Rogue Audio's new $1295 Hypex integrated

Julf · « **Reply #60 on:** 2 May 2013, 07:44 pm »

Quote from: roscoeiii on 2 May 2013, 07:29 pm

No, I'd say that there are not-so-great amps that also fall under those categories, and which may contribute to giving a type of amp a bad name if a less than good design (or less than good match for the speakers) is what you have been exposed to.

Good point - but I would also say that an amp that is sensitive to speakers and other components is not a great amp. A great amp should do its job no matter what it is driving (OK, as long as it is not just an iron nail across the output terminals).

roscoeiii · « **Reply #61 on:** 2 May 2013, 07:57 pm »

Quote from: Julf on 2 May 2013, 07:44 pm

Good point - but I would also say that an amp that is sensitive to speakers and other components is not a great amp. A great amp should do its job no matter what it is driving (OK, as long as it is not just an iron nail across the output terminals).

Nope. I disagree with you on this one. I'd rather have an amp that is better suited to a particular speaker than a jack-of-all trades amp.

I mean, c'mon, your "great amp" would exclude fabulous designs such as SETs and OTL amps. Not to mention the low-watt SS Class A FirstWatt beauties of Nelson Pass.

Even with much more conventional amps and speakers, I have found amp-speaker matching to be crucial. My SP Tech Minis (88dB or so) worked great with the Hybrid Butler 2250 I had paired with them, and didn't sound as good with the Rogue Stereo 90 (which was providing more than adequate power in my smallish listening room). My Von Schweikert VR-4s (~91dB) on the other hand sounded (and are sounding as I type) better with the Rogue Stereo 90 (now Super Magnum upgraded) than with the Butler 2250. Neither was terrible, but it was a nice improvement to really dial in an ideal match for my different speakers.

To each his own, I suppose.

bunky · « **Reply #62 on:** 2 May 2013, 07:58 pm »

Quote from: Julf on 2 May 2013, 07:16 pm

And why not?

Many respected amplifier designers frown on using negative feedback because it creates its own set of problems.http://http://www.6moons.com/industryfeatures/distortion/distortion_5.html

Julf · « **Reply #63 on:** 2 May 2013, 08:06 pm »

Quote from: roscoeiii on 2 May 2013, 07:57 pm

Nope. I disagree with you on this one. I'd rather have an amp that is better suited to a particular speaker than a jack-of-all trades amp.

OK, we might be arguing semantics - I would call that a great system or combination, but not a great amp.

Julf · « **Reply #64 on:** 2 May 2013, 08:08 pm »

Quote from: bunky on 2 May 2013, 07:58 pm

Many respected amplifier designers frown on using negative feedback because it creates its own set of problems.

And many other respected designers don't.

Neither is any sort of a factual argument for or against feedback. What are your factual issues with feedback?

Ericus Rex · « **Reply #65 on:** 2 May 2013, 08:34 pm »

Quote from: Julf on 2 May 2013, 06:00 pm

The problem with valves is that you usually have much less gain in your typical valve amp than in a semiconductor amp, and that seriously restricts the amount of feedback you can apply to reduce distortion.

I've been reading up lately about how high gain itself distorts the input signal regardless of negative feedback. It seems that you can have high gain, which distorts the signal at the extremes, then send back NF to correct some of that distortion or you can use less overall gain with no NF and stay truer to the input signal. NF, it appears, is not a panacea.

bunky · « **Reply #66 on:** 2 May 2013, 08:35 pm »

Quote from: Julf on 2 May 2013, 08:08 pm

And many other respected designers don't.

Neither is any sort of a factual argument for or against feedback. What are your factual issues with feedback?

I gave you citation with the Nelson Pass experiment from six moons and I am done with the discussion of the drawbacks of applying negative feedback to lower distortion numbers.

medium jim · « **Reply #67 on:** 2 May 2013, 08:36 pm »

Negative Feedback or better stated "Inverted Feedback" is so low in most well designed and implemented tube amps is so low that it is a non-issue, at least for me it is. In anything Audio, there will always be some compromises....

Jim

bunky · « **Reply #68 on:** 2 May 2013, 09:00 pm »

The part time audiophile did a little piece on the Sphinx and I think it is nice looking in black with the silver knobs. the idea of buying one of these and playing with it appeals to me so I think I might. http://http://parttimeaudiophile.com/2013/01/19/ces-2013-rogue-audio-and-the-sphinx/

Julf · « **Reply #69 on:** 2 May 2013, 10:03 pm »

Quote from: bunky on 2 May 2013, 08:35 pm

I gave you citation with the Nelson Pass experiment from six moons and I am done with the discussion of the drawbacks of applying negative feedback to lower distortion numbers.

Sure. I just need to point out that six moons isn't exactly a scientific publication.

bunky · « **Reply #70 on:** 2 May 2013, 10:10 pm »

Quote from: Julf on 2 May 2013, 10:03 pm

Sure. I just need to point out that six moons isn't exactly a scientific publication.

Nelson Pass wrote the article did the testing and generated the graphs. he is a professor of amplification if there ever was one

DaveC113 · « **Reply #71 on:** 2 May 2013, 10:59 pm »

Quote from: bunky on 2 May 2013, 10:10 pm

Nelson Pass wrote the article did the testing and generated the graphs. he is a professor of amplification if there ever was one

I read it and it is spot-on. Good article and easy for anyone to understand.

I also agree with Jim that in a well designed tube amp the amount of feedback required is little to none, because tubes can be very linear amplification devices. Often the price paid for lowering distortion using feedback results in an overall reduction in sound quality.

Cheeseboy · « **Reply #72 on:** 2 May 2013, 11:16 pm »

Quote from: roscoeiii on 2 May 2013, 07:57 pm

Nope. I disagree with you on this one. I'd rather have an amp that is better suited to a particular speaker than a jack-of-all trades amp.

I mean, c'mon, your "great amp" would exclude fabulous designs such as SETs and OTL amps. Not to mention the low-watt SS Class A FirstWatt beauties of Nelson Pass.

Even with much more conventional amps and speakers, I have found amp-speaker matching to be crucial. My SP Tech Minis (88dB or so) worked great with the Hybrid Butler 2250 I had paired with them, and didn't sound as good with the Rogue Stereo 90 (which was providing more than adequate power in my smallish listening room). My Von Schweikert VR-4s (~91dB) on the other hand sounded (and are sounding as I type) better with the Rogue Stereo 90 (now Super Magnum upgraded) than with the Butler 2250. Neither was terrible, but it was a nice improvement to really dial in an ideal match for my different speakers.
To each his own, I suppose.

I really agree so much with this statement. System synergy is everything.

I think the New Rogue Integrated will resonate with alot of people. I am eager to give it a listen so I can determine to with what type of speakers to recommend it or the Cronos version. I really think highly of the Rogue approach to audio equipment.

Steve

bunky · « **Reply #73 on:** 2 May 2013, 11:32 pm »

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

Rclark · « **Reply #74 on:** 2 May 2013, 11:35 pm »

Bruno Putzeys has given several talks on negative feedback and his work speaks for itself, so.

SlushPuppy · « **Reply #75 on:** 3 May 2013, 12:00 am »

Quote from: bunky on 2 May 2013, 11:32 pm

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

Congrats on the new purchase. The show reports made it sound like the Sphinx performs way above it's price range. It's amazing to me that they're selling it at that price and it's not factory direct. I look forward to your tube rolling impressions.

medium jim · « **Reply #76 on:** 3 May 2013, 12:13 am »

Quote from: Rclark on 2 May 2013, 11:35 pm

Bruno Putzeys has given several talks on negative feedback and his work speaks for itself, so.

Please enlighten all of us as to what Bruno says about Negative FB and at what point does it become a detriment? Most tube amp designers are well aware of the effects of Negative FB and can design the topography to keep it under the point were it becomes a factor.

In many cases the Negative FB is local and never reaches outside of the amp.

Jim

cab · « **Reply #77 on:** 3 May 2013, 12:22 am »

Have at it:

"The F-word - or, why there is no such thing as too much feedback"
Bruno Putzeys

http://www.linearaudio.net/index.php?option=com_content&view=article&id=97:the-f-word-or-why-there-is-no-such-thing-as-too-much-feedback&catid=41:volume-1&Itemid=73

Rclark · « **Reply #78 on:** 3 May 2013, 01:17 am »

You can pretty much google them or there should be links in the Hypex circle for a few of them. The man is a genius, and he was actually designing tube amps when he was a teenager. Anyway, with his class d Ncore amps, lots of negative feedback is one of the tricks that makes it work the way it does. Welcome to 2013.

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The amps in the OP look pretty cool for the money

Look forward to your impressions Bunky.

medium jim · « **Reply #79 on:** 3 May 2013, 01:48 am »

Quote from: Rclark on 3 May 2013, 01:17 am

You can pretty much google them or there should be links in the Hypex circle for a few of them. The man is a genius, and he was actually designing tube amps when he was a teenager. Anyway, with his class d Ncore amps, lots of negative feedback is one of the tricks that makes it work the way it does. Welcome to 2013.

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The amps in the OP look pretty cool for the money Look forward to your impressions Bunky.

Interesting, lots of Negative Feedback is one of his tricks, very interesting to say the least....

Jim