Simple Biamp question

Have not tried it but either approach is valid. What I have heard over the years is that if you go "vertical" as in one stereo amp feeds the left speaker and the other the right channel you will get the benefits that are obtained by mono blocks which is the complete seperation of the channels at the amp stage of your system.

I defer to others who have spent time trying it both ways.

If my phrasing is misleading, let me clarify: (Vertical biamping):

Output A: L eft to Amp 1
Right to Amp 2

Output B: Left to Amp 1
Right to Amp 2

Amp 1 has 2 left input, Amp 2 has 2 right inputs

Is this doable/acceptab;e - likely to be a problem?

That will most likely work fine, and should give superior results to horizontal biamping, for the reason Jjrenman cited and perhaps also because it would make it possible to use shorter speaker cables.

The reasons I say "most likely," though, (and these reasons are equally applicable to the horizontal and vertical biamp configurations) are as follows:

1)Chances are that the two sets of output terminals on the preamp are simply wired together inside the rear panel of the preamp, rather than being driven by individual buffer stages. If so, the output stage of the preamp will see a load impedance equal to 1/2 of the input impedance of the power amp. I found a spec indicating that the output impedance of the preamp is "less than 600 ohms," but that is probably at mid-range frequencies and could be much higher at deep bass frequencies. And I couldn't find a spec on the input impedance of the power amp. Given that the power amp is tube based, I'd feel fairly confident that 1/2 of its input impedance will be sufficiently high in relation to the output impedance of the preamp to not result in sonic issues, but that can't be said for sure without having more complete specs.

2)Assuming that the two sets of output terminals on the preamp are not individually buffered, the output stage will be loaded by the sum of the capacitances of two sets of interconnects. That most likely won't cause any problems, but if the interconnect lengths are particularly long (e.g., in the vicinity of say 12 feet or more, each), choose cables having low capacitance per unit length (e.g., 25 pf/foot or less). A slight rolloff of the upper treble might result if the cables are long and have high capacitance per unit length.

Regards,
-- Al

Give it a try. Vertical biamping should give you a big effortless sound.

I vertically biamp using a TAD 150 sig to 2 SS amps. In my case though since I use one of the outputs for HT passthrough (this is how they are wired - one can serve as HT pt via resistive coupling), I use the single output and a Y-adapter at the amps (saves a long IC run).

I asked Paul Grzybek (RIP) about the impedance issue and he indicated I may lose some high end, but not likely. I haven't noticed any degradation at all and this Vert Biamp config is somewhat better than other amp setups (more expensive stereo) I have tried.