any SS amp will do, and it will sound kinda tubey, but with SS slam and control. REL's (UK mfr) subs provide this option.
If the main pair are sealed boxes, match the low-pass with the main pair's own roll-off and you are done.
If they are ported boxes, stuff the ports and listen/measure the new higher slope, and match to that. Or a blocking cap on the back of the spkr's input terminals will kill any cone flap. Use a good electrolytic and by-pass it or stack some good film cap and by-pass with a $$$$ cap of 1% of the total.
Now I'm not certain about this but increasing the wattage of the input resistors in the existing sub crossover might be enough to let you use it. Most SS circuit R's are 1/4 watt, and 1 or 2-watt R's might just fit. Watch how hot they get.
The load is likely to be over 100kohms and is not going to dissipate a lot of power off 10 to 20 volts.
A valve powered sub? 60 watts minimum cf 15 watts IE 6dbw more power than the Dyna - I'd suggest.
I'd also suggest you think about putting the valve amp's own behaviour as a source to work, and go for a critically / over-damped alignment. IE a sealed box with a Q of 0.7 to 0.5, or an Rb with a c.d. QB3 alignment, even an EBS alignment.
Also, bear in mind that a small room has a quite early point (in frequency terms) where its ELF room-gain takes off. Match that point with your sub's predicted f3 point, and good clean deep bass, without heavy slow sound, just will happen.
Noting that mid and upper bass in small rectangular rooms is a whole other thing - more peaks and dips than in larger rooms.
Warmest
Timothy Bailey
The Skyptical Mensurer and Audio Scrounger
And gladly would he learn and gladly teach - Chaucer. ;-)!
'Still not saluting.'
Edits: 08/14/12 08/14/12
This post is made possible by the generous
support of people like you and our sponsors:
