I purchased some EML 300B tubes and installed them in the BeePre. I added a 100 ohm 10W wire wound resistor to the two 8 ohm 10W resistors which resulted in a filament voltage of 5.03 volts (close enough). After 10 minutes of playing the left channel went dead (the BeePre has been running since July without any problems), no filament voltage, and the B channel LEDs on both sides were not lit. Deja Vu, this happened during the initial build, could not find or solve the problem (even with help from the board) so I ordered new parts and boards for the left channel. I must have stuffed the boards correctly this time and the problem was solved and the BeePre has been humming along and sounding wonderful until the EML tubes were installed. THIS MAKES NO SENSE TO ME! (Unfortunately, a lot about this hobby does not make sense to me anymore)
I wanted to do some modifications to the BeePre so this seemed to be an appropriate time for a rebuild. For some reason I decided to build the BeePre stock, I have always substituted different parts in most of my Bottlehead builds, usually sockets, wire, terminal strips, and RCA's etc.
Installed all new components going into the C4S Boards including terminal strips...
Installed new teflon tube sockets.
Installed Khozmo Acoustic mono attenuators.
Installed new selector switch.
Replaced the original 10uf caps with Obbligato Gold Premium 10uf caps bypassed with Russian teflon .1 and .01 caps.
Installed new wire; Homegrown Audio Solid Core Braided Speaker Wire - 16 wires 22 gauge - 8 Pure Silver + 8 OFHC Copper.
Replace all RCA's with CMC silver RCA's. It just seems logical to me that if you are going to use silver wire that one should use silver RCA's.
Removed all caps, terminal strip, and wire going to the XLR jacks, I will never use these jacks, and it made an easier and cleaner installation of the Homegrown Audio wire.
For a test run I installed the kit 300B tubes (EH's). On power up only the A Channel LEDs lit up, after approximately 5+ minutes the right B channel LEDs lit, and eventually (another 2-3 minutes) the left B channel LEDs finally lit up. Now it only takes 15+ seconds for all of the LEDs to light up. ANOTHER MYSTERY?
Did a complete voltage check, everything is spot on except terminal 2 and 17. The voltage should be 90-110 VDC, but measured 72.0 and 71.2 VDC. Terminals 2 and 17 connect to the 10uf capacitor. IS THIS SOMETHING TO WORRY ABOUT? If I remember correctly the 70+VDC was the same voltage from the original voltage measurements.
Now just need to finish the base. I will add a picture if I can figure out how!
« Last Edit: September 30, 2013, 08:09:33 AM by Lee Hankins »
Lee Hankins
"End of the Road"
Homer, Alaska
