I just built the musical machine of Pointz with the 6gk5 and 6v6's. I powered up the bias/ccs transformer and adjusted the voltages -23v and -66 for the ccs. Then powered up the 6.3v filament transformer and the voltage starts falling off to -14 and -43 on the neg. supply as the heaters warm up and never rebounds. I've doubled checked everything and can't figure it out. Any help would be appreciated!
OB
OB
One other thing is I'm using a solid state rectifier for the B+ not tube. But the drop happens before I start B+ power.
It appears to me the voltages drop for CCS and bias (same source) is due to current over drawn by the 2x 6gk5. Try to set the CCS trimmer to mininum and slowly adjust until the current flow is as recommended (10mA?), monitor both voltages,
If the schematic is right, B+ serves both the 6V6's and the 6GK5's. For a possible explanation, see my suggestion in post #4.
But I'll leave it at this until TS is back.
But I'll leave it at this until TS is back.
Why? If 9.4 mA is enough, like you wrote in your post #7, how could that burn the two 330 Ohm resistors?
Heater to cathode leak is not a binary phenomenon in that there is either a full short or an infinite resistance, but a gradual phenomenon, in that there can be a whole range of different resistances between heater and cathode.
Heater to cathode leak is not a binary phenomenon in that there is either a full short or an infinite resistance, but a gradual phenomenon, in that there can be a whole range of different resistances between heater and cathode.
Thanks for the quick reply guys!
This occurs before I energize B+.
This voltage slowly drops as the heaters heat up when the 6gk5 are plugged in. It does not drop when the 6v6 are plugged in by there self.
This occurs before I energize B+.
This voltage slowly drops as the heaters heat up when the 6gk5 are plugged in. It does not drop when the 6v6 are plugged in by there self.
If there is leakage the heater resistor (maybe the heater itself) should be destoried already (yesterday) when OP powered up everything in the amp. Beside heater leakage takes a different path, it never go through CCS. There is no need to flame more for your non-logic reasoning.
Do you have separate on/off switch (S1) for heater and HT?. In the drawing both are from the same transformer. All 3 xformers are either on or off , itcan not be heater on and B+off, you care to explain?
Why would heater leakage current take a different path? Why would it never go through the CCS? The heaters are practically grounded, so sit at 0 Vdc. The CCS is being fed with -66 V. So if there any leakage between heater and cathode, why couldn't there be current flowing?
And why you resort to an ad hominem? It reminds me of this thread: 6C33C heater question
I told you no need to add flame since you don't know the details, this guy never look at the drawing when he quotes, argues a lot and never prove a word what he said, don't get me into this again..
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Are u sure it only drops when you plug in 6gk5 with only heater on and B+1 off? I'm surpprised the drop agreed with my sim with 6gk5 fully on.
I wish to expand bit if we're still on heater-cathode leak, when leak (after some heavy usage) occurs the voltage that destroyed the 330x resistors is coming from plate to cathode voltage of a few hundred volts. Not by 6.3v Ac.
So why not remove 330x2 resistor (only hum)?
I wish to expand bit if we're still on heater-cathode leak, when leak (after some heavy usage) occurs the voltage that destroyed the 330x resistors is coming from plate to cathode voltage of a few hundred volts. Not by 6.3v Ac.
So why not remove 330x2 resistor (only hum)?
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