Buzz
Preamp is up and running. Q1 is IXTP08N100D2. Thanks.
When I play music on tpa3118 amplifier with 20 db gain there is an unpleasant buzzing, when music is over Folsom tda7297 amplifier with 32 db gain buzz is even more pronounced. There is buzzing recording "11 Apr 21.53.mp3.txt" (rename to mp3). I do not have oscilloscope and my knowledge of electronics is 0. Any suggestions about what the problem is?
Preamp is up and running. Q1 is IXTP08N100D2. Thanks.
When I play music on tpa3118 amplifier with 20 db gain there is an unpleasant buzzing, when music is over Folsom tda7297 amplifier with 32 db gain buzz is even more pronounced. There is buzzing recording "11 Apr 21.53.mp3.txt" (rename to mp3). I do not have oscilloscope and my knowledge of electronics is 0. Any suggestions about what the problem is?
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Foobar shows main activity around 2.2kHz and it sounds like an oscillation. Try with only passively filtered PSU and if it goes then it should be something with the B+ regulator build or its application. Try it in two wire output mode then by shorting F+ to S+ and F0 to S0 locally at its output connector. Put a 0.1uF across the reg's input connector too. That rectification valve is being asked for too much constant current or it sees a bigger than allowed smoothing capacitor is another suspicion. If on the other hand its a wiring or build style issue see about shorter wires and bad loops or the grid stopper resistors physical distance to the grid pins and their values.
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Thanks Salas.
F+ to S+ and F0 to S0 are shorten. PSU is as in image. Rectification tube is 5C3S (5Ц3С), tefo is 250mA and smoothing capacitor motor run 4uF.
I will put 0.1uF at SSHV2 input. Wiring is bad as I'm only in trying mode, first tube project.
F+ to S+ and F0 to S0 are shorten. PSU is as in image. Rectification tube is 5C3S (5Ц3С), tefo is 250mA and smoothing capacitor motor run 4uF.
I will put 0.1uF at SSHV2 input. Wiring is bad as I'm only in trying mode, first tube project.
That's a 5U4G equivalent, see not to overload it with a bigger than 40uF capacitor on its output. As you don't have an oscilloscope the only debugging method is to remove and change or substitute things and see what happens. You will not easily know what to look for by guessing.
It's max 20uF and i know it is mission impossible. When I put it in a box I'll ask some one locally for help
So its half than for the original 5U4G. Yes, better overview the build along with someone equipped for debugging.
Do you guys think that one of these would be able to drive a 5k~ or so input impedance, like on the BA3 output stage or pass F4 "crippled" (input buffer removed)
It would be setup as a triode connected gain stage.
It would be setup as a triode connected gain stage.
Not really adequate because it has about 1.5kOhm output impedance. It will lose some max output voltage and it will up its THD by 6-7dB
Maybe I'll direct couple a mosfet follower to it then. I've got a pile of IRF820 I can press into service. That should give plenty low output impedance.
Lingwendil- so the easy answer is run the F4 with the buffer. It’s sonically invisible anyway, plus it lets the 6V6 breathe easily. Win-win.
I just don't feel like paying for the jfets in all honesty, is why I was wanting to go without. If I can do well with a source follower I would prefer to, especially since I have everything on hand to build plenty of buffers that would work.
Off topic though, I suppose.
Off topic though, I suppose.
Pin 8 - cathode voltage is 15.4V, pin 3 - plate voltage is 229V. SSHV2 pin TP is 0.6V and output is 340V.
Bought 2 Wima MKS-4 0.1uF/630V should be MKP but... Can I use it at SSHV2 input? Can I use them in cathode follower just to test CF ?
Bought 2 Wima MKS-4 0.1uF/630V should be MKP but... Can I use it at SSHV2 input? Can I use them in cathode follower just to test CF ?
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How about a bipolar transistor buffer comprising of a Diamond buffer with bootstrapped current sources (i.e. pair of resistors and a capacitor)?
Sounds fun, wanna post some more info/continue that discussion over in my thread? I'm definitely interested.
Mosfet follower, burning amp/F4?
I don't want to clutter up the 6V6 thread here...
Extra temp protection with dual fan pcb with microcontoller here in Greece the summer its too HOT
This micro controller uc consumes very little energy with this programming because it goes to sleep after 60 seconds of inactivity. It wakes up after two minutes and controls the temperature. If needed (42degrees up limit) will activate the fans and adjust their speed according to the measured temperature. It goes back to sleep when the measured temperature stays below the threshold I have set 38 degrees down limit for as long as it takes. (60 seconds)
I'm currently using a single fan for the DAC that I have 4X4 cm with a starting voltage of 4.68V very sillent having a margin of up to 10.50V but I do not think it will ever overcome 7V in the summer. Before i have 52 degrees on heatsink
now 42-43 steady.
This micro controller uc consumes very little energy with this programming because it goes to sleep after 60 seconds of inactivity. It wakes up after two minutes and controls the temperature. If needed (42degrees up limit) will activate the fans and adjust their speed according to the measured temperature. It goes back to sleep when the measured temperature stays below the threshold I have set 38 degrees down limit for as long as it takes. (60 seconds)
I'm currently using a single fan for the DAC that I have 4X4 cm with a starting voltage of 4.68V very sillent having a margin of up to 10.50V but I do not think it will ever overcome 7V in the summer. Before i have 52 degrees on heatsink
now 42-43 steady.
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