Hey guys, I have the version for Coleman reg. from 2011, and I am planning to use it for a 6B4G build.
It’s been sitting on a shelf since 2011 and it’s time to put it to good use. I have a one ohm sense resistor soldered in, but I can’t seem to find the data that led me to think that was the right value. I also have a pair of 12v 50va. Trafos…
The filament is 6.3 V at 1 Amp. And going through all the documentation I have, it seems like for each different tube The regulator is set up a bit differently, different resistor values, etc.
How can I determine what would be the correct sense-resistor, and supply voltage?
Thanks in advance
It’s been sitting on a shelf since 2011 and it’s time to put it to good use. I have a one ohm sense resistor soldered in, but I can’t seem to find the data that led me to think that was the right value. I also have a pair of 12v 50va. Trafos…
The filament is 6.3 V at 1 Amp. And going through all the documentation I have, it seems like for each different tube The regulator is set up a bit differently, different resistor values, etc.
How can I determine what would be the correct sense-resistor, and supply voltage?
Thanks in advance
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1 ohm should be correct. That's what I use - 2W at least. You should get good sound. Needs a decent size heatsink.
1ohm is correct for 1A, assuming the V4 is similar to the newer versions in that aspect. The docs for the older versions in mr Colemans site states 10,3Vdc input for 6B4G. Your 12VAC transformers allows a few volts to be dropped across resistors and/or chokes, making for a nice clean DC supply.
The V4 should need 6 to 7V headroom. I plan for 6.5V. So the input to the rag should be around 13V.
It's the V9 that has 3.5V headroom. The V4 won't work with that - needs more.
It's the V9 that has 3.5V headroom. The V4 won't work with that - needs more.
The instructions for the V9 regulator says 8,9 to 9,8V for 6B4G, 9,3V nominal. The 10,3V figure came from the V1-8 General Application Note. On the other hand, the same document calls for 12,3V for 3C24 which has a 6,3V 3A filament. I'm not sure if all the older versions has the same input voltage requirements for any given tube, perhaps mr Coleman will step in and bring clarity in this matter.
12VAC should be enough for the raw DC in any case.
12VAC should be enough for the raw DC in any case.
The V9 reg is a completely new design with one device. The preceding regs like the V4 with 2 devices need 6V headroom or a little more. I've used several of them and I can tell you that this is the right headroom.
Yes, with the older versions, more headroom was needed for Transmitter-levels of power. The 6A3 will work with this or perhaps a little lower, but with a 12V rms trafo, you will have plenty of DC voltage. Be sure to keep the heatsink around the power transistors < 50 °C and it will be very reliable for years.
The new V9s for receiving tubes need much lower input voltage, as Andy already said.
Good to know. I have a pair of V8 regulators, transmitter type, that I'm planning to use with some tubes that are not on the list.