Question re: voltage transformers
- Thread starter sapporo46
- Start date
Retroman839
Senior Member
Is it a laquer on the copper ?
Some of the lawyer de laminates and the vibrato causes the sound ,
Re lawyer could stick the lose back together stopping th esound
Some of the lawyer de laminates and the vibrato causes the sound ,
Re lawyer could stick the lose back together stopping th esound
That's what mine is doing. Seems to settle somewhat after maybe 20 mins or so but it's still noisy. I can't hear anything from the other "doughnut" style one, never have in the 7 years I've had the cab.
cliff_poole
Active member
Loose plates. The core is made of layered thin iron sheets bolted together, or held together with a steel housing. If they are loose, they'll vibrate at 50Hz causing a buzz or hum. It may quieten down after the plates heat up and expand a bit.
If bolted together, you could check if the bolts are loose. I have heard of people applying glue or resin, sometimes this is done in the factory. You'd want some proper advise though before trying anything like that.
If bolted together, you could check if the bolts are loose. I have heard of people applying glue or resin, sometimes this is done in the factory. You'd want some proper advise though before trying anything like that.
Agree with that others say about the noise and delamination of plates etc.
The first one is a toroidal type one, I think they may be newer and can be more efficient, you shouldnt have any issues swapping to one as long as it puts out the same voltages.
The first one is a toroidal type one, I think they may be newer and can be more efficient, you shouldnt have any issues swapping to one as long as it puts out the same voltages.
cliff_poole
Active member
Toriods are generally used where the electronics are sensitive to electro magnetic interference, such as test gear and audio amps. I'd don't remember the physics behind it, but I think the magnetic flux emitted stays much closer to the transformer, so you don't have to leave so much space between the transformer and the circuitry.
Thanks for the useful replies.
If you'll further indulge me - this toroidal transformer looks like it might be suitable.
One of my cabs (with the existing toroidal) has an Electrohome chassis (not sure what voltage that has for input), the other is a Kortek. What would I be looking for from the Voltage and Power options on the eBay listing, given that I likely want 120V output?
Cheers
If you'll further indulge me - this toroidal transformer looks like it might be suitable.
One of my cabs (with the existing toroidal) has an Electrohome chassis (not sure what voltage that has for input), the other is a Kortek. What would I be looking for from the Voltage and Power options on the eBay listing, given that I likely want 120V output?
Cheers
John Bennett
Senior Member
Yep, get some numbers off your existing transformer(s).
If it's not up to the power, with headroom for power-on inrush, it'll saturate and you'll get nothing out of it (well, nothing good).
The laminations in the block transformer are electrically insulated from each other with a coat of varnish (keeps eddy currents down and efficiency up), so with those and the windings, there's a lot of pieces inside a transformer and plenty of scope for something somewhere to vibrate a bit when you put 50Hz mains onto it.
It must be loud to notice it, as arcade machines are normally booming the sound out, if you're doing it properly
.
If it's not up to the power, with headroom for power-on inrush, it'll saturate and you'll get nothing out of it (well, nothing good).
The laminations in the block transformer are electrically insulated from each other with a coat of varnish (keeps eddy currents down and efficiency up), so with those and the windings, there's a lot of pieces inside a transformer and plenty of scope for something somewhere to vibrate a bit when you put 50Hz mains onto it.
It must be loud to notice it, as arcade machines are normally booming the sound out, if you're doing it properly
.
Phils Arcade
Senior Member
Is it definitely the transformer that's creating the noise? If so then as John says above, it's not just the voltage you need to look out for, it's the wattage the transformer can generate on the output. Large heavy duty power transformers do hum, but small ones inside cabs usually don't and you find it coming from interference to the speaker, usually not grounded properly or an additional capacitor needed somewhere.
You can disconnect the transformer and remove it, and apply a fresh coat of laminate or use bees wax. Bees wax is the easiest to get hold of and is simply melted in a double boiler. You dip the transformer, just the block, into the wax and agitate it so to remove as much of the air bubbles as possible. Once done, remove and let sit to allow any access to drip off and harden. You can then connect the transformer to the mains and check the voltages on each of the leads before putting back into the equipment.
If a transformer does vibrate over a long period of time continuously it can generate heat, which can degrade the laminate causing a failure and shorting the transformer.
Very few toroidal transformers, or ordinary transformers for that matter, have enough of the right output voltage/wattage in a single unit and you may find you need a couple, off the shelf , to match the right requirements, or get a second hand one that still works.
You can disconnect the transformer and remove it, and apply a fresh coat of laminate or use bees wax. Bees wax is the easiest to get hold of and is simply melted in a double boiler. You dip the transformer, just the block, into the wax and agitate it so to remove as much of the air bubbles as possible. Once done, remove and let sit to allow any access to drip off and harden. You can then connect the transformer to the mains and check the voltages on each of the leads before putting back into the equipment.
If a transformer does vibrate over a long period of time continuously it can generate heat, which can degrade the laminate causing a failure and shorting the transformer.
Very few toroidal transformers, or ordinary transformers for that matter, have enough of the right output voltage/wattage in a single unit and you may find you need a couple, off the shelf , to match the right requirements, or get a second hand one that still works.
Phils Arcade
Senior Member
Just wondering, is the transformer original to the cab, chassis and power regulator and game PCB? If not then maybe it is being overworked and not rated for the needed power, not voltage.
If you are over driving the transformer then, yes it will hum.
If you are over driving the transformer then, yes it will hum.