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

DarqueKnightDarqueKnight Posts: 6,196
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

  • pitdogg2pitdogg2 Posts: 9,831
    Tossed him right into the abyss Ray.
    Nice job on both accounts :D :)
  • Moose68BashMoose68Bash Posts: 3,525

    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, PS Audio PW Transport, DirectStream DAC; AQ Sky XLRs, Perreaux SM6 MKII Pre; AQ Sky XLRs, Perreaux Prisma 750 Amps or CAT 600.2 Dualmono Amp, Morrow SP7 Speaker Cables, SDA SRS 1.2tls (RD0198s, Dreadnought, Black Hole 5, Acousta-Stuf, Dynamat Extreme, JBWeld. Vr3 Mods: "The Abbot" Monastery-Level Xovers, Custom Internal Wiring, Binding Post Plates, & SDA ICs).

    Exercise Room, Wadia 171 iPod Dock, PS Audio PerfectWave MkII DAC, AQ Sky XLRs, Perreaux SM6 Preamp, AQ King Cobra RCAs, Perreaux PMF3150 Amp, Dreadnought, Supra Rondo 4x2.5 Speaker Cables, SDA 1Cs (Vr3 Mods Xovers).

    Synology 713+ NAS on Gigabit LAN serving PW MkII DAC & DirectStream DAC.
  • DarqueKnightDarqueKnight Posts: 6,196
    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
  • erniejadeerniejade Posts: 4,054
    Nice work!!
    Lumin D1, KEF LS50 Wireless, Cayin scd-50T, LH Labs VI Dac, Technics 1200, Denon DL160, Jolida D9, HP I7 Laptop, Wireworld Eclipse 7, Wireworld Aurora, Wireworld Electra 7, Signal Magic Digital, Cardas Quadralink 5C, Velodyne SPL1200
    USB helpers: w4s Recovery

    HT: Elite SC27, Full Polk RTI setup.

  • agfrostagfrost Posts: 2,127
    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 * Marantz DV-9500 * Modded Adcom GDA-600 DAC * Rythmik F8
    Micro Seiki DQ-50 * A hodgepodge of cabling * Belkin PF60
    Preamp rotation: Krell KSL (SCompRacer recapped) * Manley Shrimp * PS Audio 5.0
  • DarqueKnightDarqueKnight Posts: 6,196
    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
  • EmlynEmlyn Posts: 2,045
    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.
    1. Polk LSiM707, 704C, 703; Dual SVS SB2000 subwoofers; Marantz SR7011 receiver; Parasound A23 amp; Oppo 205; Toshiba HD-DVD Player; Sony 65" 4K TV; FIOS; PS Audio Power Plant Premier; MIT S2 cables
    2. JM Labs Electra 920.1; Parasound JC2 Preamp; Sonic Frontiers Power 2 amp; Sony HAP-Z1ES; Oppo 105D; Music Hall MMF7 and Acoustech phono pre; PS Audio P1000; MIT S1 Cables
    3. Polk LSiM703; Pioneer Elite SC97 receiver; Oppo 203; Squeezebox Touch; MIT S3 cables
  • DarqueKnightDarqueKnight Posts: 6,196
    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
  • gimpodgimpod Posts: 1,739
    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.
    "If you design software that any moron can use only morons will use it." JMO
    ---
    “The two most important days in your life are the day you are born and the day you find out why.” ~ Mark Twain

    Unfortunately for most of us we only get to experience the first day and then we can't even remember it.
    ---
    "Close only counts in Horseshoes, Hand Grenades and Thermonuclear Weapons."
    "50% Why... That's almost half."
    "I know, I'm sick and need help."
    ----
    www.gimpod.com
    ----
    "The best way to enjoy digital music reproduction is to never listen to good analogue reproduction." ~ Kenneth Swauger
  • DarqueKnightDarqueKnight Posts: 6,196
    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
  • honestaquarianhonestaquarian Posts: 1,934
    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)
    Living room Home theater: Upgrade Company modified Onkyo PR-SC5509,Sunfire Cinema grand Signature 5 channel amp(1st gen),Carver TFM-45,Carver M-400a,Panasonic TC-P50ST60 50" Plasma(last gen before Plasma production stopped)Pioneer Elite DVL-91,Meridian 519 Dolby AC-3 RF Demodulator,Oppo Digital UDP-205,TiVo Bolt VOX,Nakamich BX-300,Technics SL-1200MKII,Shure V15 Type VxMR cartridge,Polk SDA-SRS 3.1 TL(with RD-0198 tweeters, upgraded with Larry's rings, black hole5,an Avel-Lindberg 1000VA isolation transformer, VR3 customer crossovers and internal wiring),Polk CS-1000P(with SL-6506 tweeter),Polk Monitor 5jr(with RD-0194 tweeters),Polk RT-35i (1),Polk Mini Monitor,Polk PSW150(3),Monster Power HTPS 7000 MKII Signature series,Monster Power AVS 2000 Signature Series,Various MIT,Monster,Upgrade Company and Belden interconnect,power,HDMI,Coax and Toslink Digital and speaker cables.

    Bedroom 2 channel system:Integra DTM 40.4,Nakamichi BX-100,TiVo mini,Musical Fidelity X-LPS,X-PSU,Carver TFM-25,Sony KV-34XBR970(last of the widescreen tube sets before production stopped)Technics SL-1200MKII,Shure V15 Type V MR cartridge,Polk RT-55(with SL-6506 tweeters),Polk PSW-200 in plexiglass(2),Sony Playstation 3 slim.Monster Power HTPS-7000,Monster AVS-2000, PowerVarious Kimber,Audioquest and MIT interconnects and speaker cables.
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