Phase linear 700b transistor replacements

[Slake]

Hello
I am a new member to this site and this is my first post. I have been collection and repairing vintage audio gear for 15 years.
Yesterday I purchased a non working Phase Linear 700b (Serial# 2555). I believe it is a series 1?. The current transistors are 2N3773’s Motorola’s as the main 20 transistors. I read in the phase Linear service manual that the 2N’s were not a good choice.
My questions are :
1) what are the best transistors in 2025 to replace the main 20 with.

2) it appears the original design called for 4 other transistors, what should these be replaced with?

thanks for the help

Bob

 

[laatsch55]

MJ 21196 on the 20 anf RCA 410'S as drivers..

 

[Slake]

MJ 21196 on the 20 anf RCA 410'S as drivers..

Thank you very much. I will order these today

Bob

 

[mlucitt]

Our source for Phase Linear components is:
https://www.whiteoakaudio.com/estore.aspx
But many of the technicians here carry parts such as the output transistors.

 

[wattsabundant]

MJ 21196 on the 20 anf RCA 410'S as drivers..

I second what he said, with the exception that "anf" should be "and". Sorry Lee, you were 99% correct. The RCA 410's (located at the bottom of each heat sink) are a must for stability. Mj15024's can be used for outputs. See service bulletins in attached manual

 

[laatsch55]

Don, thats whst it sounfs like when ypu have a mouthful of....

 

[WOPL Sniffer]

Hello
I am a new member to this site and this is my first post. I have been collection and repairing vintage audio gear for 15 years.
Yesterday I purchased a non working Phase Linear 700b (Serial# 2555). I believe it is a series 1?. The current transistors are 2N3773’s Motorola’s as the main 20 transistors. I read in the phase Linear service manual that the 2N’s were not a good choice.
My questions are :
1) what are the best transistors in 2025 to replace the main 20 with.

2) it appears the original design called for 4 other transistors, what should these be replaced with?

thanks for the help

Bob

Didn't know there was a 700B Series 1 or any other "Series" . There were only the 700 (original with the split face and tiny meters), 700B (big analog meters), 700 Series II (Cylon meters). Got a picture of that 700B Series 1???? We love the 1 of a kind amps. There were a couple of off the wall specimens but I never seen an amp marked 700B Series 1

 

[Slake]

Ok, so Phase linear made a model 700, 700b and 700 series 2. So my plan is to rebuild my 700b. It sounds like I have 2 transistor options that are readily available, MJ21196's and Mj15024's each with the RCA 410's as drivers. Is there an advantage of one over the other or are they equivalent?

thanks
Bob

 

[Gepetto]

Ok, so Phase linear made a model 700, 700b and 700 series 2. So my plan is to rebuild my 700b. It sounds like I have 2 transistor options that are readily available, MJ21196's and Mj15024's each with the RCA 410's as drivers. Is there an advantage of one over the other or are they equivalent?

thanks
Bob

MJ21196G devices are the top of the heap with the best SOA in the ON Semi lineup. 15024 are OK but not SOA rated as highly as the 21196 devices

 

[Slake]

Thanks for your help. I will use the Mj21196G’s

Bob