PL400 Build help
- Thread starter BrickbyBrick
- Start date
- Joined
- Jul 30, 2022
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- Joined
- Jul 30, 2022
- Messages
- 29
Amp is fully up and running. Using the amp with my B&W CDM1NTs. Going to run this through its paces before I move them to my ATC SCM20PSL Pros.
Can't get over the low end. This is my first foray into higher powered amps, and it's dawning on my that you need a decent amount of power to push the low end. Low end sounds so much faster, fuller, punchier and clearer than my Kenwood L-07Ms, which are bone stock.
Thanks for everyones help. It feels great knowing that such a niche subject has a warm, helpful and inviting community.
Damn bent output transistor leg........
Also, the does the black wire on the VU PCB go to ground?
Can't get over the low end. This is my first foray into higher powered amps, and it's dawning on my that you need a decent amount of power to push the low end. Low end sounds so much faster, fuller, punchier and clearer than my Kenwood L-07Ms, which are bone stock.
Thanks for everyones help. It feels great knowing that such a niche subject has a warm, helpful and inviting community.
Damn bent output transistor leg........
Also, the does the black wire on the VU PCB go to ground?
It is Class AB.
For amp design, there really isn't that much new under the sun.
This is basically the amp circuit that I designed in the mid 1970s to drive the servo amps in tape drives I was designing at the time. They were class B so the only real add is the bias addition to turn it into Class AB. Modern, newer tech component offerings make a big difference in performance and reliability. I have focused on eliminating lingering reliability and ruggedness issues as I go along.
There is a wide variety of differing skill levels of folks doing these upgrades using our products. A key focus of mine is attempting to make it so that things don't break even if an assembly step is done wrong, that is the ruggedness factor. All this while improving the sound quality and not sacrificing the original Phase Linear sound. The sound clarity out of the modern White Oak product in full comp mode is quite superior to the original Phase Linear control boards.
For amp design, there really isn't that much new under the sun.
This is basically the amp circuit that I designed in the mid 1970s to drive the servo amps in tape drives I was designing at the time. They were class B so the only real add is the bias addition to turn it into Class AB. Modern, newer tech component offerings make a big difference in performance and reliability. I have focused on eliminating lingering reliability and ruggedness issues as I go along.
There is a wide variety of differing skill levels of folks doing these upgrades using our products. A key focus of mine is attempting to make it so that things don't break even if an assembly step is done wrong, that is the ruggedness factor. All this while improving the sound quality and not sacrificing the original Phase Linear sound. The sound clarity out of the modern White Oak product in full comp mode is quite superior to the original Phase Linear control boards.
The community here would have to weigh in on that. I am slightly biased so will have to recuse myself. 
I've been through SAE, and a few other "Monster Amps" over the last few years and there is nothing out there I have monkeyed with that competes with the WOPL.
Reliability and Ruggedness??? That is an understatement. Shit, who else would offer a lifetime warranty on an amplifier? In 7 years and umpteen dozen builds of WOPL's, I had one come back due to a faulty power switch which NOW get replaced with new switches and had another amp come back due to Norman Knob-Job playing around with the backside of an amp while it was plugged in AND JAMMING. Nothing that White Oak could plan for nor was it White Oak's fault. These amps are tough as nails and with solid electronics practices, these amps will last a lifetime. I hear there is another amp coming to market which will compete with a WOPL but I have not had the opportunity to get my grubby mitts on one. YET!!!!!
- Joined
- Jul 30, 2022
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BrickbyBrick
Glad you have it up and running! Did you try the meter Hack?
What ohm are your speakers?
Only thing to do now is check the heat of the PL
If its a Lower Ohm speaker or you run it hard ,,, might want to add a Fans
Glad you have it up and running!
Did you try the meter Hack?What ohm are your speakers?
Only thing to do now is check the heat of the PL
If its a Lower Ohm speaker or you run it hard ,,, might want to add a Fans
Speakers are 8ohm. ATC recommends an amp with 300w. Should probably just look for a PL700 right? haha
I have compared the PL700B WOPL upgraded amplifiers with Crown Com-Tech rack mount amps (I have two) and the Crown DC-300A amplifiers. They both seem to run out of power at higher frequencies and the bass is certainly less forceful.
I also tried the Bongiorno-designed Thoebe pre-amp and the Son of Ampzilla amplifier. This is a great combination but at only 80 Watts per channel, it is not a fair comparison. Nice sound, but my JBL speakers needed more power.
Lastly, the David Hafler DH-220 power amp, which could be bought as a kit or complete. This amplifier had great midranges and the vocals were excellent, but it lacked any form of low bass and the high frequencies just disappeared as the volume increased.
I did not compare the PL700B WOPL to any monoblock amplifier because I believe they are a waste of floor space and money.
To find a amplifier of equal accuracy and power, you would have to audition the Krell 600 at $12,500.00, Luxman M-10X at $19,995.00, or Mark Levinson 333 at $8,495.00. All of those are too rich for me, and for the price, will not give me that much of a listening difference.
I also tried the Bongiorno-designed Thoebe pre-amp and the Son of Ampzilla amplifier. This is a great combination but at only 80 Watts per channel, it is not a fair comparison. Nice sound, but my JBL speakers needed more power.
Lastly, the David Hafler DH-220 power amp, which could be bought as a kit or complete. This amplifier had great midranges and the vocals were excellent, but it lacked any form of low bass and the high frequencies just disappeared as the volume increased.
I did not compare the PL700B WOPL to any monoblock amplifier because I believe they are a waste of floor space and money.
To find a amplifier of equal accuracy and power, you would have to audition the Krell 600 at $12,500.00, Luxman M-10X at $19,995.00, or Mark Levinson 333 at $8,495.00. All of those are too rich for me, and for the price, will not give me that much of a listening difference.
- Joined
- Jul 30, 2022
- Messages
- 29
The community here would have to weigh in on that. I am slightly biased so will have to recuse myself.
I noticed when testing the amp, with my -10 gear that it sounded a bit better, had more depth and punch than when I use it with my audio interface, or am I crazy?