Best headphone amp for classical music CDs?

I recently purchased a Rupert Neve RPHP headphone amp....I am using it with Grado RS2e and it is a great amp...  it drives my 600 Beyers pretty well too.

https://rupertneve.com/products/rnhp-headphone-amplifier/

Fantastic amp,  detail retrieval is excellent, dead quiet.  Best $500 I have spent on audio in a long time.

The impedance ranges from 150 to 380, but sensitivity is 105 dB. So an amp that is fine with the impedance range and get clean 0.5 to 2 watts?. Did I get this wrong?.

If you are using the single ended converting them to balanced will help.
Since headphone amps that have balanced outputs can put out a lot of power compared to single ended, in my limited experience.

Check out the Audio-gd gear, Kingwa specs them across the wattage across impedance range for both balanced and single ended outputs, class type and also have measurements for you to look at.

In my opinion try going for Class A for sure, with headphones you will notice distortion much easily.

The HD700s are not the easiest thing to drive. would suggest something with at least 30-50 watts per channel into 8 ohms. with the impedence of the sennheisers you may be able to get a few watts output.

would also suggest you take the plunge and buy the least expensive denafrips DAC. it will blow away the chip set in your Marantz.

Happy listening.
 

Electronics don't care what you listen to- and there aren't any electronics of any sort that favor classical music (or any other music for that matter). This is a very well-established myth. You just want to get a good headphone amplifier.

I would recommend Auris Audio HA2-SE.

I have used few Audio-gd headphone amps with DACs in them. They are quite good in my opinion. Quite an amount of over engineering for the price. I never heard through Marantz CD6006 however. Folks at head-fi seem to like Audio-gd gear.