is this a cheap isolation transformer source? (australia)

[darron]

i know passive isolation transformers with good frequency response can cost around $100.... browsing for an IC i found this in altronics:
http://www.altronics.com.au/index.asp?area=item&id=C9555


AU $17 on special.

Specifications
Type: Transformer
Maximum input: 30W per channel
Frequency response: 20-20K Hz
Lead length: 60cm
Transformer dimensions: 30mm diam. X 70L mm


i don't personally have a need for one but i thought i'd share....

[brett]

Hi
this is cheap. 
However, I'm quite surprised that they can get 2x 30W at 20 Hz to 20kHz from a package that weighs 140g.  Ordinary transformer iron won't do anywhere near that well.  Consider what a 60W power transformer weighs (I'm guessing about 1kg).  And it is operating at 50 or 60 Hz, not 20Hz (which in theory needs a 3 x larger core than 60 Hz).
Maybe they are talking about 60W of white noise (ie spread simultaneously across the audio band, with almost none of the power down in the sub-100 Hz region).
cheers

[darron]

it sounds a little too good to be true, but with that frequency response and size i was thinking of A/B pedals etc. to send between two amps without ground loops etc., it wouldn't REALLY need to carry that absurd wattage.

[George Giblet]

> 30W
Off hand my guess is that's @ midband, 1kHz. (haven't checked by calculation)

Also, there's no impedance or DC resistance spec.

[Johan]

the 30W is probably a missprint. more likely is 30mW wich would be equal to a strong linelevel signal into a 10k input...that is after all what it is made for..breaking groundloops in linelevel signals...
I've used those types quit a lot and they work fine as long as you watch your impedances...if you put it before an input with too low impedance you loose all bass frequencys. but that shouldnt be a problem in most modern hifi/"prosumer"/soundcard situations where 10k pretty much has become standard...know your application, save some money.. 

j

[brett]

Hi again
Good spotting Johan!  30mW sounds right.
For cheap stuff here in Oz, I'm using Furturelec more and more and DSE and Jaycar less and less.  For $1, I can get 12 small electro caps from Futurelec or 2 from DSE or Jaycar.  Transistors and other bits are about half price.  And the same or cheaper postage.
cheers

[darron]

i haven't dealt with futurelec yet for convenience of other places being local. but if i ever do a small 'run' of pedals next time i think i might have to give them a shot.

it's a shame that you really need to source stuff from all over the place. I use altronics, then rs components, then jaycar, then i'm sometimes forced to use DSE (they still stock GE diodes and a small knob i like).

RS components also stocks just about everything, especially all of the hammond enclosures and every known semiconductor.

i did a quick PCB maufacture lookup on futurelec, it's almost twice as much in australia as it is in USA... :S

[petemoore]

i don't personally have a need for one but i thought i'd share....
  I have a need for at least 2, thank you for sharing !
  My amps must be accidentally 'balanced', when 2 are ground looping, hum/noise seems to be about the same, low.
  I would like to daisy chain amplifiers though [I run stereo echo outs to them now], this seems like it'd be a good way to do it, after swapping the connectors for 1/4'' plugs.

[Salvatore]

I bought this item somewhere for around 7.50 Euros, so don't spend that 17 $.

[Salvatore]

Ah, found it. 

http://www.new-line.nl/webshop/view.asp?i=12698