Pre-amp causing loud hiss from speakers

Your Rogue amps input sensitivity is 1V (high sensitivity). Your QS input sensitivity is 9V (very low). What this means is that the gain (and it's tube noise) from your pre-amp's tube section will be magnified substantially more with the Rogue and, especially when driving highly efficient speakers such as yours, will result in noise. This is not controllable by using your pre-amps volume control as it is in the circuit before the tube section which is always seen by the amp at it's full output gain.

Your problem could be that the tubes in your pre-amp are not 'low noise' enough for the Rogue Amp when it is amplifying your high efficiency speakers. If low noise tubes are not the problem and you still want to use your pre-amp with this amp/speaker combo you can try using in-line attenuators at the amp inputs to reduce the gain from your pre-amp. This may be inelegant but there is not much down side - it is nothing much more that a fixed value resistor in this kind of attenuator.

Hope that helps a bit.

I can't think of any reason that the balanced attenuators would sound better, or even different. What will make a difference though is the amount of attenuation that they will provide. 10db attenuators are common (and the ones that I have used) but that might not be enough. You can also get them in 20db and perhaps anything in between. FWIW Rothwell makes a nice in-line attenuator. If the hiss is really loud I'd try the 20db ones first.

Interestingly the output gain of the CJ is either 22 or 27 depending on where you look (different models?) and the BAT is 20. This suggests to me that the BAT output stage is just inherently noisier than the CJ or that the tubes you are using have not been screened for noise, i.e. 'low noise'. Maybe both.

BTW, FWIW, cabling, wires, cords, connectors., etc can have an effect on tone and clarity, but they do not create or reduce 'hiss'. If you really like the BAT's sound more than the CJ, and that's apparently the current issue, just focus on the gain issue, i.e. tubes and/or attenuator. But if the CJ is just as good to your ears when combined with the Rogue, just use it, and put the BAT in the closet until your change your mind. :-)

Veridan, Excellent observation, I missed that.

Zd542, I realize that there can be line noise on single ended connections that may be eliminated using a balanced
system and cable, especially in long runs. But this conversation was not about line noise, it was about 'hiss' originating in the pre-amp which is going to persist when passed on to the amp without change because of cabling and/or connectors. That is my experience. Your comments, without specificity anyway, baffle me, but I'm open to hearing about your experience when you encountered this issue in the past. And the techie stuff to explain it if you are aware. Thanks.............Perhaps we can all learn something.