SDA SRS 2 crossover capacitor value question
POLK3429
Posts: 24
Sanity check - am I reading the drawing correctly regarding the crossover capacitors used in the 1986 SDA SRS 2's as follows:
* All values in microFarads
(1) 0.00075
(1) 4.4
(1) 12 [Mylar]
(2) 34
(1) 65
(1) 130
* All values in microFarads
(1) 0.00075
(1) 4.4
(1) 12 [Mylar]
(2) 34
(1) 65
(1) 130
Comments
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1. The 750pF is a bypass cap. Eliminate that when upgrading to film caps.
4. That is 55uF.
Upgrade the resistors while you are at it. The first one at the top, which is hard to read is 3.5 ohm.
Eliminate the polyswitch (safety guard) and replace with a 0.5 ohm resistor.
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 -
Thanks for the feedback.
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Are the OEM crossovers just attached to the speaker terminal cup, so no requirement to remove drivers??
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Will have to remove passive radiator at the minimum- Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit.
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1. The 750pF is a bypass cap. Eliminate that when upgrading to film caps.
4. That is 55uF.
Upgrade the resistors while you are at it. The first one at the top, which is hard to read is 3.5 ohm.
Eliminate the polyswitch (safety guard) and replace with a 0.5 ohm resistor.
And since the 55uF and 130 uF are in parallel, to equal 185 uF, would it be desirable to find (2) that are closer in value to each other, such as 82 uF and 100 uF?
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If you can find any that large. Sometimes you need 3 or 4 smaller values to make the desired value. Remember you must be able to get the XO back through the hole. I made a board to attach the caps to, I then ran wires back to the XO. I did this to decrease the weight hanging off the board, plastic standoffs and binding post cup. Your first gen SDA SRS2 probably has two boards, take lots of pictures and work on one set at a time to use the other for reference.Since the 55uF and 130 uF are in parallel, to equal 185 uF, would it be desirable to find (2) that are closer in value, such as a 90 uF and a 95 uF?
Post edited by pitdogg2 on -
Any technical reasons to avoid having the crossovers outside the enclosure? Some car audio component speakers have the crossovers in a separate box:
1) INPUT = full bandwidth signal
2) OUTPUTS = connections to various component drivers -
No reason.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 -
https://erseinc.com/mpx/plusex
ERSE sold/sells 91uF caps when I rebuilt my 1Bs. No promises on them still being available. ERSE was gone for awhile, but maybe they're back.
When it was me, I removed the "Safety Guard" and replaced it with a jumper wire. Increases the treble output which my speakers needed.
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I had thought that when Erse shut down, what was left of them became US Coils. Now maybe they are going to go back to "Erse". I see a 62uF. Maybe you could use 3 of them.
https://uscoils.us/capacitors-mpx/George / NJ
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Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
Custom Vibration Isolation Speaker Stands and Sub Platform -
https://uscoils.us/product/mpx25-03-91-0/
"100 91uF caps in stock". I would want to confirm this with an actual human before sending money. I'm seeing two web-sites selling the same/similar product, and I'm wondering about scams.
