Einstein The Tube users...help

i use an einstein tube preamp into a pair of ATC 150asl active speakers.The einstein has a very low output impedance and has no problem with the low input impedance of the atc,s-but has an output that,s far too high for the ultra -sensitive ATC,s,thus causing the volume control issues mentioned above.I cured the problem with Xlr inline attenuators,connected to the ATC,s amp.inputs-but only after 3 years of messing about.I tried expensive EVS and rothwell attenutors-which cured the gain issue,but restricted the bandwidth (reduced bass and treble).The problem was that the output impedance from the attenuators was to high for the ATC,(output impedance must be below 10% of the input load,which drops down to 1k.ohm on the atc,s inbuilt amps).In the end a pair of $10 microphone -10 db inline xlr attenuators did the trick,as they have an input impedance of 600 ohms-which is Ok for the output of the Einstein,and an output impedance output of 100 ohms which is Ok for the Atc,s built-in amp input impedance.I,m assured that the 3 cheap resistors built into the attenuator have no impact on the sound,which now has fabulous band- width,tone and dynamics,plus a controllable volume. Anyone trying this solution who has a power amp with an input impedance of more than10K ohms (which is normal)would be able to use the EVS 1Kohm fixed xlr attenuators which use expensive vishay silver foil resistors.(however,I,m not convinced these offer any discernable advantages over cheap resistors,as attenuators only use 1 resistor per wire-3 in total per xlr interconnect lead,and,in theory cannot colour the sound,)Remember to connect these to the input of your power anp-rather than preamp,as this reduces your signal-noise ratio,by the attenuated amount.and reduces signal reflections at the end of the interconnects,as mentioned in the einstein product manual .Finally,i,d stick to a -10db. attenuation,rather than a -15 or 20 db,s ,as although it might limit the volume controllability somewhat,it seems to sound better-don,t ask me why!

Ideally you would build the resistors into the XLR connector,although i wouldn,t know anyone who could do this for me in the UK. I tested 4 different makes of attenuators,3 different levels of attenuation (-10,-15,and -20dbs),and 4 different impedance ratings(of the the attenuators) 200ohm,600ohm.1kohm,and 4kohm. The 600ohm -10db,s proved to be the best,by far,(and the least expensive)for me,because of the very low input impedance of the ATC,s.It would have been a bit of a nightmare to solder in all these variations.And the xlr connectors are pretty well sealed with heat-shrink covers,so,even though i now know the ideal resistor ratings,i wouldn,t be too keen to cut-open the xlr fittings.Also I,m not confident that direct soldering would deliver an audible improvement in sound quality versus seperate attenuators,which are very inexpensive.Maybe the only advantage of being 63 years old is the loss of hearing!