Tubelab has reported issues with 6AQ5s and 6005s (same thing, Mil version) overheating and sucking in their glassy envelopes when confronted with power near their stated plate dissipation limits. He says the plate is perilously close to the glass on both the 6AQ5s and the 6005s. A hot plate next to hot glass may result in envelope suck-in and vacuum loss. A private message to George may reveal the whole sordid tale. Or just do a search in the tube forum for 6AQ5 to get the scoop. BTW, the 50C5 has a pretty low max plate and screen voltage, as it was designed to be the final audio stage for a hot-chassis series string radio running off rectified 115VAC, one of those 5-tube series string wonders....
Here's Tubelab's comments on the shortcomings of 6AQ5s
Here's Tubelab's comments on the shortcomings of 6AQ5s
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I have two power transformers of sufficient voltage (296v and 360v) for this project, both are rated for 160ma. Would 160ma transformer be sufficient for the B+ this project?
Finally got this into a chassis and finished.
I printed water slide decals.
It looks good but not as good as I had hoped.
You can see they are decals when close.
I applied them and then clear coated the chassis.
It looks good but not as good as I had hoped.
You can see they are decals when close.
I applied them and then clear coated the chassis.
250+ pages... oh dear 😵💫 .....
.... lets get starting.....
...
Question until i catch up....
.... my transformer is 250-0-250/150mA and would like to make a cathode follower without a potentiometer to use it in between my dac with volume control and my F5 clone......
Would it be possible to fit a tube rectifier, C-L-C filtration, regulator on a lower plate voltage like 250dvc or 260vdc??? What regulator???
I thought to maybe use AudioNote M2 regulator with 6X5GT / ECL82 (I have the boards at home already from another project) but it is only up to maybe 35mA ... i am not sure if that will fit the bill of this preamp...
.... lets get starting.....
...
Question until i catch up....
.... my transformer is 250-0-250/150mA and would like to make a cathode follower without a potentiometer to use it in between my dac with volume control and my F5 clone......
Would it be possible to fit a tube rectifier, C-L-C filtration, regulator on a lower plate voltage like 250dvc or 260vdc??? What regulator???
I thought to maybe use AudioNote M2 regulator with 6X5GT / ECL82 (I have the boards at home already from another project) but it is only up to maybe 35mA ... i am not sure if that will fit the bill of this preamp...
Sure about that vgeorge? As I remember circuit is biased under 10 mA (long ago I thought about that.
6V6 plate resistance 50-60 k plus anode and cathode resistor, 340 vdc, ohms law
6V6 plate resistance 50-60 k plus anode and cathode resistor, 340 vdc, ohms law
Simplest solution is maybe to stack 3 0C3 VR-tubes to 315 volts and decouple them with some small caps. Works decent enough and gives you the magic ionizing glow 🙂
on top of that - if i remember on few first pages, Salas was talking that he was running his first prototype on 260VDC, 17mA and 11.2V on cathode resistor.... so i guess it might work.....
i am just asking if anybody made it that low as a final version for his system and was happy with it........ maaaybe??
i am just asking if anybody made it that low as a final version for his system and was happy with it........ maaaybe??
I only breadborded and did some tube rolls sorry. Long ago also. It needs a couple of minutes to settle down, ping in the glass envelopes to the heat etc, then it gives a relaxing but engaging enough sound character. Take care of the filament supply construction. Different samples of 6V6/EL90 draws a wide spread of current so dial that one in careful. Can starve it a little to 6 v or under