phase linear 400

[gene french]

good morning....
on my other thread about the sx1080...i was warned about the 726 transistors as being "shoot on sight"...
are there any such animals on the phase linear 400c driver board...that i need to be aware of??
i did order a "repair kit" which has a bunch of the small transistors and i like having a little stock...
maybe i will have the parts to fix known deficiencies...
any advice ??
gene french

 

[Vintage 700b]

Hello Gene,
I'm not sure what a "repair kit" is, new caps, maybe, but the thing to remember if you are not fully updating your 400, is that any component you have not reworked, is 40/45 years old. It becomes a "one damn thing after another" deal as you chase dead or failing components.
I believe you have installed Don's DC Protect board, which is a must, but the TO's are decades old, as well as your main board. The complete WOPL main board will not require you to keep "back-up" components in stock. The WOPL boards are truly the highest quality I have ever assembled. They will surprise you and put your mind at ease. The picture of the main board is my 2nd 700b but is the same you would use for your 400, they are a joy to work with.

 

[Gepetto]

good morning....
on my other thread about the sx1080...i was warned about the 726 transistors as being "shoot on sight"...
are there any such animals on the phase linear 400c driver board...that i need to be aware of??
i did order a "repair kit" which has a bunch of the small transistors and i like having a little stock...
maybe i will have the parts to fix known deficiencies...
any advice ??
gene french

No Gene
Fortunately Phase Linear used USA transistors...

 

[gene french]

i ordered a cap kit from ebay...a guy i have used before...he also offered a repair kit...various transistors and diodes...pics below....where i am parts are not available...and most of repair time is waiting 3 weeks for something to make it here...those extra parts help me sleep better...lol
i did the same with my 1080 pioneer...that took 6 months to repair and refurbish...i also got the white oak power supply cap upgrade and led upgrade...
i think if i want to really build one up...it wont be a 400...will look for a deal on a series 1 pl700...as you did!!! this 400 is for my nostalgia!!!! lol...always dreamed of owning one....yes, i did get the speaker protect board also...i appreciate the advice!!!
please keep it up...this is a nice forum...

 

[gene french]

No Gene
Fortunately Phase Linear used USA transistors...

thank you joe!!!!

 

[gene french]

this is the two kits....
i am learning...

 

[gene french]

Hello Gene,
I'm not sure what a "repair kit" is, new caps, maybe, but the thing to remember if you are not fully updating your 400, is that any component you have not reworked, is 40/45 years old. It becomes a "one damn thing after another" deal as you chase dead or failing components.
I believe you have installed Don's DC Protect board, which is a must, but the TO's are decades old, as well as your main board. The complete WOPL main board will not require you to keep "back-up" components in stock. The WOPL boards are truly the highest quality I have ever assembled. They will surprise you and put your mind at ease. The picture of the main board is my 2nd 700b but is the same you would use for your 400, they are a joy to work with.
View attachment 63982 View attachment 63983 View attachment 63984

pics of the two kits...

 

[George S.]

i ordered a cap kit from ebay...a guy i have used before...he also offered a repair kit...various transistors and diodes...pics below....where i am parts are not available...and most of repair time is waiting 3 weeks for something to make it here...those extra parts help me sleep better...lol
i did the same with my 1080 pioneer...that took 6 months to repair and refurbish...i also got the white oak power supply cap upgrade and led upgrade...
i think if i want to really build one up...it wont be a 400...will look for a deal on a series 1 pl700...as you did!!! this 400 is for my nostalgia!!!! lol...always dreamed of owning one....yes, i did get the speaker protect board also...i appreciate the advice!!!
please keep it up...this is a nice forum...

Gene, the WOAD 700 backplane boards won't fit a 700 S1 chassis, but will fit the 700B, 700 S2, or that awesome trick 700 WOAD replacement chassis and heat sinks. Reason is the 700 S1 output transistor spacing is different .
Nothing lacking with a full WOPL 400. I have two and never come close to maxing them out. Love them. One is way, way more than I'll ever need. The WOPL 700 Pro I built gets little use as a subwoofer amp. A WOPL 400 worked perfect for the subs.

 

[gene french]

thank you for your advise...i sincerely appreciate it...
i am absorbing!!!
please
explain the model history of the 700...and 400
what is quasi vs full complimentary...
terms i am not famaliar with...i read the series 1 is the model to have in the 400...joe said basically the 400 and 700 were the same animal...i assumed the series 1 would be preferable in the 700 line...enlighten me...i am afraid of the datk...lol
gene french

 

[Gepetto]

thank you for your advise...i sincerely appreciate it...
i am absorbing!!!
please
explain the model history of the 700...and 400
what is quasi vs full complimentary...
terms i am not famaliar with...i read the series 1 is the model to have in the 400...joe said basically the 400 and 700 were the same animal...i assumed the series 1 would be preferable in the 700 line...enlighten me...i am afraid of the datk...lol
gene french

All PL400 and 700s are the same basic electrical design. The back walls are electrically identical across every quasi complementary generation, no difference. PL meandered through various control boards, they had no strategy except continuous cost reduction.
Mechanical and cosmetic changes are the primary differences between generations. Four fin, 8 fin, symmetrical meters and asymmetrical meter placement, analog meters vs cylon digital meters.
The most desirable ones to own from an upgrade potential perspective:
8 fin PL400s whether series 1 or 2
PL700B or PL700 Series 2

The other ones are upgradable with varying degrees of additional difficulty.

 

[laatsch55]

And parts...

 

[gene french]

mine is a 4 fin...harder to fully upgrade??

 

[laatsch55]

No, just less cooling fins....

 

[George S.]

Gene, I have a 400 S1 8 fin and a 400 S2 (all S2 were 8 fin). Both got the full WOPL treatment. Neither run hot on the heat sinks. Fact is, the transformer runs warm, the fins cool.
Additionally, the S1 8 fin heat sinks aren't all that much better then then 4 fins. Reason being they added a U shaped piece of metal for the extra fins, with a thermal break between the two pieces.
The best 400 heat sinks are the all cast/extruded thick S2 heat sinks, also 8 fin, and 1 piece, no thermal break.
I can only speak for my amps, but the fins are always cool, and the transformer warm, never hot, even after extended time at high sound pressures. They do sit on a open shelf with Budwig feet under them for extra ventilation, not in a rack, so this may be the reason.
Before I built the WOPL 700 Pro, one WOPL 400 did sub duty for 2 Dayton Audio 15" Ultimax subs in stereo mode, and the other drove a pair of JBL Millennium's. Complete utter overkill.
I didn't need a 700, only built one because I hadn't and wanted to build one before I stopped building amps and started on other things.

 

[Gepetto]

Gene
Some 4 fin amps are really squirrely inside. PL was never very good with configuration, even in the later days. They did get better but never hit mil spec type of concern over configuration control.

Remember that Forrest Gump line, 'life is like a box of chocolates, you never know what you will get'? Well that is what 4 fin PL400s are like. You are fortunate that you got the later meters in yours. Some of the early ones had bayonet style meter lamps for illumination. That is why if you are considering a 4 fin PL400, you have to look inside before purchasing. Also some 4 fin units had the tripod mount on the control board necessitating adding one drill hole to support the more modern 2 hole board mount.

Basically you have to be a careful buyer...if you purchase an 8 fin unit, you don't have to worry about those gotchas.

 

[gene french]

great...i purchased mine blindly...i had no access to this wealth of knowledge....sure hope i lucked out...
i guess i will know more next week...when the parts start rolling in...i will do this step by step...under the watchful eyes of this forum...so many thanks...
what a nice group!!!
many thanks
gene french

 

[gene french]

Gene, I have a 400 S1 8 fin and a 400 S2 (all S2 were 8 fin). Both got the full WOPL treatment. Neither run hot on the heat sinks. Fact is, the transformer runs warm, the fins cool.
Additionally, the S1 8 fin heat sinks aren't all that much better then then 4 fins. Reason being they added a U shaped piece of metal for the extra fins, with a thermal break between the two pieces.
The best 400 heat sinks are the all cast/extruded thick S2 heat sinks, also 8 fin, and 1 piece, no thermal break.
I can only speak for my amps, but the fins are always cool, and the transformer warm, never hot, even after extended time at high sound pressures. They do sit on a open shelf with Budwig feet under them for extra ventilation, not in a rack, so this may be the reason.
Before I built the WOPL 700 Pro, one WOPL 400 did sub duty for 2 Dayton Audio 15" Ultimax subs in stereo mode, and the other drove a pair of JBL Millennium's. Complete utter overkill.
I didn't need a 700, only built one because I hadn't and wanted to build one before I stopped building amps and started on other things.

i need

 

[gene french]

well, just installed the white oak cap replacement..
then took advice i received and cleaned the adjustment pot....readjusted...less yhan 1mv...i am happy...it plays just fine...waiting on more parts to arrive!!!
still using dim bulb and throw away speakers...lol
not that i am afraid....lol
peace

 

[AngrySailor]

well, just installed the white oak cap replacement..
then took advice i received and cleaned the adjustment pot....readjusted...less yhan 1mv...i am happy...it plays just fine...waiting on more parts to arrive!!!
still using dim bulb and throw away speakers...lol
not that i am afraid....lol
peace

You’re not playing the amp with the dim bulb are you? Final bias should be set with no DBT also.

 

[Gepetto]

well, just installed the white oak cap replacement..
then took advice i received and cleaned the adjustment pot....readjusted...less yhan 1mv...i am happy...it plays just fine...waiting on more parts to arrive!!!
still using dim bulb and throw away speakers...lol
not that i am afraid....lol
peace

Glad that your offset dialed in for you. Did you check the bias as well Gene? Needs to be set to 0.350V