Klimon: The 6SN7 is not connected as cascode. Desperateaudio had allready breadboarded the 6SN7 cascaded driver so I just checked it for him. Wouldn´t recommend it either!
Your recommendations are great!
Without NFB 6C45 is the best choice, albeit it normally sounds better with a high B+ 400V and anoderesistor. Remember Milletts measurements are without load! 5842 is a nice sounding, descent tube but suffers from limited swing capability compared to 6C45.
One could even add a small amount of NFB to the 6C45 and still get an acceptable senstivity.
If one decide to use NFB a cascaded 6H30 would be the obvious choice. My idea is that the feedback shouldn´t be over the whole configuration, the input tube should be left outside the loop.
Your recommendations are great!
Without NFB 6C45 is the best choice, albeit it normally sounds better with a high B+ 400V and anoderesistor. Remember Milletts measurements are without load! 5842 is a nice sounding, descent tube but suffers from limited swing capability compared to 6C45.
One could even add a small amount of NFB to the 6C45 and still get an acceptable senstivity.
If one decide to use NFB a cascaded 6H30 would be the obvious choice. My idea is that the feedback shouldn´t be over the whole configuration, the input tube should be left outside the loop.
Just finished breadboarding the original design last night. Plugged the CD Player into a passive preamp volume control (50K) and then directly into amp. Sensitivity is an issue as previously discussed as I cannot get volume to go above a few clicks before distortion. The orginal design cannot be good for more then a few watts. Keep volume in check and she sound like she has potential.
With a 0,75A CCS and three 6080s at 100V Ua 135V B+ you can get ca 2W 5% 8ohm and 0,15W 1% 8ohm. More tubes are needed when going 8ohm!
The problems with ESLs are that that they have extremely low Z at 20kHz. But up there not so much is needed. Still I think you should have at least 5 parallelled for that kind of use!
Poynton: Why not the old Philips 9710, 800ohm
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The problems with ESLs are that that they have extremely low Z at 20kHz. But up there not so much is needed. Still I think you should have at least 5 parallelled for that kind of use!
Poynton: Why not the old Philips 9710, 800ohm
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poynton said:
The original design. My power supply PT transformer, choke and heater trans were all from a military 6AS7 power supply using 6 - 6AS7's so they are all poted trans with extreme current capabilities. I will post pics tonight before a start on the other. Also I will post current voltage measurements and power schematic.
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