Hi!
I have using a 200VA transformator 2x18V with a capacitance multiplikator, JLH updated (2003) class A amp.
The transformer has after 18 years heavy use, startade to make intermittent (now and again) sound - ”Boing”.
Anyone, what is causing this Boing? Is it foreboding a failure?
Thanks in advance
Sigge
I have using a 200VA transformator 2x18V with a capacitance multiplikator, JLH updated (2003) class A amp.
The transformer has after 18 years heavy use, startade to make intermittent (now and again) sound - ”Boing”.
Anyone, what is causing this Boing? Is it foreboding a failure?
Thanks in advance
Sigge
Check the cap multiplier output capacitor, it could be bad.
They need the output capacitor in order to be stable.
They need the output capacitor in order to be stable.
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Thanx for your answers!
I do have Sjöströms DCT02 dc filter for toroidal transformers.
The cap mult design is based on Rod Elliots ”A Simple Capacitance Multiplier Power Supply For Class-A Amplifiers”. Left and right channel has one mult cap each. Both sides make ”Boings”.
However, in my mult caps the output cap is increased from 1000uF to 4700uF - since it sounds better.
I just now measured the caps for one of the channels with my multimeter to about 4700uF.
I do have Sjöströms DCT02 dc filter for toroidal transformers.
The cap mult design is based on Rod Elliots ”A Simple Capacitance Multiplier Power Supply For Class-A Amplifiers”. Left and right channel has one mult cap each. Both sides make ”Boings”.
However, in my mult caps the output cap is increased from 1000uF to 4700uF - since it sounds better.
I just now measured the caps for one of the channels with my multimeter to about 4700uF.
Wait, are you saying that the power transformer itself makes a BOING sound, acoustically?
Or is the boing sound through the speakers?
That sound, if acoustical, could be a high current inrush in the transformer upon power up.
Is that when it happens, or is it random?
Or is the boing sound through the speakers?
That sound, if acoustical, could be a high current inrush in the transformer upon power up.
Is that when it happens, or is it random?
The Boing is not generated during power up, it is ”boing-ing” randomly while listening to music. Quite annoying…
Interesting! I also have a simple DC blocker of the Rod Elliot ESP variety which I made to cure quick growls ("boings") in toriodals, which worked.
But just yesterday I was playing a new-to-me old Adcom amp, and it was making slowly growing and fading growls, just physically from the transformer, not in the speakers. So I disconnected the input RCA cables, and the noise stopped happening, and now with a different set of interconnects, the growling hasn't come back.
IME the cheap toriodal transformers Adcom used can magnetically couple (??) with the steel case and make a touchy transformer even worse, and I've improved another noisey Adcom transformer by spacing it off the chassis...
And you already use a DC blocker, right?
Sometimes the internal electrolytic capacitors in the DC blocker do wear out, and must be replaced.
Did the DC blocker at first seem to prevent the noises, and later not prevent them?
Sometimes the internal electrolytic capacitors in the DC blocker do wear out, and must be replaced.
Did the DC blocker at first seem to prevent the noises, and later not prevent them?
Yes, I use a DC blocker.
The boings started a couple of years ago. Can’t remember their age. They are probably something like 5-10 years old. So, it started when they probably were 3-8 years old.
How long can these electrolyte caps last? Can I check their status?
The boings started a couple of years ago. Can’t remember their age. They are probably something like 5-10 years old. So, it started when they probably were 3-8 years old.
How long can these electrolyte caps last? Can I check their status?
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Have you connected your sacrificial speakers yet?
In the ESP article on DC blockers he describes measuring the 'DC' offset.
Just seems extremely unlikely for a passive Sjöström device to stop working. What happens if you bypass the DC blocker? Is it a worse sound? And it's so loud that it's heard over the music? And regular and often?
In the ESP article on DC blockers he describes measuring the 'DC' offset.
Just seems extremely unlikely for a passive Sjöström device to stop working. What happens if you bypass the DC blocker? Is it a worse sound? And it's so loud that it's heard over the music? And regular and often?