phase linear 400

gene french

Veteran and General Yakker
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Mar 6, 2022
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guayabo de bagaces, guanacaste, costa rica....
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music...the healer of souls...
I was gonna say the grandson has rather big horns….
lololol...nooo...
the grandson is the small one i am holding....
the curious one is vincent!!!!
lololol
his dad is one of the boys i adopted...he will be 25 octpber...got him when he was 4...
 

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Sunnbobb

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Mount Vernon, WA
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Bikes, baseball and big amps.
I believe 2 of those have a common point. Make sure you are measuring ONE. IIRC I had to desolder one end of those..
Thx Laatsch. They all check out after lifting and testing. I also swapped the bias resistors 5088 from side to side with no change in results. The left pot/bias has a range of 0.28 - 0.51. the right pot/bias has a range of 0.13 - 0.32. I tested all the transistors inboard, and nothing stood out. I have a couple board kits I can pull and swap transistors with. If I were to do that, what order would you begin swapping?
 
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gene french

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guayabo de bagaces, guanacaste, costa rica....
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music...the healer of souls...
thx, this was a well running amp before I caused a short.
then you aint gonna have resistors misplaced...did not realize it was running with working bias on both channels before the incident...
well, just a bunch of trial/error...so to speak...
so sorry....
 

gene french

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guayabo de bagaces, guanacaste, costa rica....
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music...the healer of souls...
Looks like they shipped him to you well packed!
they delivered him with his worldly possessions in two black garbage bags...
at that time, i was told the state had another 5000 kids similar....
it just aint fair sometimes...just do the best we can!!!!!
thanks jim...you have a good heart...
 

gene french

Veteran and General Yakker
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guayabo de bagaces, guanacaste, costa rica....
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music...the healer of souls...
its nice for me...never thought i would ever have this much!!!
sometimes "thank you" are the only words necessary....
i appreciate each and every one of you...especially laatsch for allowing me to be here..
 

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Sunnbobb

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Mount Vernon, WA
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Bikes, baseball and big amps.
Yeah Gene.
Got rid of the contractor grade power strips.
Put in two Furman PS-8R Series Two.
They are the 15 amp models.
There is a 20 amp pro version with the 20 amp plug, but I went with 15 amp because I have two available 15 amp outlets.
They advertise "power conditioning", but I'm a skeptic. I'd go with a couple massive isolation transformers instead.
I bought them because of the sequential equipment power on function.
They have a jumper across the back, so they are slaved to each other.
Eight outlets across the back and one in front of each unit.
Press the master bright orange rocker switch on, and the front outlet and rear outlets 1+2 become hot.
Press the sequential start switch on either unit (they're slaved with a jumper on the back) and rear outlets 3+4 on both units become hot.
Stand back, and in 5 seconds (a internal adjustment) outlets 5+6 on both units become hot.
Wait another 5 seconds, and rear outlets 7+8 of both units become hot.
System startup is complete.
Preamp, MiniDsp, tuners, turntable, are powered on first in both units outlets 3, 4, 5, 6. That's eight outlets in two Furmans.
The four amps, a 700 Pro WOPL, two 400S2 WOPL, and a 300S2 get powered dead last in the sequence on outlets 7+8. That's the last four outlets on the two Furmans.
Shut down is the reverse.
Hit the power sequence button, amps get turned off, then everything else in sequence.
No pops, no power surges. Proper start up and shutdown every time.
Now the bad.
These old Furmans are still bringing good money on the Bay.
They'll need recapped at a minimum due to age and the fact they came with no name cheap caps.
They're loaded with relays, two SIP resistor packages, a timer IC, a opamp, handful of transistors.
I got the cheapest units I could find that weren't totally scraped up.
One just needed a recap, the other needed a recap and the timer and opamp IC.
Couple months back I replaced both power rocker switches. Exact replacements are available from Digikey or Mouser.
I really like them, a must have with a four way active system.
That's appx 1800 watts in 8 channels going to 8 drivers. Nothing is in-between the amps output and the drivers. No caps or resistors, just Monoprice wire.
Power strips just wouldn't cut it anymore.
Were you able to locate a schematic? I have a couple of the PS-8 I'd like to bring back to life. Thx!
 
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