Toroidal Transformers - OEM Replacements Vs None OEM

[martins8585]

 

[martins8585]

Hi - I hope I'm not doubling up on the PSU thread below but I'd like some advice on replacing the transformer in my amp.

I've got a Parasound A23 which I picked up 2nd hand and although I love the sound it does have an annoying hum from the transformer. (Tried all the usual tricks, tightened restraining bolt, put some rubber sheet under the transformer etc)

I've been quoted £200 for an OEM transformer however my local TV repair shop have said they can source a none OEM transformer that will supply the correct voltages etc for around £90.

Knowing nothing about electronics (apart from it's not a good idea to make toast in the bath......) is there anything to be gained from buying the OEM part vs the cheaper option?

Many thanks.

 

[Overdose]

Knowing nothing about electronics (apart from it's not a good idea to make toast in the bath......) is there anything to be gained from buying the OEM part vs the cheaper option?

No, not really. Providing the replacement transformer is of the same specification, it will be fine and a whole lot cheaper too.

 

[Al ears]

Hi - I hope I'm not doubling up on the PSU thread below but I'd like some advice on replacing the transformer in my amp.

I've got a Parasound A23 which I picked up 2nd hand and although I love the sound it does have an annoying hum from the transformer. (Tried all the usual tricks, tightened restraining bolt, put some rubber sheet under the transformer etc)

I've been quoted £200 for an OEM transformer however my local TV repair shop have said they can source a none OEM transformer that will supply the correct voltages etc for around £90.

Knowing nothing about electronics (apart from it's not a good idea to make toast in the bath......) is there anything to be gained from buying the OEM part vs the cheaper option?

Many thanks.

I would have to say yes.

As the other PSU thread indicates the whole amplifier was built around that PSU . If you replace it with a non OEM version, irrespective of identical outputs etc., you may not get the same sound you are use to.

Was the quote of £200 from Parasound themselves?

Not knowing the price of this amp new I would suggest if you are happy with it then get them to service it.

If not flog it on rather than fit a non OEM version.

 

[Overdose]

Hi - I hope I'm not doubling up on the PSU thread below but I'd like some advice on replacing the transformer in my amp.

I've got a Parasound A23 which I picked up 2nd hand and although I love the sound it does have an annoying hum from the transformer. (Tried all the usual tricks, tightened restraining bolt, put some rubber sheet under the transformer etc)

I've been quoted £200 for an OEM transformer however my local TV repair shop have said they can source a none OEM transformer that will supply the correct voltages etc for around £90.

Knowing nothing about electronics (apart from it's not a good idea to make toast in the bath......) is there anything to be gained from buying the OEM part vs the cheaper option?

Many thanks.

I would have to say yes.

As the other PSU thread indicates the whole amplifier was built around that PSU . If you replace it with a non OEM version, irrespective of identical outputs etc., you may not get the same sound you are use to.

Was the quote of £200 from Parasound themselves?

Not knowing the price of this amp new I would suggest if you are happy with it then get them to service it.

If not flog it on rather than fit a non OEM version.

Replacing the transformer with a different unit that meets spec is not going to change how the amplifer sounds.

 

[eggontoast]

It would make absolutely no difference what so ever. £90 still sounds expensive, what is the spec of the transformer ?

 

[martins8585]

Thank you for your posts.

To cover them all:

RRP - the amp retails at £995

The quote of £200 was to supply not to fit. (I'm guessing with couriering to their approved repairers + labour it wouldn't be far off £400 That's why I was looking at a local repairer as I'm no expert but replacing the transformer wouldn't seem beyond the skils of most competent electrical repairers)

The only specs I'm certain of is it's a 1 KVA transformer - wont know the rest till someone checks the outputs.

I'm not keen on selling it on as a) It's improved the SQ when listening in stereo (I've got an AV biased set up) and if i did I'd want the new owner to be 100% happy.

Being new to the world of Hifi I don't want to waste money if an OEM won't make any difference but I also don't want to ruin a good amp.

Thanks again.

 

[abacus]

Very few transformers are built by Hi Fi manufactures, most are bought in from 3rd party suppliers and the manufacture just stamps their name on it.

I would be more concerned with finding out what caused it to malfunction in the first place. (If it was a bad design of power supply then changing the transformer may not make a difference)

Hope this helps

Bill

 

[Electro]

Hi - I hope I'm not doubling up on the PSU thread below but I'd like some advice on replacing the transformer in my amp.

I've got a Parasound A23 which I picked up 2nd hand and although I love the sound it does have an annoying hum from the transformer. (Tried all the usual tricks, tightened restraining bolt, put some rubber sheet under the transformer etc)

I've been quoted £200 for an OEM transformer however my local TV repair shop have said they can source a none OEM transformer that will supply the correct voltages etc for around £90.

Knowing nothing about electronics (apart from it's not a good idea to make toast in the bath......) is there anything to be gained from buying the OEM part vs the cheaper option?

Many thanks.

There is a possibility that there is nothing wrong with your transformer and the hum could be caused by DC on the mains .

If there is DC on you mains supply then changing the transformer might make no difference and you will still have the hum .

This is a useful article that explains more about DC on the mains supply and the problems it can cause .

http://sound.westhost.com/articles/xfmr-dc.htm

You could try a DC blocker like this one and see if it cures the problem .

http://www.mains-cables-r-us.co.uk/mains-cables-/332-the-excelium-dc-blocker-.html

It would be ideal if you could try one before you buy it and there may be cheaper versions than this one if you shop around .

 

[martins8585]

Hi Bob – thanks for your comments.

Although I’m new to the Hifi world I’ve played guitars for 20 odd years so have seen how when it comes to parts the word “custom” usually means bulk bought off an existing supplier, rebadged and the spun as a custom, bespoke design component..........

The amp is a little tatty, (scratched top casing etc) so as must reviews I’ve read suggest it’s a well designed amp with a good power supply my thoughts are it’s been damaged through mishandling.

 

[martins8585]

Thanks Electro - I did think it could be a DC problem as a) I live in a flat and b) my listening room is lounge / kitchen so there's lots of potential probs around it however I did take it to my local hifi emporium (not a Pararsound dealer but very helpful) and it hummed there to.

 

[andyjm]

Hi - I hope I'm not doubling up on the PSU thread below but I'd like some advice on replacing the transformer in my amp.

I've got a Parasound A23 which I picked up 2nd hand and although I love the sound it does have an annoying hum from the transformer. (Tried all the usual tricks, tightened restraining bolt, put some rubber sheet under the transformer etc)

I've been quoted £200 for an OEM transformer however my local TV repair shop have said they can source a none OEM transformer that will supply the correct voltages etc for around £90.

Knowing nothing about electronics (apart from it's not a good idea to make toast in the bath......) is there anything to be gained from buying the OEM part vs the cheaper option?

Many thanks.

Toroidals are tougher to wind than a normal E I stamping transformer and do seem to suffer from hum. Hum is caused by either the windings or the core laminations vibrating, and can be easily fixed during manufacturing by coating the laminations and windings with resin. Guess that would add to the cost though.

Contrary to the view of other posts on this thread, a transformer is a transformer, and if the replacement has the same spec as the one that hums, it will do just fine. £90 is a lot for a transformer - even a toroidal. It depends on the rating but looking at the RS website, £45 gets you a generic 500VA toroidal, and RS aren't known as a discounter.

Given that the hum doesn't impact the ability of the transformer to transform, can't you just put the amp in a cupboard?

Edit: Just read that its a 1KVA, that ups the price a bit. By the time you have paid VAT and delivery, perhaps £90 isn't too unreasonable. Frustrating thing is you just know Parasound paid $20 each from a nice man in China for the original..