Utilizing Gimpod's Custom SDA Boards for 1.2tl Crossover Upgrade

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  • audiocr381ve
    audiocr381ve Posts: 2,588
    edited January 2012
    F1nut wrote: »
    I wouldn't reuse anything he touched.

    lolz
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  • F1nut
    F1nut Posts: 50,574
    edited January 2012
    thejck wrote: »
    I have a 22 ohm mills resistor. I dont see that sonic craft has a 22.5 ohm resistor on their website. how bad a deal is this?

    They have them, just call to order.
    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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  • thejck
    thejck Posts: 849
    edited January 2012
    I noticed something on this board as well as the originals.
    For the T4 and the T1 circuit it seems things are wired backwards
    For T4 on the schema it shows the 7.5ohm then the .7 coil connected to the tweeter white wire
    however on the board it goes .7 coil to 7.5ohm resistor then to the tweeter

    For T1 on the schema it goes 15 ohm to 12uf cap to tweeter white wire
    however on the board it goes 12uF cap to 15ohm resistor to white wire.

    Is this going to cause a difference.
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  • michaeljhsda2
    michaeljhsda2 Posts: 2,184
    edited January 2012
    thejck wrote: »
    I noticed something on this board as well as the originals.
    For the T4 and the T1 circuit it seems things are wired backwards
    For T1 on the

    Do you mean that you noticed that the tweeter polarity is reversed for each of the 4 tweeters? If that's what you noticed then the answer is yes...it's supposed to be reversed.
    SDA SRS 2.3TL's
    Silk Audio MS-90-BT integrated tube amp
    Yaqin MS-20L integrated tube amp
    SDA 2B TL's
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  • thejck
    thejck Posts: 849
    edited January 2012
    no i knew that.
    i am talking about how on
    t1 the placement of the cap and the resistor is reversed in the circuit.
    in t4 the placement of the coil and resistor is reversed.

    I am comparing this against the original schema that is posted in the stickys at the start of the vintage forum
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  • DarqueKnight
    DarqueKnight Posts: 6,765
    edited January 2012
    thejck wrote: »
    I noticed something on this board as well as the originals.
    For the T4 and the T1 circuit it seems things are wired backwards
    For T4 on the schema it shows the 7.5ohm then the .7 coil connected to the tweeter white wire
    however on the board it goes .7 coil to 7.5ohm resistor then to the tweeter

    For T1 on the schema it goes 15 ohm to 12uf cap to tweeter white wire
    however on the board it goes 12uF cap to 15ohm resistor to white wire.

    Is this going to cause a difference.

    No. Wiring "backwards" makes a difference if + and - polarity is being reversed. The order of the series connected cap and resistor on the series connected T1 branch and the series connected coil and resistor on the T4 branch does not make a difference. It is analogous to saying 3 + 4 = 4 + 3.
    Proud and loyal citizen of the Digital Domain and Solid State Country!
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  • thejck
    thejck Posts: 849
    edited January 2012
    DarqueKnight wrote: »
    No. Wiring "backwards" makes a difference if + and - polarity is being reversed. The order of the series connected cap and resistor on the series connected T1 branch and the series connected coil and resistor on the T4 branch does not make a difference. It is analogous to saying 3 + 4 = 4 + 3.

    Thats what I was referring too. Thank you for clarifying that. I can read circuits but I fail to understand what they do. I will leave that to the electrical engineers of this world.
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  • thejck
    thejck Posts: 849
    edited January 2012
    I am still trying to decide where to mount the large coil. I do not want to put screw holes in the front of the cabinet like DK did to strengthen the brace under the crossover that he used to set the coil on.
    If I cut a length of wood to run from the center of the brace down to the bottom of the speaker to support the brace from underneath will that effect anything. I will have to run it back away from the passive right underneath.
    this is on the 1.2tl
    Also I was thinking about using long wire ties to strap the coil to the brace because when i was at Home depot I did not see plastic or aluminium screws.
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  • RickTfromAZ
    RickTfromAZ Posts: 122
    edited January 2012
    thejck wrote: »
    I am still trying to decide where to mount the large coil. I do not want to put screw holes in the front of the cabinet like DK did to strengthen the brace under the crossover that he used to set the coil on.
    If I cut a length of wood to run from the center of the brace down to the bottom of the speaker to support the brace from underneath will that effect anything. I will have to run it back away from the passive right underneath.
    this is on the 1.2tl
    Also I was thinking about using long wire ties to strap the coil to the brace because when i was at Home depot I did not see plastic or aluminium screws.

    Home Depot is about the worst place to look for specialty fasteners. Any large Ace or True-Value will have so many specialty fasteners it will make your head spin. Havent checked yet to see if either of those hardware stores stocks aluminum fasteners/hardware though. You may just want to google it and order online. I wouldnt bother with a plastic bolt, unless it is pretty substantial in diameter, because of the weight of the inductor.
    As far as strengthening the brace...You could either install a gusset under the rear of the brace or run a piece of MDF from the bottom of the brace to the speaker floor. On the front of the brace...if memory serves me right, there is about 3/4" between the bottom of the brace and the opening for the PR. You could glue a piece of MDF crossways under the brace. Or you could just screw the brace like DK did, and if it the appearance bothers you that bad, you could hide it by gluing two small circular pieces of vinyl or felt over the holes.
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  • F1nut
    F1nut Posts: 50,574
    edited January 2012
    Glue and screw (from the inside) a support bracket at each end of the cross brace. Easy peasy!
    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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  • thejck
    thejck Posts: 849
    edited January 2012
    I need to find a longer screw to attach the crossover to the plate. Do you know what a good place to do that locally would be?
    I prefer one with a black head to replace the one I have. However I was not having good luck at Home Depot.
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  • RickTfromAZ
    RickTfromAZ Posts: 122
    edited January 2012
    See the second sentence of my previous post.
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  • thejck
    thejck Posts: 849
    edited January 2012
    I ended up mounting the coil to the floor. I glued the piece of wood that I cut out onto the floor and then set the coil into it. It fits snugly and will not move. If the speakers ever need to me transported i will pull the passive out and then remove them for safety.

    I ran some 10 guage speaker wire to the coils from the boards. However I could not get 10 guage speaker wire to fit into the P and R slots of the boards so I had to shave some of it off and then tin the wire with solder and then insert it into the boards.
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  • thejck
    thejck Posts: 849
    edited February 2012
    when mounting the rdo 198 tweeter does it matter which side goes up?
    The white wire with the larger spade or the colored wire with the smaller spade?
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  • thejck
    thejck Posts: 849
    edited February 2012
    I ended up mounting my boards to the brace behind the crossover plate.
    I put the big coils on the floor and ran 10 guage wire to it with disconnects. So far they sound great but I am afraid to run them for too long as I might need to service my amp to prevent over heating.
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  • DarqueKnight
    DarqueKnight Posts: 6,765
    edited February 2012
    thejck wrote: »
    when mounting the rdo 198 tweeter does it matter which side goes up?

    No.
    thejck wrote: »
    I ended up mounting my boards to the brace behind the crossover plate.
    I put the big coils on the floor and ran 10 guage wire to it with disconnects. So far they sound great but I am afraid to run them for too long as I might need to service my amp to prevent over heating.

    You shouldn't be doing anything to your speakers that causes you to live in fear. Get a pair of digital thermometers and monitor the heat sink temperatures over a period of time to determine if your amp is having some difficulty with the lowered impedance. If you like this mod and your amp is struggling with it, make plans to acquire a different amp.

    I don't think a mod is worthwhile if it causes you to ration your listening time.
    Proud and loyal citizen of the Digital Domain and Solid State Country!
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  • thejck
    thejck Posts: 849
    edited February 2012
    DarqueKnight wrote: »
    No.



    You shouldn't be doing anything to your speakers that causes you to live in fear. Get a pair of digital thermometers and monitor the heat sink temperatures over a period of time to determine if your amp is having some difficulty with the lowered impedance. If you like this mod and your amp is struggling with it, make plans to acquire a different amp.

    I don't think a mod is worthwhile if it causes you to ration your listening time.

    No.. Its not the mod that is causing the fear.. I am still having the right channel getting hotter than the left channel. But that was the case before the mods to lower the inductance on that channel.

    I was refering to the bias issue that you told me about. I am still trying to find a proper service manual to check and adjust my HCA-3500. I am considering taking it to a local place that worked on my amps a while back. He said he could do it for 75 bucks.

    I am completely confident that the HCA-3500 can handle these speakers with plenty to spare.
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  • DarqueKnight
    DarqueKnight Posts: 6,765
    edited February 2012
    OK. I had forgotten about the bias issue.
    Proud and loyal citizen of the Digital Domain and Solid State Country!
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