604 8K Amplification

[pjkkaf]

I just set up my system and have had a few opportunities to try a few things. The 604 8K's are in original Altec 620 cabinets. I am bi amping them with a Magnavox 8600 series flea powered SEP amp on the horns. After reading how SET amps with 300B type power tubes could make these things pleasingly loud with a passive XO.

So I bought a Dynaco ST 70 thinking 35 wats would be plenty considering the 300B output. Disappointing would be an understatement, no matter what I tried I could not get the LF speaker to move like it should. So I dragged out he old Kenwood KR 8010 125wpc receiver I bought new in 1979. Sounds a hellavalot better but I know this piece needs replacement.

Any opinions on a replacement LF amp? I am totally open minded as to SS or Valves or going the passive rout, just want to get the most out of these speakers with about a grand.
Oh, and volume control is handy.

 

[Tom Brennan]

Many horn enthusiasts bi-amp using SS on woofers with tubes on compression drivers. When I was a horny I had excellent results using a 125wpc Yamaha SS amp on various Altec woofers--515s, 416s, 414s, woofer section of 605As etc. It was one of those black amps with the red LED light bars, an M-45 I think. Anyway the Yamaha combined with a Fisher SA-100 on the compression drivers was hot stuff.

 

[elitopus]

I love the way my Altec's sound with tube gear. The problem with tubes is they don't get loud enough for me. I switch my Vott's out between a SE 6bq5 amp and a Ashly mosfet amp.

The Ashly pro amps can be had for cheap, they have ample power, and have a low distortion rate.

And yes Tom is right about the biamping. I do that with another pair of Altec's. You can really dial in the xover point and LF/HF levels.

Sometimes its good to use an active crossover to figure out what crossover point you want, and then build passive crossovers at the point