PL 400 purchase

[crazy_b]

Here are some nudies of my recent PL 400 purchase. I'm wanting to WOPL this in the worst way. It appears that I can't use the White Oak dual caps, but I found some Nichicon 15000uf 100V screw caps on Digikey that would fit perfectly. The circuit board has "PL400C1" printed on the backside, and it looks different from the board shown on the White Oak site. I haven't removed the panels to access the TO-3 trannys yet. I figured that they are all probably original and need replacing.
Any suggestions would be appreciated!

 

[NavLinear]

Hey Crazy,

Do you plan on doing the full Monty? This looks to be an early four finned amp with a magic transformer.

Here's a list of upgrades that you can do and there are many threads that cover this:

New reservoir caps - looks like you have that one covered. Could you provide a part number for our reference?
Bridge rectifier with snubber caps
White Oak controller board
White Oak backplane boards - build option for full comp or quasi comp
White Oak LED light board - the incandescent bulbs get hot and over time cause the plastic VU meter housing to become brittle
Output transistors
Wattsabundent DC protect board
Wire

Part of the upgrade is transitioning to a star ground configuration.

You can go a bit deeper with upgrades if desired - keep us posted.

 

[Northwinds]

Dennis, what do you mean by a magic transformer. I have had a few of the 4 finners and I liked them, never had a bad heating issue with FC builds, quasi could get hot though

I have a absolutely beautiful 8 finner in the garage already gutted to do up as a WOPL someday

Welcome crazy B!!!

 

[crazy_b]

Hey Crazy,

Do you plan on doing the full Monty? This looks to be an early four finned amp with a magic transformer.

Here's a list of upgrades that you can do and there are many threads that cover this:

New reservoir caps - looks like you have that one covered. Could you provide a part number for our reference?
Bridge rectifier with snubber caps
White Oak controller board
White Oak backplane boards - build option for full comp or quasi comp
White Oak LED light board - the incandescent bulbs get hot and over time cause the plastic VU meter housing to become brittle
Output transistors
Wattsabundent DC protect board
Wire

Part of the upgrade is transitioning to a star ground configuration

NavLinear,
You are correct, this is a 4 finned version, but I know nothing about the "magic transformer", perhaps you could enlighten me?
The 100v 15000uf reservoir cap MPN is LNR2A153MSE, Digi-Key PN 493-7326-ND. It is a perfect match, dimension wise, for the original caps.
I was a little confused on the circuit board. Will the PL14_20 be a direct replacement for my board?
Also, what is the "star ground configuration"?

 

[crazy_b]

Welcome crazy B!!!

Thanks Northwinds!

 

[laatsch55]

You may have to drill 4 holes in the back wall to accommodate the White Oak goodies. Two for the driver board and two for the bias transistors. Fairly easy to do. Check the Archives thread for a description and drawings of the grounding schemes.

 

[crazy_b]

You may have to drill 4 holes in the back wall to accommodate the White Oak goodies. Two for the driver board and two for the bias transistors. Fairly easy to do. Check the Archives thread for a description and drawings of the grounding schemes.

No problem there, hole drilling is my specialty! Are these holes specifically for the "star ground configuration"?

 

[laatsch55]

No, for the bias transistors and mounting the driver board....

 

[crazy_b]

No, for the bias transistors and mounting the driver board....

Duh...it would help if I read your post completely first
I'll check out the archives and begin planning this build!

 

[stuwee]

No problem there, hole drilling is my specialty! Are these holes specifically for the "star ground configuration"?

His 9th post and he's already setting the bar , welcome crazy_b !!! Be careful you might send the stu into hyper-space

 

[crazy_b]

His 9th post and he's already setting the bar

Thank you, thank you...and now for my next trick... LOL!

Forgive me , but I'm unfamiliar with the "backplane" term. I see it is placed in the back of the amp though, does it take the place of all the goodies that are attached to the rear panel of the amp?

 

[NavLinear]

Thank you, thank you...and now for my next trick... LOL!

Forgive me , but I'm unfamiliar with the "backplane" term. I see it is placed in the back of the amp though, does it take the place of all the goodies that are attached to the rear panel of the amp?

You are right - the backplane board is a four layer FR-4 board set that replaces all of the point to point wiring on the back of the amp.

When I used the term "magic transformer" I was referring to the mistake on the label - yours has 1500 Watts printed instead of 750 Watts. The story goes that the guys that made the labels smoked quite a bit and screwed up occasionally.

 

[crazy_b]

You are right - the backplane board is a four layer FR-4 board set that replaces all of the point to point wiring on the back of the amp.

Cool, I thought that's what it was for. Thanks for the info!

When I used the term "magic transformer" I was referring to the mistake on the label - yours has 1500 Watts printed instead of 750 Watts. The story goes that the guys that made the labels smoked quite a bit and screwed up occasionally.

Yeah, smoked quite a bit I see, they're probably still laughing over this! I guess the quality control folks there had their share of ganja as well, letting this slip by!

 

[crazy_b]

Wattsabundent DC protect board

Hey Nav, who sells this board?

 

[WOPL Sniffer]

That's Don. Type in the Wattsabundant into your search engine. He's on this site as wattsabundant;

 

[laatsch55]

Don Imlay is his complete name. He travels around the country installing UPS's so don't be surprised if he doesn't answer for 4 or 5 days.

 

[NavLinear]

Hey Nav, who sells this board?

Here's a link to Don's website:

http://home.earthlink.net/~dimlay/

 

[oldphaser]

Early Phase Linear 400 With Midland VU Meters

It appears that your Phase Linear 400 is a very early one with Midland VU meters.

Phase Linear used several different brands of VU meters in the 400 series 1 amplifiers. Very early Phase Linear 400 series 1 amplifiers used the Midland brand. After Phase Linear discontinued using the Midland meters they began to use meters made by Dixson, Honeywell and Jewell. Of all the analog VU meters that Phase Linear ever used in any of their amplifiers the Midland’s were bar far the most unreliable which is why it is a good idea to buy a spare.

The Midland VU meters are smaller than the Dixson, Honeywell and Jewell meters. The Midland meters are 4-1/4” wide by 3-1/4” tall. The other meters were 4-1/2” wide x 4” tall. Therefore the Midland VU meter is not recommended as a replacement for anything other than another Midland meter. (NOTE: The Midland meter bezels are of a different size than the later VU meter bezels.) It is recommended that you should make sure that your Phase Linear 400 uses Midland meters before buying any as a spare.

NOTE: Early 400 series 1 amplifiers will have the words “Four hundred watts RMS” on the front panel and 4-3/4” wide heat-sinks (which will indicate that it was made prior to the implementation of the "F.T.C. Amplifier Rule" on November 3, 1974). The Midlands were typically used in early 400’s that used PL400 series PC boards. Amplifiers manufactured after November 1974 with have the words “Laboratory Standard Amplifier” on the front panel and an additional center heat-sink added.

By the way, Lee and I have a limited supply of spare Midland VU meters.

Ed

 

[crazy_b]

It appears that your Phase Linear 400 is a very early one with Midland VU meters.
Phase Linear used several different brands of VU meters in the 400 series 1 amplifiers. Very early Phase Linear 400 series 1 amplifiers used the Midland brand. After Phase Linear discontinued using the Midland meters they began to use meters made by Dixson, Honeywell and Jewell. Of all the analog VU meters that Phase Linear ever used in any of their amplifiers the Midland’s were bar far the most unreliable which is why it is a good idea to buy a spare. By the way, Lee and I have a limited supply of spare Midland VU meters.

Surprisingly, this amp works very well and the Midland meters are still fully operational! But it is good to know that you and Lee still have a few spare units available, because these old meters will be put to the test when this amp is Wopl'd!

That's Don. Type in the Wattsabundant into your search engine. He's on this site as wattsabundant;

Don Imlay is his complete name. He travels around the country installing UPS's so don't be surprised if he doesn't answer for 4 or 5 days.

Here's a link to Don's website:http://home.earthlink.net/~dimlay/

Thanks for the information. I've logged into Don's website and checked out his instructions, along with his Flickr photos of the DC protect board install. It should be a relatively easy install with all this info given! I can't wait!