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Polk PSW 200 "Auto Parts Store" resto + Zaph satellites


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I put together a sub/sat system to give to my friend John's son. The sats are Zaph designs: http://www.zaphaudio.com/audio-speaker18.html but I used the Hi-Vi B3N instead of the B3S because it looks cooler.

These are actually my second set. The first ones can be seen here https://www.diyaudio.com/forums/full-range/264317-anoter-zaph-audio-hi-vi-b3s-b3n-build.html They went to John's other son. edit: The link does not seem to work. Google "Anoter Zaph Audio hi-vi b3s (b3n) build"

The cabinet material was supplied by John. They're cut-offs from maple newel posts, with maple end caps. The caps were glued on with Gorilla Glue, then rounded over with a 3/4" router bit. Finally they were sanded and finished with Minwax Wiping Poly. The grilles came from a Chinese ebay seller and they fit the Hi-Vi drivers perfectly.

Filter/BSC networks were built according to Zaph's design. I used some salvaged 15 ohm 5w resistors in series to make 30 ohm 10w. The 4.3uF caps were made up using Carli 3.3uF + some Russian PIO 1.0uF caps I had in my parts box. The other parts were from Madisound.

The subwoofer is an old Polk PSW200 from about 1989. I bartered a friend some refoaming services for it. Wish I had "before" shots because it was a mess: Filthy, with the vinyl peeling off the front, back and base.

Fortunately that vinyl peeled right off--it's like contact paper. The "black ash woodgrain vinyl" on the tops and sides was OK so I left that. The front, back and base were sprayed with truck bed liner for a tough, pebbled finish. Came out pretty nice. CSP member dxho had recommended Wipe New, a product for black rubber bumpers, to restore some black knobs. It worked well, so I applied some to the "black ash wood grain vinyl" and it worked well there, too. So between the truck bed liner and the black bumper finish, I'd call this the "auto parts store restoration."

The amp seems to work fine but I will take it to my tech to bench test just to be sure.

So how's the sound? These little 3" single-driver satellites are amazing! But according to Zaph there is some serious harmonic distortion below 100Hz, hence the filter and the need for a subwoofer. I did have some trouble integrating the sats with the sub. Even set at its lowest possible volume setting, the sub was too boomy. Zaph wrote "Some of you with plain old stereo receivers will be tempted to to hook up a sub with a plate amp, using the high level inputs, and then run the satellites from the plate amp's speaker level outputs. Don't do it. Here's why." Then went on to give a detailed explanation AND a fix but that fix involved adding a passive impedance flattening circuit to each speaker, including a $25 8mH and a coil in each! I'm hoping to find an inexpensive used HT receiver with a sub out jack. In the meantime, I've set the xo point on the plate amp WAY below the recommended 150Hz (I'm using 70Hz) to tame the boom. This is not ideal but the system still sounds pretty darn good.

-Kent

PS: Just picked up a Kenwood VR-309 on the auction site. It has a "sub out" jack. Will report back on how that works out.

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Well, my friend gave me some more pieces of oak column so I had to make more of these. Just not sure what to do with them.

Can't seem to find the 3-1/2" metal grilles for sale so one pair is "naked" (but the coppper color cones look cool).

Zaph's original design called for a 0.12 cu ft (3.35L) sealed box. Mine are 0.11 cu ft (3.07L) so close enough I think. Swan (Hi-Vi) recommends a 2L sealed box.

Zaph was very specific about the 0.08mH coil, saying it couldn't be 0.1 or 0.05. There was a link to a calculator to determine the number of turns needed but I just took a 0.1mH and started unwinding, checking every couple of turns using an LCR meter and a razor blade (to cut through the varnish without causing damage. Removing about 25" of wire did the trick.

I do wish Zaph had been more specific regarding stuffing. I just stuffed "a lot" of fiberfill salvaged from some ARs in each one.

Zaph HiVi B3N filter 4.jpg

Zaph spkrs 4.jpg

Zaph spkrs 1.jpg

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