So started the checkout process today.
Measured 0v on R30; -370v on R7 and 4.98v across the filament.
Put in an 5AR4 and wound up the variac to 120V.
Got up to 470V on R30 and I saw a flash across the base inside the tube. At that point R7 was showing -374V. I immediately powered down.
470V B+ - is that too high when there is only the rectifier tube in?
Using the Edcor XPW131 by the way. Am I supposed to have the brown/white hooked up to T6 (I'll be using 300B tubes)? I have read conflicting reports.
Thanks.
Measured 0v on R30; -370v on R7 and 4.98v across the filament.
Put in an 5AR4 and wound up the variac to 120V.
Got up to 470V on R30 and I saw a flash across the base inside the tube. At that point R7 was showing -374V. I immediately powered down.
470V B+ - is that too high when there is only the rectifier tube in?
Using the Edcor XPW131 by the way. Am I supposed to have the brown/white hooked up to T6 (I'll be using 300B tubes)? I have read conflicting reports.
Thanks.
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"The power transformer needs to provide about 640 or 650 volts center tapped at 150 mA or more, 5 volts at 2 amps, and 6.3 volts at 4 amps. A center tap on the 6.3 volt winding is NOT required." Tubes and Applications | Tubelab
The brown/white wire on the Edcor is the 6.3v center tap which is what confused me as I had read it is required in another post (by rknize I think).
The brown/white wire on the Edcor is the 6.3v center tap which is what confused me as I had read it is required in another post (by rknize I think).
It depends on whether you want to use 2.5volt tubes or 5v tubes. In reality it does not matter because the connections are taken care of on the board itself.
Better to have the CT soldered to the board for convenience sake than to have to heat-shrink it or secure it by some other means.
So just connect it to the board as it will not harm anything or make a difference. HTH
Better to have the CT soldered to the board for convenience sake than to have to heat-shrink it or secure it by some other means.
So just connect it to the board as it will not harm anything or make a difference. HTH
So I moved to the next step (rectifier only) and tested the grid on the output tube socket.
I got the following readings:
440V and 437V
I was expecting these to be negative readings (as per the checkout).
Is it possible I am measuring the wrong thing? I hooked up to the socket pin that is top left when you look at the layout with the output sockets in the top right of the PCB. It is numbered 2 on the socket as shown in Georges page on installing the sockets. Should I be hooking up to a resistor instead (R33/R34)?
Thanks.
I got the following readings:
440V and 437V
I was expecting these to be negative readings (as per the checkout).
Is it possible I am measuring the wrong thing? I hooked up to the socket pin that is top left when you look at the layout with the output sockets in the top right of the PCB. It is numbered 2 on the socket as shown in Georges page on installing the sockets. Should I be hooking up to a resistor instead (R33/R34)?
Thanks.
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The 5842 tubes run off of the DC that feeds the reg. for the output tubes. There is a dropping resistor, 2.2ohm I believe, that reduces the voltage for them.
I ended up needing only 1ohm to have 6.2v for the 5842 heaters...
Anyway trace the connections and then we will see....
Once you have this thing up and running you are gonna like it
I ended up needing only 1ohm to have 6.2v for the 5842 heaters...
Anyway trace the connections and then we will see....
Once you have this thing up and running you are gonna like it
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