Dreadnaught build question

2

Comments

  • SchurkeySchurkey Posts: 1,726
    edited December 2017
    F1nut wrote: »
    Schurkey wrote: »
    The transformer winding is asymmetrical. It's not a 1:1 ratio, and even the wire gauge is different primary-to-secondary.

    Having the cables on the outside of the box a few feet different in length will make zero difference in the real world.

    It's 115V - 115V.
    gimpod wrote: »
    All Avel Lindberg Y23 Standard Range Toroidal Transformers have 115 + 115 V primaries and the secondary of the Y236906 are 115 + 115 V, That would make it 1:1 would it not.
    Nope, in fact it confirms that it's NOT a 1:1 ratio.

    Look at the intended purpose. The transformer was built to input 115 volts through the primary, and get 115 volts out the secondary.

    That means the Copper and Iron Losses (transformer inefficiency) have to be "recovered" by adding extra length to the secondary windings (more windings) to bring the voltage on the secondary high enough so that you still have 115V after subtracting the losses.

    The transformer was never designed to accept voltage on the secondaries, and then pull current from the primary. We do this, but it's not something the transformer was intended to do. WE use it as a symmetrical device, but that wasn't what it was intended for.

    So, yeah, the SDA signal should be louder one direction than the other. DK says it doesn't matter in real life. I say it would be better if it was a true symmetrical transformer.

    I looked around on the A-L web site, and did not confirm that the secondary windings are a different gauge wire from the primary...but I'm sure that's true, too.
    audioluvr wrote: »
    2. Does it matter if one IC cable is longer than the other ( I'm assuming, like speaker wire, they need to be the same but...)
    My point in all this is to say that given the non-symmetrical nature of the transformer, and nobody seems to be able to hear a flaw or defect in the SDA volume, having a few feet more speaker cable attached to one side compared to the other will be of no importance at all.
  • Schurkey wrote: »
    I looked around on the A-L web site, and did not confirm that the secondary windings are a different gauge wire from the primary...but I'm sure that's true, too.

    The primary and secondary wire gauges sizes are definitely different on the 800V that I bought a few years ago. Just don't recall which was thicker.

    SDA SRS 1.2TL's w/ RD0198-1's, Sonicap, Mills
    AI-1 Dreadnought
    SDA 1C's w/Clarity Cap ESA; PA, Mills, RD0194-1's
    SDA 1C's stock
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  • Viking64Viking64 Posts: 1,565
    edited December 2017
    The primary and secondary wire gauges sizes are definitely different on the 800V that I bought a few years ago. Just don't recall which was thicker.
    On my 800VA, the blue/gray/violet/brown are thicker than the black/red/orange/yellow. The first set (thicker) says "2 x 115v" on the label. The thinner wires have 2 @ 0 volts and 2 @ 115V.

    qjji8mq6l8gt.jpg

    Post edited by Viking64 on
  • I personally could careless if my 1000V Dreadnought is a true 1:1 ratio per say or not. It works and sounds great, definitely better then the AI-1 Polk made.

    I use different length wires since mine sits by one speaker. Using DK's test results I choose to use the shorter wire on the side that tested out to have the minuet lower test result and the longer wire on the side that tested higher.

    It's sounds great to me, that's what matters.

    Unless someone can come up with a better design this is as good as it gets. Why argue about tech specs when the performance results speak for themselves.

    Jealousy possibly... Hard to say. If you don't like it design a better wheel.
    "Make a man a fire and he'll be warm for a day. Light
    a man on fire and he'll be warm for the rest of his life."

  • westmassguywestmassguy Posts: 5,893
    Viking64 wrote: »
    The primary and secondary wire gauges sizes are definitely different on the 800V that I bought a few years ago. Just don't recall which was thicker.
    On my 800VA, the blue/gray/violet/brown are thicker than the black/red/orange/yellow. The first set (thicker) says "2 x 115v" on the label. The thinner wires have 2 @ 0 volts and 2 @ 115V.

    qjji8mq6l8gt.jpg

    Looks strangely familiar................
    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/
    Now Carrying Gimpod's Custom SDA Circuit Boards

    "And keep her under 70, would you, huh? Betty likes a slow ride"
  • pitdogg2pitdogg2 Posts: 8,831
    More residual's Dave hehe
  • On3s&Z3r0sOn3s&Z3r0s Posts: 1,011
    3. The case I use, which you probably saw in one of the threads, is Cast Aluminum. Aluminum is great for RF shielding. The Copper adds EMI shielding, which is different. The Copper Foil MUST be separated from the Aluminum by etching primer and several top coats of Enamel. Galvanic corrosion will result if you don't.

    In what situation does shielding the transformer from stray RF matter? I've got my transformer in a steel case (plenty magnetic). It sits in a cabinet close to the floor while all the other components are about 3 feet up from that. Is it interference from the other components that is the problem or just ambient RF from nearby transmission towers or something like that?

    I haven't ever noticed any hum or anything like that. (As an aside, I had a "high-bandwidth" amp once that I could swear would hum differently depending on where it was in the house.) I'm pretty sure I've asked this question before and been told that extra shielding from aluminum is of dubious value, but seems like aluminum is all the rage now.
  • F1nutF1nut Posts: 38,793
    It is absolutely not of dubious value.
    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."


  • westmassguywestmassguy Posts: 5,893
    edited January 30
    3. The case I use, which you probably saw in one of the threads, is Cast Aluminum. Aluminum is great for RF shielding. The Copper adds EMI shielding, which is different. The Copper Foil MUST be separated from the Aluminum by etching primer and several top coats of Enamel. Galvanic corrosion will result if you don't.

    In what situation does shielding the transformer from stray RF matter? I've got my transformer in a steel case (plenty magnetic). It sits in a cabinet close to the floor while all the other components are about 3 feet up from that. Is it interference from the other components that is the problem or just ambient RF from nearby transmission towers or something like that?

    I haven't ever noticed any hum or anything like that. (As an aside, I had a "high-bandwidth" amp once that I could swear would hum differently depending on where it was in the house.) I'm pretty sure I've asked this question before and been told that extra shielding from aluminum is of dubious value, but seems like aluminum is all the rage now.
    A guy way smarter than me confirmed the advantages of a shielded enclosure:
    http://forum.polkaudio.com/discussion/74472/the-ai-1-dreadnought-project-pt-1/p1
    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/
    Now Carrying Gimpod's Custom SDA Circuit Boards

    "And keep her under 70, would you, huh? Betty likes a slow ride"
  • westmassguywestmassguy Posts: 5,893
    F1nut wrote: »
    It is absolutely not of dubious value.
    Baked Potato?
    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/
    Now Carrying Gimpod's Custom SDA Circuit Boards

    "And keep her under 70, would you, huh? Betty likes a slow ride"
  • Viking64Viking64 Posts: 1,565
    Baked Potato?

    yl2xhdzknrxe.jpg

  • westmassguywestmassguy Posts: 5,893
    Viking64 wrote: »
    Baked Potato?

    yl2xhdzknrxe.jpg

    Pugtastic!
    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/
    Now Carrying Gimpod's Custom SDA Circuit Boards

    "And keep her under 70, would you, huh? Betty likes a slow ride"
  • VSAT88VSAT88 Posts: 569
    Same subject different question. I have a 115/120 VAC Isolation transformer from an old combo veriac/isolation transformer. Would that be OK to use ? Even if it were not an A/L would it make a good experiment ?
  • SchurkeySchurkey Posts: 1,726
    Will it pass 5+ amps without saturating? If so, it's worth a try.
  • F1nutF1nut Posts: 38,793
    There are numerous isolation transformers out there, but few are audio grade.
    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."


  • VSAT88VSAT88 Posts: 569
    F1nut wrote: »
    There are numerous isolation transformers out there, but few are audio grade.

    Thanks.
  • On3s&Z3r0sOn3s&Z3r0s Posts: 1,011
    F1nut wrote: »
    It is absolutely not of dubious value.

    <Laughing at self for being a dum bass> My bad for taking the word of the guy I got the case from.
    A guy way smarter than me confirmed the advantages of a shielded enclosure:
    http://forum.polkaudio.com/discussion/74472/the-ai-1-dreadnought-project-pt-1/p1

    Thank you for the link! That thread looks familiar, but I'm sure I glazed over before getting down to the spot with the measurements after the transformer was in the aluminum enclosure. Sounds like whenever I get around to my next batch of 2B upgrades it'll be time to move to the Neutriks since I need a new box anyway. Till then maybe I'll buy some heavy duty aluminum foil and make an AV-1000 sized baked potato.


  • audioluvraudioluvr Posts: 152
    edited February 13
    Well, got ' er done!

    1dkep9j46j4h.jpeg

    Thank you @DarqueKnight for the science experiment that created the dreadnaught!
    Thanks also to @westmassguy, @f1nut and all the other member here who provided invaluable information on building my rediculously Ghetto version. Might be the vodka talking but you guys ROCK!

    My case was created out of an old GE aluminum meter box i cut down. I lined the inside with bed liner, then copper tape, wrapped the 800 va transformer with dynomat (probably totally unnecessary), then covered the outside of the box with aluminum tape for that polished look.

    This journey was part total PITA/ part fun I'm sure I will be happy with the end results . Now if i can only get my crossovers back from DHS...
  • SchurkeySchurkey Posts: 1,726
    audioluvr wrote: »
    Thanks also to... ...all the other member here who provided invaluable information on building my rediculously Ghetto version.
    You've got nothing to be ashamed of.

    JUST WAIT until I finish mine. You guys "ain't seen nothin' yet" in terms of creative re-purposing of goofy old enclosures.

    No promises in terms of completion date...it's been two years and counting.
  • FestYboyFestYboy Posts: 1,367
    With cans on, I used to be able to hear a < .5dB shift, but sitting in a room with all the reflections, you'd never hear any shift at the levels you're talking.
  • audioluvraudioluvr Posts: 152
    After 30 years of being around heavy equipment and loud music I'm not sure I'd be able to hear a 5db difference...
  • Gerres26Gerres26 Posts: 248
    I started ordering some parts for my Dreadnought build today. I couldn't put it off any longer. I have a question though, what are you guys using to terminate the transformer wires to the back of the speakon connectors inside the enclosure? I've been reading through basically all of the old threads but didn't see it mentioned.
  • pitdogg2pitdogg2 Posts: 8,831
    edited February 18

    IIRC
    Some use quick connects and some have soldered direct.

    Personally I'd be in the gold plated quick connects camp.
  • F1nutF1nut Posts: 38,793
    You're twisting two wires together for each connection, fastons are the way to go.
    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."


  • Viking64Viking64 Posts: 1,565
    If you add jumpers between the +1 and +2 and the -1 and -2 contacts, you can use a 4-conductor wire for your interconnect cable.
  • Gerres26Gerres26 Posts: 248
    F1nut wrote: »
    You're twisting two wires together for each connection, fastons are the way to go.

    Which fastons and where is the best place to buy? Do you recommend using the same thing for the wires in the speaker cabinet or solder those since it is just one wire each?
  • RandyCroissantRandyCroissant Posts: 346
    edited February 18
    I use gold plated copper fastons available at Autozone
    Post edited by RandyCroissant on
    Yamaha RXA1030, Yamaha CD
    Polk SDA2btl highly modded
    Polk SDA 1C
    Polk CS350 LS x2
    Polk m5jr
    Kimber 8TC
    Sony 55" Bravia
    Wish list SVS sub

  • vcwatkinsvcwatkins Posts: 1,617
    I believe this is what I used, but I was ordering other parts at the time so shipping cost was not an issue.
    https://parts-express.com/gold-12-awg-1-4-female-disconnect-5-pair--095-810

    3amj97etv6mc.jpg
    Den: Rega RP6 (mods) * AT33PTGII * Parks Budgie SUT * Jolida jd9 (mods) * Roon (Sonic Transporter) * Sonore UltraRendu (LPS-1) * Wireworld Plat7 * isoRegen (LPS-1) * Lush usb * Chord QuteEX (Pardo PS) * Joule-Electra LA-100 iii * Sunfire Sig II * PSAudio p3 * MIT S3 * Polk SRS 1.2 (mods)
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  • Gerres26Gerres26 Posts: 248
    Did you use them for the connection to the neutrik inside the speaker as well? ...also, i was thinking of using canare 4s11 cable for my new interconnect cable since thats what my speaker cables are made from, what gauge should i use for this? I believe i ordered the neutrik connector with the screw down terminal.
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