Rogue Audio amp experience, anyone?

[danvu]

Hi guys,
I'm in the process of obtaining a Rogue Audio Stereo 90 Super Magnum tube amp from a pretty good deal on Agon. I'm wondering if anyone here is pairing their MLs with this model or any other Rogue tube amps. How is the overall experience with Rogue and the sound?
Thanks,
Dan

 

[twich54]

Dan, FYI....we have an 'Amplifier review' section here on the board and if you look you'll see that I wrote up a review awhile back on my Rogue M-150's (upgraded to 180 status last fall)

Short answer.......I love 'em, they are an incredible value, IMO and mate up wondefully with my Spire's.

 

[danvu]

Thanks, Dave. I'll look for your wonderful review on the Rogue . Btw, I'll be using the Rogue 90 to drive the panels and leave bass duty to the Monarchy SM70Pros.

 

[danvu]

Hi Dave,
Just got my Rogue 90 Super Magnum today. I'm using it to drive my Vista panels. It sounds very nice but unfortunately, there's a low buzz that I can hear clearly at 3-4 feet. Even at 10 feet away, I can still hear it when it's quiet. It's fine when the music plays but when it's quiet in transition between songs or when a singer pauses, I can hear it at my close listening position (about 5 feet away) and it's annoying me. I did everything the manual recommends (plugging the amp in the same power strip with the preamp to avoid ground loop, adjusting biases to 35mA). The whole system is plugged into a power conditioner and the KT90 tubes are relatively new (around 100 hours according to the previous owner)

I'm wondering if you have the same problem/can hear the buzz from your ML panels with your Rogue M150's? Is there anything that you or anyone else here can suggest to eliminate or lower that buzz?
Thanks,
Dan

 

[MiTT]

Try unplugging the amp from the power conditioner and plugging it directly to a wall outlet. You don't mention what you're using as a Pre-amp so I'd be curious about that. Also, do you have any home theater components in the system, specifically a cable box? That can contribute significant hum that may not have been noticeable with your previous amp.

 

[danvu]

Hi Tim,
So this is what I found out so far. With the amp turned on and disconnected from from the preamp (a Modwright LS100), the buzz is much much lower, almost inaudible this morning. When I tried it last night, when it's dead quiet, it was very low and I could only hear standing next to the speaker, about the same level as the transformer's hum. So what does that mean? Is the noise from the preamp, ground loop? Or interference/noise that the IC cables pick up along the way and the tubes amplify it? With a Prima Luna Prologue One using the same cables, I also heard a hum/buzz, but nowhere near this buzz. I thought the buzz was low yesterday but after disconnecting the IC cables and comparing, I'd say it's pretty loud. Also, I dont have any home theater components in here as this is a dedicated stereo system. There's a plasma tv though but it is not turned on when I listen to music.
Dan

 

[twich54]

Dan, first off I can state that my M-180's are dead quiet. regarding your 'buzz'.......that sounds like perhaps some other electrical interference, ground loops tend to be a hum and tube distortion is more of a 'rush' (quiet ocean waves if you will)

 

[jmschnur]

Is your amp's plug three prong? If so can you use a two to three prong cheater to see if lifting the ground makes a difference?


J

 

[danvu]

Thanks Dave.
Man, will need to do some debugging here to find the source of the buzz.

 

[twich54]

Is your amp's plug three prong?J

jm, is there a modern day amp that's not ??

 

[jmschnur]

ML 's power cord for the Montis in some countries is two prong.


J

 

[twich54]

ML 's power cord for the Montis in some countries is two prong.


J

j, the Montis is not an 'amp' !

 

[jmschnur]

Ah ah, it has a woofer at the bottom that is powered by an amp that receives electricity from that two prong wire.

Seriously lift the ground and see if the buzz goes away .


J

 

[InterMechanico]

ML 's power cord for the Montis in some countries is two prong.


J

My yamaha A-S2000 uses a two prong. No idea why...but its dead quiet all the way to the top

 

[danvu]

Thank you all for the help. The two prong cheater plug fixed the loud buzz. Now there's only a faint one as when the amp is powered on but not connected to preamp. I guess that's acceptable since it's about the same level and sounds like the one coming from the transformer. Is it right that tube amps are noisier (with some kind of low buzz or hum) than ss and cannot be completely quiet? So far, 3 tube amps that I have tried in my system have either noise and more audible than that of my Monarchy SM70Pros.

 

[twich54]

Dan, as I stated before, neither of my Rogue M-180's produces any 'tube rush' what-so-ever. If you have other tubes to try you may want to do that.

 

[jmschnur]

The fact that the cheater helped means there is a ground loop in your system. This could affect other components . I suggest you search for the source of the loop.


J

 

[twich54]

The fact that the cheater helped means there is a ground loop in your system. This could affect other components . I suggest you search for the source of the loop.


J

Dan, I too concur with 'J' .....check into it !

 

[danvu]

Yeah, I guess using the cheater is just hiding the problem but not solving it. So I agree. I'll hunt it down . Thanks.

 

[jmschnur]

This experiment also confirmed a ground loop so you know for sure there is a problem .


J