Adcom amps

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  • Lowell_M
    Lowell_M Posts: 1,660
    edited March 2007
    MillerLiteScott wrote:
    I had my butler copy the info and he mailed it out today.

    Look for it in a day or 2.

    Scott

    Thanks bro. I wish I had a butler.:cool:
    HT
    RTi70 mains
    CSi30 center
    RTi28 Rears
    Velodyne CHT-12
    H/K AVR-247
    ADCOM GFA-7000
    Samsung PN58B860
    Playstation 3
    2-Channel
    Polk Audio LSi15's
    Rotel RCD-1072
    Nakamichi CA-5 Pre
    ADCOM GFA-555
    Signal Cable Analog II IC's
    Signal Ultra Bi-Wire Speaker Cables
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  • heiney9
    heiney9 Posts: 25,165
    edited March 2007
    a_mattison wrote:
    Asside from wattage, what is important in the specs? I understand headroom...conceptually, but from a numbers standpoint, what do you look for in the specs?

    Damping factor can be an indicator. Specs are all over the board with diff equipment. Just like 0-60 times on cars. It gives you no indication of how the car will really be when driving.

    Wattage rating can sometimes indicate how stout something is especially if it's rated 20Hz-20kHz for less than 8 ohms, but other than that specs really don't tell the whole story as you know.

    The Outlaw, Parasound, Adcom all probably have very similar specs but you heard how different they sounded. Same with the Parasound pre and the Nak pre.

    Me personally I'm more into looking into the design, quality of parts, and build quality to kind of determine if it's merely a good or great piece. (and I'm still an amatuer when it comes to evaluating a design :) )

    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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  • jdhdiggs
    jdhdiggs Posts: 4,305
    edited March 2007
    a_mattison wrote:
    Asside from wattage, what is important in the specs? I understand headroom...conceptually, but from a numbers standpoint, what do you look for in the specs?

    To me, slew rate is more important that wattage, as is damping factor. In theory, and to my ears, a high slew rate amp has better highs and mids than a low one. A high damping factor amp will handle the lows very well and can control large/multiple drivers.

    Simplifying things, the watts (and how low will it be stable) is how good the power supply is, the peak/headroom measures how many/large the capaciters are, slew rate is how the highs sound, and damping factor is how much control will it have on the low end. Yes, I know there's much, much more to it then that, I just wanted to make it as simple as possible.
    There is no genuine justice in any scheme of feeding and coddling the loafer whose only ponderable energies are devoted wholly to reproduction. Nine-tenths of the rights he bellows for are really privileges and he does nothing to deserve them. We not only acquired a vast population of morons, we have inculcated all morons, old or young, with the doctrine that the decent and industrious people of the country are bound to support them for all time.-Menkin
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  • heiney9
    heiney9 Posts: 25,165
    edited March 2007
    ^^^pretty good general analysis :cool:
    "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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  • hearingimpared
    hearingimpared Posts: 21,137
    edited March 2007
    engtaz wrote:
    GFA 555
    200 watts per channel 20Hz - 20,000Hz @ 8 ohms with less than 0.09% THD, 325 watts per channel 20Hz - 20,000Hz @ 4 ohms with less than 0.25% THD, 600 watts bridges mode 20Hz - 20,000Hz @8 ohms with less than 0.25% THD,
    Sensitivity: 130mV
    (4Hz-150kHz), damping factor (150-200), gain (27dB), and noise (-106 dB).

    engtaz
    One thing I wish Adcom would provide is the slew rate.
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  • heiney9
    heiney9 Posts: 25,165
    edited March 2007
    hearingimpared wrote:
    One thing I wish Adcom would provide is the slew rate.

    I think they do in the original literature (glossy sales brochure) provided with the early products. I have original copies at home and I'll check it out and let you know.

    Also a-mattison if you want copies of the lit. I can make them for you. It's the orginal sales brochure's an a couple reprints of Stereophile reviews of the day.

    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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  • heiney9
    heiney9 Posts: 25,165
    edited March 2007
    Hearing, you are probably looking for the specs for the 565 mono's and when I bought my Adcom with the associated literature they weren't in production yet, so I can't help you with the 565's and the slew rate.
    "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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  • hearingimpared
    hearingimpared Posts: 21,137
    edited March 2007
    heiney9 wrote:
    Hearing, you are probably looking for the specs for the 565 mono's and when I bought my Adcom with the associated literature they weren't in production yet, so I can't help you with the 565's and the slew rate.

    Yo Bro, I called their customer service guy "Eric" (who by the way . . . well never mind) and they assured me that they DO NOT provide a slew rate on any of their products. When asked why they didn't they told me it wasn't relevent???? What the hell are they talking about. That is one of the most relevent specs ever. It is the speed of the amp. The reason I asked them for the slew rate was to make sure when I bi-amp'd my 1.2 TLs with a Parasound, the slew rates of the two amps were at least compatibly close so there wouldn't be any timing or phasing differences.
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  • heiney9
    heiney9 Posts: 25,165
    edited March 2007
    hearingimpared wrote:
    Yo Bro, I called their customer service guy "Eric" (who by the way . . . well never mind) and they assured me that they DO NOT provide a slew rate on any of their products. When asked why they didn't they told me it wasn't relevent???? What the hell are they talking about. That is one of the most relevent specs ever. It is the speed of the amp. The reason I asked them for the slew rate was to make sure when I bi-amp'd my 1.2 TLs with a Parasound, the slew rates of the two amps were at least compatibly close so there wouldn't be any timing or phasing differencs.

    Well Adcom has changed hands atleast 2 times and I'm 1% sure they provided a slew rate in the literature back in 1986. Eric (the CS guy) was probably in diapers when the brochure was printed :D
    "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 March 2007
    I'm at home for lunch and staring right at the literature and Eric is CS is absolutely right. No slew rate mentioned. Actually the specs are pretty sparse.

    Wattage
    Input sensitivity
    dynamic headroom
    damping factor
    s/n ratio
    weight and dimensions

    I wouldn't loose too much sleep over a lack of slew rate spec. IMHO, slew rate is a bit overated as a determining factor anyways.
    "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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  • jdhdiggs
    jdhdiggs Posts: 4,305
    edited March 2007
    Oh yeah, gain is kind of important too (made it a problem to bi-amp the maggies and a serious PITA to tri-amp). s/n to me falls to the background since even the cheapest/crappiest amps anymore have decent ratings.

    HI: I have some original documentation on the 565 mono's, I'll see if it's mentioned tonight.
    There is no genuine justice in any scheme of feeding and coddling the loafer whose only ponderable energies are devoted wholly to reproduction. Nine-tenths of the rights he bellows for are really privileges and he does nothing to deserve them. We not only acquired a vast population of morons, we have inculcated all morons, old or young, with the doctrine that the decent and industrious people of the country are bound to support them for all time.-Menkin
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  • davidk0512
    davidk0512 Posts: 157
    edited March 2007
    Explanation on dynamic headroom


    http://forum.ecoustics.com/bbs/messages/34579/109459.html
    David
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  • hearingimpared
    hearingimpared Posts: 21,137
    edited March 2007
    jdhdiggs wrote:
    Oh yeah, gain is kind of important too (made it a problem to bi-amp the maggies and a serious PITA to tri-amp). s/n to me falls to the background since even the cheapest/crappiest amps anymore have decent ratings.

    HI: I have some original documentation on the 565 mono's, I'll see if it's mentioned tonight.

    Thanks Brother . . .BTW I saw your pic in Doros Kharma, my conclusions >>>>we never look like we sound or write!!!!! LOL
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  • jdhdiggs
    jdhdiggs Posts: 4,305
    edited March 2007
    What did you think I looked like?
    There is no genuine justice in any scheme of feeding and coddling the loafer whose only ponderable energies are devoted wholly to reproduction. Nine-tenths of the rights he bellows for are really privileges and he does nothing to deserve them. We not only acquired a vast population of morons, we have inculcated all morons, old or young, with the doctrine that the decent and industrious people of the country are bound to support them for all time.-Menkin
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  • hearingimpared
    hearingimpared Posts: 21,137
    edited March 2007
    davidk0512 wrote:
    Explanation on dynamic headroom


    http://forum.ecoustics.com/bbs/messages/34579/109459.html
    Nice article.:)
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  • hearingimpared
    hearingimpared Posts: 21,137
    edited March 2007
    jdhdiggs wrote:
    What did you think I looked like?
    A geeky engineer with white tape holding your glasses together and a pocket protector!!! WAAAAAAAAAAAAAAAAAAAAAAAAAAA
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  • davidk0512
    davidk0512 Posts: 157
    edited March 2007
    hearingimpared wrote:
    Nice article.:)

    I have a 555 and not that it's a problem, but dynamic headroom seems to be one of the specs like slew rate that Adcom fails to advertise. Many amps on the market tout those specs, obviously, some people think they're important. Anyway, dynamic headroom is the one I've gotten curious about and I have not been able to find it documented anywhere. My distortion lights have never come on and I like it pretty loud, I'm guessing the DH is >3dB, but who knows?
    David
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  • powerlord
    powerlord Posts: 310
    edited March 2007
    Heiney,there is quite a diference in the 5500 and the 5800 sound wise,Jeff brought the 5500 over to the house today and we couldn't hear the audible difference like we could in the 5800 with my system,compared to the reciever running the mains pretty even,why is that?Hell,the 5500 is only 50 wpc less at 8 ohm than the 5800,are we hearing the double your power 3 db here?Which is what the 5800 is compared to the reciever.:confused:
    LG 50 in. Plasma
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    Marantz SR-18U
    HK AVR-7200


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    http://members.soundclick.com/powerlord66
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  • heiney9
    heiney9 Posts: 25,165
    edited March 2007
    davidk0512 wrote:
    I have a 555 and not that it's a problem, but dynamic headroom seems to be one of the specs like slew rate that Adcom fails to advertise. Many amps on the market tout those specs, obviously, some people think they're important. Anyway, dynamic headroom is the one I've gotten curious about and I have not been able to find it documented anywhere. My distortion lights have never come on and I like it pretty loud, I'm guessing the DH is >3dB, but who knows?

    From the original literature in 1987

    Dynamic Headroom @ 4 ohm

    GFA 535 3 dB
    GFA 545 2.6 dB
    GFA 555 2.3 dB

    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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  • heiney9
    heiney9 Posts: 25,165
    edited March 2007
    powerlord wrote:
    Heiney,there is quite a diference in the 5500 and the 5800 sound wise,Jeff brought the 5500 over to the house today and we couldn't hear the audible difference like we could in the 5800 with my system,compared to the reciever running the mains pretty even,why is that?Hell,the 5500 is only 50 wpc less at 8 ohm than the 5800,are we hearing the double your power 3 db here?Which is what the 5800 is compared to the reciever.:confused:

    Damn computer see below (post #83)
    "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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  • davidk0512
    davidk0512 Posts: 157
    edited March 2007
    heiney9 wrote:
    From the original literature in 1987

    Dynamic Headroom @ 4 ohm

    GFA 535 3 dB
    GFA 545 2.6 dB
    GFA 555 2.3 dB

    H9

    Great! Thank-you, now one satisfied curiosity
    David
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  • heiney9
    heiney9 Posts: 25,165
    edited March 2007
    powerlord wrote:
    Heiney,there is quite a diference in the 5500 and the 5800 sound wise,Jeff brought the 5500 over to the house today and we couldn't hear the audible difference like we could in the 5800 with my system,compared to the reciever running the mains pretty even,why is that?Hell,the 5500 is only 50 wpc less at 8 ohm than the 5800,are we hearing the double your power 3 db here?Which is what the 5800 is compared to the reciever.:confused:

    Firstly the 5800 was the flagship model at the time so to a certain degree no expense was spared (within the intended price point). I also believe Nelson Pass was a bit more heavily involved in the design which, IMO is a big plus.

    When was the 5500 you compared manufactured? Something I've been wondering is the current line of Adcom amps have been produced and manufactured for approx. 12-14 years. I wonder how a 5500 manufactured 10-12 years ago sounds compared to one produced today? They have moved production a couple times and have changed ownership atleast twice. Original parts sometimes dry up and replacement parts need to be used, etc, etc. Sure the parts might measure the same, but might sound slightly different.

    This could be part of the possible reason the difference in sound. I know there were a batch of 5500 produced (early production) that had removeable power cords. Those are the ones I'd be looking for.
    "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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  • powerlord
    powerlord Posts: 310
    edited March 2007
    Well I've had the same experience with two amps now,the 5500,and a Rotel 1080,so I'm guessing this is a power situation,seems when we get above the 250 wpc the speakers shine.So I'm going to save up and demo some more amps at that level of power.Thanks Heiney and everyone else,now I have a reference to what amp I'm in search of.
    LG 50 in. Plasma
    Eosone setup
    Marantz SR-18U
    HK AVR-7200


    My Music
    http://members.soundclick.com/powerlord66
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