• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Phase Tech PC-800-HO

andy

andy

Super Member
This mornings yars sale score was a pair of Phase Tech PC-800-HO. From a distance they appeared to be cheap 80's rack system speakers with their shallow cabinets, but they're actually very heavy with real wood veneer. They're in pretty good condition with working drivers, but they'll need new foam surrounds on the woofers and mids.

Can anyone recommend the best surrounds for these? Also, the diaphragms are covered with thin sheets of foam which is also falling apart. Does anyone sell replacement damping foam.
 

Attachments

  • phasetech1.jpg
    phasetech1.jpg
    106.7 KB · Views: 171
  • phasetech2.jpg
    phasetech2.jpg
    91.5 KB · Views: 104
Register to hide this ad
For the woofer and mid surrounds, go with Rick Cobb (looneytune2001) on eBay. No affiliation, but he really knows his stuff when it comes to surrounds.
 
There are a couple of threads, some quite recent, on refoaming Phase Tech drivers, with the associated pros and cons of doing it yourself, since they're so odd. I have a pair of the speakers previous to these, PC 8.5s, that I'm going through the same thing. I've decided to take them to a local speaker tech who used to be a PT dealer.

Phase Tech still sells new drivers for their various speakers, going pretty far back, but they're not cheap.
 
JohnVF said:
There are a couple of threads, some quite recent, on refoaming Phase Tech drivers, with the associated pros and cons of doing it yourself, since they're so odd. I have a pair of the speakers previous to these, PC 8.5s, that I'm going through the same thing. I've decided to take them to a local speaker tech who used to be a PT dealer.

Phase Tech still sells new drivers for their various speakers, going pretty far back, but they're not cheap.
Click to expand...


They're not cheap, but in my opinion they are definitely worth it. I got new woofers for my PC 40 speakers, recapped with vintage PIO, and I am very pleased with the results. Real image champs. They have a nice even, non fatiguing frequency response, tremendous inner detail and a tall and wide sound stage in the near field (these are mini monitors I have wall mounted for computer use).

I am using the Phase Tech passive sub powered by a Sansui 717.:music:

Phase Tech, especially the Phase Coherent series, are not to be underestimated!:thmbsp:
 
Last edited:
use phase tech you wont be sorry. cheap surrounds wont work with the flat drivers you must get the propper parts and they will sound great
 
The woofer's surrounds are OD: 9" and ID 7.75". The mids are OD: 5" and ID: 3.75".

The surrounds are attached to the front of the diaphragms, so I will have to remove what's left of the damping foam. It may not be possible to properly re-foam them, but I have little to lose by trying. I've been able to repair other difficult speakers, so I'm not afraid to try.
 
Here are some pictures of how the woofer is put together. The cone is a solid block of Styrofoam. It looks like a normal surround would work as long as it has a flat edge to glue to the front of the cone.
 

Attachments

  • phasetech3.jpg
    phasetech3.jpg
    68.5 KB · Views: 136
  • phasetech4.jpg
    phasetech4.jpg
    60.3 KB · Views: 122
  • phasetech5.jpg
    phasetech5.jpg
    78.9 KB · Views: 152
These people had some had to match KLH foam you might try them as well- they carry the flat edge foams you will need.

www.refoamkits.com

I have refoamed those some years back...it was a real experience. For the foam on top of the face I used auto headliner foam- it was thin light weight and came in black from the fabric store.!
Good Luck
DC
 
Well, so far no luck on the foam. I think I'm going to have to find something close, and make it fit.

With all the speakers I get than need foam, I really should invest in a whole range of sizes. Does anyone sell foam surrounds in bulk? $10-$20 each seems crazy for something that can't cost more than $0.50 each to make.
 
I finally found some surrounds on ebay that looked like they would be a close fit. All I had to do was trim a couple of mm of the inside rim. Even though the rim was slightly angled, it didn't present any problems attaching it. I just clamped the foam to the basket, and propped up the cone so that the rim sat flat against the cone until the glue set. The roll size for the mids was a little smaller than I would have liked, but the spider is still the limiting factor on excursion, so it shouldn't be a problem. The actual re-foam job was very easy thanks to the wide VC gap, and rigid solid cones which were easy to handle.

The cabinets look good after a clean and light coat of stain to fill in the scratches. The mids are isolated inside their own cardboard tubes. I found that the joint between the tube and front baffle was leaky, but it was easy to seal the gaps with silicone.

The crossover is fairly complex with a mix of film and electrolytic caps. They ESR ok, but I may go back in as replace the electrolytics at some point.

I've only had about 15 minutes to listen to them, but so far I'm impressed. They are a definite improvement over the Realistic T-100s they are replacing (not surprised there).
 

Attachments

  • phasetechl.jpg
    phasetechl.jpg
    69.7 KB · Views: 70
  • phasetechr.jpg
    phasetechr.jpg
    72.1 KB · Views: 70
  • phasetechw.jpg
    phasetechw.jpg
    85 KB · Views: 83
  • phasetechm.jpg
    phasetechm.jpg
    106.2 KB · Views: 95
Did you do anything to replace the foam that goes over the face of the driver? Or did you just scrape it off and let it be. Curious as I have a pair of 1000s sitting here and gathering dust.
 
ekmanning5 said:
Did you do anything to replace the foam that goes over the face of the driver? Or did you just scrape it off and let it be. Curious as I have a pair of 1000s sitting here and gathering dust.
Click to expand...

I've left it alone for now (most of it's gone already). I only scraped off what I needed to to remove the old surrounds. I do plan to try to replace it. How think was it originally? It's hard to tell, but it looks like it was somewhere between 1/16 and 1/8 inch.
 
ekmanning5 said:
Did you do anything to replace the foam that goes over the face of the driver? Or did you just scrape it off and let it be. Curious as I have a pair of 1000s sitting here and gathering dust.
Click to expand...

I have refoam several of these in the past. As for the "face foam" I found black auto headliner material to work perfectly. It has a thin foam layer, is light weight and can be cut to fit perfectly! Found at the larger fabric stores and upholstery shops!
DC
 
Phase Tech has offered some of the BEST sounding systems I have ever heard. I'm a happy owner of a quasi-vintage PC-80/90 system. Do yourself a favor and invest in new drivers. I replaced my 6.5" mid-bass drivers for $55.00 each and 10" DVC sub driver for $90.00 about 4 years ago due to foam rot. Not a bad investment for another 15 years of listening :)

Thankfully, their new stuff use neoprene rubber surrounds. Saving up for a pair of PC3.1 II
 
Has anyone had impedance issues with their Phase Techs? I have a set (two, actually) of PC-800's, and they tripped the protection circuitry on my Sansui AU-517 at moderate volume levels. A review I read showed that they dip close to 2 ohms! :yikes:
 
Also, the trim rings stick to the surrounds; be careful taking them off if the surrounds are OK. They will probably tear them.

Interestingly, the guy who started Phase Tech patented the soft dome tweeter!
 
I have a pair of PC 6.5s taht were completly shot so i rebuilt them with new drivers and Xovers.I still have the orginal mids and tweets but there was no woof when I got them so i decided to franken them. I'm still tinkering with the Mid s but the cabinets are built like tanks. 1" wood. no chance of resonance. I love the construction and i am looking for original drivers now.
 
dc270 said:
I have refoam several of these in the past. As for the "face foam" I found black auto headliner material to work perfectly. It has a thin foam layer, is light weight and can be cut to fit perfectly! Found at the larger fabric stores and upholstery shops!
DC
Click to expand...

Thanks for the tip. About how think was the foam you bought?
 
You must log in or register to reply here.
Back
Top Bottom