Hi All,
Fairly basic question, the transformer in my old active wharfedale diamonds is buzzing away quite loudly. I've been told this is due to coil delamination, which makes sense. However, rather than go through the whole "Bake it in the oven, relaminate the coils" palaver I'd like to buy a more modern, more efficient and more importantly quieter transformer.
My multimeter appears to be dying and I can't get a VDC reading from the old transformer output. Anyone know where I can find a suitable replacement?
Thanks in advance,
Ethan
Fairly basic question, the transformer in my old active wharfedale diamonds is buzzing away quite loudly. I've been told this is due to coil delamination, which makes sense. However, rather than go through the whole "Bake it in the oven, relaminate the coils" palaver I'd like to buy a more modern, more efficient and more importantly quieter transformer.
My multimeter appears to be dying and I can't get a VDC reading from the old transformer output. Anyone know where I can find a suitable replacement?
Thanks in advance,
Ethan
I would have thought that it would be fairly easy to find a replacement. I have a pair of active diamonds in the loft. If you are not able to find the voltage of the secondary's I will take a trip to the loft.
I don't know what my multimeter's playing at. On it's 2.5V DC setting, the needle flicks to it's maximum and bounces. So I switch it up to 10V DC, and it only twitches slightly.
Transformers output AC, that's probably why you are not getting a reading.
Be aware that transformer technology, well at least for the kind of use we have, has not changed in the last 20 years or more. So you are just going to be replacing like for like really, unless there is room in there for a bigger transformer and caps.
Be aware that transformer technology, well at least for the kind of use we have, has not changed in the last 20 years or more. So you are just going to be replacing like for like really, unless there is room in there for a bigger transformer and caps.
I'm a 3rd year Systems Engineer. And I was trying to measure DC output from a mains-fed transformer.
*Bangs head on desk*
*Bangs head on desk*
Right, it's reading 27V between the two ends, and 15V middle-to-end. Given the innacuracies of this cheap multimeter, I'm guessing its a 30V transformer...
OK, so the transformer already in the speaker case is rated at 35VA, and is a 15/30v.
Would anything (especially sound quality) be compromised by replacing it with the below linked transformer?
And do I need to think about shielding?
Click here to view the transformer
Would anything (especially sound quality) be compromised by replacing it with the below linked transformer?
And do I need to think about shielding?
Click here to view the transformer
Not compromised, more likely to see a small improvement in rail stability. Whether you will hear any difference, it may be tiny.
You are unlikely to be able to fit in any shielding that is really effective and are likely to just make overheating problems.
You are unlikely to be able to fit in any shielding that is really effective and are likely to just make overheating problems.
Thanks guys, you're a massive help. I've found a possibly better alternative: Click Here.
Also, I'm slightly confused as to how I'd wire it to end up with a 15v and a 30v using a 2x15v transformer.
Also, I'm slightly confused as to how I'd wire it to end up with a 15v and a 30v using a 2x15v transformer.
Something like this?
An externally hosted image should be here but it was not working when we last tested it.
For one, it's £6 cheaper, and I want a load of other stuff from farnell 😀
It's also 91% efficient rather than 86%, which means less noise, heat and interference.
It's also 91% efficient rather than 86%, which means less noise, heat and interference.
I would question both of those efficiency figures. Anyway all the efficiency means is less heat.
The first transformer will produce less interference (hum) as it's got a much lower magnetic field due to being toroidally wound, but the second transformer will have better immunity to noise and spikes on the mains as it has a more lossy coupling between primary and secondary.
The first transformer will produce less interference (hum) as it's got a much lower magnetic field due to being toroidally wound, but the second transformer will have better immunity to noise and spikes on the mains as it has a more lossy coupling between primary and secondary.
Given the stability of british mains, am I better off going for a toroidally wound one? Farnell sell some too. Might see if I can get a suitable mu-metal surround for it too, just for perfection's sake.
Am I right in saying I can wire the two 115V primary coils in parallel and get a 230V primary?
Am I right in saying I can wire the two 115V primary coils in parallel and get a 230V primary?
I quite like EI transformers because they have less inrush and better noise and spike rejection. You do have to consider the size and hum field issues though.
No that would result in some pretty nasty smoke. You need to wire them in series (one inline to the other).
Hi,
are your active speakers double insulated?
Do they have the concentric double square symbol?
Do you know how to maintain the ClassII rating when you modify the speaker?
are your active speakers double insulated?
Do they have the concentric double square symbol?
Do you know how to maintain the ClassII rating when you modify the speaker?
Even if they were in phase? I suppose I'd still only get 15V out of them though, just the full 50VA rating. If I wire them in series with a tap in between, I'll get a 15V AC supply at 25VA, and a 30V AC supply at 50VA, right?
AndrewT said:
No, they are not, I know the symbol you mean but can't see it. And no, I do not know how to maintain the ClassII rating.
So, given a transformer to driver distance of about 15cm, toroidal, or EI?
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