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Burn in Step up transformer with ipod.

Here is question for you guys. There are cd products out there that reduces the output of CD players to low levels so that they can burn in phonostages and step up transformers safely.

Most cs players output between 2-4 volts which can damage phono step ups. With an ipod, the headphone output is 30mv. If i pay a track via the ipod and connecting it to a step up transformer with rca and play at low volumes, wouldnt it be the same thing as what these products do?
leicachamp
leicachamp OP
103 posts
 
John. Thanks for the info.

Did you connect to the output of the step up transformer and load the inputs ?

It's interesting to hear that K&K burn their step up with line level signals. I have never read a direct case of a transformer damaged because of a high level signal, but there seems to be an urban myth that many folks out there have done irreversible damage to their step ups and phono stages.
leicachamp OP
103 posts
 
Mechans, what makes you think I was looking for budget step ups?

My questions had nothing to do with the cost of step ups!
jjrenman
279 posts
 
Line level signals are usually around 1 volt so probably not a big deal. However if the voltage is high enough you will saturate the the core of tranny. If done for extended periods you will eventually do damage to it.

Also, if your phono stage is on and you are feeding the tranny one volt I guarantee that you will severely overload the input. So hook up the tranny to the phono pre to "load" it but do not turn it on and risk damage.
john_tracy
341 posts
 
I just fed the input with the phono pre turned off. You will probably want to use a high value of resistance as a load so as not to load down whatever device you are using to provide the signal too much. Remember, if the load resistor is on the secondary you will have to multiply the load resistance you want by the square of the transformer's turns ratio. e.g. for 47K at the input with a 10:1 transformer you would use a 4.7M resistor across the secondary.
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almarg
9,670 posts
 
I would err on the side of caution and not extrapolate from Kevin Carter's practices with the Lundahl transformer to other transformers, which may have higher step-up ratios and be different designs. Putting a 1 volt signal into a 20 db step-up will result in 10 volts on an output that is intended to handle a few millivolts.

Good comments by JJ. Personally, though, I would not put a stepped up line-level signal into a phono stage whether it is turned on or not, especially if it is solid state. It's easy enough to get a resistor at Radio Shack or elsewhere and not take any chances.

Regards,
-- Al
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