SDA 2 blues...

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JayMX
JayMX Posts: 435
in Vintage Speakers
So I snagged a fairly clean pair of SDA 2A's for $25 the other day. An awesome deal that I could not ignore... Like I need another pair haha...

Hooked them up to my old Yamaha R-100 garage receiver. Right channel worked. Dimensional driver on the left worked. Tweeter on the left made a little noise, distorted, low. MW was barely there. Then the RX shut down. Disconnected the speakers from the amp. Open RX, find blown main fuse. Replace fuse. Plugged RX back in, no speakers connected. Magic smoke comes out of one of the resistors on the main power amp board. :'( Afraid repair on the RX may be a pipe dream as it doesn’t have individual transistors in the power amp section, just “packs” which may be difficult to replace if damaged. I’ll fool with that another day...

Pulled all drivers out of left cabinet. All test good for continuity and resistance. So something is probably whack in the crossover. Visual inspection of the boards yields zero clues. I assume that inductors don’t really “go bad” but maybe? Can a bad cap blow an amp channel up? Thoughts?

I will rebuild the crossovers but don’t want to put a ton of money into these as I will probably just resell them. What brand of caps would give me the most bang for the buck? I’ve seen Dayton mentioned in other threads. I’m really not familiar with cap grades mfg's, etcetera...

@westmassguy, as the crossover king, how bad are these to redo? Any guestimates on how much a middle of the road package of components will cost? Any recommendations as always are appreciated.

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Current Collection: Monitor 4a (Peerless), Monitor 5B (Peerless), Modified Monitor 7b (Peerless), RTA15TL (SL3000), SDA CRS+ (194’s), SDA SRS 2.3TL, R100's, R200’s, R300 🤩
Pairs that have passed through: Monitor 4b (Peerless), Monitor 5a (Peerless), Monitor 5b (SL1000), Monitor 5b (SL2000) (3x pair), Monitor 7b (Peerless), Modified Monitor 7c’s (194’s), Monitor 10a (Peerless), Monitor 10b (5x pair), RTA8, RTA8TL, RTA 11T, RTA12c (194's), SDA CRS, SDA 2 (2x pair), SDA 2a, SDA 2b, SDA 1b, SDA 1c, SDA SRS 2 (2x pair), SDA SRS 3.1TL (198’s) (2x pair)...and more to come, it’s a sickness.
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  • boston1450
    boston1450 Posts: 7,453
    edited June 2018
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    maybe the small Yamaha is too small. Try a amplifier with more power. Did the speakers come with the IC cord that goes from one speaker to the other on the back ? Is ports for IC blade/blade OR pin/blade? Reason i ask is a friend bought some a few years back i think were 2a n it blew his small Onkyo amp. Super Deal btw
    Post edited by boston1450 on
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    Randy/Maine
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  • JayMX
    JayMX Posts: 435
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    @boston1450 they’re blade blade. Yes I had them interconnected. the R-100 has pushed SRS2’s with the interconnect before and I wasn’t driving the SDA2a’s very hard. Just testing and poof. :(
    Current Collection: Monitor 4a (Peerless), Monitor 5B (Peerless), Modified Monitor 7b (Peerless), RTA15TL (SL3000), SDA CRS+ (194’s), SDA SRS 2.3TL, R100's, R200’s, R300 🤩
    Pairs that have passed through: Monitor 4b (Peerless), Monitor 5a (Peerless), Monitor 5b (SL1000), Monitor 5b (SL2000) (3x pair), Monitor 7b (Peerless), Modified Monitor 7c’s (194’s), Monitor 10a (Peerless), Monitor 10b (5x pair), RTA8, RTA8TL, RTA 11T, RTA12c (194's), SDA CRS, SDA 2 (2x pair), SDA 2a, SDA 2b, SDA 1b, SDA 1c, SDA SRS 2 (2x pair), SDA SRS 3.1TL (198’s) (2x pair)...and more to come, it’s a sickness.
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  • F1nut
    F1nut Posts: 49,794
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    The problem sounds like a common ground issue and it looks to me like the SDA is homemade. If so, that's where your problem is. You want large blade to large, small to small.
    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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  • JayMX
    JayMX Posts: 435
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    @F1nut - when I tested, I used an original factory interconnect cable. Those wires on the floor in the listing photo were just loose when I picked up the speakers. They were junk, I threw them in the garbage. No modifications have been made to the crossovers that I could see. It may have been a common ground issue, but I have used the same RX to drive SDA1's and SRS2's with the interconnect, so I’m pretty sure the RX is common ground.
    Current Collection: Monitor 4a (Peerless), Monitor 5B (Peerless), Modified Monitor 7b (Peerless), RTA15TL (SL3000), SDA CRS+ (194’s), SDA SRS 2.3TL, R100's, R200’s, R300 🤩
    Pairs that have passed through: Monitor 4b (Peerless), Monitor 5a (Peerless), Monitor 5b (SL1000), Monitor 5b (SL2000) (3x pair), Monitor 7b (Peerless), Modified Monitor 7c’s (194’s), Monitor 10a (Peerless), Monitor 10b (5x pair), RTA8, RTA8TL, RTA 11T, RTA12c (194's), SDA CRS, SDA 2 (2x pair), SDA 2a, SDA 2b, SDA 1b, SDA 1c, SDA SRS 2 (2x pair), SDA SRS 3.1TL (198’s) (2x pair)...and more to come, it’s a sickness.
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  • F1nut
    F1nut Posts: 49,794
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    Oki doki, not the cable then.
    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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  • westmassguy
    westmassguy Posts: 6,850
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    Double check the binding posts, red on the left, black on the right. Internally, check that one speaker has the Interconnect polarity reversed.
    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

    dhsspeakerservice.com/
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  • Schurkey
    Schurkey Posts: 2,100
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    Those crossovers would be easy. You could install FRESH electrolytic caps and be "as good as new", and it would cost almost nothing. If you do that, retain the silver-mica cap.

    I put Dayton and ERSE film caps in my 1Bs. No silver-mica required.
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  • JayMX
    JayMX Posts: 435
    edited June 2018
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    westmassguy wrote: »
    Double check the binding posts, red on the left, black on the right. Internally, check that one speaker has the Interconnect polarity reversed.
    Plastic nuts on the posts are in the correct positions. I will check polarity internally. Thank you sir!
    Schurkey wrote: »
    Those crossovers would be easy. You could install FRESH electrolytic caps and be "as good as new", and it would cost almost nothing. If you do that, retain the silver-mica cap.

    I put Dayton and ERSE film caps in my 1Bs. No silver-mica required.

    Ten-four. I cant decide how much $$ to throw at these. Maybe a full upgrade with film caps. Don’t really wanna spend on SoniCaps, but the ones I have in my Monitor 7's made a world of difference. Also, I’ve got the veneering bug, so these might go walnut.

    What does everyone think, would a fully refreshed pair with RD0-194's, caps, and veneer resell @ $375? I’m $25 in the cabs as they stand + ~$100 in veneer + $100 in tweeters, +~$150? in caps.. Can’t count my time as this is just a hobby but I do like to at least beak even... worth it?
    Current Collection: Monitor 4a (Peerless), Monitor 5B (Peerless), Modified Monitor 7b (Peerless), RTA15TL (SL3000), SDA CRS+ (194’s), SDA SRS 2.3TL, R100's, R200’s, R300 🤩
    Pairs that have passed through: Monitor 4b (Peerless), Monitor 5a (Peerless), Monitor 5b (SL1000), Monitor 5b (SL2000) (3x pair), Monitor 7b (Peerless), Modified Monitor 7c’s (194’s), Monitor 10a (Peerless), Monitor 10b (5x pair), RTA8, RTA8TL, RTA 11T, RTA12c (194's), SDA CRS, SDA 2 (2x pair), SDA 2a, SDA 2b, SDA 1b, SDA 1c, SDA SRS 2 (2x pair), SDA SRS 3.1TL (198’s) (2x pair)...and more to come, it’s a sickness.
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