I guess it would depend on the source. A lot of folks seem afraid to turn the volume control past 12 o'clock, like it's "wrong" for some reason. A lot of sources have quite a bit of output.
Another option would be paralleled 6A6 (octal version 6N7)?
I've also been thinking about using the "Nickel Wonder" line stage design with a 6A6 to drive a power tube.
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Are you assuming a preamp here?
I'm assuming a standard line output of 2v as from a DAC. In my case the DAC goes straight into the amp and the volume control is all in software in my Mac Pro. No preamp needed if the driver tube has a mu of 30 and upwards, but it needs at least 30 with 2v in. So it would be common practise to design for that.
According to the guy that posted the amp with the CCS loaded 6J5 it needs 2.8V to reach max output. It doesn't meet your criteria but might work for someone else.
The Nickel Wonder with a 6N7 (or 6A6) is just an idea of mine to use that line stage circuit to directly drive a power tube. I've got the needed Hammond 124B nickel transformer, I'll give it a go one of these days. You could use the 6J6 in the original schematic as it has a mu of 38 and with the step down of the 124B it'd likely drive the 300B.
The Nickel Wonder with a 6N7 (or 6A6) is just an idea of mine to use that line stage circuit to directly drive a power tube. I've got the needed Hammond 124B nickel transformer, I'll give it a go one of these days. You could use the 6J6 in the original schematic as it has a mu of 38 and with the step down of the 124B it'd likely drive the 300B.
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2.1VRMS from a typical CD player (full scale on the DAC),
gives 3.0V peak.
That is enough to drive some input grids into drawing grid current (there bias is less than 3V).
Of course there are some CD disks out there that only reach -10dB or -20dB Full scale on the DAC.
Just my opinions.
gives 3.0V peak.
That is enough to drive some input grids into drawing grid current (there bias is less than 3V).
Of course there are some CD disks out there that only reach -10dB or -20dB Full scale on the DAC.
Just my opinions.
I wouldn't use a software controlled volume setting. As far as I remember reading long ago, it is best to set the output of the DAC at maximum setting and set the volume from a traditional potentiometer. I'm not that good with digital stuff, but it has to do with the way the data are managed in order to lower the output.
It's a question of the lesser evil. I don't want to use a pot, it would be very inconvenient since I'm constantly switching between digital inputs. Plus it would degrade the signal in itself. But in any case I don't have much spare gain in the system, so I'm pretty close to max. Not much attenuation.
In response to using 124b, I tried that as a step-up input transformer. I wasn't too bad in fact, a lot better than a Lundahl LL1540. But it wasn't as good as a higher mu driver with no SUT.
most of the posts here are anecdotes, personal experience, includes many of mine as well.....i will never claim that they should work for every one....
i am also a firm believer in the "cause and effect" side of things....if i am not convinced, then that is it....not your fault, my shortcomings mostly...
i am interested to hear technical arguments, they teach me lessons...anecdotes do not as effectively...
i am always looking for technical explanations, where there are none, then it becomes opinions of the poster, and there are no right or wrong opinions, just opinions...
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Yes, of course. As regards subjective listening comments, I am personally most interested in shootouts. I trust an educated listener to give some useful information if a number of items (tubes, capacitors etc) are compared A-B in a careful standardised setup. The information may not be "reliable" but I see it as "useful". So a rank order has some value for me. Less so comments on just one setup, as in "my amplifier sounds wonderful" or "I love this tube". That's how I see it.
Agreed. I'm not sure someone on a forum can technically explain why one phono cartridge sounds better than other, but hearing people's personal experiences helped me chose one that sounds good. Much more than what a single "influencer" says.
Indeed, the vast majority of facts sited here are "anecdotal". There is little scientific evidence on the way a piece of DIY equipment sounds. But we have the opportunity to take into consideration other people's opinions and experiences and, judging them accordingly, make some assumptions and not definite conclusions. Then, we can use those for our experiments and judge ourselves. Other people's input may help me and direct me to a path that may lead me to an excellent result - or not. But this is helpful.
So, I don't need to rely solely on the scientific basis of my hobby. For example, scientific evidence states that adding negative feedback improves all characteristics of an amplifier. For me, NFB never had a pleasant outcome, be it solid state or hollow state equipment. Therefore, my final judge is my ears and that's always anecdotal...
Power amplifiers are not the only factor.
Whatever feeds a power amplifier sees both the static and dynamic input impedance (including when the grid voltage is near to the cathode voltage, before it even becomes positive).
The power amplifier's small signal damping factor, and large signal damping factor;
and how the loudspeaker's crossover (if present) and driver(s) react to that damping factor.
And, the un-symmetrical damping factor of non-negative feedback single ended amplifiers;
versus the symmetrical damping factor of many push pull amplifiers, that have, or do not have negative feedback.
How the loudspeaker impedance versus frequency influences the power amplifier's output stage, and how it affects the negative feedback (if NFB is present).
Playing back recorded music requires a complete analysis of the whole system, not just a single isolated part.
System includes everything starting from the musician's performance, and ending in the listening room characteristics, including loudspeaker placement, listener position, room treatments, and the room's building materials.
To forget to consider any one of the above factors, is to have a flawed analysis of the system, its causes, and its results.
Just my opinions.
Whatever feeds a power amplifier sees both the static and dynamic input impedance (including when the grid voltage is near to the cathode voltage, before it even becomes positive).
The power amplifier's small signal damping factor, and large signal damping factor;
and how the loudspeaker's crossover (if present) and driver(s) react to that damping factor.
And, the un-symmetrical damping factor of non-negative feedback single ended amplifiers;
versus the symmetrical damping factor of many push pull amplifiers, that have, or do not have negative feedback.
How the loudspeaker impedance versus frequency influences the power amplifier's output stage, and how it affects the negative feedback (if NFB is present).
Playing back recorded music requires a complete analysis of the whole system, not just a single isolated part.
System includes everything starting from the musician's performance, and ending in the listening room characteristics, including loudspeaker placement, listener position, room treatments, and the room's building materials.
To forget to consider any one of the above factors, is to have a flawed analysis of the system, its causes, and its results.
Just my opinions.
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when posters post operating points, then then is a good thing to see..
i also value feedback from those who heard my work, since i was the one who built it, then i know what clicks with the audience and what does not, and pick up from there....
i also value feedback from those who heard my work, since i was the one who built it, then i know what clicks with the audience and what does not, and pick up from there....
Correct. I stress "What I posted is tuned to sound good in my house with my Klipsch RP600M speakers." It sounds good both with my Yamaha CD deck and my turntable+EAR834 phono stage. I first tuned it to sound good with my CD deck (since I can't really tune it), then tuned the tube phono stage to sound good with a bit of tube rolling, so both sources will sound nice. This whole setup in another room probably wouldn't sound the same.
The same for me. Besides judging with my own ears, I always seek input from a couple of friends, whose opinion regarding the acoustic outcome of a built piece of equipment I highly appreciate and greatly trust.
I also trust outside critiques for "I don't hear any difference". It's easy for us to hear what we expect to hear i.e. I spent $$$$ on XYZ so it has to sound better.
I set up some listening tests at 3-Venues (conducted years ago). Not only were there three different locations, but different systems (different signal sources, speakers, room, and different listeners), except the amplifier was the same each time.
They compared 2 identical single ended amplifiers on one chassis.
The two channels gains were very carefully matched.
The Left channel output of Stereo recordings, was applied to both L and R channel inputs.
Each channel output had its own individual speaker (identical pair speakers; different speaker models versus each location).
The listeners were not told what to listen for; they were only told to see if they could hear any difference during the test.
The purpose, if any, and effects, if any, of the switches were not told to the listeners.
There were 2 un-labeled switches on an umbilical cord.
One switch paralleled, or not, the driver plates (on/off) [un-labeled].
The other switch paralleled, or not, the output tube's plates (on/off) [un-labeled].
Switch combinations: off/off, off/on, on/off, and on/on.
The test administrator could not tell which switch was which, nor the on/off position of the switches.
This was a double blind test.
The listeners were hard pressed to hear any differences, or to make any comments on any sound differences.
At one venue, an extremely knowledgeable and trusted individual, could hear an extremely slight difference of the very high frequency rolloff (the only listener who heard any difference) .
But at one venue, a listener who had the switches, was so totally frustrated because he could not hear any differences, so that he threw the switches across the room.
Fortunately, the switches only controlled 5V that went to the relays that paralleled the plates of the driver tubes, and the plates of the output tubes.
Safety First!
They compared 2 identical single ended amplifiers on one chassis.
The two channels gains were very carefully matched.
The Left channel output of Stereo recordings, was applied to both L and R channel inputs.
Each channel output had its own individual speaker (identical pair speakers; different speaker models versus each location).
The listeners were not told what to listen for; they were only told to see if they could hear any difference during the test.
The purpose, if any, and effects, if any, of the switches were not told to the listeners.
There were 2 un-labeled switches on an umbilical cord.
One switch paralleled, or not, the driver plates (on/off) [un-labeled].
The other switch paralleled, or not, the output tube's plates (on/off) [un-labeled].
Switch combinations: off/off, off/on, on/off, and on/on.
The test administrator could not tell which switch was which, nor the on/off position of the switches.
This was a double blind test.
The listeners were hard pressed to hear any differences, or to make any comments on any sound differences.
At one venue, an extremely knowledgeable and trusted individual, could hear an extremely slight difference of the very high frequency rolloff (the only listener who heard any difference) .
But at one venue, a listener who had the switches, was so totally frustrated because he could not hear any differences, so that he threw the switches across the room.
Fortunately, the switches only controlled 5V that went to the relays that paralleled the plates of the driver tubes, and the plates of the output tubes.
Safety First!
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i guess there are many of us like minded....
yes, this is also true, one visitor even told me, Tony, i was invited to listen to a million pesos setup by an audiophile, but the system did not sound a million pesos worth to my ears, our diy is by far better......of course that was his opinion...😀
Right, my brother has easily $40K USD in his system and my homemade EL34 amp with $600 Klipsch speakers I got on sale for $400 sounds better to me.