New to PL!

rollcentre

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Mar 22, 2021
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#1
Hey guys i came across a couple PL400s and a PL2000. It was recommended that I check this place out, and I'm glad I did!

Both of the amps came from the same collector, both bone stock. One is from '75 the other from '76


I installed Don's DC protection board on one of them already, but doing some WOPL mods is in the works on both. Figured I would drop in and make an introduction while I was waiting on parts.

PXL_20210323_202231072.jpg

PXL_20210323_202425038.jpg

-Keith in Dallas TX
 

mlucitt

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#2
Welcome to Phase Linear mecca. Good choice on the DC Protect Delay Relay Board. You are definitely treading on the slippery slope with that PL gear. There are many folks here to help you down the slope...
 

rollcentre

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#5
Thanks guys. I think I'm gonna like it here.

The PL400 that I have installed the DC protection on with probably be my first wopl project. The other 400 I haven't even plugged my speakers into. It does pass a DBT, and has a DC offset that is well in spec. This one will get DC protection as well.

I plan to start by refreshing the power supplies. The main filter caps, 600v bridge rectifier, then recap the main board, all new outputs. I'd most likely be keeping both of them quasi comps.

If that goes well I may get the white oak main board. I haven't had as much experience as you guys working on amps, so I don't want to bite off more than I can chew. I do want to learn though! I've got a DMM, scope(although limited experience using it) oscillator, dbt, and I believe I'll need a variac according to the fsm.

The PL400 I was have been running has had an intermittent hum since I've had it. One of those things where you think you've fixed it one day, and the next day you got to turn it on and it's humming at full bore. I have yet to track that down, but the factory service manual seems like it has a decent TS section. Instructions for testing all semis in circuit etc.

The PL2000 has been great, I've already recapped it, replaced some RCA connectors
and did a ground mod that I found on here. I've been using it with my Pioneer Spec 4 quite a bit, and love the way it sounds. At some point I may do the opamps, but for now I am happy with it.
 

FredR

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#6
Welcome! My experience is that putting in a lot of effort to fix an amp, when you are going to WOPL it, is not worth the effort. Best to strip it to the chassis and start over with WO stuff. Strongly recommend full comp.
 

mlucitt

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#8
I would not spend any of your hard-earned cash on capacitors for that original PL control board. They are a bitch to remove and replace without tearing up the circuit traces, ask any of us about this. We all have tried and failed, not due to technique, due to design and age of the board.

Spend your money on a WOA Rev G1 Control Board kit. You can learn a lot by assembling that board yourself. You will need a better quality temperature controlled soldering pencil that does not exceed 700 degrees (you didn't mention that tool). There is plenty of help here. We all started out exactly where you are today. Jump in, the water is fine!
 
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rollcentre

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Mar 22, 2021
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#9
I would not spend any of your hard-earned cash on capacitors for that original PL control board. They are a bitch to remove and replace without tearing up the circuit traces, ask any of us about this. We all have tried and failed, not due to technique, due to design and age of the board.

Spend your money on a WOA Rev G1 Control Board kit. You can learn a lot by assembling that board yourself. You will need a better quality temperature controlled soldering pencil that does not exceed 700 degrees (you didn't mention that tool). There is plenty of help here. We all started out exactly where you are today. Jump in, the water is fine!
Thanks guys!

I've got my trusty weller WLC 100 station I've had since high school, 40w and adjustable temp, a couple different tips for it as well. I normally use 60/40 .032 flux core solder.

I still have a little bit of nice wire , #22 silver plated teflon insulated stuff Ieft over from another project.

I believe I will get the new dual mono ctrl board as everyone is suggesting, would you also suggest going with the phoenix connectors?, (I assume these are the green terminals with the screw down wire clamps)

I'll be getting my WO shopping list together. It sounds like the thing to do is bite the bullet and do everything at once instead of piecing together slowly as I previously planned.

I have a mouser cart started with a 600v 50a bridge rectifier, some snubber caps for it, a couple different Heyco strain bushings for a new 14-2 power cord. Is there a specific RCA jack you guys recommend for the inputs? I have some no-name gold plated ones, but they are too small for the holes in the chassis.
 

rollcentre

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#10
I would be curious to hear your impressions of a comparison with the Mac, before and after WOPL treatment.
I don't think I was able to give it a fair shake yet, but when it wasn't humming at 60cps, that 400 sounded mighty powerful. The amount of slam it could produce, even at normal listening levels was downright addictive. The top end is a little grainy sounding, but for any unrestored 45 year old amp, I find acceptable.

I have two mc2300 that have been restored, I can run them at 600w mono blocks, probably not a fair comparison at this point. The 2300s have that polished up presentation with a sweet top end, maybe a tad rolled off. Thick midrange that is just laid back enough to be pleasant and musical, never fatiguing at any level, the low end is like a velvet hammer. I didn't find it as fast and as of a sharp transient response as the PL400 though. I feel this is where the potential lies in the PL amps. This must be due the very high damping factor of the PL. I dunno.
 

mlucitt

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#12

laatsch55

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#13
I don't think I was able to give it a fair shake yet, but when it wasn't humming at 60cps, that 400 sounded mighty powerful. The amount of slam it could produce, even at normal listening levels was downright addictive. The top end is a little grainy sounding, but for any unrestored 45 year old amp, I find acceptable.

I have two mc2300 that have been restored, I can run them at 600w mono blocks, probably not a fair comparison at this point. The 2300s have that polished up presentation with a sweet top end, maybe a tad rolled off. Thick midrange that is just laid back enough to be pleasant and musical, never fatiguing at any level, the low end is like a velvet hammer. I didn't find it as fast and as of a sharp transient response as the PL400 though. I feel this is where the potential lies in the PL amps. This must be due the very high damping factor of the PL. I dunno.
Difference between output transformers and not..
 

MarkWComer

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#14
would you also suggest going with the phoenix connectors?, (I assume these are the green terminals with the screw down wire clamps)
.
Absolutely YES on the Phoenix connectors. You won’t have to unsolder all those wires in case of repairs or troubleshooting. Also handy in case of further developments in control board upgrades. WOA products are evolutionary, so make it easier for yourself if you decide to make a change later. You’d almost require those connectors for the bias transistor connection- avoid the soldering acrobatics!

I think the G1 circuit supports both quasi and full comp, if you go for the backplane kit later, only a few minor changes are required.
 

MarkWComer

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#15
It was recommended that I check this place out, and I'm glad I did!
-Keith in Dallas TX
Welcome to the zoo, BTW.

You won’t find a better circus anywhere, the clowns here are all well trained! No snobs, no snots, genuine real people- and the best wealth of information available.
 
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