Here is one option that I played with in the past. I am not sure if it is the
"best" EQ but it works quite well.
If my source has both optical and coax digital outputs, I would send, say the
coax direct to the DAC and the optical output to my Behringer DEQ2496.
The DEQ2496 has a built in DAC but it also has optical outputs, so I'd hook
the EQ-ed digital signal from the DEQ to another input on the same DAC.
This way you can run both EQd and un-EQd signals to the same DAC and
compare them on the fly.
The DAC then feeds the pre-amp. I eventually took the DEQ out because I
preferred what I heard on the direct non-EQd path.
Another option that I tried was to use dual analog outputs on my DAC (usually
XLR and RCA) which were simultaneously active.
The XLR went out to my preamp directly.
The RCA went to a very warm tube buffer. It was an old Yaqin tube buffer IIRC
which then fed another input on my preamp. This isn't the same type of tubes
as the ARC. It's very warm and IMHO robs the music of dynamics, but by the
same token, also takes away the harshness of badly recorded music. This was
when I was using a SS preamp. Again, I could switch between the XLR and RCA
inputs and compared the sound with and without the tube buffer.
Eventually I took the tube buffer out and got the ARC. It kept the dynamics
and detail but imparted some tube lushness into the system.
"best" EQ but it works quite well.
If my source has both optical and coax digital outputs, I would send, say the
coax direct to the DAC and the optical output to my Behringer DEQ2496.
The DEQ2496 has a built in DAC but it also has optical outputs, so I'd hook
the EQ-ed digital signal from the DEQ to another input on the same DAC.
This way you can run both EQd and un-EQd signals to the same DAC and
compare them on the fly.
The DAC then feeds the pre-amp. I eventually took the DEQ out because I
preferred what I heard on the direct non-EQd path.
Another option that I tried was to use dual analog outputs on my DAC (usually
XLR and RCA) which were simultaneously active.
The XLR went out to my preamp directly.
The RCA went to a very warm tube buffer. It was an old Yaqin tube buffer IIRC
which then fed another input on my preamp. This isn't the same type of tubes
as the ARC. It's very warm and IMHO robs the music of dynamics, but by the
same token, also takes away the harshness of badly recorded music. This was
when I was using a SS preamp. Again, I could switch between the XLR and RCA
inputs and compared the sound with and without the tube buffer.
Eventually I took the tube buffer out and got the ARC. It kept the dynamics
and detail but imparted some tube lushness into the system.