Guys, I'm driving it straight from the CD player, a CD63 to be precise. There is no problem with the gain - it can get plenty loud. C3 is wired with correct polarity. And no, I don't have a pot at the input. Thanks for the suggestions and help.
I had this issue with the 20N50D part as well, but it was not as pronouced. The 6N50D2 has even higher input capacitance. So, it probably does need an input buffer. I'll try reducing the drain to 1/2 the supply first and see if it helps.
I'm driving Tannoy dual concentrics and they have a crossover. Wonder if that's too much for this simple amp.
I had this issue with the 20N50D part as well, but it was not as pronouced. The 6N50D2 has even higher input capacitance. So, it probably does need an input buffer. I'll try reducing the drain to 1/2 the supply first and see if it helps.
I'm driving Tannoy dual concentrics and they have a crossover. Wonder if that's too much for this simple amp.
The one between the Source of the Jfet and the amplifier to be driven. In
fact, there needs to be only a total of 100 ohms or so between the Source
of the B1 Jfet and the Gate of the De-Lite gain transistor.
The Original B1 ( I want to build a second piece ) has 1000 ohm at the source output ( R104 and R 204) . It could be nice to use a double switch in the front panel to connect a couple of parallel resistors , and select
Could someone point me to the link for the DeLite article? I didn't seem to find it.
I skimmed through this whole thread, plus read the nemesis article. This is stuff, a triode guy can get his brains around.
I had one random thought. On one hand you have the DeLite with no OPT and on the other hand you have the Nemesis with a gapped OPT. There is possibly a betweener here. Think para-feed. Use the bulb or CCS of the DeLite variants as the load and a ungapped OPT on the output. This buys you the higher reflected load of the OPT version, but wider bandwidth of the non-OPT version. Food for thought anyway.
I skimmed through this whole thread, plus read the nemesis article. This is stuff, a triode guy can get his brains around.
I had one random thought. On one hand you have the DeLite with no OPT and on the other hand you have the Nemesis with a gapped OPT. There is possibly a betweener here. Think para-feed. Use the bulb or CCS of the DeLite variants as the load and a ungapped OPT on the output. This buys you the higher reflected load of the OPT version, but wider bandwidth of the non-OPT version. Food for thought anyway.
In fact a power resistor should be more linear than a light bulb.
But the bulb is good looking, and cheap, and easy....always appealing, in many contexts..
Remember, that blue ribbon across the top of each page has useful menus in it!
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In this circuit at audio freqencies, the light bulb has less harmonic distortion
than the transistor. There is one other effect - in the midrange at about a
kilohertz or so, the filament will ring slightly, and you can hear it if you aren't
driving a speaker and your ear is near the bulb. It shows up as a slight narrow
peak at the frequency on the response curve.
Neither of these appears to mar the enjoyment of the amplifier.
...There is one other effect - in the midrange at about a
kilohertz or so, the filament will ring slightly, and you can hear it if you aren't
driving a speaker and your ear is near the bulb...
It was probably just a De-Lited mosquito buzzing about attracted by the glow...
Most likely a male with a dominant 2nd harmonic
In this circuit at audio freqencies, the light bulb has less harmonic distortion
than the transistor. There is one other effect - in the midrange at about a
kilohertz or so, the filament will ring slightly, and you can hear it if you aren't
driving a speaker and your ear is near the bulb. It shows up as a slight narrow
peak at the frequency on the response curve.
Neither of these appears to mar the enjoyment of the amplifier.
Infact the amplifier is very very enjoyable . I find that effect almost impossible to hear , when using halogen sticks ( 1000 watt ) .
Also I do like -a lot- the power supply with 2 secondaries and 2 bridges in series ( 2 * 30 volts ) -