SDA 1C upgrade time

Navy_Goat
Navy_Goat Posts: 375
in Vintage Speakers
First and foremost I would like to thank all the members here for showing me how to get so much enjoyment out of these 32 year old speakers. Your patience and generosity have been an unexpected bonus. Your help has been invaluable!

Now that I have my 2BTL SDAs sounding amazing they are once again front and center in the living room. Now it is time to get to work on my 1Cs. I did the 2BTLs in phases to get some idea for how the sound was changing throughout the process. I feel no need to do the same thing for the second set. I just want to skip to the end. So here is the plan:

4.4 and 12 uF caps - Sonic Craft
20 uF caps - Clarity PX
Mills resistors - Sonic Craft
Replace seals if needed - Already have Armacell on hand
H-Nuts - PE
Machine Screws - McMaster Carr
RD0194 - Midwest Speaker Repair

I think this time I will order some new boards. I wanted to see how difficult using OEM boards would be. Been there done that now. Everyone advises getting new boards and no surprise, you are all right. But you all already knew that. Using new boards adds a modest expense beyond the boards with the required connectors and hardware.

I cant find the thread anymore, but I recall reading here that someone (maybe @F1nut) recommending using a smaller resistance value for R1 (less than 2.7 ohm) or using a jumper rather than 0.47 ohm resister when replacing the polyswitch. I believe this had something to do with compensating for the more forward mid-range that the 1Cs present.

Finally, I am on the fence about inductors at this point. Seemed to be unnecessary before I experienced the massive improvement in bass response in my 2BTLs. Now I am wondering how much better it can get. I would appreciate any input you all might have on this point?

Questions and comments are always welcome....

Cheers,
Caleb
SDA SRS 2.3tl, SDA 1C, SDA 2B (TL mod), Reserve 200
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Comments

  • F1nut
    F1nut Posts: 50,542
    edited January 2020
    IMO and E, you already have the better speaker. Use the funds allotted for the 1C's somewhere else in your rig.
    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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  • boston1450
    boston1450 Posts: 7,636
    With SDA1c speakers just throw some 0194's in em & enjoy. Great speaker IMO
    ..
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  • RandyCroissant
    RandyCroissant Posts: 475
    The 1C is a good match for a mix of HT and music well worth doing the upgrades.
    Yamaha RXA1030, Yamaha CD-S2100, Yamaha AS-2200, Bluesound node 2i
    Polk SDA2btl highly modded
    Polk SDA 1C modded
    Polk CS350 LS x2
    Kimber 8TC
    Sony 55" Bravia
    Wish list SVS sub

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  • Navy_Goat
    Navy_Goat Posts: 375
    F1nut wrote: »
    IMO and E, you already have the better speaker. Use the funds allotted for the 1C's somewhere else in your rig.
    I definitely respect your opinion, but I am going ahead with modding the 1C's. I think my next significant gear upgrade will be quite a bit more $$ than this upgrade will cost.
    boston1450 wrote: »
    With SDA1c speakers just throw some 0194's in em & enjoy. Great speaker IMO
    Already ordered!
    RandyCroissant wrote: »
    The 1C is a good match for a mix of HT and music well worth doing the upgrades.
    I see that you have a CS350 LS CC. Since you have two I guess you really like it. If you have had the chance to compare it to the CS400i I would be interested in your opinion of the differences between the two.

    SDA SRS 2.3tl, SDA 1C, SDA 2B (TL mod), Reserve 200
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  • F1nut
    F1nut Posts: 50,542
    I tried.
    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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  • Navy_Goat
    Navy_Goat Posts: 375
    Ordered boards for these and my 2BTLs from Dave this afternoon.

    Hardware on order from Mouser.

    Dynamat on order (Ebay). I may look at the feasibility to use a laser engraver to cut the dynamat into precise sizes for each leg of the basket? I get bored when out to sea so I may try to work this out next time we go out.

    Sonic Barrier + H-Nuts on order from PE.

    RD0194 on order from Midwest Speaker Repair.

    8-32 screws on order from McMaster Carr.


    SDA SRS 2.3tl, SDA 1C, SDA 2B (TL mod), Reserve 200
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  • Navy_Goat
    Navy_Goat Posts: 375
    F1nut wrote: »
    I tried.

    You did. Out of curiosity, how much better are your 2.3TLs? The 2.3TLs seem like another sweet spot in the line up.
    SDA SRS 2.3tl, SDA 1C, SDA 2B (TL mod), Reserve 200
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  • F1nut
    F1nut Posts: 50,542
    Considerably.

    FYI, you don't need to cover every square inch of the baskets. A small piece on each spoke is all you need. There's no benefit to adding more.
    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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  • audioluvr
    audioluvr Posts: 5,582
    I regrettably have never heard any of the TL line so can't elaborate but I have owned the 2B's, 1C's and 2.3's. The only thing I didn't like about the 2.3's were they were too big for me to look out the window. One thing I observed was as you go up the line the bass gets bigger and more defined but then again I owned 2B's for almost 30 years so bass isn't everything (at least for me). The 1C's with the Erse inductors for the dimensional drivers will make them dig crazy deep though!
    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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  • Navy_Goat
    Navy_Goat Posts: 375
    edited February 2020
    F1nut wrote: »
    FYI, you don't need to cover every square inch of the baskets. A small piece on each spoke is all you need. There's no benefit to adding more.
    That is exactly my plan. I will be looking to use the laser engraver to cut strips that exactly fit the center part of each spoke. If I lay it out right I should be able to make this dynamat go a long way....

    I will be keeping an eye out for the right pair of 2.3s. Maybe some day I will get lucky. We will most likely be moving this summer to Pax River Maryland. I don't know if the used speaker market will be better or worse. Socal seems to be a pretty target rich environment so far.

    SDA SRS 2.3tl, SDA 1C, SDA 2B (TL mod), Reserve 200
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  • Navy_Goat
    Navy_Goat Posts: 375
    audioluvr wrote: »
    The 1C's with the Erse inductors for the dimensional drivers will make them dig crazy deep though!
    I also ordered 4 x Erse inductors (2 for each set 2B and 1C). They will all be shipped to Dave for hi to work his magic on them. B)

    SDA SRS 2.3tl, SDA 1C, SDA 2B (TL mod), Reserve 200
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  • F1nut
    F1nut Posts: 50,542
    edited February 2020
    Pax Naval Air Station? I seriously doubt you'll find any SDA 's around there. You might hear some banjos though.

    A member here and good friend of mine has a pair of modded 2BTL driven by a beast of a Musical Fidelity integrated. The bass they kick out is amazing. Perhaps a new amp should be in your future.

    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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  • audioluvr
    audioluvr Posts: 5,582
    Sorry Jesse. Just meant IMHO that the big SDA's can overpower you with bass. The 2B's and 1C's were my favorites.
    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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  • F1nut
    F1nut Posts: 50,542
    audioluvr wrote: »
    Sorry Jesse. Just meant IMHO that the big SDA's can overpower you with bass. The 2B's and 1C's were my favorites.

    Ha, I'm slighty embarrassed. I mistakenly took your post for one from Navy_Goat.
    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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  • RandyCroissant
    RandyCroissant Posts: 475
    I have not compared the CS350 to the 400i, please post some pictures of your mods as they progress.
    Yamaha RXA1030, Yamaha CD-S2100, Yamaha AS-2200, Bluesound node 2i
    Polk SDA2btl highly modded
    Polk SDA 1C modded
    Polk CS350 LS x2
    Kimber 8TC
    Sony 55" Bravia
    Wish list SVS sub

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  • Gardenstater
    Gardenstater Posts: 4,459
    @audioluvr and @Navy_Goat What model #'s of Erse Audio Inductors? The Foil Q ones? I'm modding my lowly 7Bs now after 41 years lol and I'm contemplating doing the inductors too but I wouldn't want to change the crossover frequencies. I suppose the main advantage is lowering the DCR? Would it actually change the impedance curve to a lower one?
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Onkyo A-8017 integrated
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
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  • pitdogg2
    pitdogg2 Posts: 25,437
    edited February 2020
    Most use the super Q. Some can be bought at part's express.


    http://www.erseaudio.com/Products/SuperQCoils
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  • Navy_Goat
    Navy_Goat Posts: 375
    edited February 2020
    pitdogg2 wrote: »
    Most use the super Q. Some can be bought at part's express.


    http://www.erseaudio.com/Products/SuperQCoils

    ^This, however the specific inductor needed for both my speakers is not available through PE and is always backordered through Erse. I spoke with Dave (westernmassguy) for some guidance. IDK what specs you need for the 7Bs?
    SDA SRS 2.3tl, SDA 1C, SDA 2B (TL mod), Reserve 200
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  • Navy_Goat
    Navy_Goat Posts: 375
    Gardenstater wrote: »
    @audioluvr and @Navy_Goat What model #'s of Erse Audio Inductors? The Foil Q ones? I'm modding my lowly 7Bs now after 41 years lol and I'm contemplating doing the inductors too but I wouldn't want to change the crossover frequencies. I suppose the main advantage is lowering the DCR? Would it actually change the impedance curve to a lower one?

    I believe you have it right. If you play around with the values in an effort to increase your bass response the likely end result is a slightly lower impedance.
    SDA SRS 2.3tl, SDA 1C, SDA 2B (TL mod), Reserve 200
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  • Navy_Goat
    Navy_Goat Posts: 375
    RandyCroissant wrote: »
    I have not compared the CS350 to the 400i, please post some pictures of your mods as they progress.

    I was curious because the Salvation Army in San Diego has one posted for an opening bid of 99.99 and it was just relisted because no one put in a single bid. It would be a local pick up for me so I was considering picking it up. I passed but it is back up for sale again.

    I will definitely post pictures here. The thread for my 2BTL build has many pictures. Let me know if you are looking for pictures of something specific.
    SDA SRS 2.3tl, SDA 1C, SDA 2B (TL mod), Reserve 200
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  • RandyCroissant
    RandyCroissant Posts: 475
    The CS350 LS is a very good center that also happens to sound right with SDAs.
    $100 is about right for a nice one.
    Yamaha RXA1030, Yamaha CD-S2100, Yamaha AS-2200, Bluesound node 2i
    Polk SDA2btl highly modded
    Polk SDA 1C modded
    Polk CS350 LS x2
    Kimber 8TC
    Sony 55" Bravia
    Wish list SVS sub

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  • Gardenstater
    Gardenstater Posts: 4,459
    edited February 2020
    @Navy_Goat According to my schematic (I don't have an LCR meter to check my inductors) I need 0.23mH for the tweeter circuit and 1.55mH for the Midbass circuit. They have a 16 gauge FoilQ that is 1.60mH, DCR 0.524 Ohms ($40 for 2) and they have a 14 gauge FoilQ that is 1.60mH, DCR 0.353 Ohms (2 for $54, out of stock) and another that is 0.24mH, DCR 0.165 Ohms ($16 for 2, out of stock), In the SuperQ the smallest they have is 1.5mH but they have a 16 gauge, 1.6mH, DCR 0.126 Ohms (out of stock, 2 for $19).

    I'm assuming everyone simply takes some wire (or foil) off until they get the inductance value desired according to an LCR meter?

    My inductors on the schematics resistances measure:

    Midbass inductor: 0.7 Ohms, 18 gauge
    Small inductor: 0.7 Ohms, 22 gauge.
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Onkyo A-8017 integrated
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
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  • RandyCroissant
    RandyCroissant Posts: 475
    Navy _Goat It is important to get the specs right with inductors. They contribute to the voicing aspect of the speakers.
    Yamaha RXA1030, Yamaha CD-S2100, Yamaha AS-2200, Bluesound node 2i
    Polk SDA2btl highly modded
    Polk SDA 1C modded
    Polk CS350 LS x2
    Kimber 8TC
    Sony 55" Bravia
    Wish list SVS sub

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  • Navy_Goat
    Navy_Goat Posts: 375
    Gardenstater wrote: »
    @Navy_Goat According to my schematic (I don't have an LCR meter to check my inductors) I need 0.23mH for the tweeter circuit and 1.55mH for the Midbass circuit. They have a 16 gauge FoilQ that is 1.60mH, DCR 0.524 Ohms ($40 for 2) and they have a 14 gauge FoilQ that is 1.60mH, DCR 0.353 Ohms (2 for $54, out of stock) and another that is 0.24mH, DCR 0.165 Ohms ($16 for 2, out of stock), In the SuperQ the smallest they have is 1.5mH but they have a 16 gauge, 1.6mH, DCR 0.126 Ohms (out of stock, 2 for $19).

    I'm assuming everyone simply takes some wire (or foil) off until they get the inductance value desired according to an LCR meter?

    My inductors on the schematics resistances measure:

    Midbass inductor: 0.7 Ohms, 18 gauge
    Small inductor: 0.7 Ohms, 22 gauge.
    I think you are on the right track. I would not know which one would be the best compromise. Also, another product line may work better for your situation? I would recommend seaking advice from some of the more experienced members. See my response below.
    RandyCroissant wrote: »
    Navy _Goat It is important to get the specs right with inductors. They contribute to the voicing aspect of the speakers.
    I am sure you are right. The inductors are being shipped directly to Dave. He will do the actual adjustment to get things squared away....

    SDA SRS 2.3tl, SDA 1C, SDA 2B (TL mod), Reserve 200
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  • pitdogg2
    pitdogg2 Posts: 25,437
    Navy_Goat wrote: »
    pitdogg2 wrote: »
    Most use the super Q. Some can be bought at part's express.


    http://www.erseaudio.com/Products/SuperQCoils

    ^This, however the specific inductor needed for both my speakers is not available through PE and is always backordered through Erse. I spoke with Dave (westernmassguy) for some guidance. IDK what specs you need for the 7Bs?

    Erse makes them to order so not really back ordered from what I understand.
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  • Gardenstater
    Gardenstater Posts: 4,459
    edited February 2020
    @pitdogg2 Good to know. I like the idea of the foil inductors because it seems to me you can keep the skin effect from coming into play even with a large enough gauge to substantially reduce the DCR from the inductors Polk used. What I don't know is what effect that will have on the impedance load seen by the amplifier OR the frequency rolloffs within the crossover.
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Onkyo A-8017 integrated
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
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  • Navy_Goat
    Navy_Goat Posts: 375
    pitdogg2 wrote: »
    Erse makes them to order so not really back ordered from what I understand.

    I think you are correct. I will let everyone know how long this takes. Dave suggested 2-3 weeks was normal.
    SDA SRS 2.3tl, SDA 1C, SDA 2B (TL mod), Reserve 200
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  • Navy_Goat
    Navy_Goat Posts: 375
    edited February 2020
    Hardware from McMaster Carr arrived today. I purchased enough to replace everything on my 2Bs. I really like the way it looks much better...
    SDA SRS 2.3tl, SDA 1C, SDA 2B (TL mod), Reserve 200
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  • Navy_Goat
    Navy_Goat Posts: 375
    "Navy_Goat wrote: »
    I think you are correct. I will let everyone know how long this takes. Dave suggested 2-3 weeks was normal.

    Well, here is the timeline for the "out of stock" Erse inductors.

    2/1/2020 - Ordered
    2/4/2020 - Shipped
    2/6/2020 - Delivered

    That was quick!
    SDA SRS 2.3tl, SDA 1C, SDA 2B (TL mod), Reserve 200
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  • pitdogg2
    pitdogg2 Posts: 25,437
    ;););)
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