Well that depends JLiRD808? I wouldn't use a headphone amplifier as a monitor distribution amplifier. What you have probably done gives your monitor output plenty of oomph and headroom drive capabilities while probably contributing a little higher than normal noise level and a contribution to virtually unnoticeable distortion. But if you have played other CDs through your system and find it adequate sounding, you shouldn't worry.

In my old Vintage Neve console, I have numerous different types of operational amplifiers (Op-Amps). Some of which have smaller output transistors and less drive capabilities and some with large transistors and heat sinks to provide greater load drive capabilities at the expense of small incremental noise and distortion increase. However, these plug-in amplifiers are interchangeable and in some places within my console, I swapped out a noisy lower current amplifier with what I had on hand, which was the higher current output drive amplifiers. It's never been anything that anyone else has ever noticed including myself on this vintage 36 input desk. There are those aficionados that would not do what you or I have done. But in a practical application sense, you did what works for you. Bravo! It wasn't a bad move. I just wouldn't make it a habit of using a $40 headphone amplifier as my primary monitor output, but when you think about it, even those nice standalone control room monitor controllers utilize $3 a piece IC chips, just like many consoles. So not a whole lot of difference there except in the printed specs. If you find noise excessive, it would be a factor. So it doesn't sound like a rain shower when there is no sound coming through, enjoy the peace and quiet.

Rock and Rolling peacefully. If that were possible?
Ms. Remy Ann David