I've got a B+K AV5000 power amp from the US, runs on 110 60Hz AC power. Now I have moved to china (220V 50Hz), and the thing keeps blowing the circuit breaker when I plug it into the step down transformer.
Can someone tell me if it is easy to convert to 220 power? Or should I just try to sell it an buy something locally?
TIA.
Can someone tell me if it is easy to convert to 220 power? Or should I just try to sell it an buy something locally?
TIA.
Unless the power transformer inside the unit can be rewired for 230V operation, then no.
Easiest way to tell, open the unit and find out if there are 2 primary wires or 4. If there are 4 and they are wired in parallel at the moment, then they can be wired in series for 230V use. If there are only 2, then the transformer is only designed for 120V input.
I'm assuming here that you are familiar enough with electronics to be able to do this. If not, then sell it and buy a new amp.
Easiest way to tell, open the unit and find out if there are 2 primary wires or 4. If there are 4 and they are wired in parallel at the moment, then they can be wired in series for 230V use. If there are only 2, then the transformer is only designed for 120V input.
I'm assuming here that you are familiar enough with electronics to be able to do this. If not, then sell it and buy a new amp.
Most likely you won't have 2 separate 120V windings connected in parallel (that you could connect in series to make 240V). That wold be to easy (just take care of the proper phasing) 
You have 2 options:
1. Open the amp, remove the transformer, rewire the primary coil (double the number of turns with a smaller wire). Reinstall the transformer.
2. Use a down-converter autotransformer or transformer with the size appropriate for the maximum power written on your amplifier.
You cannot use "converters" that have solid state devices inside, you need transformers (heavy, massive iron core and copper windings thingies).
You have 2 options:
1. Open the amp, remove the transformer, rewire the primary coil (double the number of turns with a smaller wire). Reinstall the transformer.
2. Use a down-converter autotransformer or transformer with the size appropriate for the maximum power written on your amplifier.
You cannot use "converters" that have solid state devices inside, you need transformers (heavy, massive iron core and copper windings thingies).
SoNic_real_one said:Most likely you won't have 2 separate 120V windings connected in parallel (that you could connect in series to make 240V). That wold be to easy (just take care of the proper phasing)
You have 2 options:
1. Open the amp, remove the transformer, rewire the primary coil (double the number of turns with a smaller wire). Reinstall the transformer.
2. Use a down-converter autotransformer or transformer with the size appropriate for the maximum power written on your amplifier.
You cannot use "converters" that have solid state devices inside, you need transformers (heavy, massive iron core and copper windings thingies).
That really is not very smart advice!
1) suggesting that unskilled people rewind a power transformer is daft and dangerous!
2) OP has already stated that it blows te breaker on his autotransformer.
The manual can be found here
easily found in Google and it includes info that the line voltage is switchable. So open the lid and look for jumpers, switches.
From page 11 in the above posted pdf file:
Line voltage 120/220/240 VAC switchable
There is probably a simple switch inside....worst case you will have to desolder and resolder a couple of connections on the AC side of the transformer.
If you don's see a switch...look on the side of the transformer for a wiring diagram. If there is no diagram, I bet the transformer has some sort of ID/reference number on it.
Don't make it a complicated thing....if all else fails...call the manufacturer.
Line voltage 120/220/240 VAC switchable
There is probably a simple switch inside....worst case you will have to desolder and resolder a couple of connections on the AC side of the transformer.
If you don's see a switch...look on the side of the transformer for a wiring diagram. If there is no diagram, I bet the transformer has some sort of ID/reference number on it.
Don't make it a complicated thing....if all else fails...call the manufacturer.
mixersoft said:
If the amplifier does not have a switch on the back indicating 110/220v it's quite unlikely it will be bi-voltage. All amplifiers released in the US are only 110v, probably because a transformer for two voltages would be difficult to design and not compromise the amp output.
Look on the back if there's a plate with the amp consumption, in amps or watts. The step down transformer should be equal or exceed that number.
Hi all,
Thanks for your input. Here's what I know
red ----- [+] --- + ----red -----) ( -------
+ ----white --) (
) (
120V open ---- gray -----) (
) (
+ --- black ----) (
black ---- [-] --- + --- brown --) (------
From the notes above, I suspect there are 2 primary coils wired in parallel, with the gray wire going currently connected to nothing. I am going to try to borrow a voltage meter to confirm this.
But can someone help me confirm that to make the switch to 220V, I just wire the 2 coils in series? Also, I'm not sure how to deal with the phase issue.
Assuming Red/Black is one coil and White/Brown is another coil, do I just connect Black+Brown or something like that?
Many thanks for your help
Thanks for your input. Here's what I know
- I have the AV5000 series 1, the sticker on the back says 120vac 60Hz
- I called the mfg, and tech support said any "service center" could switch it to 220v, but they have are no service centers outside of the US. He was reluctant to say any more to an end user like me
- I opened up the amp and the primary coil of the transformer has 5 wires connected as follows:
red ----- [+] --- + ----red -----) ( -------
+ ----white --) (
) (
120V open ---- gray -----) (
) (
+ --- black ----) (
black ---- [-] --- + --- brown --) (------
From the notes above, I suspect there are 2 primary coils wired in parallel, with the gray wire going currently connected to nothing. I am going to try to borrow a voltage meter to confirm this.
But can someone help me confirm that to make the switch to 220V, I just wire the 2 coils in series? Also, I'm not sure how to deal with the phase issue.
Assuming Red/Black is one coil and White/Brown is another coil, do I just connect Black+Brown or something like that?
Many thanks for your help
the phase issue and any other mistakes in re-wiring can be addressed safely by using a light bulb tester between the mains socket outlet and the modified equipment mains plug top.
If the bulb lights, the equipment has been wired wrongly.
If the bulb flashes briefly and goes off then check you have 220Vac at the input of the equipment and that you have the correct voltage at the secondaries.
Once you know that all is OK, plug the modified equipment direct to the mains socket outlet.
If the bulb lights, the equipment has been wired wrongly.
If the bulb flashes briefly and goes off then check you have 220Vac at the input of the equipment and that you have the correct voltage at the secondaries.
Once you know that all is OK, plug the modified equipment direct to the mains socket outlet.
I don't know the answer to that. Is 60 vs. 50Hz a big issue for a power amp? I thought that was only and issue for electric motors. I will wait for an answer on this one.
BTW, my line "diagram" didn't survive the posting, so I am uploading a photo showing the 5 leads from the transformer primary connect to the AC mains.
Is it reasonable to assume that when set for 110V, those are dual primary windings, connected in parallel and in phase?
BTW, my line "diagram" didn't survive the posting, so I am uploading a photo showing the 5 leads from the transformer primary connect to the AC mains.
Is it reasonable to assume that when set for 110V, those are dual primary windings, connected in parallel and in phase?
An externally hosted image should be here but it was not working when we last tested it.
Yes, the two other terminal blocks are empty, and the 5th gray wire from the transformer is also connected to an empty block.
I also did try to contact B+K, but they were not too forthcoming, other than to say a service center could easily do it.
But I can check for a model number on the transformer. Is this to check if it will support 50Hz power?
I also did try to contact B+K, but they were not too forthcoming, other than to say a service center could easily do it.
But I can check for a model number on the transformer. Is this to check if it will support 50Hz power?
I have confirmed with a DMM that Black+Orange is one winding and Brown+White is a 2nd winding. So my guess is that if I tie Brown+Orange together then Black+White will be 2 windings in series.
Can someone post a link to instructions on how to build a lightbulb tester? I've searched under "light bulb tester", but get lots of threads, but no actual instructions.
thx.
Can someone post a link to instructions on how to build a lightbulb tester? I've searched under "light bulb tester", but get lots of threads, but no actual instructions.
thx.
BTW, I just spoke to B+K and they flat out refused to share any information with me about the part no. for the transformer or the 220V conversion -- because I was a customer. They said they would only talk with a "service center" - I assume by that they mean a professional.
Anyone here interested in calling them for me?
Anyone here interested in calling them for me?
I just tested 220V with a light bulb tester, got an unexpected result. The test was done with the Amp standing alone, i.e. not speakers connected, no input.
The amp has a Cntrl-IN switch so the amp is on when the switch is on AND when 12v is applied to the input from the pre-amp. With this switch ENABLED, the bulb glowed for a few seconds, then turned off.
HOWEVER, when I defeated this switch, so the amp is on when the switch is on, the bulb stayed lit. The power on LED on the amp was glowing.
I tried reversing the 2nd primary winding, but in that case the light bulb lit no matter what position the Cntrl-IN switch was set to.
What does this mean? and should I be doing this test with speakers attached and/or an input signal?
thanks.
The amp has a Cntrl-IN switch so the amp is on when the switch is on AND when 12v is applied to the input from the pre-amp. With this switch ENABLED, the bulb glowed for a few seconds, then turned off.
HOWEVER, when I defeated this switch, so the amp is on when the switch is on, the bulb stayed lit. The power on LED on the amp was glowing.
I tried reversing the 2nd primary winding, but in that case the light bulb lit no matter what position the Cntrl-IN switch was set to.
What does this mean? and should I be doing this test with speakers attached and/or an input signal?
thanks.
I would perform ALL testing with the transformer secondaries DISCONNECTED from the rest of the circuit!
That way, if you make an error, it doesn't cost you the amp.
Out of the transformer should be a voltage somewhat less than the main filter caps from center tap to one of the primary leads.
So lets just say the secondary has 3 wires..... the one wire of different color from the other two is the center tap. The voltage from the center tap, or CT to one of the other secondary leads will be half that of the voltage across the two primary leads.
You MUST verify that the secondary voltage is reasonable before turning it on.
That way, if you make an error, it doesn't cost you the amp.
Out of the transformer should be a voltage somewhat less than the main filter caps from center tap to one of the primary leads.
So lets just say the secondary has 3 wires..... the one wire of different color from the other two is the center tap. The voltage from the center tap, or CT to one of the other secondary leads will be half that of the voltage across the two primary leads.
You MUST verify that the secondary voltage is reasonable before turning it on.