SMPS500R (dual voltage version) auxiliary output voltage question

[activexp]

Cristi,

I PM'd you but haven't had a reply so I thought I'd try my luck here.


I'm interested in purchasing the SMPS500R @ +-54V and the Speaker Protection Board but I'm unclear regarding the aux output voltage of the SMPS.

The manual says that for the dual voltage version it is dependent on the main output voltage.

My question is what is the aux output voltage for a main voltage of +-54V? Is it within the operating range of the Speaker Protection Board?

Looking forward to hearing from you.

Steve

[Cristi]

Steve, the aux. voltage of SMPS500R, SMPS500QR, SMPS300R and SMPS300RE is unregulated but proportional to the main output voltage. The value is given by the turns ratio. For example SMPS500R +-54V main output will have the aux. output voltage or around 11V with light load and 10.7V with ~250mA load when the main output voltage is set to +-54V. This because for the main output the transformer has 2x5 turns, and for the aux. has 2x1 turns which means that on each turn is induced about 11V. Then the output voltage will be 11xn-Vdrop (n=number of turns Vdrop=rectifier diode forward voltage drop).
The speaker protection circuit standard version can work with min. 9.5-10V DC up to 15V DC. for higher or lower voltage values, the relay must be changed and few resistors.

[activexp]

Thanks for your very comprehensive reply You've provided all the information I need and will be placing an order very soon.

Regards,
Steve

[Duffy Moon]

So I assume from the above, that my SMPS500R which is configured for 60V and an auxiliary voltage of 12V, will have a transformer that only puts out 12V and no more. So there won't be anywhere on the PCB that I can tap to give me a 15 to 18V AC for another 12V power supply?

[Duffy Moon]

My SMPS500R transformer emitted smoke when powered on. I can't see any other damage. The main output is now only 1V.

Here's a photo.

[Cristi]

As i told you in the countless mails which i sent you, the cause was an overload or a short-circuit on the aux. output. The circuit is way too simple and with correct rating fuses is almost indestructible. Of course if the fuses are replaced with whatever else we find around things will change and the weakest part will eventually give up.

Short resume: few months ago you had the same issue, I asked you to send the smps back for repair. both of them had burned diodes and track for the aux. voltage and overrated fuses 3A and 6.3A instead of 500mA ones. iIs no wonder if this happen. I repaired and tested both and they were working properly.
now since the burned winding act like a short turn, will damage worse if keep trying to power on waiting for a miracle to happen and heal itself.
i repaired first time for free, i haven't charged you even the shipping cost as I should. I wonder what you are expecting now. I can repair again, of course, but this time I will charge you the price of the damaged parts and shipping back. If you think that is unfair you can ask others opinion if is fair or not...

[Duffy Moon]

Originally Posted by Cristi

the cause was an overload or a short-circuit on the aux. output.

I wasn't using the aux. output though, Just the main one. I have a separate power supply for the 12V now. I had nothing even connected to the aux. output.

Originally Posted by Cristi

both of them had burned diodes and track for the aux. voltage and overrated fuses 3A and 6.3A instead of 500mA ones.

The fuses are 1A fuses (at least that's what they were sold to me as and that's what they say on them) - they were the only ones I could find that would fit. At the time, you said 1A would be OK.

Originally Posted by Cristi

I can repair again, of course, but this time I will charge you the price of the damaged parts and shipping back. If you think that is unfair you can ask others opinion if is fair or not...

Could you maybe just send a replacement transformer? How much would that cost? I just want to get them working.

[avr300]

Why don't you accept the offer from Cristi letting him repair the damaged unit? The only additional cost will be the shipping from UK to China - and you will get the assurance that the PSU is in working order when it leaves China.

Imaging that you get the transformer and the thing is still not working. That's bad luck.

Just my

[Duffy Moon]

Originally Posted by avr300

Why don't you accept the offer from Cristi letting him repair the damaged unit?

Thanks, but I was just thinking of ways to save money. I think it cost about £30 to send them last time ($50?). That may not be a lot to some, but I'm out of work at the moment. If I post them again, pay for repairs and return, then the total cost will be edging towards double the original cost. I had been trying to save money by not buying the Hypex SMPS400A400. Also, the whole turnaround time will be several weeks. It's taken me a year to get my speakers built. I was really hoping to have them working this summer. It's my birthday tomorrow and I find myself quite depressed about this.


Maybe I could send it to a UK transformer company to repair/duplicate? Thoughts?

[Duffy Moon]

Originally Posted by avr300

Why don't you accept the offer from Cristi letting him repair the damaged unit?

This is what I have now done. Note to self: always do what avr300 suggests - it saves time.

Cristi, I sent it on July 20th with 5-day delivery. Has it arrived yet?