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Rogue Audio Sphinx V3 Review (Tube Amplifier)

amirm

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This is a review and detailed measurements of the Rogue Audio Sphinx V3 integrated amplifier with tube buffer. It is on kind loan from a member and costs US $1,599.

The front panel of the Sphinx portrays a high-end look with its thick metal:

Rogue Audio Sphinx V3 SNR Review Integrated Tube Amplifier.jpg


Alas, that thin metal surrounding it, takes that impression away. I liked the very wide apart inputs and output terminals which "should" bode well for crosstalk measurements:

Rogue Audio Sphinx V3 SNR Review back panel phono Integrated Tube Amplifier.jpg


There is good bit of weight to the unit courtesy of power transformer. I like the inclusion of the balance control. As you see in the first picture, I had to use it to get same gain out of both channels.

Protection circuit was well done with automatic recovery and worked great no matter how hard I pushed it.

Internal amplification is provided by a pair of Hypex UCD 180 OEM class D amplifiers. A buffer state made out of tubes completes the picture.

The amplifier has won many accolades as indicated by their mention on the product page:

1624848579052.png


Let's see if objectively they are right.

Rogue Audio Sphinx V3 Measurements
As usual, I set the gain to 29 dB and feed the amp a 1 kHz tone into 4 ohm at 5 watts and see what we get:

Rogue Audio Sphinx V3 Measurements Integrated Tube Amplifier.png


What we get is not very nice. Broad set of harmonics to the tune of -80 dB do away with any notion of "tube sound." Add fair bit of noise and SINAD which is a measure of distortion+noise sinks quite low:

Best tube amplifier review.png


That's 10 dB worse than the media across 140 amplifiers tested so far. Not good. As a reference, Hypex specifications shows a SINAD of 84 dB so 15 dB was lost in the addition of the buffer stage in this amplifier.

Another thing that is not good is signal to noise ratio:

Rogue Audio Sphinx V3 SNR Measurements Integrated Tube Amplifier.png


So even at full power your 2 bits short of CD's dynamic range.

The shocker was the normally "innocent" crosstalk test which just about every amplifier does well in:

Rogue Audio Sphinx V3 Crosstalk Measurements Integrated Tube Amplifier.png


Then comes Sphinx, losing to our $20 throw-away amplifier! Clearly zero attention was paid to isolation of the two channels.

Frequency response also shows sloppy attention to producing the audible band properly:

Rogue Audio Sphinx V3 Frequency Response Measurements Integrated Tube Amplifier.png


Let's measure our power vs distortion:

Rogue Audio Sphinx V3 Power 8 ohm Measurements Integrated Tube Amplifier.png


Rogue Audio Sphinx V3 Power 4 ohm Measurements Integrated Tube Amplifier.png


Definitely much less happy driving 4 ohm load. Here is our peak and max power:

Rogue Audio Sphinx V3 Peak and max Power 4 ohm Measurements Integrated Tube Amplifier.png


So moderately powerful although without much headroom.

Conclusions
Rogue Audio takes a perfectly serviceable Hypex UcD 180 amplifiers and adds copious amount of noise and distortion with its front-end. Mind you, despite use of the tube, it doesn't give that 2nd harmonic dominant result. It just raises the noise and distortion, robbing you of transparency. But hey, folks buy audio products by how many myths are included in their design and Rogue audio gets there with that tube stage. Perfect marketing, poor engineering. Story of high-end audio.

Needless to say, I can NOT recommend the Rogue Audio Sphinx V3. You can get plenty of better amplifiers for this level of money.

------------
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tktran303

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Ok that makes sense.

this unit has been around for a long time and I always wondered why they would take a solid state power amp and pre-mix it with a tube amp.

Makes sense in music production but not reproduction, IMHO.
 

YSC

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We have guests over so can't do any listening tests.
for the name of enjoying hifi with friends;)...

anyway, thanks for the measurement and for a tub amp, I do expect this sort of performance, as long as customers feel happy...
 

YSC

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Ok that makes sense.

this unit has been around for a long time and I always wondered why they would take a solid state power amp and pre-mix it with a tube amp.

Makes sense in music production but not reproduction, IMHO.
seems like a plan for a more stable performance and not tap the tubes too much and thus the amp can be more universal for speakers, yet get all those "tube favour". though the distortion characteristic don't seem to behave such
 

H-713

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The frequency response is pretty underwhelming, but the distortion isn't bad for a tube gain stage. The crosstalk and frequency response are a little disappointing, but probably won't be offensive in real usage. I'd never buy one, but someone who hasn't already built more tube amps / preamps than they know what to do with might find it perfectly enjoyable and fun to play with.

The class D power amplifier does kind of turn me off... If I'm going old-school with vacuum tubes, then I want to pair it with something else cool for the power amp.
 

Doodski

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Ok that makes sense.

this unit has been around for a long time and I always wondered why they would take a solid state power amp and pre-mix it with a tube amp.

Makes sense in music production but not reproduction, IMHO.
Reminds me of the Luxman LV-105 hybrid. Prone to overheating and then the solder cracks/crumbles and then lots of soldering is required to get it back operating. I never saw one blow up even with all the bad solder.
1216899-40a7f201-vintage-luxman-lv105-hybrid-tube-integrated-amplifier-and-luxman-t105-tuner.jpg
 

H-713

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This is the guts of it:

Sphinx-inside-medium-600x578.jpg

Looks quite clean. I don't care for the PCB-mounted tube sockets, though that's pretty much par for the course these days. If they were power tubes it'd be a bigger issue, since they run hotter.

Looks like they're using 12AU7s, which aren't the most linear things on the planet. They are easy to get, however, and can drive a reasonable amount of current for a small-signal tube. If it were me I'd probably have designed this around 6922s or 6SN7s, but to each their own.

At the risk of offending people, I don't see the reason why this site even reviews tube equipment. It's never going to wow people here with distortion numbers compared to the solid-state solutions, and people looking at tube gear usually aren't focused on distortion numbers anyways. Even the best-engineered tube amplifier (Citation II comes to mind) would receive a negative review and the entire comment section would be filled with people complaining that they're "overpriced". It seems pretty well accepted that nobody buys tube gear to chase numbers.
 

Chester

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Looks quite clean. I don't care for the PCB-mounted tube sockets, though that's pretty much par for the course these days. If they were power tubes it'd be a bigger issue, since they run hotter.

Looks like they're using 12AU7s, which aren't the most linear things on the planet. They are easy to get, however, and can drive a reasonable amount of current for a small-signal tube. If it were me I'd probably have designed this around 6922s or 6SN7s, but to each their own.

At the risk of offending people, I don't see the reason why this site even reviews tube equipment. It's never going to wow people here with distortion numbers compared to the solid-state solutions, and people looking at tube gear usually aren't focused on distortion numbers anyways. Even the best-engineered tube amplifier (Citation II comes to mind) would receive a negative review and the entire comment section would be filled with people complaining that they're "overpriced". It seems pretty well accepted that nobody buys tube gear to chase numbers.

I do see what you’re saying, but I think it is important to review some of these types of products. Not because we expect to uncover SOTA measurements, but to highlight what type of performance you are actually paying for with some of these types of products.

My first entry into HiFi was with a tube amp, because all I heard and read was that they offered superior sound and were the only way to experience music. If this site had been around like it is today, I would have been able to judge that for myself and not naively just believed the marketing and deluded audiophiles who populate most of the HiFi related forums.
 

Veri

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Looks quite clean. I don't care for the PCB-mounted tube sockets, though that's pretty much par for the course these days. If they were power tubes it'd be a bigger issue, since they run hotter.

Looks like they're using 12AU7s, which aren't the most linear things on the planet. They are easy to get, however, and can drive a reasonable amount of current for a small-signal tube. If it were me I'd probably have designed this around 6922s or 6SN7s, but to each their own.

At the risk of offending people, I don't see the reason why this site even reviews tube equipment. It's never going to wow people here with distortion numbers compared to the solid-state solutions, and people looking at tube gear usually aren't focused on distortion numbers anyways. Even the best-engineered tube amplifier (Citation II comes to mind) would receive a negative review and the entire comment section would be filled with people complaining that they're "overpriced". It seems pretty well accepted that nobody buys tube gear to chase numbers.
But there have been positive reviews. Liquid platinum comes to mind. Some of the XDuoo, darkvoice/bottlehead, ...
 
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amirm

amirm

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At the risk of offending people, I don't see the reason why this site even reviews tube equipment.
If I don't review them, all search results would point to subjectivist reviews with random evaluations within. Pretty sure many people buy these products because they think they are much better than they are. So I review them to show the reality of them.
 

digicidal

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Even the best-engineered tube amplifier (Citation II comes to mind) would receive a negative review and the entire comment section would be filled with people complaining that they're "overpriced". It seems pretty well accepted that nobody buys tube gear to chase numbers.

I would agree with that... however, I wouldn't ever be in the market for this amp because if I'm looking for tubes and willing to sacrifice transparency for that cause... then I want to see the tubes, and I don't want class-D amps doing the heavy lifting. Maybe I'm in the minority there, but to me the greatest reason for going with tubes is because of the aesthetics. The sound has always been objectively bad on almost everything that employed them (at least that's even remotely in my budget). If I'm paying for something that looks just like any other SS amp... then I expect the same performance as well.
 

gsp1971

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At the risk of offending people, I don't see the reason why this site even reviews tube equipment. It's never going to wow people here with distortion numbers compared to the solid-state solutions, and people looking at tube gear usually aren't focused on distortion numbers anyways. Even the best-engineered tube amplifier (Citation II comes to mind) would receive a negative review and the entire comment section would be filled with people complaining that they're "overpriced". It seems pretty well accepted that nobody buys tube gear to chase numbers.

Why do people buy tube gear, then?
 

gsp1971

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"The amplifier has won many accolades as indicated by their mention on the product page"

What were the accolades for? Which part of the product's performance are they praising?
Isn't that proof enough that we should not believe in such 'awards' when there is conflict of interest between objective opinion and advertising revenues?
 

Bjorn

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The image below are the real talking point here IMO. How can a device with so high noise and distortion get so good reviews? Do the audiopress have such poor setups that they need to listen through electronics with a veil that hide their flaws? Or are we talking either placebo or "a friendly review" to please the brand? Either way, it's certainly disturbing.
1624848579052.png
 

tktran303

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The image below are the real talking point here IMO. How can a device with so high noise and distortion get so good reviews?

Well you don’t hear them as distortion.

You hear them as special effects. that crosstalk alone would be responsible for some.

so if you’re creating music or want a bit of salt and pepper and spice or flavours to favourite records..
 
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