Phase Linear 200 Series 2

[IrishboyM4]

I just picked up a Phase Linear Model 200 Series 2 for 100$. From what i can tell this is a screamin deal. I just wanted some opinions on this amp and possibly if anyone can send me a copy of the service manual.

[GRollins]

It depends on your point of view. If you want cheap watts, then perhaps you've got something you can live with. It's not regarded as a high end audio classic, though.

Grey

[fizzard]

They were well regarded in pro-audio, but even $100 is too much if you ask me.

[IrishboyM4]

fizzard
when you say pro audio exactly what do you mean? Like high end audio or more DJ type audio.

Thanks for your thoughts

[GRollins]

"Pro" audio means PA systems and the like. I'm not sure I'd call any of the Phase Linear amps suitable for that kind of use unless you were willing to use a lot of forced air cooling and were also willing to accept a moderately high failure rate.

Grey

[IrishboyM4]

I was considering upgrades the TO-3 outputs to the Motorola/ON-semi MJ15003 and the MJ15004 respectively. This was a thought to increase reliability.

[GRollins]

If I'm wrong, someone will correct me PDQ, but I think you'll find two problems:
1) I can't swear to it, but I think the original output devices were Darlingtons.
2) Substitution of bipolar output devices may give you oscillation problems.
In other words, if it doesn't work after you're done fiddling with it, it wasn't really an upgrade.

Grey

[IrishboyM4]

I just looked at the schematic and i am fairly certain that it isn't a Darlington because there would have to a driver for each output and there is only 1 driver for 2 outputs. I have heard about oscillation problems and that would be the only issue i thought i might have. I don't have a scope to check for it....

Thanks much for everyones help

[GRollins]

I think your logic is faulty regarding the number of drivers required. The entire purpose of a Darlington is to provide extra current gain, not need more...

Grey

[IrishboyM4]

What im saying is that in a Darlington there is 2 transistors for each package. The schematic has a 3 number of transistors creating a discrete Darlington with 1 output driver operating 2 output transistors.