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In Reply to: RE: Received My New To Me Cronus Magnum posted by stereo5 on August 29, 2014 at 13:28:42
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?
"Far away across the field
The tolling of the iron bell
Calls the faithful to their knees
To hear the softly spoken magic spells."
Follow Ups:
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.
"Far away across the field
The tolling of the iron bell
Calls the faithful to their knees
To hear the softly spoken magic spells."
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
Yes, the center tube is the only preamp tube. The Mullard isn't cheap, but it's worth it. It truly transformed the amp.
"Far away across the field
The tolling of the iron bell
Calls the faithful to their knees
To hear the softly spoken magic spells."
Thank you stereo5, I thought so. I'm going to order one right away.
Cheers,
Al
Enjoy!
"Far away across the field
The tolling of the iron bell
Calls the faithful to their knees
To hear the softly spoken magic spells."
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.
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.
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.
"Far away across the field
The tolling of the iron bell
Calls the faithful to their knees
To hear the softly spoken magic spells."
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
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.
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
The times, they are changing...
Please point out the "many others" who "confirm this experience". I can't seem to find that sentiment here.
Cheers,
Al
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.
The times, they are changing...
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
Big power tubes are fun to roll ;-)
But I think the smart money says to try the small signal tubes first.
Thanks.
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.
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.
The times, they are changing...
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.
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