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New to tubes

I have just acquired a new Rogue Audio Cronus Magnum integrated amp, which is my first foray into tubes. The amp is rated 90 watts per channel and I was told by my dealer (as well as read posts here suggesting the same) that tube power counts double when compared to ss. If so, I am a little confused why I have to turn the volume knob much higher (to about 2 o'clock position) on the tube amp than I had to on my old integrated Rotel amp rated at 60 watts per channel to get the same level of loudness when listening to my tt? I never had to turn past 12 o'clock to get sufficient volume from the Rotel. The associated gear is the same, my speakers are 88 dB efficient and I've tried both the 4 and 8 Ohm taps with the same result. Is it normal? Everything seems to be in order otherwise.

Also, is there a good resource you could recommend that discusses tubes in general? Things I'd like to know about are: maintenance--how often tubes need to be replaced, how do I know when they need to be replaced, why and how to clean the sockets; how long I should warm the amp for before doing serious listening; tube rolling (i.e., what are different types/brands of tubes I could try with my amp), etc...

RA has been great with answering my basic questions, but from their one line replies I get a sense I would not get a meaningful answer to all of my questions. And perhaps they shouldn't have to since there is such a wealth of knowledge out there, including this forum.

Thank you.
actusreus
actusreus OP
733 posts
 
Yes, it does. Thank you very much for your advice.

As far as the power rating, Magnum is an upgraded regular Cronus; a Cronus on steroids, if you will. It has 4 KT-90 tubes, instead of EL34, hence its higher power. It has more upgrades as well, such as better power supply and upgraded internal components.

As far as the speaker impedance, my Totem Hawks have a nominal impedance of 6 Ohms and according to the manufacturer, very stable and never dropping below 5.2. The sound is still glorious; perhaps bass a little less tight than before but the highs and midrange simply heavenly.
sogood51
2,157 posts
 
I just sold my other tube preamp, but the difference between volume control settings on that preamp (two O'clock for loud)...and the preamp I still use is quite large (ten O'clock for loud)....same amps for both preamps.

Pretty common.

Dave
dan_ed
2,451 posts
 
Double the power because of tubes? Your dealer lied.
dan_ed
2,451 posts
 
what happened to the edit feature! :-)

the knob position thing isn't comparing apples to apples most likely. that could happen between any preamp/amp, integrated depending on the position of gain stages or ration of attenuation.
cmalak
681 posts
 
Is the difference in loudness (at same volume setting between two integrateds) only there when playing TTs and not when playing CDs? If so, what cart are you using? If low or meium output MC cart, that will explain the lower loudness because the phono in your Rogue Cronus is an MM phono set for 47Kohm loading and 150pf capacitance and with only 35dB of gain. So if you are using a low or med output MC cart, there is not enough gain in the phono section. If that is what is going on, you will need to get an MM or a high output MC cart. Let us know if you figure it out. Thx
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