[62caddy]

Sancho, the 604 8(x) series had once been considered the definitive studio monitor and used in ~ 70% of mastering studios throughout a good portion of the 1970s. Aided by the latest technology, the current 604 8H & dividing network by Great Plains incorporates a number of improvements over the earlier Altec versions which many consider to be the finest Duplex of all.

As the tradeoff of high sensitivity horn type loudspeakers is some penalty to deep bass response and the 604 is no exception. Many owners place their speakers at or near room corners - and sometimes with a subwoofer. Rest assured however that a system of Altec 604/620 cabinets well calibrated and dialed in can yield some truly spectacular results.

The closest thing I've owned to the Valencias were a pair of Heathkit Legatos AS 21 which share the identical 806A HF driver & 811B horn of the Valencia but I found that combination too shrill for my liking on certain material, but not all music. I had all but given up on horns when a friend strongly suggested I try the Altec Model 14 which use the then-new Mantaray horn with Tangerine phase plug. The improvement was dramatic to say the least: all the realism and presence of the 811 but none of the piercing shrillness. The HF driver of 604 8H shares the near-identical Mantaray driver w/Tangerine of the Model 14 and as far as I am concerned, stands head and shoulders above the 811B.

Directionality is also somewhat improved over the older 811B but placement relative to listening position remains critical nonetheless.

Factory spec places sensitivity ~ 103 dB (IIRC) of the 604 8H @ 4 ft which means it should perform well with the SET unit of your choice. I run my own Model 14s, alternately, between a pair of McIntosh MC30 tube amplifiers and MC2505 solid state amplifier. I can hear no appreciable differences between the two after numerous instantaneous A/B comparisons, for whatever it might be worth.

The bottom line is that were up to me, I would go with the GP 604 8H and not look back.

HTH, Eric