Hi mates,
Recently heard a DIY 41 based amp. Find its ability to reproduce music effortlessly is very impressing.
Wonder if anyone have any opinion on building or using 41 based amp.
Also would like to see if anyone done any comparison vs 45 based amp.
Cheers.
Recently heard a DIY 41 based amp. Find its ability to reproduce music effortlessly is very impressing.
Wonder if anyone have any opinion on building or using 41 based amp.
Also would like to see if anyone done any comparison vs 45 based amp.
Cheers.
Was the valve operated in pentode or triode mode?
Anyway, a quick look at the curves show that the 41 isn't particularly linear. GE/Ken Rad rate it at 4.5W out (315V on plate, 285 on screen - pentode mode) and 15% THD - 9K load. This is rather high even by non-feedback standards and only decreases to 11% at a different operating point (and only 350mW output)
By the way, the 41 is identical to the 6K6-GT
Have you thought of using '46s? This is a DHT (directly heated tetrode🙂) capable of approximately the same power output as a '45 and is much more linear than the 41/6K6 in triode connection. It appears to be a close relative... and is placed right after the '45 in the RCA R10 handbook (from the early 1930's?). The best part is that because the '46 is rather unpopular it is much cheaper than '45's!
I have sort-of assumed that the valves will be operated in triode mode... if not, there is an interesting alternative available in Gary Pimm's PP47 amp... (reputed to sound virtually identical to PP45.. with DH pentodes) http://home.pacifier.com/~gpimm/47.htm
Triode mode anode characteristics for the 41 and 46 for reference (the 46 is the one on the right) - sorry that they're a little small but otherwise the size would be too big
Anyway, a quick look at the curves show that the 41 isn't particularly linear. GE/Ken Rad rate it at 4.5W out (315V on plate, 285 on screen - pentode mode) and 15% THD - 9K load. This is rather high even by non-feedback standards and only decreases to 11% at a different operating point (and only 350mW output)
By the way, the 41 is identical to the 6K6-GT
Have you thought of using '46s? This is a DHT (directly heated tetrode🙂) capable of approximately the same power output as a '45 and is much more linear than the 41/6K6 in triode connection. It appears to be a close relative... and is placed right after the '45 in the RCA R10 handbook (from the early 1930's?). The best part is that because the '46 is rather unpopular it is much cheaper than '45's!
I have sort-of assumed that the valves will be operated in triode mode... if not, there is an interesting alternative available in Gary Pimm's PP47 amp... (reputed to sound virtually identical to PP45.. with DH pentodes) http://home.pacifier.com/~gpimm/47.htm
Triode mode anode characteristics for the 41 and 46 for reference (the 46 is the one on the right) - sorry that they're a little small but otherwise the size would be too big
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