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-   -   Joplin PP 2A3 Question... (http://www.diyaudio.com/forums/diy-hifi-supply/190737-joplin-pp-2a3-question.html)

gray49 13th June 2011 03:55 AM

Joplin PP 2A3 Question...
 
Hello...
I am looking for printed circuit boards for the Joplin PP 2A3 amp...
Any help in locating them, or a link that will lead me in the right direction
would be greatly appreciated...
Thank you...
Peace...
Stuart

ThorstenL 13th June 2011 07:13 AM

Hi,

Quote:

Originally Posted by gray49 (Post 2603580)
Hello...
I am looking for printed circuit boards for the Joplin PP 2A3 amp...

This Amp is long discontinued, no parts or PCB's remain AFAIK. What is the problem with your Joplin, the PCB became damaged? Most damage can be easily repaired.

Ciao T

gray49 13th June 2011 05:56 PM

T...
Thank you for the quick reply...

Failing to find any PCB's...Is there anyone out there that has
a Joplin PP 2A3 amp in "ANY CONDITION" that would be willing to part with it?...

Peace...
Stuart

planet10 13th June 2011 06:05 PM

From this picture, PCB may never have existed.

http://www.dms-audio.com/system/file....thumbnail.jpg

dave

vinylkid58 13th June 2011 06:07 PM

Quote:

Originally Posted by planet10 (Post 2604232)
From this picture, PCB may never have existed.

I think the PCB was for the driver stage only. That shouldn't stop anyone from building a clone though?

jeff

ThorstenL 14th June 2011 08:12 AM

Hi,

Quote:

Originally Posted by gray49 (Post 2604220)
Failing to find any PCB's...Is there anyone out there that has a Joplin PP 2A3 amp in "ANY CONDITION" that would be willing to part with it?...

Well, I have recently been working on the "Next Gen" Joplin. It is now two Monoblocks, Tube rectified, uses Film Cap Supply and Active Bias System.

Thus is uses fixed Bias (without need to adjust), it has a further improved supply for the driver stage from the original (now 400V DC, all film Capacitors). In fact, thanks to using AC Heaters for the output tubes the count of electrolytic capacitors for signal circuit and powersupplies is zero, all film caps!

Uses ECC88 or 6CG7 as input (active load anode follower) and 5687 Driver (resistor load anode follower) with an improved operating point for the Driver (more voltage and current), which helps give the amp some extra vavavoom... Input to driver is DC coupled, only one pair of coupling cap's to the Output stage.

Bigger output transformer core than earlier Joplin for better LF. Class AB with a lot of class A, a small amount of feedback to keep the damping factor reasonable. Can use both 45 and 2A3, there is also an option for a 300B Version (separate build, not easily converted). Produces 7 Watt with 45's and 11 with 2A3's (honest watts, measured on the bench, with 5% THD). The 300B version of course has a lot more oooomph.

Uses the same project Chassis as other current diyhifisupply Amplifiers.

Should be out some time soon. Prototypes have been playing a while.

Ciao T


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