Adcom GFA-5503 common ground amp?

stoogefan00
stoogefan00 Posts: 24
in Vintage Speakers
Just bought a set of SDA-SRS that are in excellent cond. The gentlemen I purchased these from said they were the 1.2's but after delivery I noticed 13 screws in the crossover plate in front and a blade- blade connection leading me to believe I have SDA-SRS 4 ohm speakers. My question is my Adcom amp is a GFA-5503 is this amp common ground or non common ground and if it is non common ground can I run a piece of speaker wire to both neg. terminals? I checked past discussions on this but seem to find conflicting answers I'm hoping someone can help as I am a little excited to try my speakers out but at the same time I don't want to wreck them or the amp for that matter. Thank you for any time you can give me in regards to this matter.
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Best Answers

  • gudnoyez
    gudnoyez Posts: 8,159
    Answer ✓
    It is not a common ground amp I have 3 Adcoms & the 5503 is the one of the three that is not a common ground. I have heard you can strap the terminals but not sure if I would recommend it.
    Home Theater
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    2 Channel
    Adcom 555II Vincent SA-T1 Marantz SA 15S2 Denon DR-M11 Clearaudio Bluemotion SDA 2.3tl's (Z) edition MIT Terminator II Speaker Cables & IC's Adcom 545II Adcom Gtp-450 Marantz CD5004 Technics M245X SDA 2B's, SDA CRS+

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  • gudnoyez
    gudnoyez Posts: 8,159
    Answer ✓
    http://www.users.interport.net/a/d/adcom/manuals/gfa5503.html

    The 5503 is a Mosfet amp they are not common ground you could find out and strap your terminals and try it out, but like I say I would not recommend it.
    Home Theater
    Parasound Halo A 31 OnkyoTX-NR838 Sony XBR55X850B 55" 4K RtiA9 Fronts CsiA6 Center RtiA3 Rears FxiA6 Side Surrounds Dual Psw 111's Oppo 105D Signal Ultra Speaker Cables & IC's Signal Magic Power Cable Technics SL Q300 Panamax MR4300 Audioquest Chocolate HDMI Cables Audioquest Forest USB Cable

    2 Channel
    Adcom 555II Vincent SA-T1 Marantz SA 15S2 Denon DR-M11 Clearaudio Bluemotion SDA 2.3tl's (Z) edition MIT Terminator II Speaker Cables & IC's Adcom 545II Adcom Gtp-450 Marantz CD5004 Technics M245X SDA 2B's, SDA CRS+

    Stuff for the Head
    JD LABS C5 Headphone Amplifier, Sennheiser HD 598, Polk Audio Buckle, Polk Audio Hinge, Velodyne vPulse, Bose IE2, Sennheiser CX 200 Street II, Sennheiser MX 365

    Shower & Off the beaten path Rigs
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  • F1nut
    F1nut Posts: 51,700
    Answer ✓
    Strapping, if possible, affects the sound quality in a negative way.
    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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  • boston1450
    boston1450 Posts: 7,758
    Answer ✓
    GFA-555 was a sweet match for my 2b's with a 565pre.
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    by David WMG
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  • gudnoyez
    gudnoyez Posts: 8,159
    Answer ✓
    Go on E-Bay I bet there are a few Adcom GFA- 555's or GFA- 555II ' s those would be the ones to get, I have read a few negative reviews on the new Adcoms.
    Home Theater
    Parasound Halo A 31 OnkyoTX-NR838 Sony XBR55X850B 55" 4K RtiA9 Fronts CsiA6 Center RtiA3 Rears FxiA6 Side Surrounds Dual Psw 111's Oppo 105D Signal Ultra Speaker Cables & IC's Signal Magic Power Cable Technics SL Q300 Panamax MR4300 Audioquest Chocolate HDMI Cables Audioquest Forest USB Cable

    2 Channel
    Adcom 555II Vincent SA-T1 Marantz SA 15S2 Denon DR-M11 Clearaudio Bluemotion SDA 2.3tl's (Z) edition MIT Terminator II Speaker Cables & IC's Adcom 545II Adcom Gtp-450 Marantz CD5004 Technics M245X SDA 2B's, SDA CRS+

    Stuff for the Head
    JD LABS C5 Headphone Amplifier, Sennheiser HD 598, Polk Audio Buckle, Polk Audio Hinge, Velodyne vPulse, Bose IE2, Sennheiser CX 200 Street II, Sennheiser MX 365

    Shower & Off the beaten path Rigs
    Polk Audio Boom Swimmer, Polk Audio Urchin B)
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Answers

  • stoogefan00
    stoogefan00 Posts: 24
    This seems strange it seems to me some time ago I had called Adcom and talked to a rep about this and he stated after looking the specs on my amp that it was common ground this coming right from Adcom. I called him because at the time I was going to buy a set of SDA2A speakers and needed clarification but that purchase did not work out. You say you would not recommend strapping neg terminals what is my other options at this point? other than buying another amp. Also could I take an ohm meter to each of the neg terminals to check continuity to see what if any reading i am getting to also help confirm common or non common ground?
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  • stoogefan00
    stoogefan00 Posts: 24
    Thank you sir I will give that a try.
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  • gudnoyez
    gudnoyez Posts: 8,159
    Why second guess you obviously have your doubts but won't accept the adcoms reps answer nor mine. I have 3 pairs of SDA'S and they will only be hooked up to my 555II or my 545II the 5503 is used for my non SDA'S as it is not a common ground amp. I can say that 3 channel 5503 does an excellent job running my fronts and center channel nice amp plenty of power.
    Home Theater
    Parasound Halo A 31 OnkyoTX-NR838 Sony XBR55X850B 55" 4K RtiA9 Fronts CsiA6 Center RtiA3 Rears FxiA6 Side Surrounds Dual Psw 111's Oppo 105D Signal Ultra Speaker Cables & IC's Signal Magic Power Cable Technics SL Q300 Panamax MR4300 Audioquest Chocolate HDMI Cables Audioquest Forest USB Cable

    2 Channel
    Adcom 555II Vincent SA-T1 Marantz SA 15S2 Denon DR-M11 Clearaudio Bluemotion SDA 2.3tl's (Z) edition MIT Terminator II Speaker Cables & IC's Adcom 545II Adcom Gtp-450 Marantz CD5004 Technics M245X SDA 2B's, SDA CRS+

    Stuff for the Head
    JD LABS C5 Headphone Amplifier, Sennheiser HD 598, Polk Audio Buckle, Polk Audio Hinge, Velodyne vPulse, Bose IE2, Sennheiser CX 200 Street II, Sennheiser MX 365

    Shower & Off the beaten path Rigs
    Polk Audio Boom Swimmer, Polk Audio Urchin B)
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  • stoogefan00
    stoogefan00 Posts: 24
    Thanks gudnoyez not second guessing its just when you have a high end audio lab tech and an Adcom rep along with numerous others telling you to use the 5503 because its common ground and yet others state its not I just need to know because I don't want to wreck my speakers or my amp what exactly could happen if I strap my terminals that you say you would not recommend? Why would you not recommend this is what I'm asking?
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  • gudnoyez
    gudnoyez Posts: 8,159
    Strapping your terminals with speaker wire just don't sound like a good idea perhaps a solid pair of jumpers would be better.
    Home Theater
    Parasound Halo A 31 OnkyoTX-NR838 Sony XBR55X850B 55" 4K RtiA9 Fronts CsiA6 Center RtiA3 Rears FxiA6 Side Surrounds Dual Psw 111's Oppo 105D Signal Ultra Speaker Cables & IC's Signal Magic Power Cable Technics SL Q300 Panamax MR4300 Audioquest Chocolate HDMI Cables Audioquest Forest USB Cable

    2 Channel
    Adcom 555II Vincent SA-T1 Marantz SA 15S2 Denon DR-M11 Clearaudio Bluemotion SDA 2.3tl's (Z) edition MIT Terminator II Speaker Cables & IC's Adcom 545II Adcom Gtp-450 Marantz CD5004 Technics M245X SDA 2B's, SDA CRS+

    Stuff for the Head
    JD LABS C5 Headphone Amplifier, Sennheiser HD 598, Polk Audio Buckle, Polk Audio Hinge, Velodyne vPulse, Bose IE2, Sennheiser CX 200 Street II, Sennheiser MX 365

    Shower & Off the beaten path Rigs
    Polk Audio Boom Swimmer, Polk Audio Urchin B)
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  • stoogefan00
    stoogefan00 Posts: 24
    I understand and thank you gudnoyez
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  • stoogefan00
    stoogefan00 Posts: 24
    Thanks guys, sounds like a new amp is in order. What model Adcom amp would you recommend that would be common ground. I would like to stay with Adcom I've kinda grown to like them over the years having several models in the past. Once all this is ironed out I will post pics, right now very happy with the speakers I'm sure I'll be happier once I send them a signal.
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  • stoogefan00
    stoogefan00 Posts: 24
    Thanks boston1450. I was just on Adcoms sight and was looking at the GFA555SE wondering if this was a common ground amp, if so might be one to consider, what do you guys think?
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  • stoogefan00
    stoogefan00 Posts: 24
    Also found Emotiva XPA-2 power amp that might fit the bill if it is common ground. Either Adcom GFA555SE or Emotiva, which one?
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  • stoogefan00
    stoogefan00 Posts: 24
    I'll check E-bay out Thanks
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  • GlennDog
    GlennDog Posts: 3,149
    I would stick with the 5503 and spring for a tyranny / Dreadnaught. IMHO, you already have the better amp, as I've had the 555II & the 5503 for years. ymmv
    AC Regenerator PS Audio PerfectWave Power Plant 10
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  • stoogefan00
    stoogefan00 Posts: 24
    Thank you GlennDog sorry I'm not quite sure what a tyranny/Dreadnaught is, do I have to make this or can I buy one. I love these SDA'S but all this is new to me when it comes to making this amp work. If I can buy one I would do that for sure. Thanks
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  • stoogefan00
    stoogefan00 Posts: 24
    I understand, I'll do some research and see what I can find everyone has been so helpful thanks ZLTFUL and to everyone else here trying to help me resolve this matter.
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  • GlennDog
    GlennDog Posts: 3,149
    stooge, where are you located?
    AC Regenerator PS Audio PerfectWave Power Plant 10
    Source Lumin U1 Mini into Lampizator Baltic 4 DAC
    Pre Cary SLP-05
    Power Rogue M180 Dark monos
    Mains Salk HT2-TL
    Rythmik F12
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  • stoogefan00
    stoogefan00 Posts: 24
    Illinois
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  • leftwinger57
    leftwinger57 Posts: 2,917
    I have about 6 sets of speakers in my 18'x15' living room w/my 2Bs front and center w/an equilateral triangle from my couch which is 9' from the speakers. All other sets are over on the side and do work well for the room and available space. I usually never gof on or comment on someone's listening space but dude your borderline hoarder(no you are hoarding and I'm guessing you do not hear them all). Sell the ones these guys want, you'll have the cash to get the correct amp amp and as F-NUT says that still might not be enough room for g2v1v9qbr9o0.jpg
    those to breathe.blv9a58iph1h.jpg
    2chl- Adcom GFA- 555-Onkyo P-3150v pre/amp- JVC-QL-A200 tt- Denon 1940 ci cdp- Adcom GFS-6 -Modded '87 SDA 2Bs - Dynamat Ext.- BH-5- X-Overs VR-3, RDO-194 tweeters, Larry's Rings, Speakon/Neutrik I/C- Cherry stain tops Advent Maestros,Ohm model E

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  • Schurkey
    Schurkey Posts: 2,122
    edited March 2015
    C'mon, guys.

    The original poster seems to have ORIGINAL BLADE/BLADE SDA-SRS. He CANNOT use an isolation transformer. Therefore, no dreadnaught.

    Testing for continuity is NOT the same as testing for resistance. A mere 20 ohms (the result of two ten-ohm resistors) between the negative terminals of my Aragon made my 1Bs unlistenable. I was lucky, no harm done to the amp or speakers...but I lost out on considerable enjoyment until I got around to strapping the negative terminals.

    The Adcom 5503 in question is similar to my Aragon in that it is a common-ground amp EXCEPT for a pair of resistors which must be bypassed to use with blade/blade SDA speakers. The original poster can buy or fabricate an eight-inch jumper wire to connect the negative terminals of the amp, and he'll be JUST FINE. Those who say it affects the sound quality in a negative way has never tried to do WITHOUT the strapping on an amp/speaker combination that requires it.

    Aside from replacing the speakers, replacing the amp, or going inside the amp to do "solder surgery" to bypass the resistors, strapping is the ONLY OPTION. It is simple, dirt-cheap, and instantly "reverseable" by merely yanking the wire out of the negative binding posts. There's essentially no down-side.
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  • GlennDog
    GlennDog Posts: 3,149
    Oops! Missed that B/B part . . . sorry
    AC Regenerator PS Audio PerfectWave Power Plant 10
    Source Lumin U1 Mini into Lampizator Baltic 4 DAC
    Pre Cary SLP-05
    Power Rogue M180 Dark monos
    Mains Salk HT2-TL
    Rythmik F12
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  • stoogefan00
    stoogefan00 Posts: 24
    Just got off the phone to Emotiva and ordered a XPA2 today should be here Thurs. so I have to wait a few more days to get my SDA SRS up and running. I guess getting these speakers was more reason to purchase a new amp and take all guess work out of the common ground problem. I did take a multi tester to both neg terminals and sure enough non common ground amp. So thanks to all for helping diagnose this problem, now I just need to find a new home for my GFA5503 and GFA5300 amps to help offset the cost of the new amp.
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  • Schurkey
    Schurkey Posts: 2,122
    edited March 2015
    Sell the Communist emotiva, keep the Adcom, and put a five-dollar jumper wire between the Adcom's negative terminals. You could be enjoying those SRS speakers in an hour, and not contributing to the trade imbalance with the most hateful nation on Earth. (Less time than that, if you have some 16-gauge or heavier wire loitering around your home. You could scrape the paint off of the ends of a section of coat-hanger wire and be OK in the short-term.
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  • F1nut
    F1nut Posts: 51,700
    Ah, the lure of a cheap amp.
    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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  • Nightfall
    Nightfall Posts: 10,084
    edited March 2015
    Schurkey wrote: »
    ...and not contributing to the trade imbalance with the most hateful nation on Earth.

    I agree with you but it is nearly impossible to not buy anything from China.

    OP for $200 less (which leaves room for shipping) you could have had this:

    http://denver.craigslist.org/ele/4914352928.html

    01010_5b0HAObRSLU_600x450.jpg

    00W0W_8c1rw0S18az_600x450.jpg
    afterburnt wrote: »
    They didn't speak a word of English, they were from South Carolina.

    Village Idiot of Club Polk
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  • stoogefan00
    stoogefan00 Posts: 24
    To F1nut, whats your point, sorry I don't have the money to invest in a high dollar amp right now. More importantly I'm sending my daughter to a university for her degree in pathology which at this time is more important than listening to my stereo. I always try and set my priorities straight and in this case its no different. I know I could have saved money by doing what Schurkey suggested and I still can if I so desire. But for now I am going to keep this amp on order and at the very least use it upstairs in my other 2 channel system. These kind of comments are why I have been a member for so long and have never posted because there is always someone who seems to want to take cheap shots at someone who's not as fortunate as the next person. Ah, the lure of a cheap shot.
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  • F1nut
    F1nut Posts: 51,700
    More importantly I'm sending my daughter to a university for her degree in pathology which at this time is more important than listening to my stereo.

    Yet, you just bought a pair of speakers and now an amp. Ah, the lure of hypocrisy......LOL

    Chill out man, it's not like I had access to your financial statement.
    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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  • stoogefan00
    stoogefan00 Posts: 24
    Yes I did just buy a pair of speakers that are 28 yrs old and according to you an amp that's cheap, so I guess I can afford that little bit. If there is anybody that needs to chill out its not me. I'm through with this conversation.
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