Looking for advise regarding Rogue M180’s

First off - WOW, nice gift!!

The og owner’s claim that the M180 was "too powerful" is a bit odd, and Rogue’s response to them was equally odd. These amps have a very high gain, and that is the main issue when paired to high efficiency speakers. Compounding this - Rogue doesn’t make the quietest tube gear. Yeah - hums and tub hisses are quite common with high sensitivity speakers. If it’s not noticeable from your seating position then don’t worry about it. I’ve long said Rogue should use a 2nd reference system with high efficiency sepakers, so they can hear some of these issues. That said, Rogue can still make some great sounding and high-value tube gear.

It’s perfectly fine to turn on the amp with input open / unconnected. Just make sure it’s hooked up to a speaker - DON’T turn a tube amp on without a load connected to its binding posts. Also don’t connect or disconnect its inputs while it’s on.

The 5751 sub is a good choice for a couple reasons: 1. they have a different sound quality than 12AX7, with more precise imaging at the expense of image size. 2. they have a lower gain by about 1-2dB, which will help in your case. You can also sub 12AY7 and lose another dB or 2 of gain.

The KT77 sub (and bias adjustment) is fine, but not strictly necessary. The EH KT90 tubes sound a little bright and lean / dry through mids, so you might well prefer GL KT77.

An RP-1 is not anywhere near the performance level of those M180. The Hera is one of my favorite preamps ever - but it’s got a very high gain, so you’ll probaly be cutting its gain knob all the way down. And you’ll still probably be hearing some tube-rush "hisss" through your high sensitivity speakers - even from your sitting position. You’ll also hear that trademark "pting-tashhhhhh" sound of its 6H30 tubes when they’re disturbed (mute / unmute). But past that, I think it should be an amazing sounding combo! I preferred Hera to their current flagship RP-9. The RP-9’s sound reminded me a lot of those EH KT90 - not bad, but not my thing.

  @audphile1 , Thank you for your input, your experience with a vast amount of gear and your straightforward recommendations are always appreciated.                                  @mulveling , I was hopeful you’d respond and save me sending a PM. I’ve long read your advice and admired your equipment. Your knowledge of tube gear including Rogue is greatly appreciated. Your comments on small tube sound characteristics has been invaluable to me.                                                                              I was concerned about the input being open Vs closed by means of a shorted input connector. Having read online I noted in guitar amp forums it was stated to short the input when checking for hum. As I’m planning on using the JBL’s, I’m not too concerned with the noise I get with high dB speakers like my Zu and Klipsch. I also didn’t realize the the Hera had such a high amount of gain and that would explain the original owners complaints of too much power. FWIT the original owner was formerly a dealer that changed careers and went into estate law. I know he carried Rogue, Modwright, Acoustic Zen, and Dali. He once loaned me a Modwright KWI 200. After the Rogue gear he had a full quiver of Bryston with Dali stand mounts and JL Fathom subs. His current system is Macintosh and B&W’s. His room is treated with GIK items. I couldn’t live with those B&W’s, the tweeters are deadly. 

I'm not sure I have much to add, mulveling covered a lot of ground. As he said, some hiss is normal with high efficiency speakers. I think I had Klipsch speakers when I had my M180s and if you got close to the tweeters, you could hear some hiss, but while listening it wasn't noticeable.  Also consider the KT120 power tubes and give the triode / ultralinear modes a try, and try both the 8 and 4 ohm taps. I preferred ultralinear, but triode might be better with the Zu speakers. It's worth experimenting. And yes, nice gift!

Having said that, if it was me, once you are confident they are working properly, I would consider flipping them and getting lower powered tube amps that are better suited to your speakers.

@big_greg , thanks for your input. I have Zu, Klipsch, and JBL 4312A’s that are in excellent condition. My front end is Innuos, Schiit Yiggy, Thorens TT with Grado Prestige. I’m currently running the Rogue RP-1 with Telefunken G73-R’s , vibration isolation under footers and upgraded power cord. I’ve reached the limits of what it can do without adding a separate phono stage. I have a Dennis Had Inspire Sep amp with 1/2 doz NOS rectifier tubes, 8 NOS input tubes, and about 10 pairs of power tubes from NOS GEC to KT-150’s. I rotate that with a modded Akitika SS 50wpc amp. My long plan is an entire new back end with a better pre and some speakers that like that much power. I will not connect them with the ZU’s at all. I was considering new tube monos when I was gifted the M180’s. I live about 2 hours south of Quicksilver and was considering the KT’s as Mike recommended at least 100 wpc for my JBL’s. However as a near field studio monitor, they are not that musical. If this works out I’ll be looking at some speakers in the $10K region which is a lot for my modest income. And again your comments are appreciated. Regards, Mike B.

I has some of Quicksilver's Horn monoblocks for a while and they were really good with my Klipsch Chorus speakers.  I was most impressed by how quiet they were. 

I moved away from tube amps, as much as I like the sound, I got tired of the issues with tubes, the heat, and cost of replacement tubes.  

I like the combination of solid state amps and a tube pre.  My current setup is PS Audio M1200 monoblocks, Herron Audio VTSP-360 preamp, and Gershman Studio Xdb speakers. The Gershmans are pretty hard to drive and the M1200s handle them well.

If you are going to go down the nearfield monitor route, it's hard to go wrong with either a LS3/5 variant or Harbeth P3ESR.