Will a Adcom GFA-555 amp be enough power to push a set of SDA SRS 2.3 speakers?

I just bought a set of SDA SRS 2.3 off a man on facebook, they look like new and are all original. I try running them with a Onkyo 100 watt a channel receiver - the results was flat sound and no bass at all. All drivers were putting out sound, so is my problem not enough amp or do you think they need to be recapped or all the above?

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  • pitdogg2pitdogg2 Posts: 17,518
    The adcom will work. But both are long in the tooth in the cap dept.
  • tpevelertpeveler Posts: 10
    Thanks, any suggestions on the recap replacement. I can replace the capacitors my self but are there upgrades or should I replace them with the original values except upgrade them to Dayton or Sonic Crafts?
  • invalidinvalid Posts: 354
    Sonicap is what most use in the Polk crossovers, but clarity are also a good choice.
  • VR3VR3 Posts: 24,022
    I believe he means the amplifiers
    - Not Tom

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  • NightfallNightfall Posts: 9,419
    Have you done the PR/air leak test? What size room are they in? How far from the back wall are the speakers?
    afterburnt wrote: »
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  • polrbehrpolrbehr Posts: 2,674
    I think something else is amiss here; those speakers should not sound flat or have no bass just because you're using a 100W receiver. I drive my SDA 2B with a mere 60W Adcom and I have no such complaints.
    Is everything original to the speakers? What about the interconnect cable? @Nightfall has some good points as well.
    So, are you willing to put forth a little effort or are you happy sitting in your skeptical poo pile?


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  • invalidinvalid Posts: 354
    polrbehr wrote: »
    I think something else is amiss here; those speakers should not sound flat or have no bass just because you're using a 100W receiver. I drive my SDA 2B with a mere 60W Adcom and I have no such complaints.
    Is everything original to the speakers? What about the interconnect cable? @Nightfall has some good points as well.

    Totally agree, my 2a's had bass with a receiver but when I got a dedicated amp (which was the adcom gfa555) the bass was just much better and controlled.
  • tpevelertpeveler Posts: 10
    My room size 22 x 26 with a cathedral ceiling. They are placed about 6" from the wall in the back and 4' from the wall on the left side, 7' apart from each other. They are all original including the crossover capacitors. I'm not sure what the PR/air leak test is but if I pus the passive radiator all the bass drivers move in and out with it. Also I was mistaken about my receiver it's 60 wpc instead of 100 wpc. Hope I'm answering everybody questions! I've also have a set of SDA 2b and they also lack bass hooked up to this receiver. I'm in the process of ordering capacitors for the SDA 2b right now and going to upgrade them to the RD0194 tweeters. Now my Polk M4 sounds great on this receiver but they are a lot smaller also.
  • pitdogg2pitdogg2 Posts: 17,518
    edited October 5
    Place them closer to the wall, mine are less than 4" off back wall.

    Passive test is
    1. push quickly in until bottoms out and hold there and watch mid-woofers hold until MW are back at resting position
    2. count time it takes MW to recede to resting position
    3. the longer the better report back
  • SchurkeySchurkey Posts: 1,961
    Move the seating position. You may be listening in a null region within the room. Your room is nearly square--except for your ceiling, that room would be terrible with standing-waves. About the only way it would be worse would be a flat ceiling that's about 8' high.

    The '555 Adcom is well-regarded, but the caps will be far beyond their service life. Could easily result in poor bass due to power-supply degradation.


  • engie490engie490 Posts: 67
    Schurkey wrote: »
    Move the seating position. You may be listening in a null region within the room. Your room is nearly square--except for your ceiling, that room would be terrible with standing-waves. About the only way it would be worse would be a flat ceiling that's about 8' high.

    The '555 Adcom is well-regarded, but the caps will be far beyond their service life. Could easily result in poor bass due to power-supply degradation.

    Agree with first statement. Play some bass heavy tracks and walk around the room and see if you notice any changes in the bass response.

    On the second statement, older Adcom amps are notorious for the smaller electrolytic caps leaking on the boards and ruining them. You should have those caps replaced even if they are still good. Fortunately, that should not be too expensive.

    The main power supply caps (aka the beer can size ones you can't miss) should be measured by a competent tech to determine if they need replacement. My Threshold Stasis 2 has plenty of bass and appears to have the original main PS caps from 1978! Of course, YMMV...
  • SchurkeySchurkey Posts: 1,961
    engie490 wrote: »
    The main power supply caps (aka the beer can size ones you can't miss) should be measured by a competent tech to determine if they need replacement.
    Make sure that "Tech" measures both the capacitance AND the ESR.

    Adequate capacitance but with high ESR is still a failed capacitor.



  • TennManTennMan Posts: 1,107
    the results was flat sound and no bass at all. All drivers were putting out sound,
    You are describing the symptoms of speakers that are out of phase. Check the polarity of the connections all the way from the amp to the speakers. It's possible the colors on the binding posts have been reversed. Do a battery test to make sure all the drivers in the speakers are moving in unison.
    SDA 2BTL · Sonicaps · Mills resistors · RDO-198s · New gaskets · H-nuts · Erse inductors · BH5 · Dynamat · Crossover upgrades by westmassguy
    Marantz 1504 AVR (front speaker pre-outs to Adcom 555)
    Adcom GFA-555 amp · Upgrades & speaker protection added by OldmanSRS
    Pioneer DV-610AV DVD/CD player
    SDA CRS+ · Hidden away in the closet
  • tpevelertpeveler Posts: 10
    So I unplugged the cable that goes between the to speakers and now I have bass. It's not real tight bass but is full a and low. I think at this point I'm going to order the hardware to rebuild the crossovers. I have a question - I'm upgrading to the RD0198 tweeters in my SDA 2B's so can you do the same in the SDA SRS 2.3 speakers and if so what are the crossover changes that are need when doing this?
  • GardenstaterGardenstater Posts: 1,473
    Interesting but have you checked that all the polarities are correct on the MW's AND done the push test correctly as per above ^^^ on both.
    George / NJ

    Polk 7B main speakers, most mods comp. (1979, orig owner)
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    Logitech Squeezebox Touch Streamer w/EDO applet
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  • tpevelertpeveler Posts: 10
    The polarity seem to be correct on both speaker. When pushing the Passive Radiator in quickly and holing it there it takes the 6.5" drivers about 5 to 6 seconds to return to there mid position.
  • GardenstaterGardenstater Posts: 1,473
    The dimensional speakers too? I would check the polarity of the interconnect cable and make sure it isn't wired incorrectly.
    George / NJ

    Polk 7B main speakers, most mods comp. (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
  • pitdogg2pitdogg2 Posts: 17,518
    edited October 13
    Are these 2.3 or 2.3tl speakers?
    Pictures would help. 2.3 cannot be tl'd. Plus you would need all new drivers to go from 2.3 to 2.3tl. two very different beasts...

  • SchurkeySchurkey Posts: 1,961
    edited October 14
    pitdogg2 wrote: »
    Are these 2.3 or 2.3tl speakers?
    Pictures would help. 2.3 cannot be tl'd. Plus you would need all new drivers to go from 2.3 to 2.3tl. two very different beasts...
    While I grant that he'd need to change a heap of components in the HF section of the crossover, I don't see any reason the three-tweeter array couldn't be upgraded to '198s.

    If you're replacing the six tweeters anyway, and re-capping the crossover, it wouldn't be all that much more work to just build the crossovers as if they were 2.3TLs. Some extra caps, some extra resistors, a few inductors. Especially if he were to do it on Gimpod boards.

    Worst part would be potential level-matching between the "2.3TL" treble section and the "2.3" mid-bass section. Might have to play some games with resistors either in the treble or the bass.


  • pitdogg2pitdogg2 Posts: 17,518
    edited October 14
    If you're replacing the six tweeters anyway, and re-capping the crossover, it wouldn't be all that much more work to just build the crossovers as if they were 2.3TLs. Some extra caps, some extra resistors, a few inductors. Especially if he were to do it on Gimpod boards.
    I guess I should have stated "easily" any hoots how is that 2.3tl crossover going to interact with all the different drivers 2.3 has?
    Your left speaker becomes the right the right becomes the left?

    At this point I guess with the outlaying of cash they're some dang fine other speakers out there for the kind of cash that is about to be plunked down.
    Yes the RD-0198 is a very good tweeter BUT there's not a dang thing wrong with the RD-194 either. The 198 is not the be all end all in tweeters lets be honest.
  • F1nutF1nut Posts: 45,206
    tpeveler wrote: »
    So I unplugged the cable that goes between the to speakers and now I have bass. It's not real tight bass but is full a and low. I think at this point I'm going to order the hardware to rebuild the crossovers. I have a question - I'm upgrading to the RD0198 tweeters in my SDA 2B's so can you do the same in the SDA SRS 2.3 speakers and if so what are the crossover changes that are need when doing this?

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  • TennManTennMan Posts: 1,107
    tpeveler wrote: »
    So I unplugged the cable that goes between the to speakers and now I have bass. It's not real tight bass but is full a and low.
    That's just another sign that something is not right with the polarity of the speakers or crossover cable. I believe when you unplugged the crossover cable it allowed the dimensional drivers to work together with the stereo drivers resulting in more bass. @westmassguy would know more about this than I do but I believe what I'm saying is correct. You should solve this problem before replacing parts.

    SDA 2BTL · Sonicaps · Mills resistors · RDO-198s · New gaskets · H-nuts · Erse inductors · BH5 · Dynamat · Crossover upgrades by westmassguy
    Marantz 1504 AVR (front speaker pre-outs to Adcom 555)
    Adcom GFA-555 amp · Upgrades & speaker protection added by OldmanSRS
    Pioneer DV-610AV DVD/CD player
    SDA CRS+ · Hidden away in the closet
  • invalidinvalid Posts: 354
    TennMan wrote: »
    tpeveler wrote: »
    So I unplugged the cable that goes between the to speakers and now I have bass. It's not real tight bass but is full a and low.
    That's just another sign that something is not right with the polarity of the speakers or crossover cable. I believe when you unplugged the crossover cable it allowed the dimensional drivers to work together with the stereo drivers resulting in more bass. @westmassguy would know more about this than I do but I believe what I'm saying is correct. You should solve this problem before replacing parts.

    I'm not sure about the 2.3's, but I know my 2a's have less bass with the interconnect cable disconnected.
  • tpevelertpeveler Posts: 10
    What is the pin out on the Crossover cable?
  • pitdogg2pitdogg2 Posts: 17,518
    Positive
    Blade goes to ground if I'm correct
  • GardenstaterGardenstater Posts: 1,473
    96hxh1u9itix.png
    George / NJ

    Polk 7B main speakers, most mods comp. (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
  • tpevelertpeveler Posts: 10
    Checking between the ends of the cable I have continuity between the pins but the blades are open. Shouldn't there be continuity between the blades too?
  • GardenstaterGardenstater Posts: 1,473
    Absolutely.
    George / NJ

    Polk 7B main speakers, most mods comp. (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
  • tpevelertpeveler Posts: 10
    So does that mean the cable is bad because I have two cables and they are both the same?
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