Phase Linear 200 rebuild

kl0neMan

Journeyman
Joined
Jan 25, 2019
Messages
101
Location
Fort Worth TX USA
Tagline
My race is almost run.
Excessive Dc offset usually comes from Q1, Q2, Q3, Q4
Watching the unloaded amplifier output on the scope as I bring it up on the variac, I get increasing +DC with respect to return. If I bring the AC up high enough, I start seeing +DC on the scope channel where I am monitoring input. It is occurring on both channels.
 

kl0neMan

Journeyman
Joined
Jan 25, 2019
Messages
101
Location
Fort Worth TX USA
Tagline
My race is almost run.
It does not smoke. I have to wait for my loads to arrive for a full up test. I have triggered the protection circuit a couple of times and it comes right back after a delay. I tried to upload video, but it failed, sigh.
 

Attachments

Gepetto

Administrator
Staff member
Joined
May 15, 2011
Messages
13,473
Location
Sterling, MA
Tagline
Old 'Arn Enthusiast
It does not smoke. I have to wait for my loads to arrive for a full up test. I have triggered the protection circuit a couple of times and it comes right back after a delay. I tried to upload video, but it failed, sigh.
Try dragging your video clip over Dan. That usually works.
 

kl0neMan

Journeyman
Joined
Jan 25, 2019
Messages
101
Location
Fort Worth TX USA
Tagline
My race is almost run.
Hmm. It appears that I have failed to upload the video once again . I just tried again (via dragging it into a message composition window). I saw an "Oops! We ran into some problems." dialog after the transfer completes. I must have missed seeing that last time - Ugh.
 
Last edited:

grapplesaw

Veteran and General Yakker
Joined
Aug 13, 2014
Messages
2,762
Location
Vancouver
Tagline
---
I’m setting out to rebuild the 200b sitting on my self for 10 years. Many have stated the poor performance of the series one and b , the series two is compatible with a series ll 400 and 700 in basic design . My goal is a tweeter amp
well this one not a series ll so I’m gutting it and fitting a rev E board I have. This is just right size to fit in.
it’s going to be full complimentary with addition of extra output to drive the mj21195/96 pairs

gathering parts for December build. And one idea is the vu meters that I have. No idea what they came out of as they are 113 x82 mm just smaller that the 400 and 700b

should be strat forward build

thing that may need addressing are resistors in protection circuit and possibly power supply section 21D8CF48-5460-4952-8695-5C1884159BD6.jpeg F325FF46-5FE0-44EE-A458-E7B577BF9D7E.jpeg 705454FC-9795-4DE0-8ABE-6BACA8D35AAB.jpeg E2705E41-CBBF-474C-889C-259CFA0CB147.jpeg A6381B15-1AAB-4B26-BEBE-938E163BF2F7.jpeg 1E5C47E8-B185-4592-945D-8952EA6D81F4.jpeg
 

grapplesaw

Veteran and General Yakker
Joined
Aug 13, 2014
Messages
2,762
Location
Vancouver
Tagline
---
This amp has delay on with speaker protection
the protection circuit is a little curious as the main power output to the board that I senses has different values from left to right channel R57 and R58 on b and r1 and r2 in series ll schematic attached FAF91515-69D2-4CAD-8C72-9A6DFBA96559.png 36E8AE46-4022-44EB-8FFC-43F2702B3BA5.png

the other thing will be thermal bias control added via bias transistors added
 

Attachments

Last edited:
Top