I want to share this small project that come up from left over parts from other project, specifically I thought to get a good RIAA pre-amp using 6922 tube but has been a failure,
some more expert people in this website already told me to do not do it, I am been stubborn
and I was wrong so I thought what can I do instead? What I really want to have is a good tube headphone amp so I look many project but some are really too expensive so I find online an hybrid small project using a simple 12v power supply using the 12au7 valve, that I have, try it
but really did not satisfied my ears, so I simply swap the 12au7 with the 6922 and wow immediately sound was much better but a lots of distortion and clipping, I do not have oscilloscope, signal generator etc. so I simply connect to the anode and cathode two potentiometer and just try to bias the 6922 with just 12v power supply, the result is stunning, I cannot even believe myself that a one stage triode plus a conventional MOSFET can achieve this result. What I did is use just one triode of two different 6922 for have a good separation, separation already little compromise by the common power supply then other important thing I noticed is to use a very good quality cap for the input signal, suggested value 3,3 uF. I personally love the clarity cap CSA series for all my project, reasonable price and outstanding performance, then you can use basically any MOSFET, I try the IRF series also the BUZ series, but I used in my project the P16NE06 just because I have two of them, but as I said I try the other ones and the sound quality is unchanged. As a power supply you can use any stabilised 12v, 2A, I am using in my project an old 12 power supply from an old cctv system, I just change all the cap and that’s it work perfectly. Here the schematic of this project, if anybody want to give suggestion on how improve it or any other suggestion I will be very happy..
some more expert people in this website already told me to do not do it, I am been stubborn
and I was wrong so I thought what can I do instead? What I really want to have is a good tube headphone amp so I look many project but some are really too expensive so I find online an hybrid small project using a simple 12v power supply using the 12au7 valve, that I have, try it
but really did not satisfied my ears, so I simply swap the 12au7 with the 6922 and wow immediately sound was much better but a lots of distortion and clipping, I do not have oscilloscope, signal generator etc. so I simply connect to the anode and cathode two potentiometer and just try to bias the 6922 with just 12v power supply, the result is stunning, I cannot even believe myself that a one stage triode plus a conventional MOSFET can achieve this result. What I did is use just one triode of two different 6922 for have a good separation, separation already little compromise by the common power supply then other important thing I noticed is to use a very good quality cap for the input signal, suggested value 3,3 uF. I personally love the clarity cap CSA series for all my project, reasonable price and outstanding performance, then you can use basically any MOSFET, I try the IRF series also the BUZ series, but I used in my project the P16NE06 just because I have two of them, but as I said I try the other ones and the sound quality is unchanged. As a power supply you can use any stabilised 12v, 2A, I am using in my project an old 12 power supply from an old cctv system, I just change all the cap and that’s it work perfectly. Here the schematic of this project, if anybody want to give suggestion on how improve it or any other suggestion I will be very happy..
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yes RIF510, 610, 611 and 612 give the same resultWhat do you have to say about STP16NE06 ?
Is this a good MOSFET TO-220 and is there anything special about it?
Can IRF610 be just as good?
I like your project.
TUBES are as made for things like headphone amplifiers.
And with the addition of a MOSFET it looks very good.
Bet it sounds great
yes cathode load resistor is 12k, I measure on cathode 0.50 volt and anode 10.50 volt, I guess the tube set like this is gaining a very little due to the very low voltage but just enough for drive the MOSFET, I just made some other test and realise that if the power supply is increased of 2 volt so 14 volt adding a 3.3 ohm 5 watt resistor to the heather line there is a significant improvement on the volume and the previous small distortion at the max volume disappear, I will post later a schematic with all voltages
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