Amp recommendation for Polk RTA-12Cs...

jon s
jon s Posts: 905
edited July 2008 in Electronics
After recapping a pair of Polk RTA-12Cs, I am finding that my Sony TA-8650 80-wpc V-FET integrated amp just doesn't have enough grunt to drive the speakers. Above moderate volumes, the speakers seem lifeless and the amp's LED clipping indicators light up (I don't have this problem with the Polk Monitor 10Bs). I am thinking that since the RTA-12Cs impedance is so low (tested to 3-ohms) you really need an amp that can deliver power to a low impedance load. I have some options and am wondering which way to go...

1. Acurus DIA-100 (on its way) 150-wpc(@ 4-ohms) integrated amp. I understand (according to Stereophile) this amp can easily drive difficult speakers. Imaging is supposed to be first rate and it uses a passive pre-amp to eliminate any added phase or electrical signal issues.

2. I have a Nakamichi Stasis PA-5 Class-A power amp. Rated at 100-wpc (8-ohms) but I need a decent pre-amp to drive it. Not too sure on how this amp performs with low impedance speakers but I understand it otherwise is an excellent performer.

3. Adcom GFA-555 MK II power amp w/ a Adcom pre-amp(model # unk). This is a 200-wpc amp and I understand was a good performer for its price. A lot smoother than its predecessor.

4. Sony TA-N80ES 200wpc (8-ohms) MK I (i.e. U.S. model). This unit replaced the monster TA-N77ES with the BIG red VU-meters. While a decent performer, the amp has a tendacy to run hot on low impedance loads.

While power is important, I also want to know if anyone has any opinion on the sound from the above amps. i have heard the Adcoms had a little "grainy" top end. I know the Nakamichi's sound real smooth. but runs super hot as it's a Class-A design.
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Comments

  • ben62670
    ben62670 Posts: 15,969
    edited July 2008
    Adcom's are not grainy. That comes from using them with lack luster Pre's. I have a modded one in the FM. I would go used, and get an Adcom, parasound for that type of speaker.
    Ben
    Please. Please contact me a ben62670 @ yahoo.com. Make sure to include who you are, and you are from Polk so I don't delete your email. Also I am now physically unable to work on any projects. If you need help let these guys know. There are many people who will help if you let them know where you are.
    Thanks
    Ben
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  • BottomFeeder
    BottomFeeder Posts: 1,684
    edited July 2008
    Wow. I had the RTA12C's & they lived up to their reputation as being not difficult, but easy, to drive. I drove them w/a 50 wpc NAD C320Bee and had no problems at any volume - & I like my volume pretty loud.

    I upgraded to an Adcom GFA 5500 - the newer brother to the 555 I believe - & yeah, I noticed a pretty good difference. The bass was much tighter, controlled & really "slamalicious!" The highs were noticeably better - eh - everything was just better. It wasn't a night & day difference, but I liked the difference!

    Good luck.
    "Wish I didn't know now what I didn't know then." Bob Seger
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  • nikolas812
    nikolas812 Posts: 2,915
    edited July 2008
    My dad had stellar results with this amp powering the same type of speakers you have.

    No affiliation..


    http://cls.audiogon.com/cgi-bin/cls.pl?ampstran&1221283677


    Nick
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  • vonnie123
    vonnie123 Posts: 326
    edited July 2008
    I like Adcom stuff. Strong performer at a good price. Take a look at the Emotivas as well. Price wise they are hard to beat.
    [
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  • jon s
    jon s Posts: 905
    edited July 2008
    nikolas812 wrote: »
    My dad had stellar results with this amp powering the same type of speakers you have.

    No affiliation..


    http://cls.audiogon.com/cgi-bin/cls.pl?ampstran&1221283677


    Nick

    yeah, but they are WAY out of my price range....
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  • Libertyc
    Libertyc Posts: 915
    edited July 2008
    I'm using an Adcom 555 with a tube pre. Will power the RTA's just fine.
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  • BottomFeeder
    BottomFeeder Posts: 1,684
    edited July 2008
    What ^ ^ ^ he ^ ^ ^ said.

    Although, since you already have the Acurus inbound, guess you've already solved your issue. Do a search on this forum for the Polk Audio RTA12 and you'll learn a ton - I did.
    "Wish I didn't know now what I didn't know then." Bob Seger
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  • nikolas812
    nikolas812 Posts: 2,915
    edited July 2008
    jon s wrote: »
    yeah, but they are WAY out of my price range....


    I would give Emotiva a serious look then. Check out the XPA-2. Bang for buck I don't think it can be beat. They are also offering free shipping until July 31,


    http://www.emotiva.com/xpa2.html



    Nick
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  • jon s
    jon s Posts: 905
    edited July 2008
    forgot to mention...

    the seller of the Sony TA-N80ES is offering me...
    TA-N80ES 200 wpc amp
    TA-N55ES 110 wpc amp
    TA-E2000ESD Digital Preamp
    CDP-605ESD CD Player
    ST-550ES Digital Tuner

    All for $500... that's right... $500.
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  • jon s
    jon s Posts: 905
    edited July 2008
    Got the Acurus DIA-100 in today, hooked it up to the Polks...
    1. Imaging a tad better than the Sony TA-8650 in width, depth more so
    2. bottom end has a bit more oomph...
    3. the high end seems to be a bit emphasized... smooth but louder
    4. runs a LOT cooler than the V-FET amp
    5. Focus is also a bit sharper than the Sony

    overall, a bunch of pluses and one minus... oh yeah.. this amp has the Acurus bugaboo... the power LED flickers constantly. It seems that they all do this down the road... any ideas why?
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