In Reply to: RE: Here is the photograph posted by Tre' on June 16, 2012 at 09:19:56:
I put 1.5K Grid Stopper in every grid for each tube.
Additional info:
1. ECC99 is in AC Filament, with one AC leg grounded. 300B is in DC filament.
2. The output from Power supply seem good, very little ripple, no spike
3. Power supply is: 1N5408 SS diode(full wave) -> 220uF Cap -> 5H L -> 220uF Cap (connected to 300B stage) -> 750 ohm R -> 14H L(connected to 2nd stage ECC99) -> 24K R (connected to 1st stage ECC99)
For the decouplling Cap, I put each decoupling cap closed to each ECC99 stage already
4. with 1st stage grid grounded, the noise is 1mV measured in 2nd OPT winding. without grounding the grid for 1st stage, the grid of 1st stage would appear as much as 10mV P-P irregular ultra high freq oscillation.
5. For the 4. measurement, there is no any cable soldered from the grid of 1st stage yet.
It seems I have followed the cook book but don't know why it come up like that.
Regards,
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Follow Ups
- RE: Here is the photograph - Eric Chan 15:19:34 06/16/12 (2)
- information corretion - Eric Chan 15:25:00 06/16/12 (1)
- RE: information corretion - Tre' 15:54:52 06/16/12 (0)