I dont know your son but it might be interesting to know if the buffer was turned on and giving any signal. But you have probably just installed a cheap Ikea switched diode lamp😉
Btw who has left a crooked light sabre on the floor?
Btw who has left a crooked light sabre on the floor?
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After short history lesson about Spanish Inquisition to my son, the Buffer was On. No signal ran through.
🙂, no lamp yet! But I have a plan to buy one and replace switch supply to linear one.
That light is iPhone camera flash reflection from Acoustic Zen Silver interconnects cables braid. 🙂
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🙂, no lamp yet! But I have a plan to buy one and replace switch supply to linear one.
That light is iPhone camera flash reflection from Acoustic Zen Silver interconnects cables braid. 🙂
Sent from my iPhone using Tapatalk
Acoustic Zen. Sounds dangerous. Ok then I think we need to isolate the problem to a devise first. Is it the FSP and nothing else?
It is FSP 100%, since everything else is quite when I tun FSP PSU off.
Now is the question, if it is FSP itself or its its PSU... If noise will be present today too, I'll replace circuit in PSU. I still ave one RAW DC board from my old-first FSP build.
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Now is the question, if it is FSP itself or its its PSU... If noise will be present today too, I'll replace circuit in PSU. I still ave one RAW DC board from my old-first FSP build.
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Some electrostatics might have shocked something. But more likely a bad joint (solder) whilst twisting those RCA from hell. Never use them.
I would check the TP1-TP2 reading is in place first. If not in place re-adjust. Maybe higher Rs resistors are needed if it has wandered too much.
They also damp the input stage better. Then if noises insist it takes an oscilloscope on the rails to exclude spurious noises are happening there.
Joints check are high on the list also as Stajo mentioned. Especially if connectors are used for the signal cabling. Check with OHM meter and redo the screws.
They also damp the input stage better. Then if noises insist it takes an oscilloscope on the rails to exclude spurious noises are happening there.
Joints check are high on the list also as Stajo mentioned. Especially if connectors are used for the signal cabling. Check with OHM meter and redo the screws.
I see. I'll check TPs first. I do have analog and digital scopes and to see the noise will be not a problem. So far, I'm equipped to make my evening interesting and buzzy. Do not have screw terminals on that build. All wires are soldered to the PCB. I'll update you soon.
Thank you a lot for your help.
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Thank you a lot for your help.
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Checked TPs and they was little off. Adjusted according to procedure. Replaced RCAs and check all solder points. All good and that point was low chance since both camels are show noise. Noise is still there and disappears quickly now after TPs adjustment. 5-6 min and till TP reaches about 3.2V during heat up. DC in is 49.6v. B+ is 34.8v. Did not have a time to use scope. Do it over the weekend. Recorded noise, if that info is valuable...Can send it to your email. Volume is max and mic is 29 cm from speaker. Please check your emails.
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Is the noise still present when you short the inputs to ground?
Yes.
Noise is here. Can't send such file to PMs. Just change file extension to *.m4a
Frankenstein's HV Lab noises until warmed up. 😕
If its not Aliens, HAARP, The Russians, etc. then maybe some instability in the high gm Fets during warm up which makes them pick or emit things. Why it wasn't there before in the same build? Puzzling. Have I ever heard it before? No. Remembering it ever reported in the many FSP builds? No. Anybody else here who have heard it, please let us know.
What I would do after seeing on the scope that its not coming from/through the Kean multiplier or the integrated shunt PSU, is I would scope the signal path itself to see if it really comes from the first stage and not the second stage or the buffer. They warm up too. If its indeed the input stage as most likely because your adjusting the TP changed the time duration of the anomaly, I would first remove minisinks if using. Then if nothing changes, I would make the Rs resistors 25% higher and readjust. If no good result again, I would replace the input JFETS or put very small ferrite ring around their gate pins first if having any.
Oscillation instability type noises for sure but where and why of short duration in his build remains to be pinpointed first
Hair raising thoughts you are making there Staffan 😀
An externally hosted image should be here but it was not working when we last tested it.
I do think it sounds like it picks up something in the warmup startup. Its very similar to sounds that can occur when tubes warm up looking for its bias.
I heard similar noises from an old Pioneer amp that I repaired recently. It could be an intermittent transistor fault, these are really hard to spot and they usually tend to be more ...."crackly" sounding.
If you have a scope, you can trace the signal path from end to start, to see which device the noise is coming from. If you're lucky you'll find the offending transistor. Otherwise you can use the brutal force approach which would be to replace a bunch of them and see what happens... (it worked on the Pioneer!!!)
If you have a scope, you can trace the signal path from end to start, to see which device the noise is coming from. If you're lucky you'll find the offending transistor. Otherwise you can use the brutal force approach which would be to replace a bunch of them and see what happens... (it worked on the Pioneer!!!)
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