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Multi-Way Conventional loudspeakers with crossovers

Rebuilding The Great Technics SB-X50
Rebuilding The Great Technics SB-X50
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Old 10th July 2014, 02:15 PM   #11
Inductor is offline Inductor  Portugal
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Quote:
Originally Posted by Einric View Post
I have children in the house so I think it would be wise to leave the driver protection in place for now.
You must be shopping for the iron gates by now...
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Old 10th July 2014, 03:10 PM   #12
Einric is offline Einric  United States
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Rebuilding The Great Technics SB-X50
That is one reason I'm glad I have the original grille covers and the power switch for my preamp is on the rear of its chassis.
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Old 10th July 2014, 11:27 PM   #13
Einric is offline Einric  United States
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Default Crossover Shots

Hey Everybody,
Here are some nice shots of the crossovers.
I tried winding an air core with 18awg for the .33mH (that measured .263mH).
It ended up being .31Ω DCR, the DCR of the factory P-Core is only .06Ω.
Will the .25Ω DCR make a noticeable difference?
I have been running the Midrange 2db down from normal.
I think I should stick with the factory P-Core inductors, I doubt I will ever push enough watts into these to make them saturate.

As you can see the midrange is chambered, COOL.
Also I was able to salvage my 6.8uF caps from my Silver AL's "UE" build to reuse in this project.
For some reason the schematic called for 3.3uF and there is a 6.8uF in both of the crossovers.
They must have had a redesign after the documentation was published.
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Old 11th July 2014, 12:47 AM   #14
picowallspeaker is offline picowallspeaker  Italy
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From the end ;
Cool that you have the right "replacements" for the caps
And from the beginning : I would try those new .25 R inductors together with
the suppression of the L-pad ( or simple variable resistor ) since you have
an added resistance - I would try for experiment even higher AWG -
You could really bybass - or better, redo with wire - all the pots and the breakers
And oh the crossover looks terrible - It's really a mess + It's inside the enclosure.
Quote:
Originally Posted by Einric View Post
As you can see the midrange is chambered, COOL.
What would you have expected

I've just described what if a so called purist would do to bring the speakers
singularly and all together la la la
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Old 11th July 2014, 12:54 AM   #15
trans192 is offline trans192  Canada
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I'm not an expert on this but I think what you are seeing with the higher cap values can be explained. This is an artifact of converting polar capacitors to non polar capacitors. I did a quick google to support my foggy memory and found this link: Converting polar Electrolytic cap to NP - who is correct?

It sounds like it's an excellent idea to replace electrolytics where possible.
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Old 11th July 2014, 12:55 AM   #16
picowallspeaker is offline picowallspeaker  Italy
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So, make the next step and substitute the 33 electrolytic with a film one.
I see that you already put the new caps in place. Try also a singular 6.8 uF cap
You know, purists...
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Old 11th July 2014, 01:41 AM   #17
Einric is offline Einric  United States
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I have Silver PTFE wire coming from ApexJr with my order of capacitors.
I couldn't care less what "purists" have to say about the application.
I value their opinions but I'm not trying to break the bank here.
"Audiophool" 33uF caps are quite spendy and I don't really want to go that route.
The only inductor I am planning on changing is the .33mH in the midrange circuit.
The Erse Perfect Layer 14awg .27mH is rated at .09Ω and I will unwind them to .263mH to match the original since both inductors measured EXACTLY the same i figured it was on purpose.
The existing crossover capacitors are Panasonic Bi-Polar electrolytic so I shouldn't have to adjust values since all the rest match the stated values in the schematic.
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Old 11th July 2014, 03:59 AM   #18
Inductor is offline Inductor  Portugal
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Great, if you use the new Erses leave them as is (measure them before when you get them and make a matched pair), they also have tolerances. Your work looks good.
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Old 11th July 2014, 04:05 AM   #19
Einric is offline Einric  United States
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These things already are way beyond fantastic, I can't wait to finish them up.
I have some 15awg P-Core Jantzen 1.0mH I was planning to unwind to .82mh for the woofer circuit.
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Old 31st July 2014, 03:12 PM   #20
6L6 is offline 6L6  United States
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