New here and new to phase linear

roccus

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You'll blow your ears out kid
#1
Hi all I remember years back in the early 70's looking at phase linear amps is stereo shops and loved them but being young they were way out of my price range. I had a Carver TFM 55 but sold it along with all my nice stuff to dig up money for a down payment on a house. I picked up a Sansui 7070 for out in my shop.... 12 years later the old Sansui gave out so started looking around for a new stereo and came across phase linear amps on ebay. I was looking at the PL400's with the big meters and saw there were two types one with 4 cooling fins and one with 6 fins. I was not sure which would be better. I saw parts listed for them at White Oak so I emailed them asking which was better.

I had narrowed it down to two amps one with 6 fins the other with 4 fins.. I did not hear from White Oak and the one with 4 fins was ending. The one with 4 fins says it runs the other said needs work so I sent the seller a best offer and he accepted it, it is supposed to be here by this Friday. Later that day White Oak got back to me and said get one with the 6 fins. Right off the bat a mistake :shaking: Hope this is not an omen! So then I start doing what I should have done in the first place some home work and looking at pics of the differences of the two. I can't say I like what I am seeing on the PL400 I just bought.

Can someone here take a look at the pic of the PC board and tell me what you are seeing? Does this look all factory or has it been moneyed? A rheostat in the center of the board.... really? Over the past few days I have been thinking I should have gone with the 700B. If this thing runs maybe I should sell it and not put any money into is and get a 700? I plan to do some of those White Oak upgrades for sure which ever way I go to bring it up to date and make it reliable.. Will be nice to get a power amp going again for my monster speakers which I just dug out of storage, been sitting in storage on the second floor of my shop since I moved here.

s-l1600(2).jpg
 

orange

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#2
No, you are okay, somebody will help you with that I'm sure and most of the innards will get tossed upgrading to WOPL.

Welcome to Phoenix! Our WOPLs are as hot as the city!
 

orange

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#3
Just got the name, EXCELLENT! Love it! :toothy5:
 

orange

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#5
We love raucous too. We had a couple a-holes even Lee couldn't fathom but we're the other Motley Crew.
 

Northwinds

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#6
Welcome!!!

4 or 8 fin makes no big difference. The 8 fin offers more cooling surface. My first 2 400s were 4 finners
 

R1200S

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#7
As said below, you'll trash most of those innards anyway. The biggest difference (other than the fins) is how the power supply caps. and bridge rectifier are mounted. The caps are mounted with with those clamps that hold them to the side of the case instead of the strap that holds them to the aluminum cap that fits over the top of the transformer. White Oak should be able to steer you to the proper caps since their "basic" 400 cap upgrade won't mount with those side mounted clamps. Not a huge deal as long as those caps are available. Probably going to boil down to a non-issue.

I've got a 4 fin and an 8 fin that both need upgrades and I figure I'll start on the 4 fin as a learning experience. Then I can move on to the 8 fin and give that 4 fin to my brother. Then it's the 700B!

Welcome to the mad house.... you'll love it here!!!
 

laatsch55

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#8
I know Ed will want to look at that board . I've never seen a 400 board with 6 pots on it .......that's a first.
 

laatsch55

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#9
When converting a 4 fin 400 to the White Oak backplane boards you have to drill 2 holes in the back wall area to accept the location of the bias transistor Q6. The 8 fin models already have the hole in the right place. No biggie, a lot of 4 fin WOPLS out there...
 

laatsch55

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#10
It appears on that driver board that one could adjust bias and DC offset, just like the first generation PL 0171 boards used in the early 700's. Are there any numbers on that board??
 

Northwinds

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#13
PM Danimal1969, he wanted to check it out so I let him take it until he comes back down in a month or so. We were thinking about putting a Wattsabundant DC protection board in it. I was also thinking about putting the really nice faceplate on it and doing away with the non factory gain knobs. I am sure Dan will take pictures of it and get what info off the board to add to site info. Debating on just selling the extra 400 I have with the unused black faceplate
 

roccus

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#15
Not a huge deal as long as those caps are available. Probably going to boil down to a non-issue.

I've got a 4 fin and an 8 fin that both need upgrades and I figure I'll start on the 4 fin as a learning experience. Then I can move on to the 8 fin and give that 4 fin to my brother. Then it's the 700B!

Welcome to the mad house.... you'll love it here!!!
White Oak does not have those caps for this one... I see others on ebay have some that will work so no not an issue. As far as the original mounting clamps go if they are either to big or to small I could always modify them or just make new ones... I'm a fabricator
 

roccus

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You'll blow your ears out kid
#16
I know Ed will want to look at that board . I've never seen a 400 board with 6 pots on it .......that's a first.
I don't have it yet is is on the way should be here by Friday... After looking at as many pics as I could find of these boards it is the only one I have seen with those 6 pots that is why I was wondering if I got a weirdo here. When it gets here I will want to check the health of it over before I run it. I ordered a PL400 service manual but if it does not have the REV. board specs and schematics in it I will be running blind to check it out. I hope it will work for now it is way to quiet out in the shop without my music.
 

laatsch55

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#17
A 40mm clamp will fit White Oaks caps. Factory caps were 1-5/8. They can still be found also. If getting any off eBay be sure to get a pic of the date code. You don't want to buy 20 or 30 year old caps. There are also counterfeit caps. Check this website......apex jr.....they have a good selection of computer grade caps.
 

roccus

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You'll blow your ears out kid
#20
Do you have a dim bulbtester??
Yes I used to buy sell repair and restore jukeboxes did it for over 15 years mostly Seeburgs from the 50's through the 70's models. Loved working on them but then my back gave and just could not move them anymore.
 
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