[bunky]

I have a lovely pair of 93 db Silverline Audio Sonata III's that are tube friendly and easy to drive and I am interested in hearing the 10" Dynaudio woofers powered by a amp with a dampening factor of 1000.

[medium jim]

I have a lovely pair of 93 db Silverline Audio Sonata III's that are tube friendly and easy to drive and I am interested in hearing the 10" Dynaudio woofers powered by a amp with a dampening factor of 1000.

Speakers are a huge consideration when choosing an amp....the good thing for having maggies is that dampening is not an issue, just enough voltage with enough watts! However, that will lead to arguments around here....

Jim

[bunky]

Speakers are a huge consideration when choosing an amp....the good thing for having maggies is that dampening is not an issue, just enough voltage with enough watts! However, that will lead to arguments around here....

Jim

I have a pair of both the Sonatina II and the Sonata III"s and they play nicely with 15wpc SETs or 150 wpc ultralinear. that and the fact that they are gorgeous is why I hold on to them.

[Rclark]

Speakers are a huge consideration when choosing an amp....the good thing for having maggies is that dampening is not an issue, just enough voltage with enough watts! However, that will lead to arguments around here....

Jim

You would hope so 

[Julf]

Anyway, with his class d Ncore amps, lots of negative feedback is one of the tricks that makes it work the way it does.

That is why I found all the anti-feedback stuff in a thread about hypex-powered amps somewhat ironic...

[Julf]

Please enlighten all of us as to what Bruno says about Negative FB

Bruno's AES Master Class should be mandatory reading for every audiophile. He specifically addresses the Nelson Pass graphs. Anyway, Bruno's conclusion was "Don't be a wimp. Use NFB and use tons of it". That is why the hypex modules sound so good.

[medium jim]

Negative Feedback is:

http://en.wikipedia.org/wiki/Negative_feedback_amplifier

http://www.aikenamps.com/NegativeFeedback.htm

Why Op Amps (Class D) use more negative FB than other topologies:

http://www.allaboutcircuits.com/vol_3/chpt_8/4.html

Jim

[Ericus Rex]

I just ordered a Sphinx in black with the remote control and I should get it on monday or tuesday. I have some holy grail 12AU7's like Amperex Holland 7316's and Siemens nickel plates sitting here and I have a matched pair of grade A Psvane 12AU7-T II coming here shortly too so it may get interesting   

I look forward to your positive...or negative feedback on the Sphinx!

[Ericus Rex]

Bruno's AES Master Class should be mandatory reading for every audiophile. He specifically addresses the Nelson Pass graphs. Anyway, Bruno's conclusion was "Don't be a wimp. Use NFB and use tons of it". That is why the hypex modules sound so good.

I read through the first 20 pages or so of that link.  I don't see any information there at all.  I see graphs with no keys and reprints of basic op amp circuits and the rest just sounds like an infomercial.  It's as if this is the slide show to accompany a full lecture, but we don't have the lecture.  Should I scroll down more or is the rest just a waste of more time?

The concept of 'use a ton of NF to make the amp work properly' sounds to me a bit like a speaker designer stating 'use a lot of graphic equalization with my speakers in order to get an acceptably flat frequency response.'  Maybe I'm not getting the whole picture here but it sounds like NF is the only bandage holding the whole circuit together.  Is this good engineering?   

[roscoeiii]

Maybe I'm not getting the whole picture here but it sounds like NF is the only bandage holding the whole circuit together.  Is this good engineering?   

The ncores do sound great. Again, see my comment above re: "there are great sounding amps with negative feedback, there are great sounding amps without negative feedback."

I may be wrong on this, but somewhere along the way I got the impression that the excellent bass from the all-tube Rogue's may in part be due to their use of negative feedback. As well as power supplies, tubes and transformers that are up to the job. But not sure where I got this impression, so take this  comment with a huge grain of salt.

[Julf]

It's as if this is the slide show to accompany a full lecture, but we don't have the lecture.

That's exactly the case.

Should I scroll down more or is the rest just a waste of more time?

There is some pretty good information there, but you have to pick it up from the somewhat cursory slides.

Maybe I'm not getting the whole picture here but it sounds like NF is the only bandage holding the whole circuit together.  Is this good engineering?

I suggest you read through the whole set of slides. The parts relevant to feedback are between slide 25 and slide 50.

[bunky]

I look forward to your positive...or negative feedback on the Sphinx!

I want to start out with a positive attitude when I audition this amp,i will let it run for a few days or maybe a week with the stock tubes in it and then roll in some other 12AU7 variants  and find out if it is a keeper. 

[Alexdad54]

Some comments by a Sphinx owner are available here (scroll down  to the bottom half of the page): http://forums.stevehoffman.tv/threads/rogue-audio-sphinx-hybrid-integrated-amplifiers-are-now-shipping.310051/page-3

His comparisons are interesting......

[bunky]

Some comments by a Sphinx owner are available here (scroll down  to the bottom half of the page): http://forums.stevehoffman.tv/threads/rogue-audio-sphinx-hybrid-integrated-amplifiers-are-now-shipping.310051/page-3

His comparisons are interesting......

I have read the Steve Hoffman thread and just about everything else online that I could find about the Sphinx. i like fast tube amps that are not overly warm or euphonic. the midrange is the most important aspect for me because that is where the music lives. my Sonata III's use very lively Dynaudio Esotar tweeters and I am thinking that if the Sphinx is a little dry on the top end it wont be very noticeable in my system. before I saw this thread I was eyeing a pair of 40 wpc 805 SET monoblocks with over 1000 volts on the plate and chances are that I will still head in that direction.

[Ericus Rex]

Alright Julf, I'll spend a little more time with the link.

[bunky]

OK, i am working ten hour days on night shift during a power plant shut down. my daughter signed off to UPS for the Rogue Audio Sphinx integrated amp yesterday and I came home at 3:00am this morning and hooked it up to the Silverline Audio Sonata III's via Black Cat Morpheus speaker wires and jumpers and I hooked my modded MiniMax DAC to the Sphinx via Black Cat Morpheus IC's and connected my DAC to my Canary Audio CD200 with a Black Cat Silverstar 75 digital cable and let it play at low volume for eight hours while I got some sleep. once awake with a cup of fresh ground coffee in hand i played the Steve Stevens live acoustic guitar track Dementia and Zappa's title guitar track Zoot Allures and my initial impression is that it is a very nice sounding integrated amplifier. i will roll some NOS tubes in the front end next week and give some insight on it as I go.

[Cheeseboy]

Working long hours is a mixed blessing.  Not to get all religious.  I hope you get some time to give your new Rogue a serious listen.   I like to reccomend Rogue Integrated amp products to friends.  The Cronos does price them out of the market.  This could be the right product for them. 

Tubes in front of class D works for me in my application.   Thanks for taking the time to lay out the system particulars in your test.  Looking forward to hearing your thoughts and observations.

[bunky]

I just pulled the stock tubes which are JJ ECC802S and I replaced them with a brand new matched pair of Psvane 12AU7-T.the Sphinx sounds really good with the stock tubes and I am curious as to what improvement the 12AU7-T might bring once they are broken in.

[bunky]

I bought the Sphinx out of sheer curiosity and to be honest I did not really believe that it would pass muster in my main two channel rig. the truth is that in conjunction with my speakers in my system the Sphinx sounds great on the bottom end, midrange and the top end. the noise floor is non existant.i have had the Sphinx in my system for a couple of days shy of a month and I like it so much that I am going to keep it in my main rig. the Psvane 12AU7-T are fine tubes and they do everything well in the preamp section of the Sphinx.

[jtwrace]

How about a pic of it on the rack?