Clair Bros Amp

You can post all you want here Dennis, BTW I already miss your other avatar. I have her saved though :evil4:
 
laatsch55 said:
Perry, here's the thread where we tried to replace the LF-351 with a Burr-Brown OPA 134.....


http://forums.phxaudiotape.com/showthread.php/2839-Cory-s-Phase-Linear-300-Ser-II
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I would love to rekindle this topic. I am attaching some data from long ago. This deals with caps on the opamp and bias correction of the internal voltage for the OAP134. I would like to use these in my next build on 500's and would think the Clair Bro. Amps would benefit as well..

Hope to see come back on this on proper installation and setup

Glen

image.jpg

image.jpg
 
grapplesaw said:
I would love to rekindle this topic. I am attaching some data from long ago. This deals with caps on the opamp and bias correction of the internal voltage for the OAP134. I would like to use these in my next build on 500's and would think the Clair Bro. Amps would benefit as well..

Hope to see come back on this on proper installation and setup

Glen

View attachment 22996

View attachment 22997
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The White Oak RevE board uses the OPA134 in the front end.
 
Gepetto said:
The White Oak RevE board uses the OPA134 in the front end.
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Hi Joe
I had emailed you a while back about using your board with the d-500 and did not hear back so thought it was a no go.
Will it work on 125 volt rail voltage as is? If not do I need to change any resistors on the voltage reg circuit? The OAP134 is a big improvement over the lf351 / lf356 but not just a plug and play.
 
grapplesaw said:
Hi Joe
I had emailed you a while back about using your board with the d-500 and did not hear back so thought it was a no go.
Will it work on 125 volt rail voltage as is? If not do I need to change any resistors on the voltage reg circuit? The OAP134 is a big improvement over the lf351 / lf356 but not just a plug and play.
Click to expand...

The D-500 is an odd duck and uses a control board that is quite different from the other PL amps. Would require a lot of rework to make it applicable Glen.
 
Gepetto said:
The D-500 is an odd duck and uses a control board that is quite different from the other PL amps. Would require a lot of rework to make it applicable Glen.
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I agree with you Joe. The control board has high frequency section in the middle two two signal patches are fairly straight forward.

I will start a new thread for this when get started. This may be interesting to follow as it has a lot of different problems to over come. I want get it to Full complemtary without going crasy. I had talked about a mono setup but that is looking mor difficult as the inverted legs would be at 4 ohms +/- and about 1600 + watts output in mono 8 ohm load
 
Had a hell of a time trying to troubleshoot a Clair amp a guy bought from me. I sold it for "Parts Only" since I didn't have time to dick with it but he talked me into getting it up and running before I shipped it. Anyway, The right channel would not work no matter how many times I kicked it, so After probing around, I thought I found an issue with Q206 (one of the transistors with the big square heat sink) which is in the right channel on the PL-36 board. So, I went to remove it and the collector lead came out, it was broken and you couldn't see the leads since they are hidden under the heat sink. It rocks the house now. I rebuilt the PL-36 board so he wouldn't have any issues with it for a long time. I gotta tell you, the workmanship of some of these boards coming out of PL is something else. The left gobs of flux all over the place which takes a jackhammer to get loose after all these years, the wires look like they were stripped with a chainsaw etc.... I think I found one of the guys from third shifts glass eye stuck under the widget by the high speed bumper bolts... JEEEZE

P
 
Under close examination, the lead was rusted away. The Hawaii air is a killer. I think that's what it was.
 
Lee, I tried putting the Ipod straight into the amp and it did work but it wasn't as loud as I expected but it did work for troubleshooting purposes and kept me amused for a few minutes.
 
laatsch55 said:
The quality in the later years really sucked....
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I have not opened up the early models yet (serial numbers in the 9400 range). I have opened up the 11000-12000 serial numbered units but I'll do some workmanship comparisons now that I'm home and have a week off for Christmas.
 
I've only had 7 or so SerII's opened up, and compared to a middle run 700 they definately went downhill....
 
TheWOPLwhiffer said:
Lee, I tried putting the Ipod straight into the amp and it did work but it wasn't as loud as I expected but it did work for troubleshooting purposes and kept me amused for a few minutes.
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Have you measured the output of the I-pod? I would imagine it's in millivolts.....
 
Have not checked the output on the Ipod. Replaced the 40412V with 2N3439. It had 3 prongs so I jammed it in there...:shaking2:
 
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