Preamps with Dual XLR Outputs

Some of the Audio Research pre’s have dual XLR

Vinnie Rossi Signature L2 can be configured with dual XLR balanced outputs.    Standard is single pair XLR, single pair RCA's, and single pair trigger outputs for amps.  Either the RCA's or triggers can be changed to XLR's.

Questions to W4S:

1. Does the STP-SE preamp support the Balanced XLR AES48 Standard for the 2 XLR outputs?

2. Can I hook up 2 amps to the preamp. I want to use a Benchmark AHB2 amp and a Luxman m900u amp connected to 2 different speaker sets. I would turn one of the amps OFF when using the speakers connected to the powered up amp.

3. The balanced input impedance of your Benchmark amp is 50K; the balanced input impedance of the Luxman amp is 34K. Assuming those numbers apply when each amp is powered down their combined impedance is (50 x 34)/(50 + 34) = 20K

Answers from W4S:

Thank you for your email and interest.

1) yes, everything is star grounded.
2) yes, this will work well assuming the amps dont short the signal when off.
3) the input impedance of the amps are combined when on or off and as long as the paralled value is higher than 15k, there will be no problem.

Thank you and talk to you soon,
EJ Sarmento

BTW - that Luxman c900u does not support AES48. I forgot that I asked the engineers.

The W4S is what I will do a home trial with first. I many even try their w4S Anniversay DAC though the Lumin X1 DAC is something I wanted to try with a preamp that does not have an internal DAC. In about 10 days I see where the money to do this comes from.

am not sure if a tube preamp would work well with the Yamaha NS 5000 speaker. I am also not sure if I would get the benefit of super low noise floor of the Benchmark AHB2 with a tube preamp.

@yyzsantabarbara  A good tube preamp had better not be a tone control! It should just be neutral. This is not a bandwidth thing either- for example the line stage our our preamps goes out to about 400KHz- higher than many solid state preamps. The thing here to be aware of is the brightness of solid state is not on account of frequency response; just about all preamps tube or solid state will be nice and flat in the audio band. The brightness of solid state is the result of distortion, and really not a lot of it because of how the ear works.

The ear uses higher ordered harmonics to sort out how loud a sound is and because it has a range of over 120dB, it has to be very sensitive to higher ordered harmonics. So if a circuit makes higher ordered harmonics even in very small amounts it gets interpreted by the ear/brain system as brightness and harshness. We are talking about THD that might only be 0.005%.


That is different from simply being neutral. Your Yamaha speakers might be easy going on top, but if you put something extended that is also neutral this will not cause them to sound rolled off!

Regarding noise, its nearly all power amps are lower noise than a preamp. Yet people use tube preamps in systems with **horns** all the time; your Yamahas are not as efficient as horns so you've got no worries in this department :)

@atmasphere What you wrote is very interesting. I would like to have a phone conversation with you when I have the cash to buy. I am inclined to get a SS preamp, but I some flexibility in this choice, maybe get both to have some great combinations in the pairings. I need to talk to understand a few things.

Getting very close to buying time. 

Thanks guys and gals who posted suggestions on this thread. I have more than enough options now.