SDA 2B speaker and amplifier issues

Skippy54
Skippy54 Posts: 35
edited January 2012 in 2 Channel Audio
Hello,
I have a few questions about my SDA 2B speakers. First, my JVC RX-44 (50 wpc) receiver keeps shutting down when I listen to certain music (e.g. Boston) above volume 5. I realize this is probably because the SDA 2Bs are 6 ohm speakers and my receiver is struggling to drive them and probably over heating.

The problem is I've hooked up several Denon AV receivers and an Anthem MCA 20 amplifier (200 wpc) to the SDA 2Bs and they all sound like crap compared to the older JVC. The JVC has a MUCH larger sound stage and sounds crystal clear.

What integrated amplifiers can I find that will sound as good as the JVC, but be able to drive my SDA 2B speakers? I would like to keep my cost down and I'm definitely open to buying vintage equipment since it seems to sound better than the newer amplifiers. Fyi, when I call Polk Audio support they suggested NAD amplifiers. Anybody have any suggestions?
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  • evhudsons
    evhudsons Posts: 1,175
    edited December 2011
    From what I read as integrated suggestions others said the same thing. I use a pioneer elite with preouts to a parasound amp. It's also 200 watts per and sounds great. There might be a problem w the speaker, it can handle some juice
    Polk Audio SDA CRS+ crossover 4.1TL by Trey/VR3 (Rings and custom stand by Larry)-Polk Audio SDA SRS2 crossovers by Trey/VR3Parasound HCA1500aYamaha rxa-3070 with musicast-Celestion SL6S presence,- sl9 surround backNHTsuper1's surroundMagnepan SMGParasound 1500pre- Sofia "Baby" tube amp - Monitor Audio Silver RX2 Marantz 2230/B&Kst140Technics 1200mk2 Gamertag: IslandBerserker I am but a infinitesimally small point meeting the line of infinity in the SDA universe
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  • Toolfan66
    Toolfan66 Posts: 17,243
    edited December 2011
    Is that Anthem common ground?? If it's not it will sound like crap, and can damage the speakers and/or amp..
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  • Toolfan66
    Toolfan66 Posts: 17,243
    edited December 2011
    Just goggled the anthem and that amp looks like a monster!! If it's common ground or if your using a AI- 1 SDA cable that amp should kill that JVC IMO..
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  • Skippy54
    Skippy54 Posts: 35
    edited December 2011
    I'm not sure if the Anthem is a common ground, but when I called Polk Audio about amplifiers with a common ground they said I don't have to worry about that issue with my SDA 2Bs. I did notice tho that when I hooked up the Anthem to the SDA 2Bs and used my Denon AVR 2803 as the pre amp, the right channel volume\output was really low. I was worried I might have damaged my right speaker somehow using the Anthem amplifier, but I hooked my JVC back up again and the right channel was fine. I think the right channel might be out on the Anthem.

    Honestly, I'm still amazed that newer amplifier don't even come close the sound quality of my older JVC. If it weren't for my JVC shutting down at high volumes, I would definitely keep using it. It sounds amazing.
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  • Toolfan66
    Toolfan66 Posts: 17,243
    edited December 2011
    Call Anthem and ask if it's common ground and if not ask if you can strap the negative posts together without any issues or find a AI-1 SDA cable or just make one.. That Anthem should best that JVC..
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  • Toolfan66
    Toolfan66 Posts: 17,243
    edited December 2011
    Once you figure that out get a good stand alone pre-amp..
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  • pitdogg2
    pitdogg2 Posts: 25,447
    edited December 2011
    Skippy54 wrote: »
    I'm not sure if the Anthem is a common ground, but when I called Polk Audio about amplifiers with a common ground they said I don't have to worry about that issue with my SDA 2Bs.

    I'd say that was bad advice.. 100% of the SDA's I've seen they have all had a caution on the back that said "use common ground amps ONLY....If you are not using the interconnect cable then yes you need not worry BUT if you use the IC you need COMMON GROUND AMP.....you will blow something if non common ground with interconnect.....
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  • Skippy54
    Skippy54 Posts: 35
    edited December 2011
    The support guy asked me what my IC plug looked like and I told him circle with a small blade shape below the circle and he said 'ok, then your fine. If your IC plug only had the circle then you need to use a common ground amplifier'.
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  • Toolfan66
    Toolfan66 Posts: 17,243
    edited December 2011
    There is a pin/blade (circle/blade) in your case and a blade/blade

    Most blade/blade if not all need to use a common ground amp..

    Pin/blade must use a common ground amp or use a AI-1 SDA cable with a non common ground amp..
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  • Skippy54
    Skippy54 Posts: 35
    edited December 2011
    Talked the Anthem today they said they are pretty sure the MCA 20 is common ground....man this is frustrating.
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  • Skippy54
    Skippy54 Posts: 35
    edited December 2011
    Still trying to understand why my old JVC RX44 is so much better than the newer high end amplifiers. Seems like the vintage equipment is the way to go.
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  • F1nut
    F1nut Posts: 50,564
    edited December 2011
    I have a few questions about my SDA 2B speakers. First, my JVC RX-44 (50 wpc) receiver keeps shutting down when I listen to certain music (e.g. Boston) above volume 5.

    Is 5 the halfway point on the volume control?
    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

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  • FTGV
    FTGV Posts: 3,649
    edited December 2011
    Skippy54 wrote: »
    Talked the Anthem today they said they are pretty sure the MCA 20 is common ground....man this is frustrating.
    They are the manufacturer and thats the best they can do?:rolleyes:
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  • Gavin.Wright
    Gavin.Wright Posts: 125
    edited December 2011
    Step 1 - get a multimeter

    Step 2 - measure the resistance between the two ground posts on the Anthem amp

    If the resistance is low (close to zero) then the amp is "common ground" which basically just means that the ground posts on Left and Right channels are "common" to each other. It's that simple! I am surprised Anthem was unable to provide this information for you.
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  • Skippy54
    Skippy54 Posts: 35
    edited December 2011
    FTGV wrote: »
    They are the manufacturer and thats the best they can do?:rolleyes:

    Yea, that is what I thought too. They should have been able to tell me if the amplifier was a common ground amplifier. I'm going to hook up a couple Acoustic Research S-20 bookshelf speakers to the Anthem and see if the right channel is out.

    Is it possible that the Anthem amplifier is not a common ground amplifier and that is why the right channel volume\output is low? Also, I think the reason the Anthem doesn't sound as good as my JVC is because I'm using my Denon AVR 2803 as a pre amp.

    This whole process of finding an amplifier to drive my SDA speakers has been a bit frustrating, especially after hearing how good they sound with the JVC. I'm leaning towards more of an intergrated amplifier solution (maybe NAD), but I'm kinda gun shy since I can't really buy descent integrated amplifiers locally and try them out.

    I'm amazed at the difference in sound quality between amplifiers.
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  • Skippy54
    Skippy54 Posts: 35
    edited December 2011
    F1nut wrote: »
    Is 5 the halfway point on the volume control?

    Yes 5 is halfway. I would say depending on the recording, at around 5 to 6 on the volume control the JVC will eventually shut down after maybe 10 to 15 minutes of constant playback.

    Also thank you to everybody for the help. I sincerely appreciate it.
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  • F1nut
    F1nut Posts: 50,564
    edited December 2011
    As I thought. Your receiver has run out of gas at the halfway point, so turn it down. It's got very little to nothing to do with the SDA's 6 ohm rating, it has more to everything to do with the fact that 50 wpc isn't going to net you much volume. If you want to play it loud, you need more power.

    It's time to do what Gavin.Wright suggested.
    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

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  • FTGV
    FTGV Posts: 3,649
    edited December 2011
    Skippy54 wrote: »
    ... at around 5 to 6 on the volume control the JVC will eventually shut down after maybe 10 to 15 minutes of constant playback.
    Atleast it appears it's thermal protection is doing it's job.:smile: Yes as you suggested the combination of load and levels your listening at are pulling too much current through the output transistors causing them to reach temp's that trigger the thermal protection.
    As for the Anthem they claim 2 ohm stability for that amp which would be a strong indicator that it does not use a bridged/ balanced output stage thus should be common ground.However confirming with the multi meter or someone at Anthem that actually knows for certain would be prudent. I would expect strapping the negative terminals of an amp with a bridged output stage to cause instantaneous failure of some output power transistors rendering it inoperative.It's all just speculation on my part but my guess is that since one channel is fully functional and the other is but at a reduced level makes me think it not damage relating to strapping the negative binding posts but some other issue.
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  • Skippy54
    Skippy54 Posts: 35
    edited December 2011
    Ok I had the Anthem checked out and the right channel is out. So I asked the audio repair guy what he suggested for a good amplifier to use with my SDA 2Bs and he suggested the Denon PMA 100. That is a little more than I can afford but it looks like i could get a PMA 2000ivr used for about $500 - $600. Or maybe look at a Sanui AU-919. What do you think?
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  • PreCd
    PreCd Posts: 786
    edited December 2011
    The Adcom GFA-555 is a good value and will give you all the volume level you desire.
    SDA2BTL
    Marantz CD5004
    Adcom GFA-545
    Bottlehead Quickie Tube Preamp
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  • sda2mike
    sda2mike Posts: 3,131
    edited December 2011
    +1 on the adcom...i would also suggest the 'smaller' adcoms as well..the 535 and 545...keep in mind, the 6 ohm rating is nominal...your rcvr is doing the best it can with the task...give it some bookies and get some real iron for your 2b's
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  • Skippy54
    Skippy54 Posts: 35
    edited December 2011
    The Adcom GFA 555 and GFA 555 II seem to be a popular match with the SDAs. What preamp should be used with the 555s?
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  • Skippy54
    Skippy54 Posts: 35
    edited December 2011
    Looks like the best rated preamps for the GFA 555 or GFA 555 II are:

    GFP-750
    GFP-715
    GFP-710

    Any other preamps that match well with the 555s?
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  • Poee7R
    Poee7R Posts: 904
    edited December 2011
    Going from the Anthem to a 555, is taking a big step backwards.

    Ive had both, compared both, and there was nothing the Anthem couldnt do better.

    Get the Anthem fixed, save up and grab a new pre/pro and be happy. :cheesygrin:


    Dave
    Once again we meet at last.
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  • Skippy54
    Skippy54 Posts: 35
    edited December 2011
    Poee7R,
    What preamp did you use with your Anthem (was it the MCA 20?) and were you using SDAs?
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  • Poee7R
    Poee7R Posts: 904
    edited December 2011
    A custom tube pre-amp. And no, I sold my 2.3tl's before I bought the MCA 20.

    But I did sell the Anthem to the same fella I sold the 2.3tl's too, and it was a great sounding combo. He actually bought the same tube pre from me also, haha. The Anthem replaced a Nakamichi PA-7 for him, and did a great job at it.

    I actually bought the Anthem to replace a 555 that couldnt handle a pair of Martin Logans, it performed great where the Adcom had trouble with the load and would shutdown.

    Dont let this come off as im bashing the Adcom, its a great amp and will do what most folks need them to do, but as far as apples to apples, it just couldn't hang with the Anthem.


    Dave
    Once again we meet at last.
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  • Skippy54
    Skippy54 Posts: 35
    edited December 2011
    I just checked the fuse in the Anthem MCA 20 and it appears fine. Not sure how much it would cost to get the right channel fixed. If it was only $100 I might be interested.
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  • xsmi
    xsmi Posts: 1,798
    edited December 2011
    Skippy54 wrote: »
    I just checked the fuse in the Anthem MCA 20 and it appears fine. Not sure how much it would cost to get the right channel fixed. If it was only $100 I might be interested.

    I think I'd be willing to invest a little more than $100 in fixin' it.
    http://www.audiogon.com/cgi-bin/cls.pl?ampstran&1328556103&/Anthem-MCA-20-
    2-channelBelles 22A Pre, Emotiva XPA-2 Gen 2, Marantz SA8005, Pro-Ject RPM-10 Turntable, Pro-Ject Phono Box DS3B, Polk Audio Legend L800's, AudioQuest Cable throughout.
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  • Skippy54
    Skippy54 Posts: 35
    edited December 2011
    Can I use my JVC RX44 as a preamp? The JVC does not have designated preamp plugs tho....might be able to use tape in/out plugs.
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  • xsmi
    xsmi Posts: 1,798
    edited December 2011
    I don't think so...maybe someone with more experience than I will chime in, but I think you MUST have pre-outs to use it as a pre-amp.
    2-channelBelles 22A Pre, Emotiva XPA-2 Gen 2, Marantz SA8005, Pro-Ject RPM-10 Turntable, Pro-Ject Phono Box DS3B, Polk Audio Legend L800's, AudioQuest Cable throughout.
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