DK's AXPONA 2018 Experience - Pt. 3 of 3 - SDA 1C Modification

DarqueKnight
DarqueKnight Posts: 6,662
Introduction

When I told my friend and former Bell Laboratories colleague, Craig, that I was coming to the Chicago area for an audio show, he said "Great! You can modify my speakers now." For years I had been suggesting that Craig send his SDA 1C crossovers to be modified, and that doing so, along with a few other simple mods, would give him a virtually new set of speakers.

He actually was quite satisfied with his stock 1Cs until he recently heard a pair of Martin Logan electrostatics at his mechanics house. He called me shortly after that encounter telling me how impressed he was and asking me what I thought of Martin Logans. I reiterated that, for the instrumental jazz he favors, he would be happier with the result of modifying his 1Cs. I further predicted that after the modification:

1. He wouldn't like the Martin Logans any more.
2. He wouldn't need his subwoofer for music ("My SDAs don't put out enough bass.")
3. His 1Cs would sound like a significantly improved version of their former selves...like a 98 pound weakling becoming a champion bodybuilder.

Of course, Craig laughed me to scorn on all counts above. However, as skeptical as he was, he decided to trust me. It helped that Craig remembered that I had once had two pairs of modded 1Cs and that I wasn't just talking speculatively. I invited him to AXPONA on Saturday, when I would be through modifying both of his 1Cs, and when he would be able to compare what he was hearing at home to the Martin Logan electrostatics, and other speakers, at the show.

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Figure 1. I don't usually make house calls, but I made an exception to bring a good friend
into the rabbit hole.


I arrived at O'Hare Thursday afternoon, checked into my hotel, then headed straight for Craig's house.

This modification exercise consisted of the following:

1. RD0194 silk dome tweeters.
2. Gimpod's boards.
3. Mills MRA-12 resistors.
4. Sonicap Gen 1 capacitors.
5. Larry's rings (double thanks to Brian!).
6. Adona black chrome spikes.
7. Vampire BP-HEX binding posts.
8. Armacell tape gaskets.
9. Dynamat Xtreme on driver and passive radiator baskets.
10. 4" x 12" Sonic Barrier strips behind drivers.
11. Fifteen foot 10 gauge SDA interconnect made from Monster Z2 Reference speaker cable

There were also some minor cosmetic issues to be addressed: Edge banding on the bottom end caps needed re-gluing in places. Side panels were coming loose in places.

The right speaker was done first so that Craig could hear the difference between the fully modded right speaker and the stock left speaker.

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Figure 2. No evening fun this trip. I'd listen to gear all day at AXPONA and solder, drill, tape, and glue all night.

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Figure 3. Craig didn't like the sound of the RD0 tweeters at first.

Craig thought the old SL2000 tweeters had more detail. I told him they had more distortion, and that the RD0s had a more natural sound, even prior to the required 50 hours of break in. When panning the balance control left to right and vice versa, he began to notice a more "metallic" sound in the stock speaker.

We let the tuner play overnight and all day. During the next evening's A/B listening session, Craig said of the left speaker "I can't go back to that". We then proceeded to modify the left speaker.

The only snag encountered with modifying the right speaker was the brace between the stereo and dimensional drivers was off center and too close to the cutouts for the stereo drivers. This meant the ring for the upper stereo driver had to be trimmed a bit with a Dremel.

Fitting driver rings in the left speaker was a nightmare. About nine tons of hot glue had to be chiseled and pealed away from the areas near the driver cutouts.

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Figure 3. Sonic Barrier strips were placed behind the drivers for backwave damping.

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Figure 4. Easy ring hole drilling.

ylrtvqpiakds.jpg
Figure 5. Experimenting with position of the partially assembled new board.
I considered mounting the new boards in the bottom of the cabinet, but decided
to use the stock location. These boards are pure genius. They, and the extensive
online documentation, really make the crossover mod process a breeze.


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Figure 6. Enjoy your retirement!

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Figure 7. Vampire BP-Hex binding posts for speaker and SDA interconnect cables.

The left speaker, except for spike installation, was finished Friday night-early Saturday morning. Craig was thrilled with the results, but he said he never would have asked me to do this if he had any idea of the amount of work involved.

Craig joined me on day two (Saturday) of AXPONA. I took him to the Aida room first, then to the Wilson Audio rooms, then to the two Martin Logan exhibits, then we wandered around to different exhibits. He became increasingly agitated and asked "why does everything sound worse than the first room?"

As predicted, Craig:

1. Didn't like, or want, the Martin Logan electrostatics any more.
2. Turned off his subwoofer for music.
3. Was floored by the amount of improvement in his speakers. (I too was surprised at the transformation...and I have been around this block many times.)

Saturday night was spent installing spikes and making cosmetic repairs. I spent Sunday at the final day of AXPONA. Sunday evening was spent listening and discussing future stereo system upgrades.

Since the mod completion, Craig has had many questions about upgrading his electronics and cables...and so it begins...
"So hot it burns Mice!"~DK
"Polk SDA-SRSs are hopelessly out of date both sonically and technologically... I see no value whatsoever in older SDA speakers."~Audio Asylum Member
"Knowledge, without understanding, is a path to failure."~DK
"Those who irrationally rail against something or someone that is no threat to them, actually desire (or desire to be like) the thing or person they are railing against."~DK

Comments

  • pitdogg2
    pitdogg2 Posts: 20,791
    Tossed him right into the abyss Ray.
    Nice job on both accounts :D:)
  • Moose68Bash
    Moose68Bash Posts: 3,839

    Well done, Ray!

    You saved another pair of remarkable, vintage speakers from the dustbin of history!

    Is Craig going to sign up on the Forum?
    Family Room, Innuos Statement streamer (Roon Core) with Morrow Audio USB cable to McIntosh MC 2700 pre with DC2 Digital Audio Module; AQ Sky XLRs to CAT 600.2 dualmono amp, Morrow Elite Speaker Cables to NOLA Baby Grand Reference Gold 3 speakers. Power source for all components: Silver Circle Audio Pure Power One with dedicated 20 amp circuit to main panel.

    Exercise Room, Innuos Streamer via Cat 6 cable connection to PS Audio PerfectWave MkII DAC w/Bridge II, AQ King Cobra RCAs to Perreaux PMF3150 amp (fully restored and upgraded by Jeffrey Jackson, Precision Audio Labs), Supra Rondo 4x2.5 Speaker Cables to SDA 1Cs (Vr3 Mods Xovers and other mods.), Dreadnaught with Supra Rondo 4x2.5 interconnect cables by Vr3 Mods. Power for each component from dedicated 20 amp circuit to main panel, except Innuos Statement powered from Silver Circle Audio Pure Power One.

  • DarqueKnight
    DarqueKnight Posts: 6,662
    Craig is a forum member...but he prefers to read rather than write.
    "So hot it burns Mice!"~DK
    "Polk SDA-SRSs are hopelessly out of date both sonically and technologically... I see no value whatsoever in older SDA speakers."~Audio Asylum Member
    "Knowledge, without understanding, is a path to failure."~DK
    "Those who irrationally rail against something or someone that is no threat to them, actually desire (or desire to be like) the thing or person they are railing against."~DK
  • erniejade
    erniejade Posts: 5,877
    Nice work!!
    T+A PA 1530R,Wireworld Silver Eclipse 8 SC, Tyler Highland H2, Audioquest Thunderbird Interconnect , Innuos Zen MK3 W4S recovery, WireWorld Platinum Starlight 7 USB, Border Patrol SE-I

    Have but haven't used in a while: Cayin SCD50T, Technics 1200, Denon DL160, Jolida D9
  • agfrost
    agfrost Posts: 2,374
    Nice work.

    Was it your first time using Gimpod boards? I know you designed/had made boards for some (all?) of your SDAs.
    Jay
    SDA 2BTL * Musical Fidelity A5cr amp * Oppo BDP-93 * Modded Adcom GDA-600 DAC * Rythmik F8 (x2)
    Micro Seiki DQ-50 * Hagerman Cornet 2 Phono * A hodgepodge of cabling * Belkin PF60
    Preamp rotation: Krell KSL (SCompRacer recapped) * Manley Shrimp * PS Audio 5.0
  • DarqueKnight
    DarqueKnight Posts: 6,662
    Yes, this was my first time using Gimpod's boards.

    I designed replacement boards for all of my SDAs.
    "So hot it burns Mice!"~DK
    "Polk SDA-SRSs are hopelessly out of date both sonically and technologically... I see no value whatsoever in older SDA speakers."~Audio Asylum Member
    "Knowledge, without understanding, is a path to failure."~DK
    "Those who irrationally rail against something or someone that is no threat to them, actually desire (or desire to be like) the thing or person they are railing against."~DK
  • Emlyn
    Emlyn Posts: 3,463
    If you flew to Chicago I hope you didn't try to take that suitcase as a carry-on bag! TSA would freak out. B)

    Nice work on the speakers, as usual.
  • DarqueKnight
    DarqueKnight Posts: 6,662
    The tools suitcase was in checked baggage. TSA didn't have any interest in that suitcase. The suitcase they were very interested in was the suitcase that contained my clothes, and the box that the Sonic Barrier strips were in.

    323ghv6drtv9.jpg

    hfqw325vnpcj.jpg

    Since O'Hare is one of the top 20 airports for theft by TSA officers, I did have a little concern about my tools making it in and out of O'Hare without being "detained".

    https://abcnews.go.com/Blotter/top-20-airports-tsa-theft/story?id=17537887
    "So hot it burns Mice!"~DK
    "Polk SDA-SRSs are hopelessly out of date both sonically and technologically... I see no value whatsoever in older SDA speakers."~Audio Asylum Member
    "Knowledge, without understanding, is a path to failure."~DK
    "Those who irrationally rail against something or someone that is no threat to them, actually desire (or desire to be like) the thing or person they are railing against."~DK
  • gimpod
    gimpod Posts: 1,790
    ylrtvqpiakds.jpg
    Figure 5. Experimenting with position of the partially assembled new board.
    I considered mounting the new boards in the bottom of the cabinet, but decided
    to use the stock location. These boards are pure genius. They, and the extensive online documentation, really make the crossover mod process a breeze.

    Thanks @DarqueKnight for posting that, coming from you it means a lot to me.
    “The two most important days in your life are the day you are born and the day you find out why.” ~ Mark Twain
  • DarqueKnight
    DarqueKnight Posts: 6,662
    I have professional and hobbyist experience designing circuit boards, therefore I can and do appreciate the thought and effort that goes into designing a single circuit board. Orders of magnitude more thought and effort is required for designing a single board for multiple crossovers.
    "So hot it burns Mice!"~DK
    "Polk SDA-SRSs are hopelessly out of date both sonically and technologically... I see no value whatsoever in older SDA speakers."~Audio Asylum Member
    "Knowledge, without understanding, is a path to failure."~DK
    "Those who irrationally rail against something or someone that is no threat to them, actually desire (or desire to be like) the thing or person they are railing against."~DK
  • honestaquarian
    honestaquarian Posts: 2,997
    Experience is THE BEST teacher.
    You can tell someone until both you and they are blue in the face, but once they experience it then ya got `em!
    Good work DarqueKnight B)
  • westmassguy
    westmassguy Posts: 6,783
    Very nice work!
    Home Theater/2 Channel:
    Front: SDA-2ATL forum.polkaudio.com/discussion/143984/my-2as-finally-finished-almost/p1
    Center: Custom Built forum.polkaudio.com/discussion/150760/my-center-channel-project/p1
    Surrounds & Rears: Custom Built forum.polkaudio.com/discussion/151647/my-surround-project/p1
    Sonicaps, Mills, RDO-194s-198s, Dynamat, Hurricane Nuts, Blackhole5
    Pioneer Elite VSX-72TXV, Carver PM-600, SVS PB2-Plus Subwoofer
    Cables: Speaker: Furez 10/2 with GLS Locking Banana Plugs
    Interconnect: Furez 10/2 with SpeakONs
    ICs: Custom Furez by Douglas Connections
    Den:
    Bose 901 Series II Continentals Restored, Re-Built Equalizer with Elna Silmic IIs, Sonicaps, and Silver Mica Caps
    Carver CT-3 Pre, Carver C-500

    dhsspeakerservice.com/