2. amps-preamps
  3. 1403034443

Phase Linear 700 & 400 series II

There isn’t much not to love about theses amps. Clean accurate linear signal reproduction. Transparent latency output signal. If they do fail they are very easy to repair. We use to joke that it took longer to get off the shelf and take it apart then to get it back working. Usually an output or two a driver and sometimes a pre-driver along with a diode. The units rarely smoked and if they did they still where an easy fix. Biggest repair mistake was substitution of output and driver components then what was original. Can not be mixed up or blow up. Simple series II repair is to stick with Motorola NpN 15024 and PnP 15025 compliments. Use good heat sink compound or good TO-3 wafers. Watch for stressed PCB wires solder joints to the PL-36 driver board. Make those repair by just doing a complete re-solder to all wire connections. Watch for manufacture solder donut holes at capacitors legs. The old wiggle test with a magnified glass worked well. Check for over heated or discolored emitter resistors at on the main heat sink plane. If you have access to a 10 AMP Variac device using an analog meter at the outputs slowly bring up the amp after repairs and watch for excessive fast load draw. The slow power up should be very smooth and minute amp draw on the meter needle. If you have a dummy load rated up to 8Ω @ 400 watts you may bring the amp to the the rated voltage and perform a current sharing test on each bank. Just saying.
ksaldutti
quadprod
4 posts
 
Funny stuff, the usual bashing.

Hand an idiot the keys to a Ferrari and watch what happens.  Then, the self-ordained keyboard experts will bash Ferrari for being junk.  Says right in the owners manual if the amps are to be used in high power applications to add cooling fans.  Maybe they were right?

From reading though some of the comments, evidently Clair Brothers Audio never got word on what junk the Phase Linear model 700 Series two amps were, or how bad they sounded.  They went ahead and built the largest touring sound and light company in history running them.

Must be some real smart guys with an exceptional business model to have pulled off that feat - maybe just a great accounting department.  :)
rodman99999
6,158 posts
 
"Hand an idiot the keys to a Ferrari and watch what happens."                                                    Based on the plethora of 700/400s requiring repair (way back then): an atypical number of, "idiots" must have owned them.      To the technician: job security.
tomvette's avatar
tomvette
14 posts
 
The Phase Linear 400 Series 2 amp had many improvements over the series 1. It was much more stable and a low TIM distortion design. It absolutely tested better and sonically blew away my McIntosh MC 2200, throwing a much deeper sound stage with more inner detail. Both bench tested about the same producing about 270 watts per channel. 

It appears many readers don't know the difference between the series one and two amplifier and perhaps don't actually have the test equipment to understand how these amps actually perform with reactive loads. 

joysjane's avatar
joysjane
165 posts
 
The old adage of blowing up/flame linear's is a load a hooey.

Take any amp in the day and put it through the abuse the Phase Linear amps went thru, for bands, and they would have been known to fail also.
Mcintosh had the same issues when powering bands.
They all need to be kept cool when powering heavy loads.

Most folks bought used PL amps and whined when they blew up....
DUH!

Anyone that doesn't know the history of an amp cannot bash a brand.
Any used amp with age is not a reliable piece of gear without proceeding with caution...

I've had PL gear since new in 1978.
Never had a problem but, I bought them new.

Just sayin......


ebm
9,311 posts
 
Give it someone you hate asap.
More to discover