I use a Van Alstine tube pre with a similar output impedance connected to the same amp as yours. I have no problems with this setup.
Thanks Phil and Thanks David
It eases my situation a lot as difference between recommended impedance (250 or less) and impedance of pre I plan to use is 1250 is quiet huge by audio standards so I was confused a lot
The company offers a 30 day trial and I can return the product if I don't like for some reason (very rare in india) but I wanted to be double sure before placing an order
So now part 1 is solved
Next is that there are 2 versions (capacitor coupled output and transformer coupled output)
Some prefer capacitor as it gives more frequency extension and some prefer transformer as the sound is much more natural but only thing is that transformer needs to be of a very good quality and obviously that costs lots of money
If needed I will order a transformer from Intactaudio but if someone has any idea please share your views on capacitor coupled output and transformer coupled output
Its not going to be easy for me to import the transformer