hi arnold,
i am actually put another cap after the VR tube which i got good result and minimized the hum in the phonostage of frank's design. unfortunately, while playing vinyl last night, i noticed an intermittent blinking with the two VR tubes
the two VR tubes are now dead and i'm just validating if the cause of this is due to the additional capacitor after the tubes!
i have another 2 OD3 tubes coming in next week, i hope this won't happen again!
i am actually put another cap after the VR tube which i got good result and minimized the hum in the phonostage of frank's design. unfortunately, while playing vinyl last night, i noticed an intermittent blinking with the two VR tubes
the two VR tubes are now dead and i'm just validating if the cause of this is due to the additional capacitor after the tubes!
i have another 2 OD3 tubes coming in next week, i hope this won't happen again!
I think if you look back about 10 posts.... 
VR tubes don't like (much) capacitance in parallel with them,they'll usually oscillate (blink) and go dead..
Sounds like too much capacitance to me..
EDIT,Ahh yea, if the resistor drifted that much,there could be too much current going through the VR tube.. time to replace the resistor I'd say.
VR tubes don't like (much) capacitance in parallel with them,they'll usually oscillate (blink) and go dead..
Sounds like too much capacitance to me..
EDIT,Ahh yea, if the resistor drifted that much,there could be too much current going through the VR tube.. time to replace the resistor I'd say.
s2kov, if that is frank's phono, how come you're not using his regulated power supply?
what is the rectification you're using? tube i suppose?
if that's mine, i'd also ditch the choke, then use crcrcrcrc. but then you'll lose the nice purple glow and you'll have two unused sockets in your chassis. so forget what i said
what is the rectification you're using? tube i suppose?
if that's mine, i'd also ditch the choke, then use crcrcrcrc. but then you'll lose the nice purple glow
and you'll have two unused sockets in your chassis. so forget what i said
I am in the process to gain my own experiences with the OD3, I have build a preamp which looks a bit like the first stage if the karna, but with two 4p1l, running at 30mA each.
http://www.nutshellhifi.com/Karna.gif
The psu is choke input: LCLC followed by a CCS from Kevin Carter and the OD3.
As the PSU is 9H-50uF-13H-200uF it is dead quiet already. I have build a connector, so thatI can easily put the CCS and the OD3 in or out.
Well, first attempt was so-so: The upper CCS runs at 80mA, the lower in the tail at 60mA and the OD3 lights up, havin 20mA....but it is hizzing like hell, I have to build in this small cap (Hytron 1953 OD3) some people reported not to be necessary (incl. Lynn Olson)...
Other question I have: Why did Lynn have included a 330Ohm resistor between HV and the OD3 ?I guess for measuring current I would have expected 100ohm, so it might actually have a function and not just measuring purposes ? I have now a 200ohm resistor on top of mine, but not sure if it is needed actually.
http://www.nutshellhifi.com/Karna.gif
The psu is choke input: LCLC followed by a CCS from Kevin Carter and the OD3.
As the PSU is 9H-50uF-13H-200uF it is dead quiet already. I have build a connector, so thatI can easily put the CCS and the OD3 in or out.
Well, first attempt was so-so: The upper CCS runs at 80mA, the lower in the tail at 60mA and the OD3 lights up, havin 20mA....but it is hizzing like hell, I have to build in this small cap (Hytron 1953 OD3) some people reported not to be necessary (incl. Lynn Olson)...
Other question I have: Why did Lynn have included a 330Ohm resistor between HV and the OD3 ?I guess for measuring current I would have expected 100ohm, so it might actually have a function and not just measuring purposes ? I have now a 200ohm resistor on top of mine, but not sure if it is needed actually.