1000 VA Dreadnought

crcolby
crcolby Posts: 18
in Vintage Speakers
Having finished all the internal mods for my SDA 1C pair, now I want to build a Dreadnought. I read DarqueKnight's excellent posts about the 800VA then the 1000VA transformers he used. The second of those was possible only because the manufacturer, Avel Lindberg, had specially manufactured a transformer for audio use. But A-L now routinely makes 1000VA transformers and has promised to send me specs soon which I can compare with Matthew Polk's recommendations for DC resistance, current saturation and such.

Actually, A-L makes a number of 1000VA transformers. All have the same toroid diameter, weight, height and regulation. But then they arerated for volts in the secondary at 25+25 upwards through 115+115, with corresponding currents ranging downwards (!) from 20A to 4.35A. I have no idea what these voltage and current specs mean, and certainly no idea what they say for the suitability of the various 1000VA transformers for use in a Dreadnought. A-L understandably doesn't want to involve itself in audio design. DarqueKnight's 800VA toroid carries the 115+115 rating. Is that the correct one to use? The only one?
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Comments

  • DarqueKnight
    DarqueKnight Posts: 6,765
    Avel-Lindberg recommended two 800VA transformers based on the specs provided by Matthew Polk. I chose the larger and higher current capacity Y236906 model. My AI-1 upgrade project was done 12 years ago in 2008. Avel-Lindberg, or another vendor, may offer a higher performance alternative.

    The 1000VA transformer we use is the AV-047528, however, it is a special order item with a minimum order quantity. I would ask Avel-Lindberg which of their current 1000VA toroidal transformers comes closest to the AV-047528 in current capacity and especially in low noise performance.
    Proud and loyal citizen of the Digital Domain and Solid State Country!
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  • audioluvr
    audioluvr Posts: 5,578
    Their 800 VA transformer is a stock item. I built one of these and was really happy with the results. Some here have far superior systems than mine and preferred the 1000 VA tranny but I A/B'd them and on my system at least there was virtually no difference.
    Gustard X26 Pro DAC
    Belles 21A Pre modded with Mundorf Supreme caps
    B&K M200 Sonata monoblocks refreshed and upgraded
    Polk SDA 1C's modded / 1000Va Dreadnaught
    Wireworld Silver Eclipse IC's and speaker cables
    Harman Kardon T65C w/Grado Gold. (Don't laugh. It sounds great!)

    There is about a 5% genetic difference between apes and men …but that difference is the difference between throwing your own poo when you are annoyed …and Einstein, Shakespeare and Miss January. by Dr. Sardonicus
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  • crcolby
    crcolby Posts: 18
    Thanks, folks. I had a thought about the mysterious 115+115 specification: this is A-L's way of saying the primary-secondary winding ratio is 1-1. A-L specifies that all its primaries are 115+115, which I take to mean they are assuming ordinary household AC voltage. Secondary would have the same voltage only when the winding was 1-1. The plus sign must indicate some kind of parallel/series choice. Anyway, I'll put DarqueKnight's question to A-L.
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  • F1nut
    F1nut Posts: 50,496
    Get the Y236906 model, it's proven. You will be happy.
    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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  • pitdogg2
    pitdogg2 Posts: 25,412
    edited June 2020
    Kind of interested in a response from
    Avel-Lindberg for kicks.
    Who knows we may need bigger, better, faster, leaps buildings in single sine wave sort of thing B)
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  • Schurkey
    Schurkey Posts: 2,100
    crcolby wrote: »
    Thanks, folks. I had a thought about the mysterious 115+115 specification: this is A-L's way of saying the primary-secondary winding ratio is 1-1. A-L specifies that all its primaries are 115+115, which I take to mean they are assuming ordinary household AC voltage. Secondary would have the same voltage only when the winding was 1-1. The plus sign must indicate some kind of parallel/series choice. Anyway, I'll put DarqueKnight's question to A-L.
    Well...close to 1:1, anyway.


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  • crcolby
    crcolby Posts: 18
    I got this answer back from Avel Lindberg (more promptly than I have moved to post it here):
    Hi Craig:

    Based on current manufacturing, engineering offers as follows:

    Total DC resistance of primary and secondary under 0.8 ohms and preferably under 0.5 ohms.

    Please see the table below.

    Inductance of primary and secondary should be at least 10mH and ideally around 14mH.

    We don’t measure inductance on transformers and therefore values are unavailable, however, if the customer is after no load inductance on each primary and secondary values will be higher than 10mH.

    Current capacity to saturation a minimum of 5 amps.

    I am unsure about this request, usually the saturation current is applicable for inductors and not for transformers.

    Turns ration of 1:1.

    Please see the values below.

    P/N DC resistance (Ohm) Turns ratio
    Pri and Sec each at 115V
    Y236906 TA800/115/AI Pri 0.55 Sec 0.75 Pri:1 Sec: 1.05
    Y236956 TA1000/115/AI Pri 0.38 Sec 0.53 Pri:1 Sec: 1.038
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  • audioluvr
    audioluvr Posts: 5,578
    Order the Y236906
    Gustard X26 Pro DAC
    Belles 21A Pre modded with Mundorf Supreme caps
    B&K M200 Sonata monoblocks refreshed and upgraded
    Polk SDA 1C's modded / 1000Va Dreadnaught
    Wireworld Silver Eclipse IC's and speaker cables
    Harman Kardon T65C w/Grado Gold. (Don't laugh. It sounds great!)

    There is about a 5% genetic difference between apes and men …but that difference is the difference between throwing your own poo when you are annoyed …and Einstein, Shakespeare and Miss January. by Dr. Sardonicus
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  • VSAT88
    VSAT88 Posts: 1,257
    Yep that is what I was told ^ just three posts down. I sent an e mail off to them so we will see.
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  • xschop
    xschop Posts: 5,000
    Is the Y236906 model still the go-to for the 800VA Dreadnaught build?
    Don't take experimental gene therapies from known eugenicists.
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  • audioluvr
    audioluvr Posts: 5,578
    Yup
    Gustard X26 Pro DAC
    Belles 21A Pre modded with Mundorf Supreme caps
    B&K M200 Sonata monoblocks refreshed and upgraded
    Polk SDA 1C's modded / 1000Va Dreadnaught
    Wireworld Silver Eclipse IC's and speaker cables
    Harman Kardon T65C w/Grado Gold. (Don't laugh. It sounds great!)

    There is about a 5% genetic difference between apes and men …but that difference is the difference between throwing your own poo when you are annoyed …and Einstein, Shakespeare and Miss January. by Dr. Sardonicus
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  • GlennDog
    GlennDog Posts: 3,120
    xschop wrote: »
    Is the Y236906 model still the go-to for the 800VA Dreadnaught build?

    one should opt for the 1KVA instead ;)
    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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  • Toolfan66
    Toolfan66 Posts: 17,221
    edited January 27
    GlennDog wrote: »
    xschop wrote: »
    Is the Y236906 model still the go-to for the 800VA Dreadnaught build?

    one should opt for the 1KVA instead ;)

    If one can find one, the 800 is a fine piece to use, better than anything else, and has been proven, unless someone whats to try a group buy for the 1000, but I honestly don't think the demand is there anymore to make it worth while.

    Maybe I'm wrong..
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  • xschop
    xschop Posts: 5,000
    edited January 27
    From what Ive found the 1000VA wont fit my enclosure. A description of the 800VA states it was 6.3"" OD. Has it changed?
    Don't take experimental gene therapies from known eugenicists.
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  • Toolfan66
    Toolfan66 Posts: 17,221
    I owned the 800 at first, sold it after the 1000 group buy, I don’t think the 800 was that much smaller than the 1000 if at all from what I remember.

    Ray might have that info, or even a post about the two..
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  • DarqueKnight
    DarqueKnight Posts: 6,765
    800VA Y236906 dimensions: 6.3" D, 2.2" H, 13.2 lbs.
    1000VA AV-047548 dimensions: 7.28" D, 3.3" H, 22 lbs.

    kfezj4otlchz.jpg
    1000VA on left, 800VA on right.

    Spec sheets for both transformers are attached.
    Proud and loyal citizen of the Digital Domain and Solid State Country!
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  • honestaquarian
    honestaquarian Posts: 3,186
    I smell another possible group buy ;)
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  • Toolfan66
    Toolfan66 Posts: 17,221
    Okay, I do remember that now. Thanks Ray..
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  • F1nut
    F1nut Posts: 50,496
    IME, one could easily live with the 800 VA version.
    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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  • Toolfan66
    Toolfan66 Posts: 17,221
    F1nut wrote: »
    IME, one could easily live with the 800 VA version.

    100% Agree!!
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  • DarqueKnight
    DarqueKnight Posts: 6,765
    Toolfan66 wrote: »
    Okay, I do remember that now. Thanks Ray..
    Toolfan66 wrote: »
    F1nut wrote: »
    IME, one could easily live with the 800 VA version.

    100% Agree!!

    You know you want a new 1000VA Dreadnought to go with your new 2.3TLs.
    Proud and loyal citizen of the Digital Domain and Solid State Country!
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  • Toolfan66
    Toolfan66 Posts: 17,221
    edited January 27
    B)
    DarqueKnight wrote: »
    Toolfan66 wrote: »
    Okay, I do remember that now. Thanks Ray..
    Toolfan66 wrote: »
    F1nut wrote: »
    IME, one could easily live with the 800 VA version.

    100% Agree!!

    You know you want a new 1000VA Dreadnought to go with your new 2.3TLs.

    I have two of them, and I down modded my 1.2TL’s, and said goodbye to them about an hour ago. I made a straight cable for them, he will have to make his own dreadnought if he wants one, I told him if he wants help doing so I would help him put it together when he’s ready..

    I kept my tweeter face plates, the crossovers I had built for them with the red face plates, the aluminum top and bottom plates, and the outside rings. Oh I did swap the passives out, I wanted to keep the one with Matt Polk’s signature.. 😎. So glad I had a spare set..

    I’m looking forward to the 2.3tl project, I am keeping these some what simple, but will look very nice when done..
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  • Sitka
    Sitka Posts: 74
    I too am in the midst of building a Dreadnought (the 800VA version), and am curious if members here used the included steel bolt and hold down plate for mounting in an aluminum enclosure. I'm just wary of having all that steel next to the torroid. Also curious if we are still wrapping the coil in Dynamat.
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  • Toolfan66
    Toolfan66 Posts: 17,221
    Sitka wrote: »
    I too am in the midst of building a Dreadnought (the 800VA version), and am curious if members here used the included steel bolt and hold down plate for mounting in an aluminum enclosure. I'm just wary of having all that steel next to the torroid. Also curious if we are still wrapping the coil in Dynamat.

    Use an aluminum or stainless bolt if you can, I used aluminum..
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  • F1nut
    F1nut Posts: 50,496
    edited January 27
    Also curious if we are still wrapping the coil in Dynamat.
    I was not aware of someone doing that. It is the enclosure that is lined with Dynamat Xtreme.
    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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  • Toolfan66
    Toolfan66 Posts: 17,221
    edited January 27
    F1nut wrote: »
    Also curious if we are still wrapping the coil in Dynamat.
    I was not aware of someone doing that. It is the enclosure that is lined with Dynamat Xtreme.

    I think there was someone that did do that, don’t remember who though.

    Yes just the enclosure..
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  • GlennDog
    GlennDog Posts: 3,120
    I did it . . . no discernible difference
    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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  • xschop
    xschop Posts: 5,000
    I thought someone wrapped their enclosure in copper tape.
    Don't take experimental gene therapies from known eugenicists.
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  • pitdogg2
    pitdogg2 Posts: 25,412
    edited January 27
    xschop wrote: »
    I thought someone wrapped their enclosure in copper tape.

    I remember that
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  • VR3
    VR3 Posts: 28,611
    I lined ptroopers enclosure in copper foil as per his request
    - Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit.
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