I am enjoying some ear deafening oscillation in my Vfet lottery pt.1 amp, at maybe 16kHz, where I can barely hear it, but the rest of the family goes crazy. It starts after the amp has been on for about three hours. It started doing this after I connected a pair of JBL 2169H and a pair Renkus-Heinz SSD 3301 compression driver. The Renkus-Heinz driver has been connected many times before with no issue. The newest addition to the signal chain is a 15uf protection cap on the Renkus-Heinz driver, the only passive crossover component. And the JBL 2169H. Both pairs are highpassed from 210Hz electronically via minidsp.
I have used the amp for 9 months with no problem. Maybe some really high pitched sinus tones, but nothing like this.
I have used the amp for 9 months with no problem. Maybe some really high pitched sinus tones, but nothing like this.
I can turn it on again, wait 3 hours and see what happens when I disconnect one of the drivers.
If I turn off the amp and on again in a minute, the problem disappears.
I have another PSU I can try as well. Always double up.
The speakers current tweeterless configuration:
I did not notice if it was both channels, but I think so since the highpitched noise had excellent soundstage.
I think so, but I changed the PSU, and I have not experienced the loud ringing in five hours now.
I am not putting the defective PSU back to verify.
The faint (to me) noise that is still there after switching PSU is similar to the coil whine I got from a Philips Hue Led strip when I connected two lengths of strips to the same Philips Hue SMPS. You can do that, according to the manual, but it resulted in an annoying coil whine that filled the room, and I had to buy an extra Philips Hue SMPS to make it go away.
It is difficult for me to place if it is coming from the speakers or the V-FET SMPS, because it just fills the room. Mostly annoying to my girlfriend, who thanked me tonight when shutting it off after an eight hour "stress test" with no more oscillation sounds with the new SMPS. But with a lot of coil whine that I can choose to ignore, but others with less worn ears cannot.
That is why I want to move away from a PSU with a coil, not meaning to be rude to Mark Johnson and his Tuba. The Tuba will most likely be too complicated for my skill level anyway. But if the Tuba uses two SMPS then they will endure half the load and have less to whine about, just like my Philips Hue light strip SMPS.
It is difficult for me to place if it is coming from the speakers or the V-FET SMPS, because it just fills the room. Mostly annoying to my girlfriend, who thanked me tonight when shutting it off after an eight hour "stress test" with no more oscillation sounds with the new SMPS. But with a lot of coil whine that I can choose to ignore, but others with less worn ears cannot.
That is why I want to move away from a PSU with a coil, not meaning to be rude to Mark Johnson and his Tuba. The Tuba will most likely be too complicated for my skill level anyway. But if the Tuba uses two SMPS then they will endure half the load and have less to whine about, just like my Philips Hue light strip SMPS.
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Hi, if it is 16KHz, then I think it is not SMPS related. Most SMPS's oscillate at more than 30 KHz. Since 16KHz is within the audio range, I strongly suspect the amplifier. Most probably the inductive/capacitive loads of the speakers are causing oscillations. Some sort of correction has to be introduced in the negative feedback path within the amplifier, IMHO
I think I have narrowed it down. It is the damn Nutube Korg B1 Triode preamp that is ringing from the music that I am playing. It is a known issue with the preamp. It is ringing for a minute after closing the music, so not obvious at first. But the sound did improve when switching to new PSU for both the Sony V-Fet Lottery P-channel amp and the B1 Triode preamp. I will order some butyl and sorbathane to try and dampen it. The horns make it worse I think. I don’t know if it can ring from the speaker membrane acting like a microohone, or from vibrating the aluminium chassis. Most likely both. I love the sound so much that I have two finished B1 Triode preamps and another to build, but if I can’t dampen it somehow I will have to sell them.
I wa
I was clever enough to solder the nutubes pins to 4cm wires and then hang it in silicone. Didn’t help. Then it fell down. But butyl and sorbathane are on the way!