I have always felt, and I believe Doc and PJ are with me on this, that attenuation at the amplifier offers the best solution. Of course, the option to attenuate at the Foreplay is built in, but after about 470k of padding resistance, it really becomes best to add attenuation at the amplifier inputs.
It always helps to know which resistors you have installed in the preamp currently, and how many clicks on the volume control you use before things are too loud.
likely the easiest way to pad your amps will be to add one resistor inside the Quicksilvers. They say 100k input impedance, so if you openned one up, you would see a 100k resistor from the center pin of the RCA jack to the grounding tab. To pad the input, you will remove the end of the 100k resistor that attaches to the center pin of the RCA jack, and insert a resistor between that removed end of the 100k and the center pin of the RCA jack, creating a voltage divider.
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fupload.wikimedia.org%2Fwikipedia%2Fen%2Ff%2Ff4%2FImpedance_Voltage_divider.png&hash=b4315fd02d20dc68b5d078ac026d0eab0e4a58a4)
The wire that feeds the amp from the center of the RCA jack would then solder to the junction of these resistors. In the photo above, you have a 100k Z2, and no Z1, so we are adding Z1 and moving Vout.
