Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thread

[laatsch55]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

Like I said Jer, Thank You for what you have done for this forum and the people in it. A lot of what you do, hell , most of it is done out of sight and out of mind, but you come through every time with something better, faster, cooler and funner!! My man you have my heartfelt thanks and I hope this amp gives you years of service, and as the first White Oak 1000, it has a lifetime , personal guarantee....from me. Thanks Jer!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

[Gepetto]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

Hi Lee, the single point ground made a significant difference in distortion readings so I will be providing you some additional guidance on what I have found. The gremlin in my lab mule was a blessing in disguise because it pushed me to experiment with what works better. The results speak for themselves. Filling in the excel sheets now and will post a little later on. I am feeling really good so far about this change. I also equalized the 2.7 ohm resistor in location R2R and R2L and now I get nearly identical power outputs on each channel with the same input signal. This was not the case before.

 

[laatsch55]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

Ah Joe, excellent!!!!!!!Could you provide a link for the BOM at Mouser?? The last one you sent didn't work. Oh and bill me for 10 (ten) boards.

 

[Gepetto]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

Yes will send you a link to the Mouser BOM and we can debug that to make sure it works for you. And sure thing on the second request.

 

[laatsch55]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

Thanks Joe.

 

[Gepetto]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

Here are the new distortion figures after rewiring the same chassis for the single point ground, all other conditions identical except I used the 80KHz low pass on the HP8903B instead of the 30KHz filter which is a more severe measurement than using the 30KHz setting.

 

[laatsch55]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

Jeez Joe , the MJ's are exponentially better in the distortion department!!!!!

Joe, I'm pretty sure you didn't run a PNP MJ with an NPN, and then unmatched NPN's!!!

 

[Gepetto]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

Yeah pretty good eh

 

[Gepetto]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

Here is what I did to achieve this.
1. Removed the white 22AWG chassis ground wire that runs from the copper bus pad between the input RCA jacks to the White Oak PL14_20 PCB, pin 5R.
2. Removed the 16AWG bus wire jumper that Phase normally installs between this same copper bus pad and the right channel speaker ground binding post.
3. I left the 2 signal grounds in the signal twisted pairs that originate at this copper bus pad between the input RCA jacks that run to the White Oak PL14_20 pin 2R and 2L respectively.
4. I added an 18AWG tinned solid copper bus wire jumper between the right and left channel ground (black) speaker binding posts.
5. I added a #10 ring lug with 2 white 20AWG wired into the ring lug on one end and into the White Oak PL14_20 PCB pin 5R and 5L respectively. The #10 ring lug was attached under one of the large bulk capacitor ground bus bar screws that connect the 2 bulk caps together.
6. I changed R2L from 56 ohms to 2.7 ohms.

This makes the large ground bus bar between the 2 bulk caps into the Single Point Ground for the entire amplifier. This wiring scheme eliminates the common mode noise from the large speaker ground from entering and affecting the low level input and low level ground reference on the White Oak PL14_20 PCB (caused by the bus wire jumper that Phase Linear installed between the right speaker negative binding post and the copper pad at the input RCA jacks)

Hope this is clear what I did. I will try to document in a diagram later on.

 

[laatsch55]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

To one who has been elbow deep in many a PL Joe this is very clear and elegant in its simplicity. I will copy that post in its entirety and post it in my thread at AK.

 

[Gepetto]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

Here are a couple of photos of the mule on the bench and the lab setup to perform these tests.

 

[laatsch55]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

That test equipment makes me drool!!

 

[laatsch55]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

Jer, we wil implement this grounding scheme before your White Oak 1000 gets shipped.

 

[Gepetto]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

Here is the difference that the White Oak Cap Board upgrade made in the ripple and noise on the main power supply rails in the amp under test

 

[laatsch55]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

How can you trace ac and dc on the same scope trace??? That to me is amazing, man i gotta get some better test eq.

Nevermind i see Ch1, and Ch 2 superimposed on each other.

 

[laatsch55]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

Joe, does that amount of ripple have an effect on the Power Supply Rejection Ratio of an amp??

 

[mlucitt]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

A quick update on my end. Angela Electronics made good on the shipping mistake of sending me two red input jacks, I received two black input jacks today.

One of the Apex Jr. caps had a stripped terminal because someone left the screws partway in the cap connectors and they got bent over in shipping. Steve agreed to replace the cap so now I am just waiting for a new cap. I will go ahead and test the board with the original caps because they seem (and test) fine.

Can you check my PL700B wiring please:
Colors are for my own reference

Channel A (Left)
1L - Left Channel Input > Black Coax
2L - Left Channel Input Shield > Black Coax
3L - Negative Drive (Base of Q12) > Beige
4L - Negative Current Limit (Collector of Q14) > Yellow
5L - Star Ground > White
6L - Output (Output Rail) > Grey
7L - Positive 100V Fused (Collector Q11) > Orange
8L - Positive Current Limit (Emitter Q13) > Tan
9L - Positive Drive (Base Q11) > Light Brown
10L - Bootstrap (Base Q13) > White w/ Green and Black Stripe
11L - No Connection (Board Jumpered Positive 100V)
12L - Negative 100V (Twisted w/ 12R) > Black

Channel B (Right)
1R - Right Channel Input > Black Coax
2R - Right Channel Input Shield > Black Coax
3R - Negative Drive (Base of Q12) > Beige
4R - Negative Current Limit (Collector Q14) > Yellow
5R - No Connection (Board Jumpered Ground)
6R - Output (Output Rail) > Grey
7R - Positive 100V Fused (Collector Q11) > Orange
8R - Positive Current Limit (Emitter Q13) > Tan
9R - Positive Drive (Base Q11) > Light Brown
10R - Bootstrap (Base Q13) > White w/ Green and Black Stripe
11R - Positive 100V > Red
12R - No Connection (Board Jumpered Negative 100V)

Thanks

 

[Gepetto]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

That wiring you list is correct Mark. Remember as well your 2 bias transistors that need to be wired in.
Joe

 

[mlucitt]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

You made those Q6 Bias transistors so easy I didn't even bother to list them.

I ordered ten of those 7.5K Ohm 1/2W resistors from Parts Express and they sent me ten packages of ten each (100) resistors. If you need some, I can mail 80 of them to you tomorrow morning.

 

[Gepetto]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

Lee to answer your question on ripple rejection, any ripple gets through to a certain extent. The higher the frequency, generally speaking, the more that gets through due to bandwidth limitations of the amplifier. If you have 2V of PS noise and an amp with a 60dB PSRR then 2 mv of noise will be riding on the output signal. If the noise is caused by the opposite channel it will not be coherent with the signal (unless the amp is running the same sine wave through both channels) and become a larger distortion contributor. Good focus on power supply aspects generally net good sonic improvments. Witness the lengths that the high end phono preamp manufacturers go to for great, very low noise power supplies.