[Jingo Lingo]

Don't know if this is the most appropriate forum, anyway...

I'm considering purchasing one of these headphone amps. Problem is they only come with a 100V wall wart. The amp itself requires "Power source: DC12V 500mA (JEITA)"

My question is would I be able to use any old 12V 500mA wall wart? Or is there some special type I would need?

Thanks DIYers.

 

[El_Doug]

regulated and linear, to be on the safe side

 

[Jingo Lingo]

Any way to tell by looking at one if it is regulated and linear? If it doesn't specify is it safe to assume it isn't?

 

[tenzip]

Quote:

Originally Posted by Jingo Lingo /img/forum/go_quote.gif Any way to tell by looking at one if it is regulated and linear? If it doesn't specify is it safe to assume it isn't?

If it doesn't say so, it's generally pretty safe to say it isn't. Regulated + Linear = More expensive.

 

[DKJones96]

While most people here hate them...

I like my switchers

 

[Juaquin]

Switching supplies are fine, if properly filtered - which isn't necessarily easy. Linear just happens to be easier to get a clean signal out of. For audio I'd stick with linear.

 

[Vizzini]

The easiest way to determine if a wall wart is regulated is to check it with a meter. A regulated supply will output the rated voltage into any load up to the rated current. A non-regulated power supply will output a higher voltage at less than the rated current. Since a meter presents a very small load, the measured voltage of a non-regulated wall wart will be significantly higher than the rated voltage--maybe up to 18 or 19 volts for a 12 volt supply.

 

[Jingo Lingo]

Thanks for the replies. I have a multimeter so i'll try that out. Would you think the power supply needs to be exactly 500mA? Could I get away with using a 400mA or 600mA wall wart?

 

[vhbaske]

Another way to know is if the SELLER states so!!!

 

[nux]

Quote:

Originally Posted by Jingo Lingo /img/forum/go_quote.gif Thanks for the replies. I have a multimeter so i'll try that out. Would you think the power supply needs to be exactly 500mA? Could I get away with using a 400mA or 600mA wall wart?

The current rating is its maximum supply current. Hence it needs to be equal to or greater than the maximum current drawn by the device. So assuming it does need 500mA, you would need a 500mA or higher power supply.

This one is probably fine, although it is a switchmode one. Just check what sort of plug you need.

 

[Jingo Lingo]

Quote:

Originally Posted by nux /img/forum/go_quote.gif The current rating is its maximum supply current. Hence it needs to be equal to or greater than the maximum current drawn by the device. So assuming it does need 500mA, you would need a 500mA or higher power supply. This one is probably fine, although it is a switchmode one. Just check what sort of plug you need.

Awesome! Thanks a bunch.

 

[Leviator]

Hi,
 
I am planning to get STAX SRS-3100 system from japan. My question is for the SRM-252S power supply most probably they ll give a wall wart which is designed to get 100v AC from the power socket and convert it to 12v/4w DC.
 
correct me if i am wrong this is my understanding.
 
I reside in India where the AC from my power socket is 220-240v. I was thinking of two options 
 
1. To get a step down transformer to convert 220v to 100v and plug the stax wall wart to it.(I was not able to find a step down from 220V to 100V in my country)
2. To get a new wall wart that supports 12v/4W DC.Since the polarity is reversed in the STAX. I am not sure which adapter i should choose and really confused with the polarity reversal..
 
Any help is Appreciated.

 

[Muamp]

Hi Leviator,

The Stax 3100 is a superb system!
The Stax SRM-252s is powered from a 12v psu, as you say about 500mA, and any 12v adapter will be ok, IF the jack plug for the SRM-252s has the polarity of centre pin ground and +12v on outer. You can buy this type of psu from Argos in the UK, or ebay where the voltage / polarity are switchable. Also, try Mjolnir for Stax PSUs, he sells them.

David.

Edited: I have used Switch mode power supplies (3 or 4 different PSUs), regulated linear power supply and Lithium battery packs for powering the SRM-252s and all have been fine, with no problems.

2nd edit: To add to the SMPS Vs Linear comments, the SRM-252s has Switching circuits in the device itself to get the HV needed from the 12v supply.