[mpcrelly]

I have two tube amps.  one is a 16wpc chinese with one 6n3 tube per channel.  I'm not sure what that means for a tube circuit design, but that amp is NOT tireing to my ears.  my other is a rogue audio cronos magnum (100wpc) with 2 kt120 power tubes per side.  from the first time I listened to the amp (possibly cold, less than 30min warm up) it sounded o.k., but one of my ears started to ache.  I was not playing it loud at all.  over the next few days (going on the 6th today) I've thought that my ears are responding to something in the sound that maybe I can't hear.  when I get done listening for maybe a couple of hours, it takes many more hours for my ears to feel relaxed and hearing clearly??

believe me I wanted to have this amp sound wonderful, which it does, but I did not expect this tired ear response.  I'm going to try and listen JUST to my chinese or bryston b100 amp tomorrow and see how my ears feel.

again I'm not trying to play super loud for long periods of time just moderate, like 80-85 dbc most of the time

thanks for your feed back!!

mike

[Ericus Rex]

Are the tubes fully broken in?

[FullRangeMan]

Is the Cronos push pull or ultralinear??

P.S.> One 6N3 is a SET class A circuit.

[kernelbob]

Any chance of ultrasonic energy going on?

[electricbear]

You should try and borrow a spectrum analyser like the Sencore SP295 and see if there is anything weird going on.

[medium jim]

Sounds like your tubes might need to be biased.

Jim

[rollo]

   My guess is if not played in awhile it needs time to settle in again. If bias is OK, tubes OK [ meaning broken in ] then sorry to say it is what it is in your system. The Cronos is not hard or bright sounding in any way or form. If you changed tubes maybe the tubes are just not good sounding.
   It would be helpfull to know what was not liked. Top end ? Upper midrange, both ?


charles
   

[rooze]

Microphonics maybe? tube ringing?

I remember my Aesthetix preamp sounding more 'relaxed' with Herbie's tube dampers...

[catastrofe]

   My guess is if not played in awhile it needs time to settle in again. If bias is OK, tubes OK [ meaning broken in ] then sorry to say it is what it is in your system. The Cronos is not hard or bright sounding in any way or form. If you changed tubes maybe the tubes are just not good sounding.
   It would be helpfull to know what was not liked. Top end ? Upper midrange, both ?


charles
   

I think it sounds fine to the OP, but he's experiencing fatigue caused by something outside the audible band. 

[Scott F.]

I'd bet my paycheck that the issue is the driver tubes. The Cronus uses 12AXs and 12AUs. Depending on the brand use are currently using, I would point to those as the issue. AXs and AUs have HUGE swings in sound quality (SQ). You're probably running either the stock tubes, that or EH or Sovteks. None of those give you the best SQ from an amp. Try some NOS AXs and AUs. You'll find that the SQ will change pretty dramatically.

For me, Mullards (old label) and Telefunkins are the best sounding NOS tubes out there in the AX and AU series. Others will suggest decent lessor priced tubes, some new production. I'm (personally) not a fan of those but they are an option if you don't have the cash to invest. Then again, tube rolling can be a nice adventure. The experience is well worth it.

...just my $.02

[galyons]

I have Rogue Magnum  M150's with the Rogue audio upgrades.  IMO, they are voiced to be 'detailed', like solid state.  I had to pull the Mundorf Supreme plastic caps and replace with PIO's to get a more relaxed, musical voicing.  Everyones ears/brains are sensitive to different voicings, so YMMV.  But, to me, the improvement in timbre, imaging and musicality was not subtle.

Cheers,
Geary

[medium jim]

What's curious is that it is in only one ear?

Jim

[decal]

What's curious is that it is in only one ear?

Jim

I was thinking the same thing Jim. Maybe a trip to the audiologist is in order.

[rpf]

I'd bet my paycheck that the issue is the driver tubes. The Cronus uses 12AXs and 12AUs. Depending on the brand use are currently using, I would point to those as the issue. AXs and AUs have HUGE swings in sound quality (SQ). You're probably running either the stock tubes, that or EH or Sovteks. None of those give you the best SQ from an amp. Try some NOS AXs and AUs. You'll find that the SQ will change pretty dramatically.


...just my $.02

Agreed. The small signal tubes in the Cronus Magnum have a very large effect on the sound: much more so than most tube amps.

[mpcrelly]

ok, wow thanks for all the responses!  I'll try and address all various queries.

ericus: I've played the amp for probably about 20hours so far and checked/adjusted bias 3+ times with minor 1or2 miliamps? adjustments.

kernelbob: I tried using a audio spectrum app on my galaxy s3 to see if there was any higher stray frequencies.  when I was younger and my ears were better I'd hear tv's and monitors whining at 15khz.  with the app I've seen occasional 15k and 20/21khz tones that are constant for a few seconds and fairly strong.  I've tested the app on different room situations and seen it at friends house and work, so I'm kinda ruling that out.  at least below 21k...

electric bear: see above

medium jim see above

rollo: whats weird is tangibly speaking (?)  the music seems to sound fine.  the fatigue or ache seems to be an after effect or accumulates during the listening session.

rooze: microphonics, tube ringing?  I've hear OF these terms, but not sure if I've really experienced them. 

scott f.:  the tubes are 4 tung sol kt120, (3) 12au7 (jj ecc 82), (2) 12ax7 (jj ecc  803s) http://www.facebook.com/photo.php?fbid=10151437938846170&set=a.10150245236816170.343571.500066169&type=1&theater

medium jim: one ear?  only on the first day and it was my good ear not prone to sensitivities.  now both ears, not as much pain, but feels like my ears are relieved when I stop the music, even soft music and turn off the amp.

New question:  alright what low to mid priced tube rolling suggestions???  pre or power or both??  I'm trying to get this evaluation done before my 30 return policy runs out! 

thanks!!
 

[mpcrelly]

OK THIS MIGHT BE MY PROBLEM....

I remember while hooking up my amp and putting the power tubes in that half way through I realized they were numbered with the position markings V1, V2, V3, V4  (on the box)  being a tube newbie I thought maybe this would not be a big deal as long as I let them burn in and recheck the biasing.

apparently rogue pre burns in the tubes and takes them out and puts them in numbered boxes.

so the big question is: does this mean two tubes that burned in together or all four will not sound right if not in their burn in positions???  can I reverse it or have to buy new tubes!!???   

[Ericus Rex]

The power tubes in the Cronus are individually biased so don't worry about not putting them in the proper spots...so long as you've properly rebiased them.

Tubes require at least 100 hours before fully broken in.  If you want to roll for fairly cheap I'd recommend going with NOS American tubes: RCA, GE, Sylvania, etc for the 9 pin.  They usually can be had for not a lot of dough.  You can try EL34s in that amp and a quad of SEDs is not too much dough.  NOS power tubes are far too expensive for the most part.  But 1980's stock RFT/Siemens sound great and aren't too expensive...compared to other NOS power tubes.

Personally, I'd give the tubes another 20-30 hours before dismissing the amp or spending more money on tubes.  Have you tried altering your speaker position?  I find when I get that 'head-in-a-clamp' feeling a little toe-out helps.

[Ern Dog]

Try pulling each tube out of the socket and re-setting them back in. 

[mpcrelly]

ern dog: bad connection?

[mpcrelly]

talked to rogue today and they suggested I continue to try and burn in the amp more.  says amps are burned in about 24 hours at factory.  suggested I try rolling the center preamp tube to a used or old stock 12au7.  says they use JJ tubes for reliability and certain models for sound they thought was good.  don't know if the tung sols are currently produced.  he suggested telefunken, rca, or sylvania for rolling the preamp tube.

he said the tube numbering for positions of the power tubes was just to help initial bias matching and that if I rebiased each that was fine.