[b]wad 6550[/b] World Audio 6550... Visually: This amp looks the biz. its big...the earlier wad amps were fairly compact, I suspect to keep costs down, but this one really does look like a commercial product now. A massive, and I mean massive mains transformer sits at the back, flanked in front by 4 of those lovely 6550 valves...now they are fat...makes the el34s look anorexic by comparison. A nice thick solid ...no boxer analogies intended...aluminuim front panel finishes it off, together with some tall proud rectifier valves... General Description: get to the bloody sound...ok its coming..patience...this amp was designed by andy groves of audionote, who hifi world have plucked and moonlighted to do their amps...its a straightforwardish valve circuit, which uses an ecf 80 input to both amplify and phase split the input which is an interesting way to do it...before passing it on to those 6550s..it runs in class A, gets hot, and puts out about 40 watts..I haven't tried to get it above 1/2 way on the volume control..The power supply is a choke filtered valve rectified affair, and its easy to run all the heaters ac, thus having no silicon in teh circuit whatsoever..its an ultralinear design, meaning some of the output is fed back into the final 6550 valves..this is easy to convert to a triode by connecting one of the grids to the anode. Sound Quality -at last...well this comes as a bit of a suprise,.its very clean, laid back, and after one adapts to it, moreish, addictive. At first you think its too much so, but then anything else sounds forced...it has great presence...vocals are lovely, bass is in the correct proportion with no overhang. Very detailed too...comparing it to a typical mass market transistor, it has better tonal colour..and far more natural sounding..the ebb and flow of strings, acoustic guitar...it rocks too capturing the harmonics of distorted guitars beatutifully..it seems to be a little ethereal having an odd phasey, wispyness in a pleasant sort of way..its indefinable but not coloured. The soundstage is very tangible and makes that tranny amp sound flat...piano is very noticable..you get the dynamics and liquidity.. Sure you get sound with a tranny amp, but if you really want expressive and musicality, there is no doubt that it goes further... you must here this. Listened to via marantz ki cd, yamaha ns1000 speakers and home made cables..
