant. Many tube amps (not all!) make a bit of the 2nd harmonic which gives the amp a lush quality. While this is fun to listen to, its not neutral by any means. Many solid state amps are considered neutral as they don't make the lower ordered harmonics. But they do make the higher orders, which the ear interprets as brightness and hardness. That's not neutral either although many audiophiles give that a pass.

                      Back in the 1970s, Sony introduced the VFET (also known as Static Induction Transistor or SIT). These had triode linearity curves and more importantly, soft clipping. If Sony had continued down this road (instead of their usual MO which is to shoot themselves in the foot: Elcasette, Beta, minidisk...) we might have been able to leave tubes behind. But they didn't (for example the SITs were power devices but there really weren't any driver or voltage amplifier examples) and that's that. SITs don't handle a lot of voltage; despite that they do sound really good. Nelson Pass has a thread on DIYAudio with a revamped circuit using SITs. Sounds like most of the devices he obtained are sold out; to his credit Nelson also had a semiconductor house make some SITs for him but the house folded. IMO this is an area that is at the leading edge of audio (unless Class D somehow brings home on the promise...).

                      The funny thing is tubes can be really linear and so should not be making that much in the way of distortion. But they often do, simply due to topography of the circuit in which they reside. We avoided the typical 2nd harmonic thing simply by designing our amps to be fully differential- which incidentally is a common trait in solid state designs. Back in the 1970s Sunn (a guitar amp manufacturer) built a series of solid state amps that were renowned for their lush character. These amps used FETs in the preamp operating single-ended and zero feedback; the power amp section was single-ended right to the output transistors where are rather substantial transformer did the conversion from single-ended to push pull. So these amps make a lot of lower ordered harmonics much like tube amps (but still had the solid state harsh clipping otherwise). As long as you didn't drive them too hard they gave a lot to tube guitar amps a run for the money.

                      So topology and its effect on distortion plays a role as well has the characteristics of the devices themselves. Like you might expect, its not any one thing.

                      Comment


                      • #14
                        Originally posted by atmasphere View Post
                        ^^ I don't think that has much to do with it.

                        As far as I can tell, its all about distortion. All amps distort and if they make higher ordered (and especially odd ordered) harmonics they simply aren't going to sound as pleasant. Many tube amps (not all!) make a bit of the 2nd harmonic which gives the amp a lush quality. While this is fun to listen to, its not neutral by any means. Many solid state amps are considered neutral as they don't make the lower ordered harmonics. But they do make the higher orders, which the ear interprets as brightness and hardness. That's not neutral either although many audiophiles give that a pass.

                        Back in the 1970s, Sony introduced the VFET (also known as Static Induction Transistor or SIT). These had triode linearity curves and more importantly, soft clipping. If Sony had continued down this road (instead of their usual MO which is to shoot themselves in the foot: Elcasette, Beta, minidisk...) we might have been able to leave tubes behind. But they didn't (for example the SITs were power devices but there really weren't any driver or voltage amplifier examples) and that's that. SITs don't handle a lot of voltage; despite that they do sound really good. Nelson Pass has a thread on DIYAudio with a revamped circuit using SITs. Sounds like most of the devices he obtained are sold out; to his credit Nelson also had a semiconductor house make some SITs for him but the house folded. IMO this is an area that is at the leading edge of audio (unless Class D somehow brings home on the promise...).

                        The funny thing is tubes can be really linear and so should not be making that much in the way of distortion. But they often do, simply due to topography of the circuit in which they reside. We avoided the typical 2nd harmonic thing simply by designing our amps to be fully differential- which incidentally is a common trait in solid state designs. Back in the 1970s Sunn (a guitar amp manufacturer) built a series of solid state amps that were renowned for their lush character. These amps used FETs in the preamp operating single-ended and zero feedback; the power amp section was single-ended right to the output transistors where are rather substantial transformer did the conversion from single-ended to push pull. So these amps make a lot of lower ordered harmonics much like tube amps (but still had the solid state harsh clipping otherwise). As long as you didn't drive them too hard they gave a lot to tube guitar amps a run for the money.

                        So topology and its effect on distortion plays a role as well has the characteristics of the devices themselves. Like you might expect, its not any one thing.
                        Yes Sony has shown at a couple of shows lately the V-Fet amplifiers driving their speakers. I want to say there are two or three pairs of these amplifiers using V-Fets in existence. AFAIK, Nelson had the last of the V-Fets and they have officially gone the way of the dinosaur.
                        Myles B. Astor, PhD, Administrator
                        Senior Editor, Positive-Feedback.com
                        ________________________________________

                        -Zellaton Plural Evo speakers
                        -Goldmund Telos 300 stereo amp
                        -Goldmund Mimesis 37S Nextgen preamplifier
                        -Doshi EVO and Goldmund PH3.8 phonostage
                        -VPI Vanquish direct-drive turntable
                        -VPI 12-inch 3D Fat Boy dual pivot tonearm, VPI 12-inch 3D Fat Boy gimballed and SAT LM-12 arm
                        -Lyra Atlas SL Lambda, Fuuga Mk. 2, vdh Colibri Master Signature, MutechHayabusa, MOFI Master Tracker, Sumiko Songbird cartridges
                        -Technics RS1506 with Flux Magnetic heads, Doshi V3.0 tape stage (balanced)
                        -Assorted cables including Transparent XL Gen. 6, Skogrand, Viero, Kubala-Sosna, Audience Au24SX, Genesis Advanced Technologies and Ensemble Power Cords
                        -Accessories including Stillpoint Aperture panels, Cathedral Sound panels, Furutech NCF Nano AC receptacles; Silver Circle Tchaik 6 PLC, Symposium ISIS and SRA Craz 3 racks, Audiodharma Cable Cooker, Symposium Ultra and assorted SRA OHIO Class 2.1+ platforms.

                        Comment


                        • #15
                          Atmosphere may I ask what Amos you make ?
                          preamp , Amps , headphone or speakers.
                          analog stuff.
                          otari mtr 10 2 track 1/4 made new by soren
                          otari mtr 10 2 track 1/4 1/2 combo made new by soren
                          sota sapphire used eminent tech ver 2 arm
                          new sota nova table has magnetic levitation platter and full speed control and latest motor same arm as above
                          thorens td124 sme ver 2 arm
                          thorens td125 sme ver 2 arm
                          kenwood direct drive sme ver 2 arm
                          phono preamp Ml no 25 all re capped
                          speakers cust infinity IRS V , new caps and LPS , magnets etc.
                          mark levivson pre no 26 amps no 33
                          digital three cust servers , win ser 2016 , AO
                          Dacs lampi various

                          Comment

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