No, I haven't. As FR can see if he reads any of the articles I've published or posted, I use whatever technology is best to achieve the engineering goals needed for the application.
I use an SRPP front end on my hybrid valve/MOSFET amplifier.
It gives a very clean sound, I was very pleased with it.
It gives a very clean sound, I was very pleased with it.
Just to be closer to the absolute truth ,you could replace "clean" with pleasant. 😀
CAUTION:
One of the "problems" of a DIY website is that you get folk repeating "Popular wisdom" with no actual experience, whether to try to be helpful or just to try to appear knowledgable doesn't really make a difference.
This results in some tubes getting an undeserved bad name, the 12AU7 is one of these. 12AU7 are stunning if run up at 8.5 to 10mA idle current. At some stage someone has done a design with a 12AU7 running at 1.5 to 2.5 mA and stated that it sounded bad and that has been repeated by enough folk that it is now accepted as a fact.
The real problem with tubes like the 12AX7 and the 12AU7 is that they are so readily available and relatively cheap that they have been used in more bad designs than any other tubes in the history of audio. Both can stunning when used correctly in the right place.
One other thing I saw in circuits above. The LM317 used as a current source. It actually can make a reasonable CCS when used in the right place. In most instances however its high device capacitance means that you get a CCS whose output impedance (the measure of a CCS "goodness") falls rapidly at higher frequencies. Occassionaly that won't matter, usually it does. I don't recommend using LM317 and similar for CCS duty.
Cheers,
Ian
Thought for the day:
The difference between theory and practice is that in theory there is no difference between theory and practice whereas in practice there is.
One of the "problems" of a DIY website is that you get folk repeating "Popular wisdom" with no actual experience, whether to try to be helpful or just to try to appear knowledgable doesn't really make a difference.
This results in some tubes getting an undeserved bad name, the 12AU7 is one of these. 12AU7 are stunning if run up at 8.5 to 10mA idle current. At some stage someone has done a design with a 12AU7 running at 1.5 to 2.5 mA and stated that it sounded bad and that has been repeated by enough folk that it is now accepted as a fact.
The real problem with tubes like the 12AX7 and the 12AU7 is that they are so readily available and relatively cheap that they have been used in more bad designs than any other tubes in the history of audio. Both can stunning when used correctly in the right place.
One other thing I saw in circuits above. The LM317 used as a current source. It actually can make a reasonable CCS when used in the right place. In most instances however its high device capacitance means that you get a CCS whose output impedance (the measure of a CCS "goodness") falls rapidly at higher frequencies. Occassionaly that won't matter, usually it does. I don't recommend using LM317 and similar for CCS duty.
Cheers,
Ian
Thought for the day:
The difference between theory and practice is that in theory there is no difference between theory and practice whereas in practice there is.
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Me too , I was thinking the same things while reading this thread , yesterday.I fully agree.
Though I sadly admit that I can be included in the big mindless crowd
Very fashionable. It will work but the gain is ridiculously high for modern sources and the performance will be less than optimum compared to a common cathode-cathode follower combo. Probably good enough if you're not a perfectionist and you're in love with SRPP.
The LF roll-off will only be 1.6Hz when the output is not loaded. With a 50K load the LF point will be 33Hz. The output impedance may be 850ohms, but only from around 1.9kHz up. The cause in both cases is the 0.1uF output cap.
It looks like the same circuit, but with a bigger output cap and a smaller output ground resistor.
Would this be an acceptable 6DJ8 Circuit?
Is there any simple way how to reduce gain of this pre? Without changing tubes.. Probably some resistor from output to input
SY,
I am willing to experiment with gain, preferably around 5x, as I am changing amplifier's gain too. SRPP is not a must, and load is about 4k, variable to 15k. I am just trying different circuits, so see which one sounds best for my ears.
I am willing to experiment with gain, preferably around 5x, as I am changing amplifier's gain too. SRPP is not a must, and load is about 4k, variable to 15k. I am just trying different circuits, so see which one sounds best for my ears.
For that low of a gain (and it's a reasonable target!), you'll need to do a feedback topology if you want to use ECC88. Will the source be directly connected to the input or will you have a volume control?
SY,
I am targeting to use 6N1P, "almost" equivalent of 6922/E88CC, with mu about 35 (different values in datasheets, but well 33-37,5). There wont be any potentiometers, directly connected to source. I was trying different simulations in Tina TI, and once I tried simple resistor, just like for chipamps, to set gain.
I am targeting to use 6N1P, "almost" equivalent of 6922/E88CC, with mu about 35 (different values in datasheets, but well 33-37,5). There wont be any potentiometers, directly connected to source. I was trying different simulations in Tina TI, and once I tried simple resistor, just like for chipamps, to set gain.
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