Re: ampeg 70s stones amp
Date: October 23, 2005 13:46
There's various versions: V4, V2, VT-22, VT-40. The V4 is 100 watts, V2 is 50 watts, VT-22 is a 2*12 combo with the 100 watt V4 as amp, the VT-40 is a 4*10 combo with either the 100 watt V4 or the 50 watt V2 as amp. For the real Stones sound, I personally prefer the VT-40, as the 4*10 speakers give a somewhat tigher rythm sound. Remember that 100 Ampeg watts is too loud for modern use, but there's a trick: just take out the two tubes far left and right, You now reduced 100 watts to ab out 40, without altering the sound.
There's two main versions of the Ampeg V-serie: the first one is from 1969 until approx. 1976, and featured five rocker switches above the volume and tone knobs. One of the rocker switches is called "sensitivity", and together with the treble pot, this is where the overdrive happens. The second version, from 1975 until 1980 didn't have these rocker switches, and there's only one way to overdrive these amps: turn the volume to 10, which blows you off the stage. I once tried to tame these amps with a load boax, but that doesn't work really well, as the sound became really gritty.
By the way, the SVT uses 6550A tubes, which is the American equivalent to the British KT-88. The 6550A is actually just a larger 6L6, and both tubes are still produced today. Sonicaly, there isn't any difference. The V-series amps use 7027A tubes, and some use 7591A tubes. It is very confusing, but the only difference between all these tubes is the maxiumum rating in watts. IN fact, there is NO difference between a standard 6L6 and a 7027! The 7027 has one pin more in the socket, but this pin is shorted anyway. You can replace any 7027A by any 6L6 tube without a problem. All modern 7027 tubes are just 6L6 tubes with a different label. The 7591A and 7581A tubes (found in the old Boogie Mark 1 amps) are just bigger versions of the 6L6. A standard 6L6 delivers 25 watts, a 7591 about 30, and a 7591 about 35. All these tubes are fully interchangeable. Just one thing: old tubes from the 70's sound much, much better than tubes produced today. An original set of G.E. 6L6 or Phillips 7581 blow any modern tube out of the water. This reflects in the price: modern 6L6 cost $15 each, G.E. 6L6 cost $150 for a matched set.
Mathijs