The question is the preamp output voltage is not used much. The mu can swing to extreme +/-15 to 20V without any problems but after the peak outputs of 10V and beyond the distortion increases. The question is are the preamplifiers are driven hard here? I dont think one will use beyond 3V peak on the output. Unless the power amplifier gain is very low. I have tried mu in driving the amps the quality was quite good no doubt but it had hum issues for which it seems solved. Regarding the distortion the dominant second harmonic is good as its sitting a bit higher which has is sonic advantage and also responsible for higher THD figure but if you look at the 3rd harmonic its at somewhere less than -100db which is more than sufficient. I guess the harmonic profile is the one which makes it sound better.
Alright, I'm convinced that we're being trolled. This is unreal.
I feel like someone from Reddit got banned and decided to come have some fun.
Pls post a photo of one example amplifier, top & bottom uncovered, of your wizardry in this field in order to demonstrate your ability to identify the hot end of a soldering iron.
And if you are really confident, a schematic.Do you know what K9P is??
Yes, N101N is trolling. In regard to line preamps (mic too) i see all sorts of nonsense from people who seem having quite good reputation, so many build from their schematics.
We mostly agreed there is rarely need for 3-6x preamp gain and hefty drive when inputs have modern 10k or higher impedance. People that build cathode followers for gain ~0,9 mostly don't even need this kind of buffers, let alone 10mA or more drive.
It could be argued tubes like 6V6 used as preamps have nice sound because of big anodes and certain biasing, although such approach requires attenuator after attenuator...possibly ruining sound they should make better.
Pro audio has a lot to offer, exotic circuits as often shown in audiophile circles seem like research which mostly leads back to classic solutions.
We mostly agreed there is rarely need for 3-6x preamp gain and hefty drive when inputs have modern 10k or higher impedance. People that build cathode followers for gain ~0,9 mostly don't even need this kind of buffers, let alone 10mA or more drive.
It could be argued tubes like 6V6 used as preamps have nice sound because of big anodes and certain biasing, although such approach requires attenuator after attenuator...possibly ruining sound they should make better.
Pro audio has a lot to offer, exotic circuits as often shown in audiophile circles seem like research which mostly leads back to classic solutions.
I would load the tail of the cathode follower with a CCS.
Actually, come to think of it, I would use a mosfet instead, and still use CCS load the tail... Then I might use 6J5GT instead (if I had extra sockets and was being cheep).
Of course, there is not any decisive difference.
The mu stage delivers high gain and high driving capacity at the expense of high distortion. The common idea that high gain gives low distortion should defy common sense, but it doesn`t. In actuality, low distortion is rarely a priority.
The fraudulent mathematical signal analysis represents the ultimate level of trolling.
Genetically? Hard to say without a DNA test.
The mu stage delivers high gain and high driving capacity at the expense of high distortion. The common idea that high gain gives low distortion should defy common sense, but it doesn`t. In actuality, low distortion is rarely a priority.
The fraudulent mathematical signal analysis represents the ultimate level of trolling.
Genetically? Hard to say without a DNA test.
For the past decade I've been listening to a 6SN7 mu follower based on Bruce Rosenbilt's 12AU7 mu follower. I built it from parts scavenged from my work. The 6SN7 and 12AU7 have similar specs with the exception that the 6SN7 wants more heater current and prefers much more B+, preferably 300-400V. My transformer could not provide much more than 225V. I later found the 12SX7 sounds better with my lower B+ supply. I originally floated the DC heater supply at about 100V. Eventually I contructed another heater supply tied to ground for the lower tube. Hum was never an issue and the sound has always been fast, smooth and creamy with low distortion. I measured my Zout with the 6SN7 at 1500 ohms. It has no issues with a 12 foot interconnect to my 47Kohm Zin amplifier. My favorite 6SN7s are vintage Sylvanias. 12SX7s are all RCAs.
can any one explain me what is the role of R9 in the above circuit im using 330ohms
similarly R7 is at 390ohm and R8 is at 5.5k. Is there any issue with that combination as soon as I move the preamp into the chassis it starts giving strange noise and little hum.
