Hi, with this measures your expose in 2A3: 110mA*250v=30W; 160mA*300v=48watt.
I checked this on the plate curves in both tubes.
The 2A3 is 15 watt, and the 300B is 36watt.
Did you confirm this measures with your multimeter? Check the current in the cathode resistor. The amplification factor is 4,2 vs 3,2, that's no big difference.
I checked this on the plate curves in both tubes.
The 2A3 is 15 watt, and the 300B is 36watt.
Did you confirm this measures with your multimeter? Check the current in the cathode resistor. The amplification factor is 4,2 vs 3,2, that's no big difference.
for the 2A3 is around 48mA I will take measurements for the 300 next week and report back, meanwhile I will let it cook more and test the sound
Hi Mousi, in the plate curve from 2A3 must be 110 with this negative voltage and with this plate voltage. Is the 2A3 a special one? Watch out in the attached curves.
Assuming the amp uses fixed bias, is only 48V bias for 300B not a little hot?
If the 300B lacks low end the OT will probably not be up to the job. Because the 2A3 performs good (and the 300B tubes are new) it will probably come down to core saturation because of wrong biassing.
If the 300B lacks low end the OT will probably not be up to the job. Because the 2A3 performs good (and the 300B tubes are new) it will probably come down to core saturation because of wrong biassing.
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The amp actually detects whether 2A3 or 300B are installed, presumably it could also change the operating point to suit the 300B as well? I have heard some of the other kits, they work quite well and seem to be reasonably well engineered.
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