considering that your main amps are 1Vrms sensitivity - maybe best way for you is to use decent attenuator with output buffer ....... because every modern source will give more than enough voltage for full blast , and buffer will add necessary muscles ;
as they say ARCDB - LS25 - 18uV is amount of noise , IHF weighted
are you using proper balanced connection between amp and pre ?
Maybe your balanced to unbalanced connection (adaptor, cable) links XLR pin1+3? Some equipment don't take it well, when its a standard in pro connections non the less. All XLR ready made adaptors do that linking. Or there are RCA outputs already?
Change some tubes then and see. One may have gone hissy.
Don't know with ARC but I have checked some BAT differentials with 6H30 and they were silent enough. Not like some SS but no problem.
I've already ordered 2 new ones to see if it is the tubes.
Don't hold your breath. The tubes are only used as followers and their contribution to noise is minimal. I have once owned this unit and have no memories of excessive noise but maybe my noise requirements are not so demanding. Otoh, do not judge the sound of high quality tube preamps by the LS25 or any other ARC unit for that matter. Despite what a lot of audiophiles on agon say, they all suck sonically. No opinion about their power amps.
looking at schematic - there is no need for pins 1 & 3 tying on LS25 side
anyway - I still think that active stage is redundant , having 1V sensitivity of power amp ;
regarding full compatibility-do not over-estimate their knowledge over their greed .
feed that amp from any source which have variable output and that will be music , comparing to LS25 usage in that situation .
then you can sell preamp and buy something "passive " with buffer
The good thing about popularity is I can sell the LS25 for no loss in equity.
That is also the reason i sometimes buy used commercial high end equipment -it tends to preserve value ahead of inflation. And i get to sulk at it
As for recommendation for other brands, not much help i'm afraid. All the commercial preamps i have owned have been really poor in some respect. For some reason i find it much easier to come to terms with factory made power amps rather than preamps.
It is always useful to keep a good passive attenuator around. These usually work well with tube power amps and even if they show some deficiencies of their own, in comparison to most active preamps they can really shine. My definition of a good pre is thus simple: the transparency of a Shallco attenuator switch but with much better bass and dynamics. Gain, as Zenmod says is entirely optional.
Yes, I do. I'll try it direct. .........
...... The thing is the preamp is convenient in that I can plug all my different sources into it. Also, it has a recording loop as I do a lot of analog tape recording.
I hope that meaning of "direct" isn't " without volume control "
certainly ; but - I meant that you try that for test , then decide have you enough gain/grunt/music without active preamp