#6sn7 cathode follower plus#
The 7.5 ♟ capacitor … is fairly misguided though. Overall distortion peaks at 0.4, output impedance is just 828 plus the 1k series resistance, and the total drive voltage loss is only 0.6dBv. As Fahey (or someone) said above, around 10 kΩ.Īnd … 10 kΩ is a perfectly good output impedance for a preamplifier, especially driving what looks like “high end” audio equipment. Output impedance (perhaps unexpectedly to you as a newbie…) is rather markedly lower than 33 kΩ tho'. Moving along however, the next stage has a 33 kΩ cathode resistor and is seeing 165 V on the grid. The result is that the signal tapped up on the anode resistor will be quite linear. Without a cathode bypass resistor, the 1,500 Ω cathode resistor will be exerting a strong local-negative-feedback moderation to the already-quite-linear 6SN7's triode transfer function. In turn, the 22 kΩ anode resistor will DROP 84 volts, leaving the valve to “see” 250 - 84 = 166 volts on anode. What was the function of the tube in the circuit (for instance someone mentioned a 6SN7 as a cathode follower in a post above that's a very different use than a voltage. If person A says tube B didn't sound good, it offers very little useful information. Which corresponds on the 6SN7 load-line datasheet diagram to … just that. Here is a simple reminder: random subjective opinions are not very useful in general. This induces a voltage of 5.7 V in the 1,500 Ω cathode 'auto-bias' resistor. The circuit shown ought to have a 3.8 mA quiescent (no signal) current in 6SN7 (left). Reduce and remove things not needed (such as the power supply leading to ground … with a blôody capacitor on that path (to the right)). Instead, concentrate on the values your little diagram has, at various positions. A cathode follower has little to no gain. Take the advice now already given: you do not need an output transformer on a preamp. PS - but thank you for admitting you are new-to-tubes, and they're confusing. "Design" looks like randomly copypasted schematic snippets from different places. Not even shorted tubes will blow any currently available fuse. 07 capacitors? Besides the nil effect on filtering, what do you expect them to accomplish?Īnd the hardly useful F1 fuse on the +V line? Not too sure either about the "do nothing" RCRC filter C1-C3-C4-R8ġ ohm resistor?. Not randomly placed because of some intrinsic quality they may impart to sourrounding components by their mere presence.Īlso the "connected to nothing" voltage divider and smoothing capacitor R4-R7-C5 Maybe you read "they improve xxxxx" (xxxxx being some desirable quality) and so HAD to add one.ĭesign does not work that way, but a real Technical need has to be solved, and components are calculated and chosen for that. Hey, what you did with that unneeded MUR460 diode. In that case, you may simply mount o e in your chassis, without even connecting it to anything. Unless your question is not technological buy mystical: "transformers have such and such magical properties and I want them in my design, just by randomly adding one" Click to expand.Hardly a transformer needed there and you omit the most important data: what is your load?
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