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Another Phase Tech PC60 / PC50 refoam thread (success with details)

QUiKSR20 said:
What a great informative thread, I recently picked up some larger PC70's, Initially I thought "PhaseTech" what is this some white van crap? Them im like these are dome mid, dome tweeter, hardwood corners with real wood veneers.. Not possible, turns out these are great speakers designed by Bill Hecht and still in business.. Picked these up my PC70s for $15, just need to secure the proper foam surrounds and re-create the centers... Do you have a link or a better description on the material you used for the center piston? Yours turned out great and id love to replicate it..

Pics of my speakers : No way I could pass these up for $15 ( this is after a light sand & stain ).

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Send me a PM and I'll send you some of the material I used to re-face the pistons. I have some extra, more than enough for at least a couple more sets.
 
QUiKSR20 said:
What a great informative thread, I recently picked up some larger PC70's, Initially I thought "PhaseTech" what is this some white van crap? Them im like these are dome mid, dome tweeter, hardwood corners with real wood veneers.. Not possible, turns out these are great speakers designed by Bill Hecht and still in business.. Picked these up my PC70s for $15, just need to secure the proper foam surrounds and re-create the centers... Do you have a link or a better description on the material you used for the center piston? Yours turned out great and id love to replicate it..

Pics of my speakers : No way I could pass these up for $15 ( this is after a light sand & stain ).

View attachment 2915499
Click to expand...
Can you post a pic of the crossover?
 
ivandezande said:
Cool thanks. Not as crazy as the one in my PC60's which is surprising. Would really say to replace those purple caps.
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Looks like theres 5 per speaker, Ill see how these play first after my re-foam and if that goes as planned ill def look into replacing those. I got the woofers prepped just waiting on foams, One is questionable but we shall see....
 
Well got part one done :) Foams attached to the cones/pistons, The one woofer that appeared questionable turned out fine.. It just didnt spring back like the other woofer and was probaly pushed with bad foam.. Both woofers feel healthy now just waiting on the center material from @dogwan which im super appreciative of! Id assume its best to attach the center material before I attach the foam to the basket..

IMG_9562.JPG

Gonna ultimately do a PC70 thread just for anyone else in the future that tackles this, When I find an exact thread it helps me a ton and id love to help others.
 
I put the center disc on last. I think you're fine to finish attaching the foams and test play them.

I'll be heading home this afternoon from my housesitting gig. Will get the material packaged up and ready to head to the P.O. on Wednesday.
 
dogwan said:
I put the center disc on last. I think you're fine to finish attaching the foams and test play them.

I'll be heading home this afternoon from my housesitting gig. Will get the material packaged up and ready to head to the P.O. on Wednesday.
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Perfect, ill get these mounted up shortly.
 
alright you inspired me. I bought a PC60 with a bad surround for 4 bucks from goodwill about 10 years ago and its just been sitting around and I just couldn't throw it away. I just bought a matching single off ebay for 80 bucks (ouch) and surrounds. So going to attempt what you did and be in ~100 USD in for a pair. More than I wanted to spend, but if they turn out good I guess that is a solid pair compared to the inflation adjusted value of what they once cost. Thanks for the inspiration and detailed information!

For the center I was thinking about just using a "rubber coat" black spray paint instead of heavy felt. Thoughts?
 
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nwellinghoff said:
alright you inspired me. I bought a PC60 with a bad surround for 4 bucks from goodwill about 10 years ago and its just been sitting around and I just couldn't throw it away. I just bought a matching single off ebay for 80 bucks (ouch) and surrounds. So going to attempt what you did and be in ~100 USD in for a pair. More than I wanted to spend, but if they turn out good I guess that is a solid pair compared to the inflation adjusted value of what they once cost. Thanks for the inspiration and detailed information!

For the center I was thinking about just using a "rubber coat" black spray paint instead of heavy felt. Thoughts?
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Novel idea. I’m curious to see how that works out.
 
Do you guys know the power handling of these speakers. I hooked mine up to a Denon DRA-825R which does 90w channel into 8 ohm and turned them up like 1/3 of the way and the fuse instantly blew. I thought these things could handle 150 watts?
 
That's a great write up, thank you. I'm trying to decide if re-foaming or replacing the driver is even worth the costs as I am unfamiliar with Phase-Tech. I was given a PC-50 that all appears to be functional aside from the driver. Is this subwoofer even in demand?
 
Mark Alan said:
That's a great write up, thank you. I'm trying to decide if re-foaming or replacing the driver is even worth the costs as I am unfamiliar with Phase-Tech. I was given a PC-50 that all appears to be functional aside from the driver. Is this subwoofer even in demand?
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Contact Phase Tech. They my have a replacement for it.
 
nwellinghoff said:
Do you guys know the power handling of these speakers. I hooked mine up to a Denon DRA-825R which does 90w channel into 8 ohm and turned them up like 1/3 of the way and the fuse instantly blew. I thought these things could handle 150 watts?
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Funny you say this because I ran into the same issue a few times, I turned up my 60wpc Sansui 7070 to like 1/4 maybe a tad louder which ive done countless
times on other speakers and tripped the breaker in the speaker.. Pushed the button and im back in biz and it would happen again.

Im wondering if the protection is triggerd by the tweeter/mids being over loaded and if so I wonder if they are ferro-fluid cooled and need to be refreshed.

I would have to look that up but have since sold these after rebuild.
 
nwellinghoff said:
alright you inspired me. I bought a PC60 with a bad surround for 4 bucks from goodwill about 10 years ago and its just been sitting around and I just couldn't throw it away. I just bought a matching single off ebay for 80 bucks (ouch) and surrounds. So going to attempt what you did and be in ~100 USD in for a pair. More than I wanted to spend, but if they turn out good I guess that is a solid pair compared to the inflation adjusted value of what they once cost. Thanks for the inspiration and detailed information!

For the center I was thinking about just using a "rubber coat" black spray paint instead of heavy felt. Thoughts?
Click to expand...

Two reasons this isn't a good idea:

1. Anything other than water based will likely dissolve any exposed polystyrene (Styrofoam) on the cone and/or planar baffle.
2. Take note of the back side of the cone on these drivers, many have numbers written in black (often in the 3.X range). This is the weight of the cone in grams. Ken Hecht (son of Bill Hecht who founded United Speaker Systems that eventually created Phase Technology (1981) has a good video on these drivers:
So using this rubber will ABSOLUTELY affect the performance, pretty significantly too.

When it comes to these, (I have repaired a set of PC-60's, PC 1.1 Series II, and currently doing a pair of PC-1000's I have left the flat planar baffle cleared of the old dusty foam and simply brushed in a very light coat some permanant black acrylic paint (thinned a little with demin water) just to make it all black and left them.

I feel if you want to put some foam back on, you'll want something like camera light seal foam that is used inside old film camera bodies. The trick here is finding a suitable way to apply some adhesive. It comes both w/o adhesive back. I would choose w/o because that adhesive back is too heavy. https://www.amazon.com/dp/B0BS1WQS1...d0FDuj9h3ldNtIqLMsrE5dAOriJDSsdrdcv4qA==&th=1

Cheers!
 
mike j said:
View attachment 2915973View attachment 2915974
Here’s my before & after pictures of my pc-60 woofers. Painted the piston with Simply Speakers cone edge sealer, poured a bit of black detail embossing powder on them, than distributed it with a 100hz signal!
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Very interesting, is this like "flocking" that is sometimes used to line the inside of jewelry boxes etc? I like this concept because it's light weight and would fill the old rough surface of the planar baffle from the factory foam glue. I would like to find a wat to mask off the surrounds and spray/mist a WB adhesive and then apply the flock and run the test tone to distribute.

Thank you.
 
dogwan said:
That's about it. Hopefully someone will find this info useful.

I think I paid less than $25 for both sets of surrounds (couldn't order just one 10" woofer). They all came from the same seller "zhzy5500" on eBay if that's helpful.

So, after I finished them up I had them playing and after about 30 minutes I heard a bunch of sudden distortion out of one of the tweeters then it just dropped out. I figured it was the one I re-soldered the lead on, but no, it was the other one. It has severed in the same place as the 1st tweeter. I managed to get it repaired as well. However, I might be hearing some distortion out of both tweeters now. This wouldn't surprise me since the clearance where I soldered the connections is minimal there is a distinct chance that when reassembled, my less than elegant connection may be slightly rubbing or vibrating. Luckily Phase Tech still stocks the correct tweeter and they are only $50 each. I went ahead and ordered a pair and they should be here by the end of the week. Otherwise they sound great. And I really like the subwoofer integration since it's a bespoke fit with the satellites. No adjustments to sit there and obsess over or 2nd guess. It just plays and plays right.

This set is a very early set of the 1st generation (no revisions) series with the really cool push button plunger type connections (see pics of subwoofer bottom). Not the later cheaper spring clip terminals. There's a Stereophile review of the 1st gen PC60's that mentions a problem with the initial run up to serial 3801 (?) or so. These are after that so have the corrected crossovers. The serials are sequential.

This spring when the weather warms up I will do a finish re-fresh on them. So far I have roughly $157 into them (including the new tweeters).

OH, and I also have a pair of the PC-60 CA (30th anniversary limited edition) and am looking forward to doing a head to head comparison between the original design and the no-holds barred version of the same design!
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When I picked up my set of PC-60's they were in fine working condition, but cosmetically (cabs and the flat planar foam) needed attention. So when I pulled the drivers and the crossover that's when things got interesting. My first experience with Phase Tech was a restore of PC 1.1 Series IIs and I reached out to Soundtube (owned by MSE but also took over the Phase Technology line) asking about the trapezoidal shaped tweeter diffraction foam and a sound engineer/manager by the name of Michael responded to me saying they have those pieces in stock (mine were shot). But at $35/ea plus shipping I found a way to make my own, wasn't easy.

Okay back to the PC-60's I have...I reached back out to Michael and asked him about these PC-60's I have because I could not find any at the time on the web that had rear spring clips, breaker and L-pad POT for the tweeter. He replied back saying I must have some modified Frankenstein version. Then 4 days later he replied back again and said he spoke to Ken Hecht (son of Bill Hecht that founded United Speaker Systems back in the late 50's with Fisher and then in 1981 spun up Phase Technology) said mine were the first generation. The ones with simplified XO's, fuse, and binding posts were made later. My XO's had a date on the hard board mount of Nov. 2, 1984.

Here's a good thread here about these: https://audiokarma.org/forums/index.php?threads/phase-technology-pc-60-crossover-recap.854799/

Cheers!
 
motleypixel said:
Very interesting, is this like "flocking" that is sometimes used to line the inside of jewelry boxes etc? I like this concept because it's light weight and would fill the old rough surface of the planar baffle from the factory foam glue. I would like to find a wat to mask off the surrounds and spray/mist a WB adhesive and then apply the flock and run the test tone to distribute.

Thank you.
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It’s very similar to flocking powder, but I couldn’t find any, so I bought what I thought would work!
Me thinks it did!
I just used a small paint brush to apply the glue.
 
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