Please teach me about input transformers

[Alonzo]

So it's an odd time here, no amps being worked on while I save up for a Mainline (the DAC will have to wait, my Cayenne needs new coils...).  I have the Smash on order and wondered if instead of using attenuators on it, would it benefit from input transformers?  Also, what about using input transformers on SET's.  Would my 45 or my tweeter amp benefit from a pair of B7 10K:10K from MQ?  My sources are Turntables, SONOs and computer, so I have varied input ranges.  Would input transformers work for a wide range of inputs?
Thanks,
Alonzo

 

[Paul Birkeland]

10K input transformers will drag the input impedance way, way down.  It will also put a piece of iron in the signal path that you absolutely don't need.

If you want to add a balanced input, or run really long cables and need to break a ground loop, the input transformers will serve you well.

-PB

 

[Alonzo]

Ok, it was just an idea.  The Smash will only be a little over 8 feet from the amps so that won't be a problem.  It will be on a dampened shelf to cut down on the microphonics.  I would like to avoid in line attenuators that other people have had to use and thought using transformers at the amps input would isolate them from any grunge picked up. 
Probably should wait till I get them in and installed before inventing fixes for problems I don't have.

 

[Paul Birkeland]

The use of inline attenuators is for the situation where a very high gain amp is used with efficient speakers.  If you have 99+ dB speakers and a 1000 Watt amp, the combination will be so hyper sensitive that the input of the amplifier will have to be padded.

If you had tapped transformers, you could use a pair of input transformers in the power amp as a means of reducing gain, but then you would end up reducing the input impedance of the power amp, which isn't a good thing. 

-PB

 

[roscoe primrose]

If you had tapped transformers, you could use a pair of input transformers in the power amp as a means of reducing gain, but then you would end up reducing the input impedance of the power amp, which isn't a good thing. 

-PB

How do you figure that?  Using a tapped transformer to lower the level will lower the driving source impedance seen by the power amp, but will increase the input impedance seen by the driving stage by the square of the turns ratio between the full winding and the tap...

Roscoe

 

[Paul Birkeland]

While this is true, you may find it necessary to play with the loading on the transformer for optimal performance, which may end up negating the reflected impedance in the first place.

-PB