DBX 160a Power transformer

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timtom

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Apr 27, 2016
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My DBX 160a power transformer started to hum annoyingly. I opened the unit and it's called Billion 26-0240 49/ 95.
It has 3 wires going to the board. I measured 23vac between the center and the outer wires, and 47vac between the two outer wires.
I already recapped the 1000uf smoothing caps.

Is there any replacement available?

On the board the voltages labeled +24/-24V and +15/-15V are ok.
 

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Whoops

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Does it work correctly and the problem is only Acoustic Hum or Buzz?

If that's the case,
remove it and dip it 3 times in varnish, let the varnish impregnate.
Normally the acoustic buzz is gone after that
 

timtom

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Apr 27, 2016
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31
Location
Berlin, Germany
Yes it's only acoustic hum or buzz that gets amplified by the housing.
I'll try this out. Otherwise I will replace it with a 2x18v transformer. It should be enough voltage as only the the +24v is used for the leds.
 

Whoops

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Yes it's only acoustic hum or buzz that gets amplified by the housing.
I'll try this out.

Normally that acoustic buzz is the Lams starting to vibrate over time, it starts to happen with some Power transformers with age, where the old varnish just got too dry and breaks.
Impregnate it again is easy and cheap.

if it doesn’t work then that’s also a simple transformer so easy to replace for a new one.

like Scott said excessive current draw can also cause that , plus extra heating, but if you didn’t change anything in the circuit that needs an higher current draw than it’s just normal transformer aging
 
Last edited:

CJ

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Jun 3, 2004
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actually low current draw can make the xfmr hum also. especially a no load situation. the secondary is trying to fight the flux of the primary but it has no current to work with and therefore no counter voltage as per Lenz's Law. This causes the flux created by the primary to soar until the core reaches saturation. When the core saturates, it makes noise.

Sometimes the blocking which goes in between the coil and core in the form of some type of shim made of wood or Glastic can develop excess clearance. So if you re-block the coil with a bigger shim, the hum might stop. if no blocking is used, then it might be a matter of the varnish or air dry epoxy no longer gluing the coil to the core.
 
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