Indeed, even if a volume control precedes C1, though in such a case the value of the resistor should be at least twice that of the value of the volume control.
Since this is the Tubes/Valves forum, I think that is time to add this circuit here which fulfils the OP's original need.
This has 12 dB gain, but it can be even reduced with bigger cathode resistor.
An externally hosted image should be here but it was not working when we last tested it.
This has 12 dB gain, but it can be even reduced with bigger cathode resistor.
Attachments
By the way... Why is this R1L resistor a 10k and not the 15k as in the design Rod Elliott has in the stage 2 of his design? As he has in Figure 4?
Rods Design
Rods Design
Sorry, I guess this is getting away from the Tubes theme... I run a tube amp and spend time on this forum.. This opamp design lets me get something that fits the bill for like 10 bucks I think.
This is more temporary till I can get some $$ for a real tube build preamp..
If Frank Berry or someone can answer my last couple questions I'd really appreciate the time doing so.
Sorry if this is getting to be too long in the wrong forum
This is more temporary till I can get some $$ for a real tube build preamp..
If Frank Berry or someone can answer my last couple questions I'd really appreciate the time doing so.
Sorry if this is getting to be too long in the wrong forum
Other than the remark about the type of switch, it looks fine to me. However I'm not sure if you'd like the sound quality. As a temporary solution, it should be fine.
So now I'm torn over bothering with this... I think I'm going to just sit pat with my system and save up to do a tubes build.. Like this 6N1p.
One item that I'd like to clone.. The Audiophile Tube Amplifiers and Loudspeakers by DECWARE
They have a ZSTAGE
One item that I'd like to clone.. The Audiophile Tube Amplifiers and Loudspeakers by DECWARE
They have a ZSTAGE
Having used a good quality passive preamplifier for a long time, then gone over to building my own powered preamps, I would personally not go back to the passive solution except maybe temporarily in a dire emergency. Since you are already thinking about a longer-term solution, I would strongly suggest that you aim for rebuilding your passive pre into a good quality active one. You will not only enjoy what it brings to your music, but you will also end up with less clutter of separate boxes and interconnects. I have used 5687, 6n6p and 6cg7 for this purpose. The best results I got from indirectly heated valves was from 6cg7's run in parrallel. (ie 1 tube per channel with both halves connected together. This was quite capable of running a pair of solid-state amplifiers per channel. With tube power-amps, which don't suffer from such low input impedence, you could probably get just as good results without parallelling. You will have plenty of gain soyou could easily equalise your input signals by putting a resistor divider on 1 input.
If you are a bit nervous about building tube amplifiers, you can get a pretty respectable result from using a single 2sk170 (or other) j-fet per channel run in class A - but tubes definitely rule. Ultimately, you might want to end up with a DHT preamp, but that is another story...
If you are a bit nervous about building tube amplifiers, you can get a pretty respectable result from using a single 2sk170 (or other) j-fet per channel run in class A - but tubes definitely rule. Ultimately, you might want to end up with a DHT preamp, but that is another story...
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