Don Imlay's Phase Linear 400 Series II Quasi -Comp.

[Gepetto]

Hi Lee
Nominal gain is 32.9dB Lee so you should choose an amplitude range that spans ~26dB to 36dB to give you maximum resolution and allow you to clearly see the -3dB points. If that is what you are asking me.

Also not sure what your instrument is capable of in terms of tailoring the sensitivity on your Y axis.

 

[laatsch55]

Yep, that's what I was asking you. Seems there's quite a difference in dbr, dbu, dbv,dbm,dbg. the last question may take me awhile to find because .........well because. I think it changes, or I should say the range changes with the amplitude units, and there are a lot of units.

 

[laatsch55]

Can i send you a link to the owners manual?

 

[Gepetto]

Sure thing Lee.

 

[laatsch55]

Here it is Joe, http://ap.com/display/file/34

 

[laatsch55]

THD & N sweeps

 

[laatsch55]

Some pics of the stock configuration. Phase certainly got cheaper as time went on, they lost that relentless battle with the bean counters. There is no longer solid copper wire coming out of the tranny housing, stranded #14.

 

[Gepetto]

The beancounters always win after an acquisition. Many a good company went this way post acquisition.

 

[laatsch55]

Sometimes a good thing, sometimes a bad thing.

 

[laatsch55]

Like the PL020 boaRD THE BIAS TRANS IS soldered in on the edge of the board. I have scavenged some #26 and will heed the cautionary wisdom that has been dispensed lately.

 

[laatsch55]

Is this the AP Van Meter design??

 

[Gibsonian]

A.P. seemed to make most things sound worse in the PL line, imo. Prolly wasn't all his doing though.

 

[laatsch55]

Probably not. I'm sure HE had even less pull with the bean counters than the illustrious founder.

 

[mlucitt]

I think the Van Meter designs start to show up in the PL P 3800 preamp, the T 5200 tuner, and the DRS series of amps. I think the electronic designs are good but the overall components were housed in plastic and they look cheap.

 

[laatsch55]

A.P. seemed to make most things sound worse in the PL line, imo. Prolly wasn't all his doing though.

Ya know the guy had quite a few patents from his time at Macintosh.

 

[mlucitt]

I think A.P. was a genius, he just didn't know how to run the engineering side of the company after Bob Carver left. The investors were chasing units sold per quarter or some stupid thing. Another website gives him credit for the Series II - http://www.phaselinearhistory.stereomanuals.com/

 

[Gibsonian]

For me the series 1 stuff just sounds better, be it preamp or power amp. I haven't heard it all for sure, but what I have heard was that way, and I am comparing recapped units, so it was apples to apples. I'm not considering looks at all, just how they sound.

 

[laatsch55]

I like the industrial look of the Series I's, something about em.........

 

[laatsch55]

Gonna get Don's amp done tonight, Oilfield Gods willing..
After a final THD & N reading out comes the board. The old PS caps are history too. This is what happens when 2 sided sticky tape goes bad YUCK!

Took about 30 minutes of elbow grease and acetone, but it's clean now. Joe's board sinked up and Gepetto mod added.
And the cap kit. A PCB takes the place of the bus bar. There are solder masked holes for Common(star ground) +, -, And some good size holes for the BR feed.

 

[Skratch]

Men, Had an interesting morning, Was scoping a 400 that I just upgraded, ran it up to 40volts at 20, 200, 2000 and 20000 Hz. Everything was perfect until 10000Hz and above on the right channel. as I brought up the input voltage the output voltage started to drop 40 v left 22 right. Checked everything. then I switched the 2 DVM's around and it followed the DVM. One is a Fluke 70 II and the other is a 112. Was wondering if some DVM's are frequency sensitive