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In the Forum: Melquiades Amplifier
In the Thread: Planning my DSET
Post Subject: Try to debug more.Posted by Romy the Cat on: 1/1/2019
 anthony wrote:
Firstly, the -200V Bias supply takes ages to come up to voltage but it does get there...no issues for the +200V side, it charges is 200uF caps almost instantly, but 9,000uF on the negative side takes almost 90 seconds to get to -200V, and the negative 0A2 does not light up until about 90 seconds after the bias supply starts to power up.  There is an issue there...how long does it take your negative 0A2 to ignite Romy? 
 
I think it takes around 60 seconds on my amps. I have 2 minutes delay for high voltage, so it all within the limit. Do not be too hurry, for the first 30 minutes the amp do not sound so great anything. Those 6C33C need some tome to burn in and to reach the cruse operation state. I think after 30-45 min they are fine. If you did not use the amp for let say a week then burn the tubes for 2 hours at least to make the amp so sound “soft” again.

 anthony wrote:
Secondly, and these issues may be related, the First Stages 6E5P (for Channels A, B, C) are not behaving as I would expect.  I've checked the wiring a number of times and as far as I can tell it matches the schematic, and while A and C sit at about 200V at their anodes, Channel B sits at 400V or so and its 15K 12W resistor is staying cool and not drawing any current which means that the tube is not conducting.  I've checked resistances from the tube socket to other parts of the circuit and swapped tubes and nothing changes.

I had it many times and it was always that I found in the end that that I did something wrong. If the channels A and C do give you 200V but C does not then C is not wire in the same way. You should have 400V on plate, 3.5-4V on grid, the heater should be up, the pun 5 and 2 have to be shunted by a small resistor and you should have quite hot plate loading resistor. There is a remote chance that a pin your tube socket got broken and the tube pin does not get voltage…

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