We use small ref filtering capacitor here and it does not go because it comes up fast, although I have shown it could be Zener protected in an old post for avoiding the odd smoke. I will see about it again when I will check the SSHV2 if with a bit bigger cap.
Which cap are you talking about? Across the shunt mosfet I use a MKP 156nF cap, series with 1R, and the result is excellent. Any lower value cap could not be used in my case, and the 1R was compulsory too.
Before the reg I have a RCLC filter with low ESR, large C values.
Before the reg I have a RCLC filter with low ESR, large C values.
The Vref filtering capacitor (c2). That one needs time to charge up and can give a spike when on/off. Also the wider the BW, the spike can be more vicious.
I see. I use a 33uF there. Anything lower was a bit too much noise and the slow startup too fast for what I wanted.
Depends on the application's own gain and noise floor demands. I try keep it all MKP if possible since its mainly used for not that spectacular noise floor tube line stages and the like.
C2 is at zero volts at start up.
As the CCS starts to pass current, the voltage across Q4 & Q2 b-e rises rapidly to become enormous.
Expect the devices to pack in eventually.
As the CCS starts to pass current, the voltage across Q4 & Q2 b-e rises rapidly to become enormous.
Expect the devices to pack in eventually.
With the value used it holds fine for maybe 3 years now in so many builds, but if with bigger cap, a zener should be employed as discussed.
Salas I suppose that I can implement four wire remote sense Kelvin in your HV reg?
Sure, I have shown schematic in the past. As in the other regs. SSHV2 will have as standard, if proven it mixes well. But I will have to go visit a friend that has #26 and horn speakers, and tweak there, compare SSHV installed already, gather opinion etc. Want to keep it comparably low parts count with gains in frequency etc. with no further stages, to can practically give better subjective impression also. A juggling act on trying to surely practically improve on a so widely liked and used circuit, not easy.
Originally Posted by merlin el mago http://www.diyaudio.com/forums/powe...et-hv-shunt-regs-post2714890.html#post2714890
What about the quality of AZ1 Siemens?
Nice Rectifier and good sounding, but I prefer the 5xx versions because they are more practical (socket). If you are looking for more exotic rectifiers have a look at the 80 or 274.
What about the quality of AZ1 Siemens?
Nice Rectifier and good sounding, but I prefer the 5xx versions because they are more practical (socket). If you are looking for more exotic rectifiers have a look at the 80 or 274.
I've been doing some more rigorous testing of my SSHV SPUD Single Feed OPT SET heamp.
With the spud tube (WE417) loaded at 100k (600ohm headphones on the 32 ohm secondary) I can easily output 1V (2.5rms in) with good THD (2H -60dB).
Now when I plug in the 32 ohm headphones on the 32 ohm secondary (equals a 5k load on the tube) well after .5V's and above the distortion get very high (2H -20db by .8v out).
Now 32 ohm headphones don't need .5V's and overall at normal listening levels this thing sounds great but I find it odd that this circuit runs out of steam so fast with the tougher load on the tube.
Could this be related to the undefined SSHV issue with inductive loade? Or is it more likely a transformer or poor operating point issue? Tried what is on the schematic as well as ~150V/15ma/1.8V. My SSHV is set for 40mA and has ~200V in. The second mofset reads about 280F on its tab.
With the spud tube (WE417) loaded at 100k (600ohm headphones on the 32 ohm secondary) I can easily output 1V (2.5rms in) with good THD (2H -60dB).
Now when I plug in the 32 ohm headphones on the 32 ohm secondary (equals a 5k load on the tube) well after .5V's and above the distortion get very high (2H -20db by .8v out).
Now 32 ohm headphones don't need .5V's and overall at normal listening levels this thing sounds great but I find it odd that this circuit runs out of steam so fast with the tougher load on the tube.
Could this be related to the undefined SSHV issue with inductive loade? Or is it more likely a transformer or poor operating point issue? Tried what is on the schematic as well as ~150V/15ma/1.8V. My SSHV is set for 40mA and has ~200V in. The second mofset reads about 280F on its tab.
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If it could oscillate it, you would see a wide spray of harmonic noise across the FFT screen. If that's not happening its highly probable the THD is happening due to the audio amplifying section. But, can it be needing more current to set for such driving conditions?
I don't think it's the shunt reg. My shunt reg (a different design but still shunt reg) works just fine with basically the same circuit as yours using a 6C45P-E.
What will the usual fft on a soundcard show if the tube is oscillating at a few MHz?
What will the usual fft on a soundcard show if the tube is oscillating at a few MHz?