Einstein The Tube users...help

What Newbee means to say is the input sensitivity to your amps is too LOW for your Einstein. Pass would likely suggest that it's just perfect for their preamps, and they would be correct in saying so. The answer is to either buy/make a fixed or stepped attenuator to place between your preamp & amp, or if you are to keep the Einstein, have ITS gain lowered. That is an amazing preamp, one I would certainly keep, and your issue is easily remedied.

Tbooze, FWIW I have read about Pass amps and pre-amps. As a prior owner of one of his Threshold SA amps, one of the finest SS amps I've heard and owned BTW. Several folks thought that Pass amps and Pre-amps sounded best in combo. It may just be that this gain issue was one of their considerations.

FWIW, there are a lot of things which bring the 'matching' gain issues to the surface have to do with folks who buy new and more efficient speakers. Personally I got this experience 15+ years ago when I upgraded some 82db panels which required huge amps to drive to some more efficient, 86db speakers. All of a sudden I had some residual tube hiss from my pre-amp that was very noticible (An ARC SP10 which had not output gain control) and selection of low noise tubes in the line stage became as critical as in the phono stage. I then 'up-graded' to 92db speakers and if I wanted to use the SP10 I'd have to not only pay more attention to tubes, but in order to get a reasonable range out of the volume control I had to put an attenuator between the pre-amp and the amp (10db).

There are a lot of modern high power amps with input sensitivity as high as .5v, many at 1v and 1.5v. Interesting to note that amps primarily designed for use with very high efficiency speakers have input sensitivities upwards from 2.5v. Creates less of an issue for users who don't want to get a new pre-amp or listen to residual noise.

Of course another issue which compounds the sensitivity problem is the input (gain) from the source. For example a 2v output from a CDP is standard now but if it were lower, say 1v or .5v (like Wadia provides) you get a lot more use of the volume control without changing the amp/pre-amp ratio. Ergo, a pre-amp which gives you control over the input gain from a source it can be as valuable to many as a gain selection in its output section (My SP10 has one of these and was very useful when I used MM cartridges with very high output).

Its not rocket science, but its a trap for the unaware. Its just another synergy problem, albeit electrical rather than tonal.:-)

Thanks for the explanation Boa2. I was confused a bit by the lower/higher sensitivity thing. It makes sense that Pass has a low sensitivity (not a lot of input voltage required to drive it to full output). So it seems that the Einstein must have too high an output? I will check about having it adjusted.

BTW, I am also going to audition the BAT VK-51se and it has an output of 50Vrms. Is this too high?

Can someone explain what the preamp output number means?

Thanks Boa2, In self defense, for the anal folks like me, I feel it necessary to editoralize on the issue of input sensitivity numbers and their actual meaning in practice. :-)

While the input sensitivity number is lower it means that the amp can be driven by a lower voltage from the source. What that actually means is its sensitivity is higher than for example if its rated input sensitivity were represented by a higher number. Sounds kinda ass backwards but thats how it works.

Thanks Boa2, In self defense, for the anal folks like me, I feel it necessary to editoralize on the issue of input sensitivity numbers and their actual meaning in practice

No worries. It was obvious you knew exactly what the issue was, and if I wasn't such an "Ernie Einstein", I'd have let it Pass. Boy, I crack myself up! In truth, if not for having had this issue with several components, how it works would still confound me.

Tbooe, in response to your other thread, my suggestion would be to keep the Einstein, and have its gain reduced. It's an incredible preamp, IMO. The issue you're having is simple to fix, and worth the minimal effort. What you will notice when you have the gain correctly matched is a tremendous improvement in the highs, and an overall richening of the music.

If you like, I can send you some cheapie fixed attenuators to use until you get this resolved. Email me privately if you like.