Phase Linear 400 - will fuses protect me?

Gavin.Wright
Gavin.Wright Posts: 125
edited July 2011 in Vintage Speakers
I'm about to go out and look at a Phase Linear 400 series I to power my SDA-2's. I've heard stories about these amps letting go and taking speakers with them. Would a simple fast blo fuse in front of the speaker protect my speakers? I'm not so concerned with low level DC protection but rather protection against catastrophic failure. Quick replies appreciated as i'm heading out shortly to look at this amp! Thanks guys :smile:
Post edited by Gavin.Wright on
· Share on FacebookShare on Twitter

Comments

  • heiney9
    heiney9 Posts: 25,165
    edited June 2011
    Probably not, the fuses are to protect the amp not the speakers. Don't know of anything that can protect for catastrophic failure. If it were me and I had a fear of catastrophic failure of a piece of gear, I wouldn't buy that piece of gear.

    If you have to take precautions because of the reputation of Flames Linear, I mean Phase Linear, then why are you buying it? What's the motivation?

    H9
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul!
    · Share on FacebookShare on Twitter
  • FTGV
    FTGV Posts: 3,649
    edited June 2011
    No.Fusing the speaker is not a fail safe method of protecting them from potential large DC voltages in case of an amplifier output stage failure.
    · Share on FacebookShare on Twitter
  • george daniel
    george daniel Posts: 12,096
    edited June 2011
    If you have to have it,,contact these guys,,they have a good tech in their employ,who is seemingly very familar with this amp/line--BTW--good folks too.


    http://vintagehifipgh.com/
    JC approves....he told me so. (F-1 nut)
    · Share on FacebookShare on Twitter
  • victor. askew
    victor. askew Posts: 50
    edited June 2011
    Phase Linear amps are good amps for the money. That being said I have owned 3 of them in the past and all 3 had out put device failures that took out both spkrs each time. Fuse protection will protect the spkrs frop AC overcurrent ( to much volume). I use a 1.5 amp inline fuse from both of my amps and I have plenty of volume before they blow.. Phase linear failure mo is to send DC into your spkrs and the fuse will more likely than not ride it out and not blow. If you buy this amp have the DC protection circuit kit installed before you ever hook it up to your system. There is an service tech with listings on E bay under title Phase Linear that will service your amp for around $250. I know nothing about the quality of his work but it's a start. Look into it.Good luck.
    Amps- Nakamichi PA 7 & PA 5.
    P Amp- Classie Audio. Nakamichi CA 5
    Tape- Tandberg 3014A.
    Tape- Nakamichi 600.
    CD Calif Audio Tercet 3.
    CD-Rotel 1078.
    Spkrs- Polk Audio RTI 150 Towers.
    Spkrs- ADS L1290 Towers.
    Spkrs- Yamaha- NS 670,NS 500m,NS 200m, NS 200ma
    NS 200ma hybrids.
    · Share on FacebookShare on Twitter
  • Gavin.Wright
    Gavin.Wright Posts: 125
    edited June 2011
    Thanks for the feedback everyone. I checked the amp out and it was in pretty rough shape. I'm going to save up some cash and try to get something a bit newer than won't make me question the safety of my speakers!
    · Share on FacebookShare on Twitter
  • paingod
    paingod Posts: 31
    edited July 2011
    I wouldn't try this! I also have (3) phase linear power amps.
    And All 3 have recently been serviced.

    (excuse my lack of electronic terminology)

    Phase linear amps DO NOT like Polk SDA
    Speakers due to a "common ground" issue.

    I tried running Them with my sda-srs and the amps simply
    Got too hot!! Thankfully I was there to turn them off before any damage
    Was done. The amps barely get warm with any other speaker
    I have (which is quite a few)

    I now run my sda-srs with (2) McIntosh 2205's in mono = PURE BLISS!
    · Share on FacebookShare on Twitter
  • paingod
    paingod Posts: 31
    edited July 2011
    I wouldn't try this! I also have (3) phase linear power amps.
    And All 3 have recently been serviced.

    (excuse my lack of electronic terminology)

    Phase linear amps DO NOT like Polk SDA
    Speakers due to a "common ground" issue.

    I tried running Them with my sda-srs and the amps simply
    Got too hot!! Thankfully I was there to turn them off before any damage
    Was done. The amps barely get warm with any other speaker
    I have (which is quite a few)

    I now run my sda-srs with (2) McIntosh 2205's in mono = PURE BLISS!
    · Share on FacebookShare on Twitter
  • heiney9
    heiney9 Posts: 25,165
    edited July 2011
    paingod wrote: »
    I now run my sda-srs with (2) McIntosh 2205's in mono = PURE BLISS!

    How does that work? SDA's can't be run with mono's because of the common ground issue. SOme SDA's (not the original SRS's) can use the AI-1 cable which allows use of non common ground amps.

    What you are doing is a no, no and now I think I realize why you are having issues with your SDA's. It's very likely you fried some drivers because you were using mono amps.

    H9
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul!
    · Share on FacebookShare on Twitter
  • Gavin.Wright
    Gavin.Wright Posts: 125
    edited July 2011
    I ended up not getting the phase linear - but I checked the schematic and the PL400 is a common ground amplifier so it would be fine with SDA's - other than the slight risk of smoking your speakers if it failed...

    I just picked up a Carver cube - M400A that i'm now powering my Dahlquist DQ-10's with in the man cave and they sound fantastic!
    · Share on FacebookShare on Twitter
  • Joe08867
    Joe08867 Posts: 3,919
    edited July 2011
    I think we just found out why paingods speakers aren't working right. He is running monos. that no worky with SDA's
    · Share on FacebookShare on Twitter
  • paingod
    paingod Posts: 31
    edited July 2011
    Actually I had been running them without the sda cable ( I didn't have one at the time)
    However due the the small room size, running 2 amps was pointles.
    So I moved the extra amp to a different room. (one is way more than enough power!):biggrin:
    · Share on FacebookShare on Twitter
  • heiney9
    heiney9 Posts: 25,165
    edited July 2011
    Ah, ok some more information. If you never used the sda cable and ran the mono's then you should be a-ok from that issue.

    H9
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul!
    · Share on FacebookShare on Twitter
  • Joe08867
    Joe08867 Posts: 3,919
    edited July 2011
    That cures one issue but that is also why some of your drivers are not working. Without the SDA cable half of your drivers will barely do anything if anything at all.
    · Share on FacebookShare on Twitter
  • paingod
    paingod Posts: 31
    edited July 2011
    Joe08867 wrote: »
    That cures one issue but that is also why some of your drivers are not working. Without the SDA cable half of your drivers will barely do anything if anything at all.

    That was quite a while ago! Ive since aquired a cable
    And moved the 2nd. Amp to a different room. So I was using 1 amp
    When I noticed the weaker right channel.
    · Share on FacebookShare on Twitter
  • paingod
    paingod Posts: 31
    edited July 2011
    heiney9 wrote: »
    Ah, ok some more information. If you never used the sda cable and ran the mono's then you should be a-ok from that issue.

    H9

    Sorry, should have pointed that out. It's kinda hard to remember
    All the different things I've tried over the years. I've been a "hoarder" of vintage Stereo stuff for over 25 years and have TONS of amps and speakers!

    It wasn't until that TV. Show came out that I decided to sell
    Off some stuff, before I turn on the TV and see some therapist
    Standing in my livingroom!

    P.S. (do I still get the farm?)
    · Share on FacebookShare on Twitter
  • FTGV
    FTGV Posts: 3,649
    edited July 2011
    Joe08867 wrote: »
    He is running monos. that no worky with SDA's
    Not necessarily,it depends on how the output stage of a particular design is configured.If it has a bridged/ balanced output stage then it's a no go.If it's a non bridged output where the negative speaker terminal is tied internally to ground then the two mono's can be strapped thus making them common ground.

    As for his Mac's I don't know but it would be prudent to contact the manufacturer before atempting to strap any amplifier(s)thus risking the appearance of the magic smoke.
    · Share on FacebookShare on Twitter