Rare Phase Linear stuff

[Northwinds]

Lee has a 400 with the gain knobs sitting in my garage. I wondered if it was a proto or one off myself. The meters are different also, same size in the bezel but totally different in physical dimensions

 

[Northwinds]

 

[Northwinds]

The Dual 500 would look way better with analog meters

 

[laatsch55]

I think this thread needs to go to the PL HISTORY forum..
Thoughts?

 

[Northwinds]

I think this thread needs to go to the PL HISTORY forum..
Thoughts?

It would seem to apply, man what an archive we have here!

 

[laatsch55]

The Milo mods were a different emitter resistors and Zoebel network caused a lot of stability problems. Any that came back to the factory were immediately changed back.

 

[laatsch55]

True Przem, the first 5 or 6 700's only had 16 output devices. Ed has some pics...

 

[oldphaser]

Phase Linear 700 (Ultra Rare Bridge Amp)

Here is a photo I took of Bob Carver this afternoon with my Phase Linear 700 bridge amp (made in 1970). This was the very first generation of the Phase Linear 700 amplifier. Approximately (3) were built. This is the only known survivor. No known schematic exists.

 

[laatsch55]

Does he remember building it??

 

[oldphaser]

Phase Linear 700 (Kelly DeYong) (Rare Second Generation Amp)

Here is a photo I took of Bob Carver this afternoon with my Phase Linear 700 (made in 1970) (a.k.a. Kelly DeYong 700 since Kelly DeYong ended up with some of them in Vancouver, BC). This was the second generation of the Phase Linear 700 amplifier. It came out after the "bridge amp" and before the PL0171 series pc board in 1971. Exact production numbers of this amp are unknown. This is the only known survivor at the moment. What is also unique about this amplifier are trimpots in the protection circuit. I also have a schematic.

 

[laatsch55]

But still only 16 output devices....

 

[oldphaser]

Does he remember building it??

Either Bob Carver or Steve Johnston built it. No way to tell for sure. I also spoke to Steve a year or two ago about it and he said the same thing.
Very interesting story about how the amp came into existence which I hope to be able to tell a little later. Perhaps after I get a little rest and I get over all the excitement we had today. Stay tuned.

 

[laatsch55]

Interesting the outputs are oriented 90 degrees from later...

 

[laatsch55]

Dig you get to bring up the "coffee can" amp??

 

[oldphaser]

But still only 16 output devices....

Yep only (16) devices. Even the very early 700's built in 1971 with the PL0171 pc board only had (16) transistors. (12) outputs and (4) drivers. These early amps often times had no serial numbers on them.

The bridge amp had from what I can tell so far.... no drivers mounted to the heatsinks.
I am certainly no expert on this one yet. I hope to spend some more time with Bob and get to know this amp better.

It does not have the original output transistors which I had asked Bob about several years ago. He stated that they were Motorola transistors. I have installed GM/Delco DTS411's for the moment or until Bob gets a chance to review some of his old Motorola data sheets and tell me what the originals were.

 

[laatsch55]

Yep only (16) devices. Even the very early 700's built in 1971 with the PL0171 pc board only had (16) transistors. (12) outputs and (4) drivers. These early amps often times had no serial numbers on them.

The bridge amp had from what I can tell so far.... no drivers mounted to the heatsinks.
I am certainly no expert on this one yet. I hope to spend some more time with Bob and get to know this amp better.

It does not have the original output transistors which I had asked Bob about several years ago. He stated that they were Motorola transistors. I have installed GM/Delco DTS411's for the moment or until Bob gets a chance to review some of his old Motorola data sheets and tell me what the originals were.

I would hazard a guess it is not a paragon of low noise....

 

[oldphaser]

Dig you get to bring up the "coffee can" amp??

I spoke to him about it a number of years ago. There are a variety of different stories I have heard from people that were at the McIntosh clinics or knew Bob at the time. Some people say it exists some people say it doesn't. Some people say it refers to an open chassis. Others say it was a coffee can full of blown output transistors that were accumulated while Bob was designing the original 700. Some say it was kicking around for a while as a door stop. I have seen photos of a coffee can amp in a brand new Folgers coffee can. Needless to say, I will check into the "coffee can" story more for you.

 

[oldphaser]

I would hazard a guess it is not a paragon of low noise....

We did spend some time discussing safe operating area.

 

[laatsch55]

There is a post in the "Ask Ed " forum....if you wouldn't mind.....

 

[Gepetto]

Here is a photo I took of Bob Carver this afternoon with my Phase Linear 700 (made in 1970) (a.k.a. Kelly DeYong 700 since Kelly DeYong ended up with some of them in Vancouver, BC). This was the second generation of the Phase Linear 700 amplifier. It came out after the "bridge amp" and before the PL0171 series pc board in 1971. Exact production numbers of this amp are unknown. This is the only known survivor at the moment. What is also unique about this amplifier are trimpots in the protection circuit. I also have a schematic.

Looks like a lot of engineering changes by the look of the board backside...