Burn in Step up transformer with ipod.

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.

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.

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

If I plug the output of the mc transformer to a line input in the preamp( not phono) what load would that supply the mc transformer? Or does only a phono input provide the right load to the step up?

Also by plugging to the line input, that would prevent any damage to the phono stage.

If I plug the output of the mc transformer to a line input in the preamp( not phono) what load would that supply the mc transformer?

That's a good thought, at least potentially. The load impedance will be approximately equal to the specified input impedance of that input. Often 47K, and usually somewhere between around 20K and 100K.

Or does only a phono input provide the right load to the step up?

No. If the line level inputs and the phono input have a similar input impedance, the transformer (and the source) won't know the difference. But there would be much less chance of damaging a line level input than a phono input.

Still, though, I'd be hesitant to send 10 volts or so into a line level input of a solid state preamp for prolonged periods of time, even if it is turned off, without being familiar with the design of the input circuit or obtaining an ok from the manufacturer. I doubt that it would be a problem, though, with tube equipment.

Regards,
-- Al