PL400 glad I found this forum.

[Gepetto]

There is a lot of misinformation flying around on this thread...please look at the info at the bottom of page 1

 

[gene french]

I can't find it. But Gene is on target. He's the man to help you Gary. I only play with WOPLs.

no i aint....please hang around mr. george...they would have to drive a railroad spike through your ear for me to beat you at checkers...

 

[gene french]

no i aint....please hang around mr. george...they would have to drive a railroad spike through your ear for me to beat you at checkers...

see....i had it backwards....

 

[gene french]

this was what you sent me mr. joe when i was working on the 400c board...
that is where i got the info i posted...

 

[Gepetto]

this was what you sent me mr. joe when i was working on the 400c board...
that is where i got the info i posted...

View attachment 75901

Yup, what the release note says. You were retaining the PL909 originals (not recommended) which is why the call out on the good PL909s in column 1 and 3

 

[gene french]

this was what you sent me mr. joe when i was working on the 400c board...
that is where i got the info i posted...

View attachment 75901

it did function after i followed these instructions...this was the 400c board...

 

[gene french]

Yup, what the release note says. You were retaining the PL909 originals (not recommended) which is why the call out on the good PL909s in column 1 and 3

ok....so if you are changing to the 96s...drivers in col 1 and 3...
if your are retaining the original 909s....drivers in col 2 and 4...
am i correct????

 

[gene french]

would it work with the 96s .... if the 410 or 2741 drivers in all of the bottom row????

 

[Gepetto]

Hi Gene
It will work fine per the picture that I included in the document 8 posts prior to this one.

PL909 or MJ21196 devices are fine in all the locations except the 2 specified as RCA410 or SJ2741 in the diagram. From an SOA perspective, the MJ21196 devices are far superior to the original PL909s that PL used.

 

[gene french]

would it work with the 96s .... if the 410 or 2741 drivers in all of the bottom row????

because i only bought 12 of the 96s....i would not have enough to populate the unit...if the drivers wont function in all of the bottom row...
am i explaining good enough to understand??
probably not...lol

 

[Gepetto]

because i only bought 12 of the 96s....i would not have enough to populate the unit...if the drivers wont function in all of the bottom row...
am i explaining good enough to understand??
probably not...lol

Hello Gene, now it is coming across what you are asking. You can use the RCA410/SJ2741 in all 4 columns, bottom row if you have them.

 

[gene french]

and if not....for using the 96 outputs....col 1 and 3 would be 410/2741....would be viable...

sorry....for the confusion...
and
thank you for the explaination....

 

[Gepetto]

Maybe we should start with what devices you have available Gene

You are thoroughly confusing me, not sure what you are intending to do.

 

[gene french]

i have 12 mj..96s....that i bought from you to possibly repopulate an entire 400...if i bought one that was the worst case scenerio...i should have bought 14 as i now understand....in case i dont have 4 drivers....

possible configs ... with mj96s....
1. with 2 drivers....as listed in the documentation....bottom row...columns one and three drivers and the 14 96s...in the vacant spots...
2. with 4 drivers in the bottom row and 12 96s...in all other vacant spots...
correct?????

now with 909 outputs....

1. with 4 drivers in the bottom row and 12 909s...in all other vacant spots...
2. with two drivers....and 14 909s ....
which columns do i put the drivers in...????????

in the 400c amp that i had...and fairchild 909s....you instructed me to put the drivers in rows 2 and 4...and 14 909s in the other spots....
which i did...and it worked for a year before i wopled it..

there is my confusion....your docs say put drivers in columns 1 and 3 ...

is there a different rule between the 96s and 909s as to the column location of the drivers and or the quantity of them???

please help me understand what i am missing???

and i appreciate the education....

 

[GaryCooper]

also...i always hooked up my grounds on the common ground between the big caps...
the input jacks are chassis insulated for example...

Yea mine are to that same point , curious why inputs are chassis isolated? Gene did you see the C6 diodes, also the 33pfs collector-base on q7&10 they were suppose to reduce hf ocsilation to run those drivers ha.. so can I just put the 410 in leave the MJ15024 outputs?

 

[Gepetto]

i have 12 mj..96s....that i bought from you to possibly repopulate an entire 400...if i bought one that was the worst case scenerio...i should have bought 14 as i now understand....in case i dont have 4 drivers....

possible configs ... with mj96s....
1. with 2 drivers....as listed in the documentation....bottom row...columns one and three drivers and the 14 96s...in the vacant spots...
2. with 4 drivers in the bottom row and 12 96s...in all other vacant spots...
correct?????

now with 909 outputs....

1. with 4 drivers in the bottom row and 12 909s...in all other vacant spots...
2. with two drivers....and 14 909s ....
which columns do i put the drivers in...????????

in the 400c amp that i had...and fairchild 909s....you instructed me to put the drivers in rows 2 and 4...and 14 909s in the other spots....
which i did...and it worked for a year before i wopled it..

there is my confusion....your docs say put drivers in columns 1 and 3 ...

is there a different rule between the 96s and 909s as to the column location of the drivers and or the quantity of them???

please help me understand what i am missing???

and i appreciate the education....

Read the doc carefully Gene.

If you are starting at the output binding post side, column 1 is closest to the binding posts and column 3 is 2 columns over from column 1.
If you are starting at the transformer side, these same 2 columns mentioned above become columns 2 and 4 when you start at the transformer side.

Same locations no matter how you reference the columns.

These are the only 2 locations that have any sensitivity in the bottom row. You can also put 410/2741 drivers in the bottom most row in the other 2 non critical columns. Or you can put PL909s or MJ21196s in these same non critical columns. Above the bottom row, you can either populate with 12 MJ21196s or 12 PL909s.

The MJ21196 devices are clearly better devices but you can put the old PL909s in there as well.

 

[gene french]

that cleared it up...slower than most....
thanks a bunch...

 

[gene french]

anyway....my first post on this was correct....i started from the transformer so 2 and 4 will coincide with the docs location starting at the speaker posts as columns 1 and 3....
no harm....no foul....

 

[George S.]

Yea mine are to that same point , curious why inputs are chassis isolated? Gene did you see the C6 diodes, also the 33pfs collector-base on q7&10 they were suppose to reduce hf ocsilation to run those drivers ha.. so can I just put the 410 in leave the MJ15024 outputs?

The RCA input jacks are isolated from chassis ground with fiber washers, each RCA gets two fiber washers. This is to prevent a ground loop and hum.

 

[gene french]

Yea mine are to that same point , curious why inputs are chassis isolated? Gene did you see the C6 diodes, also the 33pfs collector-base on q7&10 they were suppose to reduce hf ocsilation to run those drivers ha.. so can I just put the 410 in leave the MJ15024 outputs?

mr. joe recommended mj21196...thats what i did...
and if i give up and wopl it...i already have the outputs the upgrade calls for....no wasted money...
i have no clue about the mj15024....
maybe someone smarter can answer about that transistor...however, since you have it making music...one could conclude they work...swap out drivers...mr. watts said that would fix you up...use dbtester and dcp...just to cover you....