I've just assembled a DIYTube Stereo 70 driver board and installed it in my 1963 Dynaco. Upon power up (no rectifier) the lowest I can set the bias with the wire-wound pots is -41.7VDC (both channels). Is this too high to move on to the next step of biasing with the rectifier in place? I don't want to screw up the amplifier
The amplifier is as follows:
- 1963 Factory-assembled Stereo 70 with original chassis / transformers / power & rectifier tubes
- DIYTube Stereo 70 driver board with 5751 and 12AU7s
- CE Manufacturing 80/40/30/20 can cap
- uf4007 mod on rectifier socket (rectifiers in line with HV on socket to protect the 5AR4)
- New uf4007 in bias supply
- New 47uF / 100V electrolytics and 10k / 2W caps in bias supply
- New 10 ohm / 1/4W cathode resistors
- New 1k resistors from driver board to pin 5 of EL34s
- New X1/Y2 caps on both legs of AC line + CL90 inline with fuse
Thanks in advance,
-D