View Full Version : My Phase Linear 400 journey continues...


Celadon
09-16-2006, 09:49 PM
A while back I posted questions about setting the bias on my PL400, thanks for the help guys!

I got her up and running but something just wasn't right, I found a couple of dead caps and decided to replace the 'lytics with some Elna Cerafines and Nichicons.

The bias dialed right in and it's running pretty cool which surprises me (~92 degrees at idle.) I measured DC offset and came up with L side -2.9mv R side 4.1mv.

I had forgotten how much I love this amp, and how much the neighbors hate it - seriously :(
I'm a SS guy from way back but I've been listening to SET monoblocks/Khorns for the past few years, so this is a fun change while I do a little work on the monoblocks.

I will be getting some meter lamps from Dgwojo and I want to use some blue condoms over the bulbs just for kicks, he says he has those too! I need to get a PL wooden cabinet for it but that's gonna have to wait for now.

I'll post some pics once I get the bulbs in.

Do you guys think I should replace all the ceramic caps too ?

Richard

http://i107.photobucket.com/albums/m290/Cinder-Lou/pl3.jpg

http://i107.photobucket.com/albums/m290/Cinder-Lou/pl4.jpg

http://i107.photobucket.com/albums/m290/Cinder-Lou/pl5.jpg

EchoWars
09-16-2006, 09:57 PM
Do you guys think I should replace all the ceramic caps too ? Not unless you're just bored.

A good project for these is to add DC protection. That should keep you busy.

http://sound.westhost.com/project33.htm

Celadon
09-16-2006, 10:07 PM
Not unless you're just bored.

A good project for these is to add DC protection. That should keep you busy.

http://sound.westhost.com/project33.htm

Thanks for the link Echo,

Not having any speaker protection is pretty scary. I do have my speakers fused, but a real remedy is definately in order. This project looks like it may be over my head but, there's only one way to learn :)

Richard

EchoWars
09-16-2006, 11:02 PM
He sells the PC board...it is the only way to do this.

You also have to pick your relays (on an amp this powerful, I'd run a relay for each channel), and calculate the dropping resistor for the relays, and decide if you want to run the relays in series or parallel. Series makes more sense, since you have large supply voltages and this makes the dropping resistor smaller (also lowers current through the relay driver transistor).

You also have to find a place to mount the relays, which may well influence your choice. There are only two styles suitable for this amp...the large Omron MJN relays, and the smaller LY-style, either one in the DPDT config.

I put this kit on a PL700B. You can't use his parts list, as the transistors will self-destruct at the voltages used on the PL400. I do have it all documented as to how I built it for high-voltage amps.

HAWK58
09-17-2006, 04:18 PM
hi celadon
i am a proud owner of a phase linear 400 to
have had some problem with replacing power transistors but
now it is working just perfect
about changing the ceramic caps i dont think jou have to do the work
but if you want to do it all go for it
what is a facelift if you dont do the nose too
keep on playing loud and proud
HAWK

frankmarsi
09-22-2006, 09:28 AM
Can you fix mine? I have two that need repair and one just adjustments or one or two small caps on the output replaced. I'm in NYC and shipping might hurt me. Thanks,
FM

HAWK58
09-23-2006, 08:26 PM
I live in sweden
whats your problem?
HAWK

Celadon
09-26-2006, 02:37 PM
Can you fix mine? I have two that need repair and one just adjustments or one or two small caps on the output replaced. I'm in NYC and shipping might hurt me. Thanks,
FM

I personally wouldn't feel comfortable repairing your amps, heck, I'm just learning myself.

That said, there are lots of knowledgeable people here at AK that would do a wonderful job :thmbsp: Hope you get the amps up and running soon.

Machineghost
11-14-2009, 02:22 AM
Glad I came across this thread. Got a PL 400 on my hands recently. It will need a recap.

d3imlay
11-14-2009, 06:33 AM
He sells the PC board...it is the only way to do this.


There is another option. I designed a relay board for the 400's that mounts on the existing binding post so as not to require drilling. I did a lot of research on circuits and relays before I settled on this one. I did extensive testing including dumping the 80V power supply into a speaker with a knife switch. No damage to the speaker and I did it at least 10 times.
Early on I tried the board that EW refers to. It works but I didn't like the options for mounting the relay.

See my web site for more info on the relay, a link for pics on flickr, and repair info.

400 relay (http://home.earthlink.net/~dimlay/)