Stephens Phase Linear 400--In for the works.

[laatsch55]

First things first---Check your test equipment---

 

[laatsch55]

Residual Noise----UNWEIGHTED--


Did a quick check after the new jacks, 130-150 Micro volts--uNWEIGHTED, weighted less than 100, 80-90 average.

 

[laatsch55]

Residual Noise IEC "A" weighted

 

[laatsch55]

Frequency Response--10 watts output, 8 ohm load,

 

[laatsch55]

THD & N--

 

[laatsch55]

Signal to Noise

 

[laatsch55]

Max Output.


Good Night Fellers...

 

[laatsch55]

I put in the old RCA jacks while waiting for the WBT's. Was checking crosstalk last night, and the previous THD & N readings and SNR is now suspect. Suspect in that they will be better with new jacks.

 

[Gepetto]

Joe, is less IMD a hallmark of an FC over a quasi?? I believe I hear a difference there....

Usually a hallmark of amp slew rate Lee and the FC is slightly better than the QC in that regard.

 

[laatsch55]

I swear I can hear it. Could be the Blackgates Steve sent...

 

[laatsch55]

Managed to get goldears down in the mancave today and messed with the output posts, she can hear a difference between a channel bypassing the DCP. I can't put a definate on that till I replace the jacks but that will be another test, on the AP as well as Jani's ears.

 

[laatsch55]

You can tell it's Christmas time when UPS delivers on Sunday. Yep the WBT's made it. I'm impressed, when the Germans do something right it's a beautiful thing. They are excellent in workmanship, and in one pic down the throat there a 4 contact points, all are offset to each other and exhibit a grip that is solid but not a deathgrip so to speak. We'll see how it affects the sound in a bit here as soon as I can unplug the little darling and get it back on the bench...

 

[laatsch55]

Max output test gone bad. After putting the WBT's in, max output test on the AP did not go well. Overvilted the input at 2.25, blew both 5 amp rail fuses And B- pico fuse on right channel. Symptoms---Minus 50.57 volts DC on the right speaker out. Plus 8.8 volts DC onthe left speaker out. Replacing the pico fuse, D10, Q7 fixed the left channel. Posting this before troubleshooting the left. I'm guessing small sig transistor on the left channel.

 

[laatsch55]

Left channel was B+ pico fuse, Q7, open between Base and emitter. Q7 on the right was shorted between base and emitter. Back on the horns and sounding fine!!

 

[kevin]

This has been such a good thread !!!!! I've watched it like is was my amp !!! Your unreal Lee ! You should have somekind of award for the effort you put into all this PL stuff you do !! It's such a privilege to know ya man !!!! Really is !!!

 

[laatsch55]

Thanks Kevin, but I really do it because I love to do it. AND to see/hear their reaction when they are expecting the old Phase Linear sound and the get a face full of White Oak---priceless!!

 

[laatsch55]

I shaved a couple hours off the heatsinks this time too, and got some repeatability going on them too. I do need to be able to do the flats where the TO-3's mate up different though. That's the time burner now, hand filing those pretty much SuCK. We have enough machines in the shop I shouldn't have to. Like a 7" long reach 1-1/2 fly cutter maybe....

 

[laatsch55]

Kev , Joe is the one needing the award, he's the guy!!

 

[Gepetto]

Kev , Joe is the one needing the award, he's the guy!!

It's a team effort guys. Merry Christmas and Happy New Year!!

 

[laatsch55]

Joe, best of luck dodging those ice spears, and Merry Christmas to you and yours!! Got the boys in town yet??