Low output gain amplifier for ZU 101db Efficient speakers

My RP-5 arrives at Rogue today. Hopefully, they can fix the super loud white noise (plus buzzing in headphone section). My goal is to keep the RP-5

I'm updating my power amp by the end of the year regardless how quiet the RP-5 comes back. I'm keeping my ZU omen defs. I really want a tube power amp. I also understand the firstwatts are fantastic.

Anyway, here are the specs for the RP-5:

- Tube complement: 4 x 12AU7/ECC82 tubes
- Frequency response: 1Hz – 100KHz +/- 1 dB
- THD: <0.1%
- Gain line stage: 10 dB
- Rated output: 1V
- Maximum output: 27V RMS
- Output impedance: 500 Ohms
- Gain phono stage: 40dB, 50dB, 55dB, 60dB
- RIAA accuracy: +/- 0.1 dB
- Dimensions: 18.5 ”W X 4.5 ”H X 14.5” D
- Weight 30 pounds
- Shipping weight 45 pounds
- Power requirements 115/230V – 50/50Hz

For reference, the specs of my current amp:

-GeneralPower output80W x2Ch @ 8 Ohm
-Input impedance51k Ohm
-Output impedance30m Ohm*
-Gain34.8dB
-Frequency response20Hz - 80kHz
-Sensitivity0.45Vrms
-Signal to noise ratio100dB
-Total harmonic distortion<0.03%
-Power supply115 / 230V
-Power consumption3.15A/ 1.57A
-Nominal input level0.6V

Now, with the above specs in mind, along with buying blind (I'll make sure there's a good return policy). What amp specs should I be looking at for low noise and good matching with the RP-5 and Zu's? I'm not looking for brands...just specs where I can at least narrow down my choices. I'm not worried about having high power. The 80 (SS) watts I currently have is more than enough for my speakers. 

I know my current amp does have high gain (34.8) for my system, however, with my old Peachtree Nova, the amp hiss was only audible if I placed an ear on tweeter.

Here are the Nova Pre specs:
Variable RCA Stereo Output: 7V rms/11.2V peak •
Pre Out 1 Output Impedance: 50 Ω (discrete class A) •
Pre Out 2 Output Impedance: 15 Ω •
S/N at the Variable Analog Output: 96db •
Jitter Measured at the Master Clock: < 3.0ps •
Power Supply: 8700µF of filtering •
Stereo Separation: 94db • Maximum Power Consumption:
60W, standby less than 1W


Thanks for your help. Looking forward to responses. Once I hear back from Rogue, I will report their findings

"   One thing I could also do is go to a high end passive preamp. "

which I offered to you to try and sent you a message, but you never got back to me.     would have been really no money out of your pocket except for return shipping.....

With speakers that are over 98dB there's really no advantage in having a preamp with gain, as you've found it's a diadvatage, you'll find many now are starting to go for passive preamps as per this Nelson Pass quote:

George I heard Nelson say basically the same thing in an interview but then he qualified it by saying that his amps sound better with an active preamp. He basically said that it’s an unexplained phenomenon. 

Honestly, with that much gain in the pre-amp, all you really need is an impedance converting amp. You don't need an amp that provides ANY voltage gain given the extreme sensitivity of those speakers. You're close to getting away with running the output of the pre-amp straight into transformers and right into the speakers. The amp I'd be looking for would be one, maybe two, stages at the very most. It would have a mediocre damping factor of 15 or 20. 20 watts through those speakers would literally deafen you in very short order. It's not hard at all to get VERY respectable distortion out of a single ended design with the kind of power you need. Speakers like those are EXACTLY the kind of speakers Nelson Pass had in mind when he designed the F4. The problem with the F3 is it has a low input impedance that might not mate well with a tube line stage and it's got a weak damping factor. But, it does have some modest gain you might want. The problem with all the old First Watt amps is Nelson only builds 100 of them. They're like hen's teeth to find and they tend to find homes they never leave. The upside is you can build you an F3 or F4 for about $1000, and if you don't like either, it's a very small investment to just yank the amp boards and mount new ones; like maybe $200-250. That's a hell of a deal for a totally different amp. The J2 is still for sale and that's well known as being an excellent amp for Zu speakers. In any event, it would be worth looking over the specs for those amps at the First Watt page and maybe reading through the owner's manuals. Those are the kinds of specs you're going to be wanting to look for. Modest power, mediocre damping factor, decently high input impedance, possibly single ended, low noise. I wouldn't sweat crazy low distortion numbers because you're not going to be needing so much power that the distortion will rise much. 

I have read a couple of faverable reviews with the J2 paired with ZU speakers. RENO hi fi has a couple demo j2s for sale