Hi,Cat,
Just finish asemble the Mrz M7 last night, too tire till accidently broke 1 pcs of my 5687 tube..... money gone...
Attach is photo of it, still need fine tuning as got LF hum, should be dur to insufficient capacitance, on the pcb suppose to put 2 pcs of 220uF/450V but i only put 10uF/450V as my 220uf still not arrive.
What the power rating of your power supply? my 1 is 350V-0-350V at secondary, anyway even a 280v-0280 will be sufficient.
For tube power supply, my rectifier tube is 6X4. and i just use normal C-RC filter to obtain the voltage i need.... the value of R is depend on your DC output after rectifier.
current running at 295V & 275 voltge, need to fine tune by changing the R or adding another C-R-C.
Refer my diagram, the 3.3k is to reducue the voltage to tube place as 350V ia a bit high, 6X4 tube's max rating actually ~350-400 dc out.
R1 is to reduce the voltage in my case as i only got 450V cap, so my 295V is in between R3 &R4, and 275 volt is after the R4. in this case i use 2 pcs of 220k as bleeder resistor. My R4 is ~3.3k which is cause ~20V voltage drop.
In this case if i which to get ~280V & 260V then i just need to increase either R2 or R3 or place 1 more stage of CRC.
for 12ax7 filament i use dc, and connect them using wire from the bottom and the negative just connect using 1 wire to the ground.
Later need to add a metal separator in betweent pwer & signal section...
For B2+, i use 2 pcs wire same length connect to left & right B+ then connect this 2 wire with another wire to the power supply. (i prefer a balance, same distance for both left & right) |