I posted here the other day and have to say thank you to everyone. I am very excited to have found this community of Phase Linear focused folks! I have been reading and digging into my new to me PL700B. On some levels it may be better than expected when I purchased it. Below is a list of what I have found so far. Please correct any miss statements. I am a mechanical engineer and a car nut, but a neophyte when it comes to electronic repairs. I can repair the visual problems found on a board or component that have smoked, but I am not an electrical component technician like I found with in this community. I have a Fluke MM but no Oscope. Thanks in advance for an and all help.
Good
1. Face plate is nice
2. All UV meters light
3. 700B faceplate lights (2 out of 3 bulbs)
4. All original from a design (some might not see this a good but I think it cool)
5. Orginal RCA 410 CV 514 driver transistors
6. It doesn't appear to have previous board repairs/hot spots
7. Bob Carver Phase Linear 700B Serial Number 3210. Just cool. Anyone know when this amp would have been born?
Bad
1. The output transition are a mixture. Some Fairchild PL909 540 and MJ21194G BM1306 MEX (assuming the MEX is Mexico). I have read that mismatch transistors are bad but don't know what bad means? If transistors are the same ratings why would it matter???? Also some of the F PL909 are 540 and some a label Hong Kong? Are they different?
2. The left channel UV meter bounces when turning on the first time. The right meter doesn't not move when the left bounces that first time. I haven't hook the amp to a speaker yet, so I don't know about scratching or anything else really.
3. I pots are very scratchy feeling. Who knows when they were clean/lude
Unknowns
1. It has Sangam DCM Capacitors 9,800 MFD 100VDC I have not clue what the age would be? What was original cap in these amps?
For some background I have previous owned and loved a PL400. I was always very happy with the sounds. quality and power. I did fry it once in a party environment and buzzed the speakers. I now understand from reading that I was sending DCV direct to the speakers. Those NHT 2.5 are long gone now. I see why there is now a protection relay upgrade.
I am currently reengaging in hifi. I am wanting to plan if I should use this amp (as a 700B) with a little updates or go White Oak. If I go to White Oak do I go full White Oak or just control board. I am leaning towards using it at least for a while as a pl700B and then maybe upgrading. He is the current plan.
Current Plan
1. Test the output transistors and make them all consistent. Is there a recommendation. Should I put back in OLD F PL909 or is there an upgrade before go to the full White Oak back plan. That is above my pay grade.
2. Clean the potentiometer with contact cleaner
3. Replace back light bulbs
4. Install Watts Abundant output protection relay before using them with reference speakers. I may play with some cheap good will stuff.
5. Clean the unit well and start to give it hell!
Please comment on what you all think and see.
Good
1. Face plate is nice
2. All UV meters light
3. 700B faceplate lights (2 out of 3 bulbs)
4. All original from a design (some might not see this a good but I think it cool)
5. Orginal RCA 410 CV 514 driver transistors
6. It doesn't appear to have previous board repairs/hot spots
7. Bob Carver Phase Linear 700B Serial Number 3210. Just cool. Anyone know when this amp would have been born?
Bad
1. The output transition are a mixture. Some Fairchild PL909 540 and MJ21194G BM1306 MEX (assuming the MEX is Mexico). I have read that mismatch transistors are bad but don't know what bad means? If transistors are the same ratings why would it matter???? Also some of the F PL909 are 540 and some a label Hong Kong? Are they different?
2. The left channel UV meter bounces when turning on the first time. The right meter doesn't not move when the left bounces that first time. I haven't hook the amp to a speaker yet, so I don't know about scratching or anything else really.
3. I pots are very scratchy feeling. Who knows when they were clean/lude
Unknowns
1. It has Sangam DCM Capacitors 9,800 MFD 100VDC I have not clue what the age would be? What was original cap in these amps?
For some background I have previous owned and loved a PL400. I was always very happy with the sounds. quality and power. I did fry it once in a party environment and buzzed the speakers. I now understand from reading that I was sending DCV direct to the speakers. Those NHT 2.5 are long gone now. I see why there is now a protection relay upgrade.
I am currently reengaging in hifi. I am wanting to plan if I should use this amp (as a 700B) with a little updates or go White Oak. If I go to White Oak do I go full White Oak or just control board. I am leaning towards using it at least for a while as a pl700B and then maybe upgrading. He is the current plan.
Current Plan
1. Test the output transistors and make them all consistent. Is there a recommendation. Should I put back in OLD F PL909 or is there an upgrade before go to the full White Oak back plan. That is above my pay grade.
2. Clean the potentiometer with contact cleaner
3. Replace back light bulbs
4. Install Watts Abundant output protection relay before using them with reference speakers. I may play with some cheap good will stuff.
5. Clean the unit well and start to give it hell!
Please comment on what you all think and see.
