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Received My New To Me Cronus Magnum

100.40.101.47
Posted on August 29, 2014 at 13:28:42
stereo5
Audiophile

Posts: 1356
Location: New England
Joined: June 22, 2008



I received a Cronus Magnum with the KT120 tubes. I am quite impressed with the quality considering the price. So far, the amp is working perfectly and I am using the stock KT120 tubes. The previous owner said they have around 175 hours on them. The amp is very quiet. I did have to change the transformer tap to 4 ohms as my speakers sounded better at that setting.

The presentation is quite different to what the Rogue amp replaced which was an Audible Illusions Modulus 3A preamp and a Classe' Fifteen 175wpc solid state amp. I may fool around with the signal tubes once I get more familiar with the sound.

I set the bias for the KT120 tubes at 35ma. Is this what Rogue recommends?


"I've always been mad, I know I've been mad, like the
most of us...very hard to explain why you're mad, even if you're not mad..."


 

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RE: Received My New To Me Cronus Magnum, posted on August 29, 2014 at 14:26:33
fantja
Audiophile

Posts: 15518
Location: Alabama
Joined: September 11, 2010
 Beautiful pic! Maybe Abe will chime in he has been using Rogue for some time now.

 

RE: Received My New To Me Cronus Magnum, posted on August 29, 2014 at 17:19:50
AudioSoul
Audiophile

Posts: 4594
Location: north central AZ
Joined: July 9, 2005
Congrates on receiving your amp intact. They are heavy suckers aren't they? Let us know how it plays well with your other components....

 

RE: Received My New To Me Cronus Magnum, posted on August 29, 2014 at 18:37:39
Gary
Audiophile

Posts: 1294
Location: New York, NY
Joined: April 21, 2000
 35ma is the bias setting recommended by Rogue. I've had mine for almost a year. I still think it's one of the best audio purchases I've ever made. It's the only tubed component for which I never had the urge to try different tubes. I like it just the way it is. Enjoy yours.

 

RE: Received My New To Me Cronus Magnum, posted on August 29, 2014 at 22:06:43
AbeCollins
Audiophile

Posts: 46280
Location: USA
Joined: June 22, 2001
Contributor
  Since: February 2, 2002
I'm very impressed with the Cronus Magnum and enjoy mine a lot. It has a full bodied robust sound w/o being 'dark' or 'thick'. I've owned much more costly equipment, both tube & SS, and the bargain Rogue is right up there with the best of them, and better in some cases.

Mine originally came with Chinese EL34 tubes and it sounded pretty bad initially. I think the problem was the lower power output from the EL34s barely driving my not so sensitive Thiel CS2.4 speakers.

Switching to KT90 power tubes and moving the speaker binding post taps to 4 Ohms made a huge difference with the Thiels. The music came alive with dynamics and clarity and was perfectly enjoyable at that point but....

I decided to pony up some cash for a quad of KT120s which if I recall correctly set me back about $200. Wow! The KT120 is an incredible tube and that's what I've been running ever since.

I haven't tried swapping the small signal tubes. Mine came with a couple JJ's and some pretty commonly available and cheap NOS tubes. I might try playing with those this winter.

One of my first systems is similar to yours. I had a Classe 10 SS amp driven by a CJ PV-12L tube linestage back in the early 1990s. I liked it a lot but honestly, I don't remember how it sounded.

How would your describe the Cronus Magnum sound vs. your Audible Illusions / Classe combo?

You got a great 'little' tube amp there. Enjoy!




 

I had one of the early amps, posted on August 29, 2014 at 22:28:27
Frihed89
Audiophile

Posts: 15703
Location: Copenhagen
Joined: March 21, 2005
 It was exceptionally good for an entry-level tube amp and like you I didn't like the EL34s and quickly switched to KT77s. I sold it about 6 months later and got my money back, since I bought it used. Very stable bias. But in those days there were no KT90 or above, as i recall. It convinced me i wanted more!

 

RE: Received My New To Me Cronus Magnum, posted on August 30, 2014 at 09:33:44
abs1
 Congratulations on your Cronus Magnum!

I purchased my Cronus Magnum new with the KT120's factory installed. I've owned it for over a year. The factory owners manual that was supplied with my amp specified 35mA bias, so that's where I keep it set.

I've not yet done any tube rolling with it.

Cheers,
Al

 

Ah, Christmas in August, posted on August 30, 2014 at 09:51:35
airtime
Audiophile

Posts: 11287
Location: Arizona
Joined: February 4, 2003
 Sweet! Now email Jim McShane and enjoy some good old fashion tube a-rollin.

enjoy
charles

 

If KT 90s were good and KT 120s are better, posted on August 30, 2014 at 10:17:25
M3 lover
Audiophile

Posts: 6599
Location: SW Mich
Joined: May 29, 2005
Contributor
  Since: July 4, 2007
 how about the newer KT 150? Are they compatible with the Cronus Magnum?

The little I've read about them sounds favorable.

"The secret of life is honesty and fair dealing, if you can fake that you've got it made." Groucho

 

RE: If KT 90s were good and KT 120s are better, posted on August 30, 2014 at 13:44:00
mulveling
Audiophile

Posts: 222
Location: Atl
Joined: April 29, 2011
 I called Rogue a few months ago and they advised against the KT-150 in their current amp lineup. The KT-120 are the way to go, and they're half as expensive.

 

RE: Received My New To Me Cronus Magnum, posted on August 30, 2014 at 16:40:46
Mendel
Audiophile

Posts: 1207
Location: GTA
Joined: January 17, 2009
 When you decide to try tube rolling, I would start with the 12ax7 input tubes. They will make the biggest difference. Quality NOS 5751s are nice, as are RCA or Raytheon blackplates, Matshushitas, Seimens 12a7s or Mullards if you want warmth.
Rogue amps are great.

 

RE: Received My New To Me Cronus Magnum, posted on August 30, 2014 at 17:07:27
marc g.
Audiophile

Posts: 3330
Location: New Orleans
Joined: October 14, 1999
 I've no reason to think this integrated would outperform my AtmaSphere amp and pre system, but I'd love to hear it considering the high praise it tends to receive for its sound quality and perceived value. That, and still I dream about a lil' integrated to cut down the gear clutter :-) Enjoy!

voolston - audiophile by day, music lover by night!

 

RE: Received My New To Me Cronus Magnum, posted on August 30, 2014 at 19:25:19
Trouser Trout
Audiophile

Posts: 286
Location: New England
Joined: August 25, 2010
 Congratulations on the new addition! I've had my Cronus Magnum for several months now. Same silver face as you have, same fan in the window too. Throws off to much heat for the summer so I've been using a spare integrated.

My unit is pre-owned and shipped with 4 different pairs of power tubes. The KT120 are my favorite for both power output and sound. I've been rolling the small signal tubes and currently have a RCA clear top 12au7 in the center, 2 CBS/Hytron 5814 on the outsides and 2 GE 5751 triple mica black plates in the front.

After a few problems in the beginning it has really grown on me. Just the right amount of "tubeyness"

Having to remove the cover and fumble around near high voltage wiring to change the taps is pretty tacky.

 

RE: Received My New To Me Cronus Magnum, posted on August 31, 2014 at 06:09:43
tube524
Audiophile

Posts: 254
Joined: August 1, 2009
 There is a review by HiFi News and Record Reviews in the September 2014 issue.

t.

 

RE: If KT 90s were good and KT 120s are better, posted on August 31, 2014 at 12:17:20
AbeCollins
Audiophile

Posts: 46280
Location: USA
Joined: June 22, 2001
Contributor
  Since: February 2, 2002
 Same here. When I inquired about using KT-150s in the Cronus Magnum they recommended staying with the KT-120. I thought the KT-120s were a bit pricey but a quad of KT-150s would put a huge dent in my wallet.

 

RE: Changing Preamp Tubes?, posted on August 31, 2014 at 12:19:20
stereo5
Audiophile

Posts: 1356
Location: New England
Joined: June 22, 2008
 Wow, I can't believe so many chimed in on the amp, I appreciate all the information that everyone has given me. I have been listening to the integrated for the last 3 days, 8 hours a day since it is in the room my computer is in. The listening is mostly casual while I concentrate on my work via computer. My biggest observation is that I am not getting the bass that I was getting previously when my Classe' 15 amplifier (175wpc) and Modulus 3A tube pre were being used.

Is there a preamp tube that I can change to ripen the midbass/lower midrange, and if so, what?


"I've always been mad, I know I've been mad, like the
most of us...very hard to explain why you're mad, even if you're not mad..."


 

RE: Received My New To Me Cronus Magnum, posted on August 31, 2014 at 12:23:46
AbeCollins
Audiophile

Posts: 46280
Location: USA
Joined: June 22, 2001
Contributor
  Since: February 2, 2002
 Same silver face as you have, same fan in the window too. Throws off to much heat for the summer so I've been using a spare integrated.

Me too. I'm running a solid-state integrated most of the day but not because of heat. If I'm listening to background music while I work, I can't justify burning up a good batch of tubes in the Rogue.

Having to remove the cover and fumble around near high voltage wiring to change the taps is pretty tacky.

High voltage wiring? It's only 'high voltage' if you forget to turn the amp off and let the caps discharge. ;-)

For most folks I don't think this is a problem. I swapped the taps inside once, and I'm set. If you look inside and on the outer surfaces of the chassis, I can't see where there would be room for a pair of toggle switches to change taps.

 

RE: Received My New To Me Cronus Magnum, posted on August 31, 2014 at 12:26:46
AbeCollins
Audiophile

Posts: 46280
Location: USA
Joined: June 22, 2001
Contributor
  Since: February 2, 2002
 Rogue amps are great.

Rogue tube amps are great! ;-)

I tried one of their hybrid class D amps (Medusa) and it was horrible. Worse than a couple 'standard' class D amps I've owned.



 

RE: If KT 90s were good and KT 120s are better, posted on August 31, 2014 at 12:43:10
stereo5
Audiophile

Posts: 1356
Location: New England
Joined: June 22, 2008
 I think a quad set of matched KT150 tubes at The Tube Store are around 430.00. Too pricey for my wallet.


"I've always been mad, I know I've been mad, like the
most of us...very hard to explain why you're mad, even if you're not mad..."


 

RE: Received My New To Me Cronus Magnum, posted on August 31, 2014 at 12:46:46
Trouser Trout
Audiophile

Posts: 286
Location: New England
Joined: August 25, 2010



Oh, You have to unplug it. ;^)


 

RE: Changing Preamp Tubes?, posted on August 31, 2014 at 13:55:17
AbeCollins
Audiophile

Posts: 46280
Location: USA
Joined: June 22, 2001
Contributor
  Since: February 2, 2002
I don't have a tube recommendation to get more bass out of the Rogue. I can only confirm what you're hearing. The most 'robust' and 'full-bodied' sounding system I ever had was the Pass Labs X150.5 SS amp driven by the very dynamic and 'robust' Cary SLP-05 tube linestage. That being said, speaker placement relative to the walls and your seating location might bring up the bass. I had too much bass in my smallish listening room with the Tannoy speakers. Repositioning the speakers a bit made a big difference in my case.



 

RE: Changing Preamp Tubes?, posted on August 31, 2014 at 16:01:21
stereo5
Audiophile

Posts: 1356
Location: New England
Joined: June 22, 2008
 What about something that would ripen the midrange a bit? I want the sound a bit more lush but don't want to change output tubes.


"I've always been mad, I know I've been mad, like the
most of us...very hard to explain why you're mad, even if you're not mad..."


 

RE: Changing Preamp Tubes?, posted on August 31, 2014 at 17:52:59
classfolkphile
Audiophile

Posts: 533
Location: Florida
Joined: December 17, 2002
 What small tubes are you using now? Driver, and phase splitter as well as pre-amp.

You might check out my recommendations below on your previous thread. They will give you about as much fullness as you can get. Also add the Tungsram 12AU7 and 12AX7 to the list.

 

RE: Changing Preamp Tubes?, posted on August 31, 2014 at 23:29:55
AbeCollins
Audiophile

Posts: 46280
Location: USA
Joined: June 22, 2001
Contributor
  Since: February 2, 2002
I really couldn't tell you. A wild guess might be Mullard small signal tubes but others here are more qualified in this area. I have yet to tube roll the small tubes in my Rogue.





 

RE: Changing Preamp Tubes?, posted on September 1, 2014 at 02:14:56
Nunki
Audiophile

Posts: 644
Joined: November 27, 2010
 i switched over to RFT ECC82/12AU7 in my ATLAS magnum. clearer, "darker" bass performance as result. (as a tube collector i have tested dozends of brands in my gear...).
i also gave away those KT120 tubes the amp came from stock. with a great start after approx. 100 hours they turned over to a flat, boring and muddy performance. the worst output tube i ever met. can`t tell the reason for this but many others confirm this experience.

i am happy with penta KT88SC now.

Nunki

 

RE: Changing Preamp Tubes?, posted on September 1, 2014 at 06:28:25
abs1
 Please point out the "many others" who "confirm this experience". I can't seem to find that sentiment here.

Cheers,
Al

 

RE: Changing Preamp Tubes?, posted on September 1, 2014 at 06:54:14
Nunki
Audiophile

Posts: 644
Joined: November 27, 2010
 read the statement of member "xti16" in

http://www.audioasylum.com/cgi/vt.mpl?f=tubes&m=258804

for example.

3 other of my audio mates here in europe had the same probs with their KT120. if you like that tube, stick with it but may be we all had bad charges in our amps.

N.

 

RE: Changing Preamp Tubes?, posted on September 1, 2014 at 09:55:18
AbeCollins
Audiophile

Posts: 46280
Location: USA
Joined: June 22, 2001
Contributor
  Since: February 2, 2002
I read the link you provided and it appeared that the vast majority (all!) had nothing but praise for the KT120. I honestly didn't understand the post by xti16. It seemed to me he didn't like the KT120 tube but changed speakers then liked the tube again. I didn't quite follow but I just skimmed his post.

I have no complaints with my KT120s and I'm sure I have well over 100 hours on them. Just for grins, I'll go dig up my KT90s which are stored somewhere in the basement.

Will the Rogue take KT88 or 6550? I have plenty of those too.


 

RE: Changing Preamp Tubes?, posted on September 1, 2014 at 10:21:39
Nunki
Audiophile

Posts: 644
Joined: November 27, 2010
 hm.... i can only speak for my magnum. it can take from EL34 over KT77 any tube up to KT120 and of course 6550/KT88/KT90. bias for EL34 may be 30 mA only! even the stronger types take not more than 35 mA. (they would not sound better at 40 or 45 mA)

my logic says that this amp design can only work perfectly with one tube type and not match with all the others. nevertheless it sounds great with each type (exept my quad KT120)- very funny...

N.

 

RE: Changing Preamp Tubes?, posted on September 1, 2014 at 11:31:44
AbeCollins
Audiophile

Posts: 46280
Location: USA
Joined: June 22, 2001
Contributor
  Since: February 2, 2002
I know that the original Cronus non-Magnum was designed around the EL34. My Magnum version came with EL34s and they were horrible sounding but possibly due to insufficient power to drive my Thiel speakers and I had no idea how many hours were on those tubes.

I plucked out the Chinese EL34s in a hurry and installed a quad of KT90 and that was a huge step up in performance. The KT120s were even better but now that I have 100+ hours on them I might try the KT90s again.

I may be wrong but my assumption is that the Atlas Magnum is essentially the Cronus Magnum w/o the linestage section.

Thanks.

 

RE: Changing Preamp Tubes?, posted on September 1, 2014 at 16:07:04
abs1
 Nunki,

I read xti16's post and it seemed to me that he really liked the KT120's on his Raidho speakers. Did you interpret his post differently? I guess that the KT120's are so inferior that ARC, Conrad-Johnson, Rogue, and many of the other tube manufacturers have adopted them as standard equipment;-)

Abe,

To the best of my knowledge the Atlas Magnum is the same as the Cronus Magnum minus the preamplifier section.

I tried the KT90's in my friends Atlas Magnum before I bought my Cronus Magnum w/KT120's. If I all I had available was the option of KT90's I wouldn't have bought my Cronus Magnum. The KT120's kicked the KT90's butt. Smoother all across the board, more pronounced mid-range (in a good way) and way better bass. I'd advise you to save your money and don't waste your time. But as always YMMV, horses for courses, and all that stuff :-)

Cheers,
Al

 

RE: Changing Preamp Tubes?, posted on September 2, 2014 at 09:04:49
mulveling
Audiophile

Posts: 222
Location: Atl
Joined: April 29, 2011
 Any of the following small tube swaps have yielded me an improvement towards a lush, beautiful midrange in my Apollo monoblocks:

* GE 5751 TM BP "silver clips" version (1952-54 only) -- excellent tube. The non-"silver clips" TM BP GE can be good too, but not as good.
* Mullard 12AX7 long-plate (late 1950's) -- surprisingly amazing clarity (though not a lot of lushness) compared to the wooliness of the later Mullard short pates and box plates
* 12BH7 Sylvania oval BP (neutral, but smoother and more weighty than a 12AU7) or RCA (warm; all variants). Sylvania gray-plates are not as good in my experience (leaner, maybe strident). RCA will give an additional mid/upper bass boost. Use in place of 12AU7. Also the round-plate Japanese 12BH7 (often branded "Channel Master") are good. Tung-Sol are a bit bright.
* GE TM gray plate 5814 -- I also like these, though they're not as good as the best 12BH7; use in place of 12AU7

 

RE: Changing Preamp Tubes?, posted on September 2, 2014 at 11:24:06
AbeCollins
Audiophile

Posts: 46280
Location: USA
Joined: June 22, 2001
Contributor
  Since: February 2, 2002
Big power tubes are fun to roll ;-)

But I think the smart money says to try the small signal tubes first.

Thanks.

 

RE: Bought A Tube, posted on September 12, 2014 at 13:45:11
stereo5
Audiophile

Posts: 1356
Location: New England
Joined: June 22, 2008
 I bought a Mullard CV4003/12au7 nos tube from Upscale Audio. It was expensive, but it gave me the midrange richness I desired. I am quite the happy camper at this moment.


"I've always been mad, I know I've been mad, like the
most of us...very hard to explain why you're mad, even if you're not mad..."


 

RE: Bought A Tube, posted on September 13, 2014 at 09:27:30
abs1
 stereo5,

Thanks for the heads-up on that Mullard from Upscale Audio. I'm going to try one. Can I assume that you used it in the center (preamp) tube position?

Cheers,
Al

 

RE: Bought A Tube, posted on September 13, 2014 at 16:51:11
stereo5
Audiophile

Posts: 1356
Location: New England
Joined: June 22, 2008
 Yes, the center tube is the only preamp tube. The Mullard isn't cheap, but it's worth it. It truly transformed the amp.


"I've always been mad, I know I've been mad, like the
most of us...very hard to explain why you're mad, even if you're not mad..."


 

RE: Bought A Tube, posted on September 14, 2014 at 08:58:09
abs1
 Thank you stereo5, I thought so. I'm going to order one right away.

Cheers,
Al

 

RE: Bought A Tube, posted on September 14, 2014 at 16:31:41
stereo5
Audiophile

Posts: 1356
Location: New England
Joined: June 22, 2008
 Enjoy!


"I've always been mad, I know I've been mad, like the
most of us...very hard to explain why you're mad, even if you're not mad..."


 

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