"Mytek Empire monoblock power amps, with GaN based technology."

10K Ohms is too low for tube preamps? Since when? That’s relatively, but not absolutely, high. Low impedance to me is in the 600 to 5K range.

Please keep in mind that a "low impedance amplifier" is not the same as with low impedance speakers. The amps present a flat, resistive load. This means that there are no hills and valleys in the response curve like with a speaker attached to a tube amp.

Worst case scenario for most tube preamps is that you will lose a little bass due to the output coupling capacitor which is in the 1uF to 4uF range and a little maximum gain (which you don’t use anyway).

A tube pre with 1uF output caps could be down around 5 dB at 20 Hz (I’m in the middle of a few things so my math could be a little off). With 2uF caps around -2.9 dB. This may actually be helpful in the right room!

Look at this example:

https://www.stereophile.com/content/zesto-leto-ultra-ii-line-preamplifier-measurements

It handles 600 Ohms output just fine.  My point is, we can't universally exclude 10K input impedance amp from use with tube pres.  Some may do awful with it, but I suspect many will be fine.

Our preamps can drive 10K ohms no worries. Our MP-1 and MP-3 can driver 600 ohms no worries.


Having said that a 10K input impedance will exclude ARC preamps and a good number of other tube units as well as sources if a passive volume system is used. I don't see why the input impedance would be that low for consumer gear; the input circuit is opamps anyway, which can be set up to have input impedance as high as 1M.

the input circuit is opamps anyway, which can be set up to have input impedance as high as 1M.

Higher impedance = higher noise, but 25K to 50K is more typical than 10K for a solid state amplifier. It’s not exactly low either to me... it is still 17x more than 600 Ohms.

I'm not surprised at all your preamps can drive 10K. ;-) Most should.

The input impedance on my modded IceEdge amp that I was playing with was 47K after the first mod. I then raised that resistor to 148K and it sounded noticeably better. This was driven by a 50 ohm source that is biased with 10 ma of current on its discrete output stage (using a low capacitance 2 foot balanced cable). So, if a 50 ohm source sounds better with 148K.....why would you want less? There was no difference of noise idling or otherwise with the 148K.......dead silent.
You have to do listening tests to know anything. This is not theory......this is reality......your ears know what is real.

Nuprime is using 1meg input impedance in their latest 2 top of the line class D amps.   They say it sounds better.

Ask to have Tammy contact you

That’s what was done, too late now this thread now stays.

You’ll only get noise with high (100k) input impedance amps, if there’s nothing plugged into that input, which no-one would do anyway.
Think I remember all Rouge M120 and M150 monoblocks when I had them here for reco all had 1meg ohm input impedance, anything could drive them.

Cheers George