Which is better TDA8551 or TDA7315 ?

I was made audiometer using dac and digital atttenator [ some resi. and ic 4051 ].
But that ckt is bulky need + - supply .
Now i go for battery operated a.meter for that i am using r-2r for dac and for digital att i am thinking to use TDA8551 / TDA7315 i already used TDA7315 but for small size i want to go with TDA8551.
I actually ever not used TDA8551.
What is you suggestion.
Thank you for reply.

The 7315 is a pre-amp stage to an amplifier (for in-car or budget hi-fi use) with serial control (64 step) volume and tone stage. The 8551 is a 1W audio amplifier with a 64 stage step up/down attenuator at its input (with no memory).

If you are just after a digitally controlled attenuator try something designed for the job (e.g. Maxim / Dallas both offer 64 - 256 stage pots with NV memory, up/down or serial control). Combine that with a decent headphone amp and you are away with better results. If you need the tone controls as well, stick with the 7315, or National & Maxim both have some good alternatives.