phase linear 400
- Thread starter gene french
- Start date
What is the difference between Quasi Complementary and Full Complementary?
With fully comp circuit topology, the positive half and negative half of the signal are amplified through the final current gain sections with symmetrical circuit design through the use of NPN drivers in the plus half of the signal and PNP drivers in the minus half of the signal.
The quasi comp used NPN on the plus half, like the full comp version but the minus half had the PNP driver emulated by a combination of a small PNP transistor coupled with 2 NPN pre driver and driver instead of using PNP devices. When the Phase Linear was initially introduced, this is what the designers had available to design with so they went with it.
In the last of the PL400 and PL700 production, PL did convert to fully comp on a small number before end of life of the product.
Some benefits, amp gain is more equal on the positive and negative half of the signal. In the quasi comp version, the gain of the negative side was always higher than the positive half. The global feedback compensated for this difference however and quite effectively nulled it out.
The bias settings are now extremely close for both positive and negative half. Part of this comes from the use of precision 1% resistors in the bias resistor locations, the balance comes from the symmetrical topology.
The current limit protection circuits are also now fully symmetrical leading to a more balanced onset of protection for each of the plus and minus sides.
Of course with this PL400 Backplane board, the configuration of full comp or quasi comp is easily selected by several components, jumpers and of course the choice of output drivers.
In the full comp versions, the MJ21196 (NPN) is used in the pre driver and driver positions on the plus half and the MJ21195 (PNP) is likewise used in the pre driver and driver positions on the minus half.
The use of these outstanding drivers everywhere leads to a more robust output stage as a side benefit.
With fully comp circuit topology, the positive half and negative half of the signal are amplified through the final current gain sections with symmetrical circuit design through the use of NPN drivers in the plus half of the signal and PNP drivers in the minus half of the signal.
The quasi comp used NPN on the plus half, like the full comp version but the minus half had the PNP driver emulated by a combination of a small PNP transistor coupled with 2 NPN pre driver and driver instead of using PNP devices. When the Phase Linear was initially introduced, this is what the designers had available to design with so they went with it.
In the last of the PL400 and PL700 production, PL did convert to fully comp on a small number before end of life of the product.
Some benefits, amp gain is more equal on the positive and negative half of the signal. In the quasi comp version, the gain of the negative side was always higher than the positive half. The global feedback compensated for this difference however and quite effectively nulled it out.
The bias settings are now extremely close for both positive and negative half. Part of this comes from the use of precision 1% resistors in the bias resistor locations, the balance comes from the symmetrical topology.
The current limit protection circuits are also now fully symmetrical leading to a more balanced onset of protection for each of the plus and minus sides.
Of course with this PL400 Backplane board, the configuration of full comp or quasi comp is easily selected by several components, jumpers and of course the choice of output drivers.
In the full comp versions, the MJ21196 (NPN) is used in the pre driver and driver positions on the plus half and the MJ21195 (PNP) is likewise used in the pre driver and driver positions on the minus half.
The use of these outstanding drivers everywhere leads to a more robust output stage as a side benefit.
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- music...the healer of souls...
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from what i read...i believe a lot of these early designs were governed by the availability of parts...
i understand delco made the original transistor (later used in the phase linear under a pl designation) for the automobile ignition systems...
and mr. carver thought to repurpose the transistor...
pass the chalk...
thanks
i understand delco made the original transistor (later used in the phase linear under a pl designation) for the automobile ignition systems...
and mr. carver thought to repurpose the transistor...
pass the chalk...
thanks
- Joined
- Mar 6, 2022
- Messages
- 5,555
- Tagline
- music...the healer of souls...
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i gathered that...does joe have a last name??
or is he like cher??
i would like to know more about his link to phase/carver accomplishments...for me, those were the apex of home audio!!!
* disclaimer: if its not top secret....or you would have to kill me if you told me...in that case, i dont want to know...
or is he like cher??
i would like to know more about his link to phase/carver accomplishments...for me, those were the apex of home audio!!!
* disclaimer: if its not top secret....or you would have to kill me if you told me...in that case, i dont want to know...
I didn't get as much time in on the amp as I wanted last night. Girlfriend wanted some attention. I have a call with our China division tonight at 8, but I'm hoping to get the control board mounted and wired and another row or two of transistors in before then.
I ended up re-routing the DCP ground, since I originally had the AC along the top all alone and the DC and ground both run along the bottom. After reading ALL of Georges PL700 Pro build thread, I realized that this ground needed to be rerouted. Twisted and ran the AC with ground as a pair to the DCP board and terminated all of those connections. I want that satisfying 'click' that I haven't heard yet. Went through and double checked for any shorts from collector to chassis ground, and found no conductivity. I actually checked for conductivity from chassis ground to chassis and found that the anodized finish does a really good job of isolation. I was reading open even just a few mm distance from the star point ground to any point on the chassis back wall surface. Hopefully that's typical.
I ended up re-routing the DCP ground, since I originally had the AC along the top all alone and the DC and ground both run along the bottom. After reading ALL of Georges PL700 Pro build thread, I realized that this ground needed to be rerouted. Twisted and ran the AC with ground as a pair to the DCP board and terminated all of those connections. I want that satisfying 'click' that I haven't heard yet. Went through and double checked for any shorts from collector to chassis ground, and found no conductivity. I actually checked for conductivity from chassis ground to chassis and found that the anodized finish does a really good job of isolation. I was reading open even just a few mm distance from the star point ground to any point on the chassis back wall surface. Hopefully that's typical.
Gene, Joe is Gepetto here on the site and he's the reason most of us are here on this site keeping the Phase Linears alive and he supplies us with all the upgrade parts (He's White Oak Audio). Get out the credit card and finish buying the upgrade parts so that 40 year old amp quits fuckin with your brain (It will blow again, it's just a matter of weeks). 
CHER????
HUH?
CHER????
HUH?
