Troubleshooting an humming WOPL : need help!
- Thread starter Coldsmoke
- Start date
- Joined
- Jan 14, 2011
- Messages
- 75,030
- Location
- Gillette, Wyo.
- Tagline
- Halfbiass...Electron Herder and Backass Woof
- Joined
- Jan 14, 2011
- Messages
- 75,030
- Location
- Gillette, Wyo.
- Tagline
- Halfbiass...Electron Herder and Backass Woof
- Joined
- Jan 14, 2011
- Messages
- 75,030
- Location
- Gillette, Wyo.
- Tagline
- Halfbiass...Electron Herder and Backass Woof
- Joined
- Jan 14, 2011
- Messages
- 75,030
- Location
- Gillette, Wyo.
- Tagline
- Halfbiass...Electron Herder and Backass Woof
I think that fishing could deserve a specific thread here, like to share smoking recipes for instance 
My girlfriend is danish, you can't imagine what she does with a raw fish
My girlfriend is danish, you can't imagine what she does with a raw fish
I'm glad there was an intervention - thanks Lee! I almost left this one alone butt I just couldn't help myself.
I found someone that may be able to help your Danish girlfriend with the fish. What do you think? She's easy and very helpful.
Attachments
I do hold back a bit. 
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.<o
></o>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.<o
></o>I hope you will excuse my lack of knowledge or my misunderstanding of perhaps very simple principles, but, I see it as a change of amplifier class. As if the amp was passing from a B or AB functioning to a A class functioning.... Am I really wrong ....?
Florian
It was Class AB when it was Quasi Comp and remains Class AB when converted to full comp. Now we have REAL PNP transistors that can do the job rather than emulating a PNP transistor. Read below:
"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."<o></o>
It was Class AB when it was Quasi Comp and remains Class AB when converted to full comp. Now we have REAL PNP transistors that can do the job rather than emulating a PNP transistor. Read below:
"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."<o
></o>Well
I received the backplanes yesterday and just finished the soldering of the components ont one of them.
I thought that the soldering cups would be hard to place but the little threads are real bitches to solder cleanly!
Apart from this threads, the kit is a real pleasure to work with Joe!
It's lovely to have all components clearly identified.
I received the backplanes yesterday and just finished the soldering of the components ont one of them.
I thought that the soldering cups would be hard to place but the little threads are real bitches to solder cleanly!
Apart from this threads, the kit is a real pleasure to work with Joe!
It's lovely to have all components clearly identified.
I use a 50w nobrando setable soldering station with silver solder (wich requires a lot of heat too). I actually had difficulties with keeping the threads in the hole without poping. With some expérience, the process is very straight forward.
As you may know, I own a little mechanical workshop. We are designing and building skids and small équipements for the process industry, especially for the pharma and brewing fields.
One of my daily question is to evaluate the human labor required by each of our project.
When I see what it takes to work on audio equipements I guess that the human labor has been the largest part of the price of audio equipements for long... For instance, I recently recaped a 1965 bang & olufsen integrated amp. A real bitch to work on, with very poor accessibility. It was hand made of course : I don't see how it could take less than 50hrs to build it. If such équipement had to be made today I could'nt imagine the price...
As you may know, I own a little mechanical workshop. We are designing and building skids and small équipements for the process industry, especially for the pharma and brewing fields.
One of my daily question is to evaluate the human labor required by each of our project.
When I see what it takes to work on audio equipements I guess that the human labor has been the largest part of the price of audio equipements for long... For instance, I recently recaped a 1965 bang & olufsen integrated amp. A real bitch to work on, with very poor accessibility. It was hand made of course : I don't see how it could take less than 50hrs to build it. If such équipement had to be made today I could'nt imagine the price...