Hi,
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
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
From this picture, PCB may never have existed.
dave
An externally hosted image should be here but it was not working when we last tested it.
dave
I think the PCB was for the driver stage only. That shouldn't stop anyone from building a clone though?
jeff
Hi,
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
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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