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Integrated Amps: An Addicts Guide.


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I need to sell a few things to loosen up some cash!

I wonder if I should have a boxing day sale?

I do want to Koloss but I'm having to tightly ration my coins at this point, I also have other audio areas I'm playing with at the moment and I've already lashed out and got hold of a Burson PP 160 to try with the ML1s. I'll get back to this thread before the end of the year (I've still got 4 amps on hand that I have yet to fire up!) but for now I'm sort of vacationing in Lenehan Land.

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  • 5 weeks later...

Well, it was only a matter of time until my love of integrateds came to the fore once more. 

 

Don't worry, I'm still working on the power amp thread idea but this new amp showed up, and it was all shiny and new and I just had to plug it in and hit play.  It is an addicts thread, after all!

 

Does anyone remember John Darko mentioning the QLS QA100 "Full Digital Amplifier" a while back?  Well I investigated a little further and bought myself one back on the 9th.   It is currently running in.  The same idea as the NADC390DD and NuForce DA100 but where the NAD costs $3k and the NuForce $650 this little QLS tips the scales at $450 (delivered to your door).  Since I have heard both the NAD and the NuForce it seemed to make sense that I should hear this one too (and the fact that it was fairly cheap didn't hurt either!).   I know the Xindac A08 and the Primare I22 are not "direct digital amplification" designs but since they can be used in the same way I think it is fair to compare the QLS with them as well (remember, both of them retail at about $2k).

 

Early days yet of course, it has only had about 7 hours to run in but it already sounds far better than my memories of the NuForce and much more pleasant to listen to than the Xindac.  It is never going to match the power and presence of the NAD but that's allright because it isn't meant to, this is a direct digital amp that sounds very much like a traditional class A/B amp.  I'll have to wait a few days before I can write up a full review but I am already thinking that this puppy teamed with a pair of Usher S520s and a cheap cd player would give great sound for under $1k (and since it comes with a digital cable all you need to buy are speaker cables!).  It also comes with a remote control and has adjustable channel outputs.  Pretty damn good for a price southwards of $500.

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Looks like I am not the only one who rates the Primare I22. From The Absolute Sound CES REPORT: SOLID STATE ELECTRONICS UNDER $12,000, see:

http://www.theabsolutesound.com/articles/ces-report-solid-state-electronics-under-12000/

"Best Sound (for the lowest price)

At a system price of $7000 (sans cabling) for a Primare I22 integrated amp/DAC (80W), CD22 CD player and a pair of Vienna Acoustics Mozart Grant (Sic, should be Grand I think) Symphony Edition speakers, the sound was pretty darn nice."

Edited by Telecine
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So this QA100 is a direct digital amp, which is a sort of subclass of class D.  It uses 2 Texas Instruments chips which have some very impressive stats.

 

see here for details on the chips.  tas5162 chip in QLS QA100.pdf

 

And it is a variant of class D that uses MOSFETs!!!  Neat.

 

So how does this rather interesting variant of a subclass of amps that until now have a distinct "love them or hate them" reputation sound?  Pretty damn good as a matter of fact!  These chips can put out 210 watts max, but by keeping the voltage low (about 30 volts, see the graph on the pdf) QLS ensure decent THD figures.  I don't know if these chips can be run in "dual differential" mode like DACs but I suspect they can, and are.  Very impressive output figures since most of us are still used to seeing Tamps that put out 25 watts maximum.

 

The NAD C390DD has power and detail and clarity but it sounds like a class D amp, which means it is a bit "digital" in that it can be said to sound harsh due to it sounding so clear.  It can also be said to contain digital glare and maybe a touch of brightness as well, personally I liked the NAD (alot!) but I can understand why some people don't and if you don't like the sound of the NAD then you won't like the sound of the NuForce DDA100 as it sounds fairly typical of class D as well.  It would be difficult to mistake the NAD or Nuforce direct digital amps for a more main stream class A/B amp, but not for the QA100.  I would say on 4 songs out of 5 it is dead easy to forget that the amp is class D, or direct digital, because it sounds alot like a less bright Rotel RA1520 or a less bassy Emotiva Mini-X, personally I think it leaves both those amps for dead but that is the quickest way I can think of to describe the sonic signature.  And on song 5 of 5 it doesn't sound hard, or glarey or bright it just sounds a class A/B amp that is sounding a "bit class D-ish" rather than the other way around.

 

I'm going to print out some note pages and give this QA100 a complete write up over the next couple of days (just because I like to make things difficult for myself) following a similar layout to my intended power amps thread so I won't say too much more now.  I'll just finish by saying that this $450 amp (including postage) does a far better job of bridging the class divide than the DDA100 has, having heard it and going by the sound quality I could understand if QLS were asking twice the price for this little wonder, maybe even three times the price!

 

I can't wait to hear what the next generation of direct digital amps can do!  Exciting times await us.

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Cables:  LBP Taranui speaker cables with a Choseal digital cable supplied with the amp.

Preamp:  N/A

Source:  cd120

Speakers:  Osborn Eclipse floorstanders

 

Name:  QLS QA-100 Direct Digital Integrated Amp

 

Physical Details

Weight,                        3kg                 

construction details,      Steel case

 

Info from website:

ï‚·  Digital input: RCA Coaxial, BNC Coaxial, Optical, EBU/AES, I2S

ï‚·  Digital format: 16bit to 24bit, 32K to 192K Stereo (sampling rate and bit adaptive)

ï‚·  Power Stage chip: TAS5162 *2

ï‚·  Master Volume: 0 ~ 80;  L/R Volume Trim: -5 ~ +5;

ï‚·  Use 2PPM TCXO Crystal for ASRC (crystal JITTER is below 10PS) .

ï‚·  Total harmonic distortion (-2.5dBFS, 8 Ω) <0.06 %

ï‚·  Dynamic Range, a-weighted 101 dB

ï‚·  S/N ratio, a-weighted 102 dB

ï‚·  Channel separation 92 dB

ï‚·  Frequency response, audio range (20Hz - 20kHz) +/-0.5dB, 8 Ω

ï‚·  Power: AC 90V ~ 240V 50/60Hz

ï‚·  Speaker Impedance range: 2-8 Ω

ï‚·  Power output, 4 Ω  100W  * 2CH
Power output, 8 Ω  60W * 2CH

ï‚·  Dimensions approx. 11.4" x 9.45" x 2.4" (with all the sockets)

ï‚·  Package weight: 3kg

ï‚·  Package Dimension: L440 X W300 X H110(mm)              

                       

looks    Love the big red letters of the LCD display, the old school look is a nice counterpoint to the technology inside.              

 

Music.

Highs:    Very pleasant and expansive, a little breakup and harshness was experienced initially but disappeared after 50 hours or so of run in, there is a “class D ting†barely noticeable on some high pitched piano notes, triangles were very clear with no metallic harshness to be heard, nice snap (not as nice as the Burson but pretty good none-the-less)

7.5

 

Mids:    Friendly to the ear, flows and images well with a nice sense of space around voices and instruments, could use a little crispness but other than that no complaints.

7.5

 

Bass:    Wide and deep but also well controlled without being tight, enough detail comes through that differences in depth of instruments are easily heard, acoustic bass sounds very natural, good strength and depth, strong impact with a smooth and clear decay, very nice detail within the bass frequencies.

8.0

 

Vocals:  Very clear, no break up on any S or T sounds, female vocals sound nicely extended without ever being harsh, probably rolled off in the highs but done so very well, male throaty and strained vocals come through exactly as they should.

8.0

 

2D Soundstaging:          Good but not exceptional (though to be fair the Osborns do smooth out the placement of instruments a bit)

6.5

3D Soundstaging:          Good but not exceptional (as above)

6.5

 

Overall performance Integration:   including Foot Tapping Factor and PRAT.

Instrument and vocal separation and integration is excellent, a very loyal performance of which the artist could be proud.  Brass instruments really sound like brass instruments, loved Wagners Ride of the Valkyries.

8.0

 

Ability to Emote:  Far better than it should be considering the Class D design.

7.5

 

Electric Guitar Test:    The equal of any integrated I have heard to date.  Joe Satriani was a definite pass.

8.0

 

80's Rock Test:    Often when playing older recordings they come out sounding softer and emptier than I remember them, not so here, loved the amp so much I worked my way through The Miracle, Alanah Myles Rockinghorse and then Twisted Sisters Greatest Hits.

I could go through my entire collection on this thing and love every minute of it. 

8.5

 

Personality Summary:

An excellent amp that conveys a performance that is very true to the artist.  It sits on the neutral side of expressive, not the expressive side of neutral.  It could use a little more pep but then it wouldn’t sound so natural.  The more I listen to it the more I like it.

 

Pros:  Accuracy and detail without sacrificing enjoyment, no need for a DAC, supplied with its own digital cable (a $16 Choseal which I used for this review), can be used with TV optical out to watch TV shows, universal power supply

Cons:  No analog in, soft pops through speakers whenever the cd player spins up a disc.

 

Pics in previous post.

 

Final Score:  76

 

So the first amp to have a complete work up comes in at 76, which brings me to the scale explanation.

 

Scale:

1 to 3 means a performance below par with one being somewhere in the vicinity of fingernails on a blackboard while a poorly tuned AM radio shrieks out static in the background and 3 being just bearable.

4 to 6 is average, listenable but nothing noteworthy, 4 being a bit messy or harsh and 6 being pretty good but nothing to write home about.

7 to 9 is better than you would expect then to be, with 7 being a good performance, 8 being an exceptional performance and 9 being the best you are ever likely to hear.

And it is pretty damn unlikely that I will ever award a 10 because that would mean it is the best of the best of the best.

(Multiply them all by 10 for an idea of what the final score means, and remember from 30 to 60 you can go from an absolute stinker to an amp that is pretty good at what it does, anything above 60 is likely to be something worth investigating)

 

For the sake of comparison I would rate the Exposure 2010S bass performance as a 9 or an 8.5 and the Myryad Z142 as an 8.5 or an 8 (I don’t have either on hand to refresh my memory so that is as good as I can do at the moment) the 2010S smooth character would also give it a good score in ability to emote I think, probably an 8.0.  Most of my current top 10 favorites would probably rate a final score somewhere between 70 and 85.  Which means the QA100 is definitely in the top 10, probably 4, 5 or 6ish.

 

So the QA100 is far cheaper than either of those two amps and it rates bang in the middle of “better than expected†and an “exceptional piece of gearâ€.  I plan to keep the rating all about the music/sound/emotion rather than about the $$, having said that I will certainly mention the price but I’m not going to adjust the scale to correct for it.

 

Edit:

One thing I forgot to mention is that the QA100 contains 2 clocks so it looks like they take their jitter reduction (and or reclocking) very seriously.

Edited by Cafad
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So this QA100 is a direct digital amp, which is a sort of subclass of class D.  It uses 2 Texas Instruments chips which have some very impressive stats.

 

see here for details on the chips.  attachicon.giftas5162 chip in QLS QA100.pdf

 

And it is a variant of class D that uses MOSFETs!!!  Neat.

 

I'm no expert, but I think it is a very straightforward standard Class D amp module. The use of MOSFETS is also normal practice IIRC.

 

I'm not too keen on the fairly high distortion at low power (5W to 10W) into 4 ohms. That is a typical home audio listening situation.

 

Also not too keen on what looks like non-linear gain at loads less than 8 ohms, due to thermal effects.

 

Love your review, though, well done.  :thumb:

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I'm no expert, but I think it is a very straightforward standard Class D amp module. The use of MOSFETS is also normal practice IIRC.

 

I'm not too keen on the fairly high distortion at low power (5W to 10W) into 4 ohms. That is a typical home audio listening situation.

 

I didn't realize it was normal practice, this is the first chip datasheet that thows the whole MOSFET idea in you face so I couldn't help but notice, I'll have to go back and look at the other chip datasheets now.

That second point is a good one, the distortion heard through my easily driven Osborns is going to be much lower than the distortion that an owner of more stubborn speakers would have to put up with, so even though the manual says that 2 Ohms speakers are just fine to connect to the amp it doesn't mean they will sound the same as 8 Ohm speakers.  Potential buyers beware on that!

 

In my case though, the Osborns bottom out at 5.8 and the ML1s about 6, so everything works out just fine.

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Loving the reviews Caf, but are you keeping everything else the same when you start making comparisons between amps?

I mean, it would be plain silly to make a comparison of the bass control or slam, the extension of the highs or the expansiveness and accuracy of the soundstage between amplifier A and amplifier B if you used different speakers for each review (or changed preamps, source, or even source material).

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Loving the reviews Caf, but are you keeping everything else the same when you start making comparisons between amps?

I mean, it would be plain silly to make a comparison of the bass control or slam, the extension of the highs or the expansiveness and accuracy of the soundstage between amplifier A and amplifier B if you used different speakers for each review (or changed preamps, source, or even source material).

 

It's often difficult for us hobby reviewers to maintain a reference system over a sufficient period of time to ensure all reviews are performed in a consistent manner. However, unlike speakers (where differences are probably more prevalent and easily identifiable), amplifiers I imagine would present their different character traits on a much smaller scale; thus heightening the importance of keeping the rest of the system the same across reviews.

Edited by twwen2
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I agree wholeheartedly guys, but that's why I put the cables, preamp, speakers info up the top of the review so if I do change anything it is noted down for everyone to read (hopefully with a note from me saying why I changed something).  I am going to stick as close to a standard as I can WRT cables and source but things will inevitably vary, eg; when you have a direct digital amp then things like ICs don't come into it at all and I am thinking the source wouldn't have a huge effect either.

 

But if I do find an amp that doesn't work on the Osborns, or doesn't like LBP cables (a Myryad for example! :confused: ) then I have alternatives to try to see if I can get a decent performance out of it.   All that should happen prior to a review being written and would be mentioned as part of it so not all changes are bad.

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Looks like I am not the only one who rates the Primare I22. From The Absolute Sound CES REPORT: SOLID STATE ELECTRONICS UNDER $12,000, see:

http://www.theabsolutesound.com/articles/ces-report-solid-state-electronics-under-12000/

"Best Sound (for the lowest price)

At a system price of $7000 (sans cabling) for a Primare I22 integrated amp/DAC (80W), CD22 CD player and a pair of Vienna Acoustics Mozart Grant (Sic, should be Grand I think) Symphony Edition speakers, the sound was pretty darn nice."

 

I think i would like that.  I liked the primare at the GTG and others have rated the VA very highly.

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Great work CAFAD...fantastic read and review...seems to me this little amp would be great as a desk top amp for a computer setup.

 

Bring on the Power Amp Reviews...oh and best of luck with securing some employment...Rob

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I'll get to the power amps Rob, but I have had some integrateds sitting around for so long I really feel I should push them through and get them over and done with.  The SonofaGum and NAD 3120 are among them, so a few more integrateds to go before I get to the power amps.  Then when I do get to the power amps I have a couple of ICs that have been leant to me to try out.  It's going to be a busy February I think.

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I am already thinking that this puppy teamed with a pair of Usher S520s and a cheap cd player would give great sound for under $1k (and since it comes with a digital cable all you need to buy are speaker cables!).  It also comes with a remote control and has adjustable channel outputs.  Pretty damn good for a price southwards of $500.

 

Have you had a chance to try this combination? I'm looking to grab a pair of cheap bookshelves to have a second system in my bedroom for late nights and rainy mornings, would be keen to hear your thoughts on how the QA100 performs in a sub-$1000 setup.

 

Great work on the thread, it's a fantastic read from start to finish!

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 Name:  Rotel RA820BX Integrated Amp

 

Cables:  LBP Taranui speaker cables with Redgum ICs.

Preamp:  N/A

Source:  cd120

Speakers:  Osborn Eclipse floorstanders

 

Physical Details

Weight,                        3kg                 

construction details:     Steel case, light but solid.

Power:                         35 x 2 into 8 Ohms  170 watts maximum.

Inputs:                         3 line level plus phono and tape out.

Approx 25 years old with no TLC apart from a few blows out with compressed air (I had to get the dust out somehow!).

 

Music.

Highs:    Fair but not greatly extended, slightly thin, reasonable amount of snap but brings a touch of glare with it, metallic decay is reasonable, no air around the highs, bit of breakup on Norahs voice when she wails.

5.5

 

Mids:    Not particularly fast on the transients but sounds nicely balanced across the mid range, ever so slightly bright acoustic guitar.  Get a song going that stays in the mids and this is a very nice amp to listen to, it only has issues when it goes into the highs and lows.

7.0

 

Bass:    Nice impact but lacking a bit in depth and body on drums which can lead to the drums sounding a bit hollow on occasion, bass performance varies from song to song so bass control is not very good.

5.5

 

Vocals:  Male vocals a little light 5.5, Female vocals thin-ish and lacking some emotion, particularly in the highs 4.5

5.0

 

2D Soundstaging:          OK, but no real sense of height.

5.0

3D Soundstaging:          Can show decent depth but is inconsistent in showing it.

5.5

 

Overall performance Integration:   including Foot Tapping Factor and PRAT.

A decent performance within the mid range, stay in the mids and things are good, but when the highs and the bass come along it is lacking.  (using compressed remasters might just be able to bump this up to a 7.0!)

5.0

 

Ability to Emote:  Decent, it carries a nice rhythm with fair harmonics provided it sticks to its strengths (ie mid range)

6.0

 

Electric Guitar Test:    Passable but lacking a bit in depth and decay, soundstage also sounds a bit small.

5.5

 

80's Rock Test:    Allows several of the standard weaknesses of 80s rock to stand out, lack of depth in the bass, thin vocals and flatish guitar.  Some would say that this is how stereotypical 80s rock should sound but it sounds a bit more stereotypical than I feel is acceptable.

5.5

 

Personality Summary:

Well is an amp from the 80s that was built to a price point and it still gained quite a reputation, because it has that nice mid range and does a fair job outside of it.  If the music strays outside its comfort zone it just does its best and keeps going because it knows the overall performance it provides is still pretty good.

 

Pros:  Build quality!  Decent grunt as those watts are bigger than they seem, cheap as chips back when they were new, excellent value for money.

Cons:  After 25 or so years one of the buttons is missing and the red power LED is dead, no remote (not that you would expect one at the price).

 

Pics in previous post.

 

Final Score:  55.5

 

I think it is safe to say that this amp would have scored 58 or 59 when new, excellent value when you consider it was about $250.

 

Scale:

1 to 3 means a performance below par with one being somewhere in the vicinity of fingernails on a blackboard while a poorly tuned AM radio shrieks out static in the background and 3 being just bearable.

4 to 6 is average, listenable but nothing noteworthy, 4 being a bit messy or harsh and 6 being pretty good but nothing to write home about.

7 to 9 is better than you would expect then to be, with 7 being a good performance, 8 being an exceptional performance and 9 being the best you are ever likely to hear.

And it is pretty damn unlikely that I will ever award a 10 because that would mean it is the best of the best of the best.

(Multiply them all by 10 for an idea of what the final score means, and remember from 30 to 60 you can go from an absolute stinker to an amp that is pretty good at what it does, anything above 60 is likely to be something worth investigating)

 

So why did I choose the little Rotel as my next amp?  Well this little thing was my very first amp, I picked it up from the pawnbrokers in Mount Isa with a pair of Bose 301s (series 3s) for around $350 in 1997.  It has yet to fail so it holds a special place in my audio memories.  I still remember how good the guitar riffs sounded while I played Mechwarrior 2 on the original Playstation.  Now that I have a scoring system I really wanted to see how this piece of history scored.  All things considered I think it did well.

 

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