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Recent upgrade to Cronus Magnum

A few weeks ago, my system consisted of the following components ...
Apple TV >> Naim Unitiqute (v1) >> Harbeth P3esr

While I liked the overall sound, I wanted to move up the chain and try something different. I felt the Unitiqute was a little underpowered. So when an Audio Rogue Cronus Magnum came up for sale (local craigslist), I jumped at the chance and bought it. I had a Cambridge Audio Azure 851D stored in my close, which I added to the chain. So now my system looks like this...
Node 2i >> CA Azure 851D >> Cronus Mangum >> Harbeth P3ers

When I first made the change, I was quite impressed with the increased loudness and a wider soundstage. However, I realized that, unlike the Naim, I was getting listener fatigue. There was a certain harshness (like metallic sound) to the vocals, especially female vocalists. Also, I was expecting some tube magic, which frankly is just not there. The Cronus Mangum sounds much closer to a solid state. Yesterday I put the Naim back in the system and much to my surprise the little box is keeping pace with the much more powerful Cronus Magnum. Yes, it doesn't play as loud and the soundstage is not as wide, but the sound is so much more refined, smooth and balanced. I'm wondering if I made a mistake. So before I make further changes, maybe the good folks at Audiogon can provide some relief.

What do you think is the weak link in my system? Should I keep the Cronus Magnum and try a more musical, refined DAC? If yes, what do you guys suggest (prefer used, below $2000)? Or do I ditch the Cronus and go for a more tube-like sound (Primaluna, Rogers, vintage ARC, etc)? The little voice inside me is telling me to sell the Cronus and move up the Naim integrated chain (e.g. Supernait), since I really liked the Unitiqute's refinement and balance. But then again, what if it's not the amp (Cronus) but the DAC (CA Azure 851D) that's the likely culprit here? Should I change the DAC first? Or maybe try rolling different (smoother?) tubes?

As you can see, I'm mighty confused and can use some pointers. So many variables ... aargh!!!!
128x128arafiq
arafiq's avatar
arafiq OP
1,664 posts
 
@avanti1960  sorry, forgot to mention that its version 2.
davekayc
173 posts
 
I had a mullard in my center position and removed it almost right away . Didnt sound good . The stock tube produced hiss so i ordered a mulllard . I was disappointed . So i put the mullards to the outside position and put one of the better stock tubes back in center . Good sound was back. Now i have a gold lion with great results . A ting sol was great . High detail. 
The mullard sounded woody the 400 hz area came up and the very highs went down. Tubes can be different sounding even though labelled same. Very satisfying gains can be made with tube rolling . I recommend some nos rca . Beautiful sounding And affordable. Check your settings you shouldnt have to turn that amp up past 11 oclock to have decent sound level . Set the node to fixed. Very very gently tap the tubes to see if they are microphonic . If they are that could be a good source of noise . Obviously dont have the amp where it can vibrate as volume goes up (sharing a table with speakers etc. )

regards 
davekayc
173 posts
 
Ps. Wiggle the tubes a little bit but be super careful while off . Make sure they are seated nice . I had a super small crack in a power tube and all hell broke loose, good thing i was standing there to shut it off . Shipped it to rogue . Service is outstanding they even sent it back with all new screws in it. 
mod_asored
19 posts
 
I have a very similar setup
851N to Rogue Tempest
The Tempest is the next one up the chain but I think it is very similar. Now I have the Tempest 3 Super Magnum for what that is worth. I really like the 851N, however I am a modest guy just looking for great music.

I was looking for more of a "tube" sound, I loved the detail and punch of the unit but wanted more so I:1) Switched from Ultralinear to Triode mode2) Switched to KT-88 tubes (PSVane), I think this is a more musical tube than KT 90's or 120's3) Rolled my 12AX7 to a 5751 (Raytheon windmill getter)
Rolling to the 5751 had the most impact, this is a lower gain tube and I think it brings our more midrange detail and has a more natural tone than the stock 12ax7
Second biggest impact was the KT-88's, I did like the sound better, to my ears more musical and I don't really need the extra watts, my speakers are fairly efficient and my room is not huge.

Ultralinear to Triode, I think this helped, I found myself in much longer listening sessions once I did this.
Now I love it. I listen mostly to acoustic music. It works like a charm for me, I think the power output dropped from 90 watts to probably more like 30-40 watts but as the resolution, detail and tonality improved I found myself enjoying the music much more and also listening at lower volume levels.
Good Luck
avanti1960
1,474 posts
 
good info arafiq.
you have the CM II, it is an excellent amplifier that is neutral sounding but can be made more laid back with the right tubes etc.  you get a huge 3D sound stage and great dynamics with the KT 120 tubes and 100 watts. 
once you check the speaker terminals and adjust or confirm 8-ohms at the terminals-
1) check the tube bias for all 4 power tubes- once set it only needs to be checked every few months or so, mine never needed adjustment.
2) definitely no silver plated speaker cable.  i tried nordost and the sound was edgy and unrefined.   I use Kimber 8PR and the sound is smooth and excellent.   Very economical if you buy in bulk and make your own connections.  
3) defiitely no mullard !  everyone keeps saying mullard- i tried 3 diffeent ones and they all sounded dirty / unrefined in the lower treble.  here is my tube map for smooth success-

center preamp tube- (brent jessee)  screened for low noise (ask) 

12AU7 Amperex Bugle Boy type, Amperex Heerlen Holland factory code, blank label or Amperex white label or made for Dario, Philips, Adzam, Gulbranson, Eico, and others, original 1960s. New Old Stock original box and White Box. Very well made, low noise tubes. These are the originals from Holland, made in the same Heerlen factory , and at the same time as the Bugle Boy tubes, but labeled for other brands. Save big over the Bugle Boy label tubes and still get fantastic Bugle Boy quality!

49.00 single tube


front row 12AX7

RCA 5751 Premium industrial grade 12AX7, 2 mica

New Old Stock in white box, thick mica spacers. The best bargain going in a genuine NOS 5751, the RCA set the standard for all the other brands. MATCHED PAIRS ARE $110.00.

back row 12AU7

814A Premium industrial grade 12AU7, RCA JRC military TRIPLE MICA type, blackplate.

New Old Stock in original boxes. A really fine military grade triple mica blackplate of the 12AU7 family, made by RCA for the military. The early type triple mica blackplate 5814A of RCA tubes are very scarce, as they were not available to the general public, but are well worth the search. These are exactly the same electrical characteristics as the 12AU7 and can be used with improved results in any application calling for a 12AU7 or ECC82. Excellent quality that lasts. MATCHED PAIRS $99.00 PER PAIR

These changes will make the sound smooth and refined all day long and let you understand why people say it is such a great amplifier.  



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