Yamaha AX-500

clapster · 16th January 2007, 06:06 PM

Hi There

Ive been given a Yamaha AX-500 Amplifier but the power transformer is not working . Ive tried getting hold of an original transformer with no luck . Does anybody know of any other transformer that can be used in this amplifer .

Thanks Clapster

anatech · 16th January 2007, 08:58 PM

Hi Clapster,
Hmmm, you do like to have transformer issues, don't you?

You will need two transformers. One will give you your + - 60 V rails (?) and the other for your low voltage stuff. I don't know off-hand what the ratings are.

-Chris

clapster · 16th January 2007, 09:22 PM

Hi There Chris

I must admit , it does look a bit bad on the transformer issue , he he he , what are the chances of been given an amplifier with the exact problem as the one you have . Ive been told that this Yamaha amplifier is a very good bit of kit ( when its working ) .
Ive checked the transormer myself and i can read the high voltage but there are no low voltage readings .The transformer seems to be a bit more complicated than that of the Rotel because it is linked to a voltage selector switch at the rear.Would you be able to bypass this switch all together and use a 220v trasformer as we do not use 110v here .I hope this makes scence as im quite new to this sort of thing .

Thanks Clapster

XEAGLEKEEPER · 16th January 2007, 10:14 PM

clapster
Have you tried( Partstore.com ) . I did a brief search and found a mains power transformer for a AX-596,AX-550 and a RXV-396 maybe one of those might be in your ballpark!
I see no problem by-passing the selector switch if the unit is for your own personel use. I had to do that to a Yamaha CDX-930 I could get a 120 vac only I couldn't find a multi-voltage transformer.
Dave

anatech · 16th January 2007, 10:59 PM

Hi Clapster,
Does the primary have a resistance reading? I have seen bad voltage selectors before as well. The secondaries may possibly short, but I doubt they would go open.

So, if you have primary continuity, measure the AC voltages on the secondaries.

This on also may burn out the 22R fuse resistor on the negative rail to front end supply, I believe they sub it with a 4R7 now, flameproof.

-Chris

clapster · 17th January 2007, 08:46 PM

Hi There

Do you think a 55V+55V 225 TOROIDAL TRANSFORMER would do the trick in this amplifer .

Many Thanks Clapster

anatech · 17th January 2007, 08:48 PM

Hi Clapster,
I'd use an EI transformer if I were you. Just compare the core size for the correct wattage.

-Chris

clapster · 17th January 2007, 09:02 PM

Hi There Chris

Are you suggesting me using an EI Transformer due to the fact that the amplifier has a voltage selector switch or is it due to another reason . Sorry for all the questions but this is all so very new to me , until 2 weeks ago i did not even know what the inside of an amplifer looked like . I must say though that this forum is brilliant as what i have learnt in this short space of time from the likes of people such as yourself and many others is great and much appreciated .

Many Thanks Clapster

anatech · 18th January 2007, 12:44 AM

Hi Clapster,

Quote:

Are you suggesting me using an EI Transformer due to the fact that the amplifier has a voltage selector switch or is it due to another reason .

Better line garbage rejection. There is nothing wrong with EI transformers and they are often passed over due to fads. The original was an EI, right?

-Chris

clapster · 18th January 2007, 07:28 AM

Hi There Chris

Yes the original one is a EI Transformer . Do you by any chance know of a webiste were i can do some reading up on transformers to get a better understanding of all the technical bits that one needs to know ie: rail voltage , wattage etc.

Kind Regards

16th January 2007, 06:06 PM	#1
clapster diyAudio Member Join Date: Jan 2007	Yamaha AX-500 Hi There Ive been given a Yamaha AX-500 Amplifier but the power transformer is not working . Ive tried getting hold of an original transformer with no luck . Does anybody know of any other transformer that can be used in this amplifer . Thanks Clapster

16th January 2007, 10:14 PM	#4
XEAGLEKEEPER diyAudio Member Join Date: Jan 2006 Location: central Iowa	clapster Have you tried( Partstore.com ) . I did a brief search and found a mains power transformer for a AX-596,AX-550 and a RXV-396 maybe one of those might be in your ballpark! I see no problem by-passing the selector switch if the unit is for your own personel use. I had to do that to a Yamaha CDX-930 I could get a 120 vac only I couldn't find a multi-voltage transformer. Dave __________________ Ret. USAF... AKA- Avionic * Solder slinger for hire...*

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16th January 2007, 08:58 PM	#2
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	Hi Clapster, Hmmm, you do like to have transformer issues, don't you? You will need two transformers. One will give you your + - 60 V rails (?) and the other for your low voltage stuff. I don't know off-hand what the ratings are. -Chris

16th January 2007, 09:22 PM	#3
clapster diyAudio Member Join Date: Jan 2007	Hi There Chris I must admit , it does look a bit bad on the transformer issue , he he he , what are the chances of been given an amplifier with the exact problem as the one you have . Ive been told that this Yamaha amplifier is a very good bit of kit ( when its working ) . Ive checked the transormer myself and i can read the high voltage but there are no low voltage readings .The transformer seems to be a bit more complicated than that of the Rotel because it is linked to a voltage selector switch at the rear.Would you be able to bypass this switch all together and use a 220v trasformer as we do not use 110v here .I hope this makes scence as im quite new to this sort of thing . Thanks Clapster

16th January 2007, 10:59 PM	#5
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	Hi Clapster, Does the primary have a resistance reading? I have seen bad voltage selectors before as well. The secondaries may possibly short, but I doubt they would go open. So, if you have primary continuity, measure the AC voltages on the secondaries. This on also may burn out the 22R fuse resistor on the negative rail to front end supply, I believe they sub it with a 4R7 now, flameproof. -Chris

17th January 2007, 08:46 PM	#6
clapster diyAudio Member Join Date: Jan 2007	Hi There Do you think a 55V+55V 225 TOROIDAL TRANSFORMER would do the trick in this amplifer . Many Thanks Clapster

17th January 2007, 08:48 PM	#7
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	Hi Clapster, I'd use an EI transformer if I were you. Just compare the core size for the correct wattage. -Chris

17th January 2007, 09:02 PM	#8
clapster diyAudio Member Join Date: Jan 2007	Hi There Chris Are you suggesting me using an EI Transformer due to the fact that the amplifier has a voltage selector switch or is it due to another reason . Sorry for all the questions but this is all so very new to me , until 2 weeks ago i did not even know what the inside of an amplifer looked like . I must say though that this forum is brilliant as what i have learnt in this short space of time from the likes of people such as yourself and many others is great and much appreciated . Many Thanks Clapster

18th January 2007, 07:28 AM	#10
clapster diyAudio Member Join Date: Jan 2007	Hi There Chris Yes the original one is a EI Transformer . Do you by any chance know of a webiste were i can do some reading up on transformers to get a better understanding of all the technical bits that one needs to know ie: rail voltage , wattage etc. Kind Regards