SOUND BLASTER E5 DAC/ HEAD­PHONE AM­PLI­FIER

DAC/HEAD­PHONE AM­PLI­FIER

Australian HIFI - - CONTENTS -

A DAC from a com­pany that made its name in com­puter au­dio? When you think about it fur­ther, it makes per­fect sense, says re­viewer Stephen Daw­son.

Is it too cheeky to in­clude in th­ese au­gust pages a re­view of a DAC that costs a mere $350? In­deed, a DAC that comes from what is es­sen­tially a com­puter pe­riph­eral com­pany? A DAC that’s also an ADC, a mi­cro­phone pack, a pow­ered head­phone am­pli­fier and an au­dio pro­ces­sor? After run­ning it through its paces, I don’t think it’s too cheeky, be­cause it turns out that you can get some very re­spectable sound out of this de­vice.

The Equip­ment

The com­pany is Cre­ative Tech­nol­ogy. It didn’t invent com­puter sound for IBM com­pat­i­ble PCs (this was way be­fore Win­dows), but brought to­gether the syn­the­sis of sound and dig­i­tal to ana­logue con­ver­sion in com­put­ers with its Sound Blaster cards for com­put­ers. That was 1989 and the DAC ca­pa­bil­i­ties were by to­day’s stan­dards some­what prim­i­tive. For­get about high res­o­lu­tion au­dio. It could han­dle only 8-bit mono au­dio at 12kHz sam­pling. For some years Cre­ative dom­i­nated the field, and although those glo- There is no set­ting for a fixed line-level out­put, which is some­thing I would have pre­ferred. That way one could ded­i­cate the level con­trol to head­phone out­put. ry days are long gone, it man­aged to sur­vive the gen­eral in­cor­po­ra­tion of au­dio fa­cil­i­ties into com­puter moth­er­boards by aim­ing at the higher end of the com­puter user mar­ket, pri­mar­ily gamers.

The de­vice un­der re­view is the Sound Blaster E5, a small unit which is far from any­thing that would be placed in­side a com­puter. It has lots of ca­pa­bil­i­ties, but let’s start with the Mi­cro-B USB port. Plug this into a com­puter and it be­comes a USB DAC. A USB DAC with a head­phone am­pli­fier. In that role, it kind of per­forms like the Sound Blasters of old (ex­cept it doesn’t don’t have an FM synth any more… all that stuff is done in soft­ware th­ese days), but it per­forms much bet­ter since it sup­ports dig­i­tal au­dio with bit depths to 24-bits and sam­pling rates to 192kHz. In­deed, us­ing the Cir­rus Logic CS4398 DAC chip it fea­tures a dy­namic range of 120dB, while noise and THD is spec­i­fied at –107dB. The chip sup­ports DSD, but this has not been im­ple­mented in the Sound Blaster E5.

There’s a line out­put (all ana­logue con­nec­tions use 3.5mm stereo sock­ets), two head­phone out­puts and an op­ti­cal dig­i­tal au­dio out­put, just in case you pre­fer to use your own DAC. Both head­phone and line out­put lev­els are con­trolled by a ro­tary vol­ume con­trol on the unit.

There is no set­ting for a fixed line-level out­put, which is some­thing I would have pre­ferred. That way one could ded­i­cate the level con­trol to head­phone out­put and let one’s au­dio am­pli­fier look after level con­trol from the line out­put.

Driv­ing the head­phone out­puts is a Texas In­stru­ments TI6120A2 head­phone am­pli­fier chip. I know we tend to be keen on dis­crete com­po­nents and all that, but be­fore rush­ing to judge­ment, con­sider that this am­pli­fier has a max­i­mum out­put of 1.5 watts, an A-weighted sig­nal-to-noise ra­tio of 128dB, and THD of 0.00024%. It uses cur­rent feed­back ar­chi­tec­ture, fa­cil­i­tat­ing high slew rates (it’s rated at 1,300 volts per mi­crosec­ond). The im­ple­men­ta­tion in the E5 re­sults in an out­put im­ped­ance of just 2.2 , leav­ing head­phones of vary­ing im­ped­ances across their fre­quency range largely un­af­fected by the volt­age di­vider ef­fect.

There’s also a USB Type-A socket into which one can plug an iPad or iPhone (it didn’t seem to work with an iPod Nano) or some An­droid de­vices for mu­sic play­back. There is also a combo 3.5mm ana­logue au­dio in­put and op­ti­cal dig­i­tal au­dio in­put, so you could use it as a CD DAC.

But there are more in­puts than that. Specif­i­cally, Blue­tooth. Im­pres­sively, in ad­di­tion to the stan­dard SBC codec the de­vice sup­ports both the higher-qual­ity AAC codec used on Ap­ple de­vices, and the higher-qual­ity aptX codec sup­ported by many pre­mium An­droid de­vices.

In this re­view I am re­strict­ing my­self to those func­tions and fea­tures. But there’s another side to the de­vice. It has mi­cro­phones and a com­bi­na­tion mi­cro­phone, line and op­ti­cal dig­i­tal au­dio in­put, along with an ana­logue-to-dig­i­tal con­verter. You can use it with an iOS de­vice or a com­puter for record­ing… or use it as a hands-free sys­tem with a smart phone. There’s a but­ton that works to an­swer calls and hang up, the rest of the time do­ing duty as a switch for the au­dio pro­cess­ing fea­tures.

There’s also a built in recharge­able bat­tery with a 3200mAh ca­pac­ity. That al­lows the unit to op­er­ate as a DAC for an An­droid phone or iOS de­vice, or run with Blue­tooth sources away from any ex­ter­nal power.

The bat­tery is rated for up to eight hours of op­er­a­tion. The E5 mea­sures 70×24×111mm (WHD) and weighs 164 grams.

It also has a DSP built-in, which can do things such as EQ the au­dio or cre­ate a vir­tual mul­ti­chan­nel ef­fect for head­phone lis­ten­ing. Those things are con­trolled us­ing the driver con­trol soft­ware which you in­stall when us­ing the E5 with Win­dows or on a Mac, and sim­i­lar fea­tures can be con­trolled by app on iOS and An­droid de­vices.

I did not use the DSP but kept things sim­ple with a straight-through au­dio path.

Sub­jec­tive Per­for­mance

The Sound Blaster E5 de­liv­ered quite a few sur­prises, most of them good, but not all.

There was one thing I just did not like at all, and that was what I as­sume to be an auto in­put se­lec­tion. I would have far rather had man­ual con­trol over this. I started to try to work out which in­puts had pri­or­ity, or if there was just some kind of mix­ing go­ing on, but soon man­aged, just by us­ing first the USB Type B in­put, then the mi­cro-B USB in­put, to hope­lessly up­set the unit. Mu­sic was played with a loud clat­ter, like the sound of a play­ing card against the spokes of a bi­cy­cle wheel. Fix­ing that took both sev­eral switches on and off and a re­boot of the com­puter, so I aban­doned the ef­fort.

I can re­port that the unit worked well at play­ing back mu­sic from an iPad Mini 4 and an An­droid phone with On-The-Go sup­port. (Most pre­mium An­droid phones and not a few mid­dle mod­els pro­vide this sup­port, which al­lows pe­riph­er­als to be plugged in, in­clud­ing DACs.) Like­wise the op­ti­cal and ana­logue in­puts, and the Blue­tooth con­nec­tion. You can have two de­vices paired to the E5 by Blue­tooth at once. To add a third you have to dis­con­nect one of the ex­ist­ing ones.

I did most of my lis­ten­ing us­ing the E5 as a DAC for a Win­dows com­puter. I mostly used Foo­bar2000 and JRiver Me­dia Cen­ter as play­ers be­cause with them I could choose a more direct con­nec­tion to the DAC, us­ing the WASAPI in­ter­face. The driver pack­age also in­cludes ASIO sup­port which tends to be what pro­fes­sional soft­ware prefers. Or­di­nary Win­dows pro­cesses can send mu­sic to the de­vice us­ing the or­di­nary Win­dows in­ter­face. That means you can play Spo­tify mu­sic and YouTube clips and such through it. But it is best to go WASAPI or ASIO if player soft­ware sup­ports them be­cause Win­dows in­sists on con­vert­ing ev­ery­thing to a fixed sam­pling fre­quency (not to men­tion that it mixes in all other sys­tem sounds).

I have to say that the sound us­ing the Sound Blaster E5 as a DAC for my com­puter was sim­ply ex­cel­lent.

Not just ex­cel­lent for a low­ish-cost de­vice like this, but just all-round ex­cel­lent. The sim­ple mat­ters were of course fully cov­ered. The tonal bal­ance was per­fect. There was no au­di­ble noise. Noth­ing un­to­ward ap­peared in the sig­nal. But there was a very classy tan­gi­bil­ity in the stereo imag­ing, and sur­pris­ing sub­tlety in the de­liv­ery. As I write this, for ex­am­ple, I have the Giles Martin-pre­pared al­bum ‘Love’ play­ing, con­sist­ing of sub­stan­tial remixes and cut-and-pastes of Bea­tles tracks.

The tiny birds tweet­ing (in the tra­di­tional mean­ing of the word) around the song Be­cause ap­pear here, there, up above the speak­ers, down be­tween them, and at var­i­ous dis­tances be­hind them.

That was re­peated with all man­ner of mu­sic, lit­tle of it from au­dio­phile sources. The imag­ing sur­prised me with its depth and pre­ci­sion. I was sim­ply not ex­pect­ing this.

Us­ing the head­phone out­puts the per­for­mance was of a sim­i­lar high qual­ity, but there are two im­por­tant things to note. First, there was no ap­par­ent bias of fre­quency re­sponse with head­phones which vary in im­ped­ance ac­cord­ing to fre­quency, which tends to cor­rob­o­rate the com­pany’s claim of an out­put im­ped­ance of just 2.2Ω. Se­condly, there was no prac­ti­cal lim­i­ta­tion on out­put vol­ume. Even us­ing my el­derly Sennheiser HD535 head­phones, with their rather low sen­si­tiv­ity and high­ish im­ped­ance (around 160Ω), the Sound Blaster

E5 could push them to re­mark­ably high lev­els cleanly, with fine con­trol. And that was without switch­ing the E5’s gain switch from low to high, which would have added ten deci­bels. It man­aged those head­phones ef­fort­lessly, with an open sound, as spa­cious as can be man­aged with head­phones.

With lower im­ped­ance (26 ), higher-sen­si­tiv­ity head­phones, again things were clean and con­trolled. There was no noise in­tro­duced into the sound by the E5.

ob­jec­tive Per­for­mance

I ran some tests on the E5 us­ing RightMark Au­dio An­a­lyzer soft­ware. The re­sults were mixed, although mostly very, very good. Let’s start with what most of us spend most of our time lis­ten­ing to: 16-bit/44.1kHz au­dio. Us­ing the line out­put the E5 pro­duced a flat fre­quency re­sponse, down by 0.1 deci­bels at 20.7kHz, hit­ting a brick wall shortly be­yond that. And after ac­count­ing for a 0.2dB droop at 20Hz from my mea­sure­ment rig, down by around 0.25dB at 20Hz.

Ini­tially the noise per­for­mance was so-so: –88.4dB A-weighted. In­audi­ble, to be sure, but not at the the­o­ret­i­cal lim­its of 16-bit sound as you’d hope. But then I re­peated the test with the com­puter dis­con­nected from power, run­ning on its own bat­tery, and the noise lev­els dropped con­sid­er­ably to give a re­sult of –98dBA.

And that fig­ure is, I think, pretty close to the best I’ve ever mea­sured with 16-bit au­dio. THD was 0.002% and IMD+Noise down at 0.0047%.

All that said, noise from a con­nected com­puter re­ally ought to be blocked by one’s DAC, not be per­mit­ted to af­fect the ana­logue sig­nal… and es­pe­cially not al­low it to be over­laid with spu­ri­ous spikes (the worst at –93dB) at sim­ple frac­tions of the sam­pling fre­quency.

With 24-bit sound the noise level fell fur­ther to –109dBA. Also very im­pres­sive. Of course, this was with the com­puter run­ning on bat­tery. I’d learned my les­son. The fre­quency re­sponse at 96kHz sam­pling was ex­tended at the top end, to be down by less than 0.5dB at 30kHz and only –0.9dB at 40kHz. THD: 0.0018%, IMD+noise: 0.003%.

The DAC sup­ports 192kHz sig­nals, but the wheels seemed to fall off a lit­tle. Noise and both THD and IMD were just about the same as for 96kHz, but the fre­quency re­sponse was weird. It took up a nar­row wob­ble above 2kHz, down by nearly 0.2dB at 6.5kHz, back up to nearly full level at 12.5kHz, down at 19kHz, up at 24kHz and with another brief lo­cal peak (al­beit half a deci­bel down) at 34kHz be­fore plum­met­ing.

Au­di­ble sig­nif­i­cance? I defy any­one to no­tice in blind tests but th­ese kinds of things make me worry that some­thing has gone wrong with my mea­sure­ments. So I repli­cated it but used a dif­fer­ent brand of por­ta­ble DAC/ head­phone amp as the DAC. It ex­hib­ited the ex­pected smooth roll-off to –3dB at greater than 62kHz. Then I re-mea­sured the E5 with iden­ti­cal re­sults to the ear­lier mea­sure­ments.

But what about the head­phone out­put? Given the 192kHz wob­bles, I mea­sured that for 96kHz/24-bit sig­nals. The fre­quency re­sponse graph pre­cisely aligned with that for the line level out­put. Noise was, A-weighted, four deci­bels higher than for the line level. The mea­sured level at –105.8dB was roughly a mile below au­di­bil­ity.

At max­i­mum set­ting, the line-level out­put was 2.01V RMS for a full mod­u­la­tion sine wave. Into a 295 load the head­phone out­put man­aged 1.84 volts RMS, which is 11.6 mil­li­watts, which in turn means some 10.6 deci­bels more out­put than the sen­si­tiv­ity spec­i­fi­ca­tion of head­phones. If your high-im­ped­ance head­phones have a rating of 95dB for 1mW in­put, you can ex­pect bet­ter than 105dB SPL us­ing the E5. (More us­ing the high gain set­ting).

With a 15.9 test load max­i­mum out­put re­duced. Or, rather, I re­duced it be­cause at full out­put it was clip­ping. For the 1kHz and 10kHz test fre­quen­cies drag­ging it down to 1.25-ish volts out­put elim­i­nated clip­ping, while it had to go all the way down to 0.81 volts out­put into 100 to avoid clip­ping.

But even at 100Hz that was over 40 mil­li­watts out­put, yield­ing 16dB above the head­phone sen­si­tiv­ity rating.

con­cLu­Sion

I guess if you pay a lot more than $350 you can get a DAC with com­pa­ra­ble per­for­mance, plus im­proved noise re­jec­tion from the USB in­put. But that aside, I’d have to say the qual­ity of the per­for­mance of the Sound Blaster E5 makes it a true high-fi­delity DAC. So it’s quite the bar­gain as just a DAC, and if you can make use of all the ad­di­tional func­tion­al­ity avail­able it be­comes even more of a bar­gain. Stephen Daw­son

Noise was four deci­bels higher than for the line level. The mea­sured level at –105.8dB was roughly a mile below au­di­bil­ity.

Fre­quency re­sponses and noise and dis­tor­tion analy­ses. (See copy)

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