What makes a Class A amp....a Class A amp?

treitz3
treitz3 Posts: 19,033
edited May 2011 in 2 Channel Audio
Just as the title says. It was recently a typo error that led me to believe [I'm guessing] that a sand amp I bought was a Class A amp. That said, now I'm curious....

What is the difference between a Class A amplifier and a Class A/B?

I know there is Google and other sites out there that will teach me. Thing is, I trust this site. There are also apparently different types of Class A.

What is pure Class A?




What say you?
~ In search of accurate reproduction of music. Real sound is my reference and while perfection may not be attainable? If I chase it, I might just catch excellence. ~
Post edited by treitz3 on
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  • dorokusai
    dorokusai Posts: 25,577
    edited May 2011
    High Power Audio Amplifier Construction Manual
    ISBN 0-07-134119-6

    Audio Power Amplifier Design Handbook
    ISBN 0-7506-5636-0

    A must have for the audio bookshelf.
    CTC BBQ Amplifier, Sonic Frontiers Line3 Pre-Amplifier and Wadia 581 SACD player. Speakers? Always changing but for now, Mission Argonauts I picked up for $50 bucks, mint.
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  • BlueFox
    BlueFox Posts: 15,251
    edited May 2011
    H9 beat this issue to death a month or two ago.
    Lumin X1 file player, Westminster Labs interconnect cable
    Sony XA-5400ES SACD; Pass XP-22 pre; X600.5 amps
    Magico S5 MKII Mcast Rose speakers; SPOD spikes

    Shunyata Triton v3/Typhon QR on source, Denali 2000 (2) on amps
    Shunyata Sigma XLR analog ICs, Sigma speaker cables
    Shunyata Sigma HC (2), Sigma Analog, Sigma Digital, Z Anaconda (3) power cables

    Mapleshade Samson V.3 four shelf solid maple rack, Micropoint brass footers
    Three 20 amp circuits.
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  • heiney9
    heiney9 Posts: 25,165
    edited May 2011
    Oh Christ, not this again???? :wink::smile:

    http://www.polkaudio.com/forums/showthread.php?t=112785

    Debated, covered, confused here ^^^^^^^

    Some further reading

    http://www.passlabs.com/pdfs/articles/seclassa.pdf

    http://www.passlabs.com/pdfs/articles/leaving_class_a.pdf

    http://www.passlabs.com/pdfs/articles/sweet_spot.pdf

    http://www.passlabs.com/pdfs/articles/distortion_and_feedback.pdf

    http://www.passlabs.com/pdfs/old%20product%20manuals/a30manr0.pdf

    Decide for yourself.

    H9
    "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!
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  • txcoastal1
    txcoastal1 Posts: 13,287
    edited May 2011
    That aught to about cover it
    2-channel: Modwright KWI-200 Integrated, Dynaudio C1-II Signatures
    Desktop rig: LSi7, Polk 110sub, Dayens Ampino amp, W4S DAC/pre, Sonos, JRiver
    Gear on standby: Melody 101 tube pre, Unison Research Simply Italy Integrated
    Gone to new homes: (Matt Polk's)Threshold Stasis SA12e monoblocks, Pass XA30.5 amp, Usher MD2 speakers, Dynaudio C4 platinum speakers, Modwright LS100 (voltz), Simaudio 780D DAC

    erat interfectorem cesar et **** dictatorem dicere a
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  • cnh
    cnh Posts: 13,284
    edited May 2011
    H9 has got this...the only thing I'd add is the 'price'? lol Try to buy one of these on the cheap? Good Luck!

    cnh
    Currently orbiting Bowie's Blackstar.!

    Polk Lsi-7s, Def Tech 8" sub, HK 3490, HK HD 990 (CDP/DAC), AKG Q701s
    [sig. changed on a monthly basis as I rotate in and out of my stash]
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  • txcoastal1
    txcoastal1 Posts: 13,287
    edited May 2011
    I am looking at Ushers R.1.5 which boasts 40+ watts in class A 150watts in A/B@8 OHM

    for $2500 this is one of the most cost effective amps on the new market boasting class A

    I am hoping this will work well between Cary SPL98 and mini dancer 2 for my 2 chnl system


    http://www.tnt-audio.com/ampli/3_power_amps_e.html
    2-channel: Modwright KWI-200 Integrated, Dynaudio C1-II Signatures
    Desktop rig: LSi7, Polk 110sub, Dayens Ampino amp, W4S DAC/pre, Sonos, JRiver
    Gear on standby: Melody 101 tube pre, Unison Research Simply Italy Integrated
    Gone to new homes: (Matt Polk's)Threshold Stasis SA12e monoblocks, Pass XA30.5 amp, Usher MD2 speakers, Dynaudio C4 platinum speakers, Modwright LS100 (voltz), Simaudio 780D DAC

    erat interfectorem cesar et **** dictatorem dicere a
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  • mhardy6647
    mhardy6647 Posts: 33,804
    edited May 2011
    cnh wrote: »
    H9 has got this...the only thing I'd add is the 'price'? lol Try to buy one of these on the cheap? Good Luck!

    cnh

    Inexpensive (and excellent) Class A amplification is quite achievable if one doesn't mind slinging a little solder.
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  • heiney9
    heiney9 Posts: 25,165
    edited May 2011
    mhardy6647 wrote: »
    Inexpensive (and excellent) Class A amplification is quite achievable if one doesn't mind slinging a little solder.

    IMO, that's highly debateable if you are talking something new if you are talking transistors with any kind of power output. But then it depends on how you want to define class A.

    H9

    P.s. you talking about building your own?
    "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!
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  • heiney9
    heiney9 Posts: 25,165
    edited May 2011
    txcoastal1 wrote: »
    I am looking at Ushers R.1.5 which boasts 40+ watts in class A 150watts in A/B@8 OHM

    for $2500 this is one of the most cost effective amps on the new market boasting class A

    I am hoping this will work well between Cary SPL98 and mini dancer 2 for my 2 chnl system


    http://www.tnt-audio.com/ampli/3_power_amps_e.html

    Not familiar with Usher amps. Looks to be a Threshold copy or atleast heavily based on a Threshold from days past. Probably a very capable amp. $2500??? There are a lot of great amps in the price range used. If you get it, be sure to post your impressions.

    H9
    "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!
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  • FTGV
    FTGV Posts: 3,649
    edited May 2011
    Chassis and heatsinks look like complete vintage Thresold knockoffs.
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  • mhardy6647
    mhardy6647 Posts: 33,804
    edited May 2011
    heiney9 wrote: »
    IMO, that's highly debateable if you are talking something new if you are talking transistors with any kind of power output. But then it depends on how you want to define class A.

    H9

    P.s. you talking about building your own?

    Not with transistors (or with much power output) - not big fans of either.
    www.passdiy.com will lead one along interesting paths for reasonable investments, though.
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  • treitz3
    treitz3 Posts: 19,033
    edited May 2011
    Thank you gentlemen for your answers. I apologize if this has been beat to death in the recent past. You have to realize that I only log on to a thread if it interests me. Seeing as how I have not had a Class A amplifier and when I thought I was all of a sudden getting one, I became interested.

    My bad.

    Any additional information is more than welcome and it seems I have a lot to learn when it comes to this question. All in due time. Thank you again. You gentlemen rock!
    ~ In search of accurate reproduction of music. Real sound is my reference and while perfection may not be attainable? If I chase it, I might just catch excellence. ~
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  • dorokusai
    dorokusai Posts: 25,577
    edited May 2011
    True Class A or not, it's a nice amplifier Tom. The aesthetics are flashy but not overdone.
    CTC BBQ Amplifier, Sonic Frontiers Line3 Pre-Amplifier and Wadia 581 SACD player. Speakers? Always changing but for now, Mission Argonauts I picked up for $50 bucks, mint.
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  • treitz3
    treitz3 Posts: 19,033
    edited May 2011
    Thanks Mark, I'm unpacking it now.......time for some fun!
    ~ In search of accurate reproduction of music. Real sound is my reference and while perfection may not be attainable? If I chase it, I might just catch excellence. ~
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  • strider
    strider Posts: 2,568
    edited May 2011
    dorokusai wrote: »
    True Class A or not, it's a nice amplifier Tom. The aesthetics are flashy but not overdone.

    How does True Class A compare with Pure Class A?
    Wristwatch--->Crisco
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  • FTGV
    FTGV Posts: 3,649
    edited May 2011
    strider wrote: »
    How does True Class A compare with Pure Class A?
    James and Brock,its go time boys.:wink::smile:
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  • txcoastal1
    txcoastal1 Posts: 13,287
    edited May 2011
    FTGV wrote: »
    James and Brock,its go time boys.:wink::smile:

    Get a rope:biggrin:
    2-channel: Modwright KWI-200 Integrated, Dynaudio C1-II Signatures
    Desktop rig: LSi7, Polk 110sub, Dayens Ampino amp, W4S DAC/pre, Sonos, JRiver
    Gear on standby: Melody 101 tube pre, Unison Research Simply Italy Integrated
    Gone to new homes: (Matt Polk's)Threshold Stasis SA12e monoblocks, Pass XA30.5 amp, Usher MD2 speakers, Dynaudio C4 platinum speakers, Modwright LS100 (voltz), Simaudio 780D DAC

    erat interfectorem cesar et **** dictatorem dicere a
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  • megasat16
    megasat16 Posts: 3,521
    edited May 2011
    Washington Apple vs. Fiji Apples,

    Which one is Real? :biggrin: :tongue:
    Trying out Different Audio Cables is a Religious Affair. You don't discuss it with anyone. :redface::biggrin:
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  • FTGV
    FTGV Posts: 3,649
    edited May 2011
    megasat16 wrote: »
    Washington Apple vs. Fiji Apples,

    What one is Real? :biggrin: :tongue:
    Niether.:tongue:
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  • megasat16
    megasat16 Posts: 3,521
    edited May 2011
    FTGV wrote: »
    Niether.:tongue:

    You love Oranges? :tongue: :biggrin:

    California Oranges vs. Florida Oranges?

    Which one is Real? :wink:
    Trying out Different Audio Cables is a Religious Affair. You don't discuss it with anyone. :redface::biggrin:
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  • FTGV
    FTGV Posts: 3,649
    edited May 2011
    Florida ,cuz dem single ended.
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  • megasat16
    megasat16 Posts: 3,521
    edited May 2011
    FTGV wrote: »
    Florida ,cuz dem single ended.

    Uh...You need to get unstuck from the Florida ones. :wink:

    I'll tell ya the real stuff. The wife and I came back from San Fran to LA like 3 weeks ago; she wanted to buy some Garlic at Gilroy in the local produce stand.

    We stopped by at Gilroy junction and bought a few bags of Garlic, and I found these Huge Naval Oranges. $4 bucks for a whole bag (may be like 10lbs or more). I regret I bought only a bag coz they are the sweetest Oranges I ever tasted in my entire life.

    Well, next time it is. :wink:
    Trying out Different Audio Cables is a Religious Affair. You don't discuss it with anyone. :redface::biggrin:
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  • dragon1952
    dragon1952 Posts: 4,899
    edited May 2011
    I compared the Music Hall Mambo, which is supposed to be Class A, to my tube integrated a while back. I preferred the tube integrated overall but I really liked that Mambo too.
    2 channel - Willsenton R8 tube integrated, Holo Audio Spring 3 KTE DAC, audio optimized NUC7i5, Windows 10 Pro/JRiver MC29/Fidelizer Plus 8.7 w/LPS and external SSD drive, PS Audio PerfectWave P3 regenerator, KEF R3 speakers, Rythmik F12SE subwoofer, Audioquest Diamond USB cable, Gabriel Gold IC's, Morrow Audio SP5 speaker cables. Computer - Windows 10/JRiver, Schiit Magni 3+/Modi 3+, Fostex PMO.4n monitors, Sennheiser HD600 headphones
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  • treitz3
    treitz3 Posts: 19,033
    edited May 2011
    dragon1952, could you possibly describe the difference? I'm not backing you to a wall and I appreciate the fact that you may back down, given recent activity. That said, I would like to know what your observations were. No holds barred.
    ~ In search of accurate reproduction of music. Real sound is my reference and while perfection may not be attainable? If I chase it, I might just catch excellence. ~
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  • mhardy6647
    mhardy6647 Posts: 33,804
    edited May 2011
    megasat16 wrote: »
    Washington Apple vs. Fiji Apples,

    Which one is Real? :biggrin: :tongue:

    Fiji... or Fuji?
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  • dragon1952
    dragon1952 Posts: 4,899
    edited May 2011
    treitz3 wrote: »
    dragon1952, could you possibly describe the difference? I'm not backing you to a wall and I appreciate the fact that you may back down, given recent activity. That said, I would like to know what your observations were. No holds barred.

    Man...it was a while ago and I didn't have my current CDP. I think I was using a Music Hall CD25.2, but I'm pretty hooked on the tube sound. I like the smoother top, and more lush mid-range. The Mambo was smoother than a regular class A/B type solid state but it still sounded solid state. Very detailed highs, livelier faster paced, brighter, etc. So like a smoother, higher end solid state sound I guess, but definitely not the 'tube sound'.
    2 channel - Willsenton R8 tube integrated, Holo Audio Spring 3 KTE DAC, audio optimized NUC7i5, Windows 10 Pro/JRiver MC29/Fidelizer Plus 8.7 w/LPS and external SSD drive, PS Audio PerfectWave P3 regenerator, KEF R3 speakers, Rythmik F12SE subwoofer, Audioquest Diamond USB cable, Gabriel Gold IC's, Morrow Audio SP5 speaker cables. Computer - Windows 10/JRiver, Schiit Magni 3+/Modi 3+, Fostex PMO.4n monitors, Sennheiser HD600 headphones
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  • treitz3
    treitz3 Posts: 19,033
    edited May 2011
    fastz28 wrote:
    Some aficionados who prefer class A amplifiers also prefer the use of thermionic valve (or "tube") designs instead of transistors, especially in Single-ended triode output configurations.....
    Nice post BTW, thank you.

    Thank you as well, Dragon1952 for your observations. One of the main things I miss with the new [to me] amp I recently acquired is that I can also tell that it is without a doubt, an SS amplifier. Right now I'm torn between the transparency, precise imaging and a multitude of other aspects that the MF amp gives but while listening it seems that I yearn for that tube sound.

    Don't get me wrong, I have tubes in the rig [pre and CDP] but no longer in the amplification department until I put the Anthems back in. I was thinking to myself today that maybe I should start looking at class A tube amplifiers. Best of both worlds, I would imagine.

    I think I'll start a new thread about that here in just a minute.
    ~ In search of accurate reproduction of music. Real sound is my reference and while perfection may not be attainable? If I chase it, I might just catch excellence. ~
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