Ryan, I have both mux and direct drive clocks here and I have never heard the singing some report. I would think it's just my ears going away but the wife would surely say something. (Maybe she's deaf too). As far as flicker goes I have noticed that if the HV drops much below 170v you can see it.
As far as tube life goes, I have a direct drive IN14 clock that's been running 24/7 for about five years now with no problems. Pretty short span as I know many on hear have been running them longer than that. Personally I wouldn't recommend increasing the anode resistor to increase dimming. You should do that through PWM. Decreasing the anode voltage can lead to poisening. I like both the 555 and the 1771 and the component layout can be tricky on either one. As far as I'm concerned the 555 is pretty tough. I have used up a few 1771s accidently so I really triple check my work now before powering up a new supply. Either one will easily power 6 IN14s. I use the 555 if I'm not concerned about efficiency. But it seams that the 1771 adjusts much better than the 555. Dennis On 3 Aug, 15:55, Ryan McDonald <[email protected]> wrote: > Ok. I've decided that my 6-tube clock will either do a direct drive > using six 74141's and three shift/latch chips *OR* a 2x3 mux. I'm > kinda leaning towards the direct drive because it won't sing or > flicker. Questions: > > Will the 2x3 mux really be noticeably dimmer? I know folks say that a > 1x6 really sings. Can anyone comment on whether a 2x3 sings/flickers > and how noticeable it is? > > I'm concerned about tube life with direct drive since the duty cycle > is 3 times higher over a 2x3 mux. Can the tubes be dimmed by > increasing the anode resistor WITHOUT stressing the tubes (ie. is it > unhealthy to "underdrive" the tubes assuming you at least make the > strike voltage)? > > I know most folks here on the list prefer the max1771 based supply > over the common 555 based one due to efficiency. I have read though > that the 1771 ps is *very* finicky to things like board placement, > lead lengths, and component flavors. The 555 seems simpler and more > reliable at the expense of efficiency. Firstly is this true? And > secondly, would the usual 555-based design be adequate to drive six > IN-14's? > > -Ryan -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
