Those EL84 Amps

If ever an urban myth there was, there is, the myths regarding EL84 tubes.

I have had the pleasure of listening to both the Ming DA and Shuguang EL84 tube amps (with of course, Shuguang EL84 tubes) and came away with a completely different disposition that I had going in. Most audiophiles are not familiar with these tubes or amps and on first notice, see their diminutive size (in both tube and amp size) as a negative. Hmmm. For those of you With size issues, I am here to help.

Myth # 1 - The Power is too small.
That's what I thought. Until I heard these amps drive Quads, Acoustats, ribbon speaker etc. to reasonable listening levels with uncanny detail and smoothness.

Myth # 2 - These small tubes can't produce deep bass
If ever a myth needed dispelling, its this one. On the contrary, watt for watt, these tubes produce a deeper bass than a comparable EL34 amp and even close to KT88. They even take the best of a solid state amp - deep bass and transparency to a new level. I am not talking tubby bass here, folks. Bass real tight and deep. Kick drums are a new experience

Myth # 3 - Folks will make fun of me if I drive Large horns with these amps

This of course, I cannot help. But, they will not make fun of the sound. These amps are the most neutral and detailed of all tube amps that I have heard and a perfect match for folks who own horns and other high efficiency speaker systems.

Myth # 4 - I am not the SET amp type.
Well, these EL84 amps really do not soud like a SET amp. As mentioned before, the deep kick drum bass response and the extended high end are not necessarily what I associate without the best of SET amps. With the EL84, you get seem to get the best of solid state/SET / KT88 amps in a low cost package.

What a shame if will be this year, when folks take their hard earned money and buy and NAD, Rotel or Cambridge amp and miss the detail, deep bass and righteous high end of these amps.

All the best ....

Vic

The State of the DAC Union -

So, I have been kind of out of it. But, I promise to be back with a vengeance discussing DACs, CD Players, preamps and amps. But first back to the DACs.

So much has happened since we started the foray into the upsampling comparison. I have had to stop and re-think my ranking. So far, this is what I have. (and by the way, after much berating, I am switching my ranking. #1 being the best and #X being, well, the most challenging to listen to.)

1. DAC 62
2. Modified DAC 60
3. DAC 68
4. DAC 38
5. DAC AM Modified
6. Great March Madness!
7. DAC AM
8. Great March Modified
9. Great March
10. DAC AH Modified
11. DAC AH

If its not on the list - I have not heard it. More DACs we will be getting in: Musiland MD 10, Great March II and DIYEDEN DAC 05.

DACS With Up Sampler

Okay, I am chopping at the bit to see if my theoretical as described in my previous BLOG http://victrolax.blogspot.com/2006/06/whats-with-oversampling-upsampling-and.html was correct. The premise was that up sampling will exacerbate and not fix shortcomings in DAC sound. So here is my revised ranking (hypothetical) going from no-so-hot to hot sounding (this ranking assumes that the signal is up sampled to 96 kHz and is based on my listening bias):

1. DAC AH Modified
2. DAC AM
3. DAC 60
4. DIYEDEN Great March Modified
5. DAC 38
6. DAC 68
7. DAC 60 Modified




Music

I had to pick music that I thought was revealing. Here is what I listened to:

Dire Straits - Brothers in Arms
The Jones Street Boys
Eileen Farrell, Torch Songs
Chicago, Theme from the Movie
Harry Connick – When Harry Met Sally
Rickie Lee Jones – Traffic from Paradise

Equipment:

XianSheng D-2020A KT88
The smoothest integrated around. The D-2020A neutral midrange and neutral high end – Poseidon adventure shattering bass for a 30 watt tube amp make it a perfect amp for evaluation.. Its the 5Z3Ps that I am addicted to.

Speakers:

Infinity 360s
Acoustat Spectra 11
Aurm Cantus Leisure
Proac 1sc
Headphones: Grado SR 225 with Ming Da MC 66AE headphone amplifier

Categories:

I broke my listening biases into categories an assigned points. Here they are:

Smooth High End
A DAC scored above 15 if the high end was smooth and rolled off. Constrictions and beaming scored points less than 15.

Mid Range Smoothness
Lucid and smooth scored over 15 points. A sucked out midrange scored between 10 and 15 points. Nasal sounding midrange scored less than 10 points.

Deep tight Low End
A deep tight low end scored more than 15 points. A rolled off low end scored between 15 and 10 points, a flabby low end scored less than 10 points.

Annoying Mid bass
Over 15 points meant that the mid bass was relatively neutral. Less than 15 points was a slightly bloated mid bass.

Resolution – distance between instruments
A DAC scored over 10 points if the background vocalists were clearly distinguishable from the lead and had placement. Over 15 points if the background vocalists were then distinguishable among themselves, Less than 10 points if I could not tell who was who

Dynamics
A DAC scored over 15 points if the movement from quite to loud shocked me. A DAC scored between 10 and 15 points if I noticed a difference. A DAC scored less than 10 points if I felt like I was listening to a CD through a pancake.

Articulation
If I clearly hear the plucking of guitar strings, I gave the DAC over 15 points. If the guitar strings were just Ok and had no sense of depth or presence, It scored between 10 and 15. If it sounded like nails on a chalk board, I gave it less than 10.

Now that I have my music, equipment and criteria, here we go.

The “Bunch”

First, let me give you a reference. We took a “bunch” of CD players readily available on the market and put them through our tests. The CD Players ranged from $300 - $1000. We then averaged the scores. Here is how they played out.

The “Bunch” Scores:


Smooth High End 10
Mid Range Smoothness 9
Deep Tight Low End 15
Annoying Mid Bass 17
Resolution 9
Dynamics 10
Articulation 10
Total 80


The “Bunch” scored a value of 80 , which we will now have to try to beat either through stand alone DAC or up sampling.

The DAC AH Modded

I was not sure what to expect when the up sampler was used with a NOS DAC. My first thought was the upper midrange and high end would become glossy and have a metallic sheen to the sound. In other words, it would exacerbate the DAC AH’s weaknesses.

The compete opposite happened.

I chose the 96kHz up sample with the DAC AH.. What a difference! Gone was the aggressive constrictive high end. The upper midrange just sang. And here is the best part: the dynamics of the NOS method were kept in tact. This is definite winning combination that places the DAC AH / Up sampler combination above the pack.

The DAC AH Modified without the Up sampler


Smooth High End 10
Mid Range Smoothness 12
Deep Tight Low End 17
Annoying Mid Bass 17
Resolution 12
Dynamics 19
Articulation 17
Total 104

The DAC AH Modified with Up sampler

Smooth High End 18
Mid Range Smoothness 18
Deep Tight Low End 18
Annoying Mid Bass 17
Resolution 14
Dynamics 19
Articulation 14
Total 118

The Lite DAC AM

And now I turned my attention to the DAC AM, the DAC I like best in the less than $400 dollar range. As a matter of fact, I like it better than the stock DAC 60 and I highly recommend it if your system can reveal inner details of the midrange. It’s a killer combination with the XianSheng D-2020

To my surprise, the up sampler just ruined this DAC and turned it into a syrupy mess.

The DAC AM Modified without the Up sampler

Smooth High End 18
Mid Range Smoothness 18
Deep Tight Low End 14
Annoying Mid Bass 18
Resolution 18
Dynamics 14
Articulation 18
Total 118


The DAC AM Modified with Up sampler


Smooth High End 18
Mid Range Smoothness 18
Deep Tight Low End 10
Annoying Mid Bass 18
Resolution 15
Dynamics 10
Articulation 16
Total 105


In my next installment, I will visit the DAC 60 Modified, the DAC 68, the Great March Modified and the DAC 38.

What’s with Oversampling, Upsampling and Non-Oversampling (NOS) ?


When we were vinyl, we had our own vocabulary: belt drive, direct drive, servo, anti-skate, counter weight, tracking angle – remember? Now that we are optical, a whole set of new words spook our vocabulary: Upsampling, Oversampling and Non Oversampling. Needless to say, these words are creating confusion out there in the press and among some audio jockeys (not you, of course) and they are used interchangeably, which is a big no-no.

Let’s first start out with some basics: oversampling is the realm of the conversion between digital to analogue and the upsampling is the realm of digital. Non oversampling is an enigma wrapped in a mystery. You cannot use these words interchangeably because they all mean different things.

You want a DAC to correct the anomalies in the conversion process. Take some of the earliest DACS, that were 16 bit and extracted data at a rate of 44.1 kHz / 16 bits. When the DAC converts data in the 20-20kHz range, it leaves some canard above the 22kHz range that must be cleaned up. If it did not, inter modulation distortion and ultrasonic frequencies would wreak havoc on your system – destroying tweeters, midrange drivers and turning mylar into chewing gum. In order to prevent this, a filter is applied. The filter that filters this out is called a “brick wall”, and it abruptly chops off frequencies at 20kHz. This filter, while not allowing the digital leftovers to blow your tweeter to smithereens, does cause audible distortions. The abrupt filter is responsible for some of the sonics coming from early vinyl copies of Fleetwod Mac’s Tusk that were digitally recorded and mastered or some circa 1980 digital recordings(Ry Cooder) . Cymbals sound like tambourines, highs are compressed as well as dynamics. If digital was going to make it into high end, something had to be done. Enter Phillips with its 4X oversampling player.

In a 4X oversampler, the digital signal is fed through a special digital converter that samples it four times. When a CD is sampled four times the sample rate becomes 176.4 kHz(44.1 X 4). When the filter is applied here, there is less of chance that the filtering roll off will make its way into the audible range. A filter applied at 176.4 kHz sweetens the music as it removes most of the grunge. As cost allows, oversampling pays off in a big way. The DAC 60 and DAC 38 use Burr Brown’s latest PCM1704UK chip which is 8X oversampling at 96kHz. The DAC 68 uses Analogue Devices AD1835 chip which samples as high as 192kHz. The AD1853 is fully compatible with all known DVD formats and supports 48 kHz, 96 kHz and 192 kHz sample rates with up to 24 bits word lengths. The higher bit lengths of these DACs allow them to act more in a linear fashion during the conversion process and results in superior sound quality.

Now I digress, to the DAC AH that is a non oversampling DAC using 8 TDA1543 chips with no digital filtering. From our discussion above one would assume that the grunge left over should have blown up tweeters and mylar alike. But, that’s not what happens. So what gives?

This has to do with the 8 TDA1543 that the DAC AH employs and the algorithm used for designing non oversampling DACs. The non-OS algorithm by definition introduces a slight roll off in the treble, so by the time you get up to damaging frequencies, the output of frequencies above 22kHz isn't really all that high. Hence, intermodulation distortion still makes its way into the DAC AH and other non oversampling DACs. This may explain why some non oversampling DACs sound compressed at the higher frequencies. The DAC AH modded, less so, only because the superior OP AMP compliments the conversion process in that it is able to open the sound a bit. Some NOS DACs add a digital filter – but that really defeats the whole purpose of the NOS DAC anyway – its kind of like adding MSG to a low salt diet.

So what is “upsampling”? First let me take away some of the confusion. There is belief in many an audiophiles’ minds about the power of upsampling or oversampling to create data. It is not possible to create more accurate information than is already in the digitally sampled signal. Think of blowing up a digital picture: if the data is not there, blowing it up does not increase detail.

Upsampling differs from oversampling in that upsampling is between the transport and the DAC. In the case of the Lite DAC 39, it sits between your transport (CD player) and a DAC – like the DAC 60 or DAC 38. In this case the DAC 39 feeds the DAC 60 a 96 Khz signal instead of the 44.1 kHz. In theory, when a superior upsampler is mated with a DAC that can handle the upsampling, the true 96kHz 20 bit processing can be achieved. The resulting filtering process operates in a linear fashion which yields better sound quality. So, it has to be a careful match. An upsampler should only be used with a DAC capable of handling the high sample frequency.

So the next question is how do they sound? Theoretically speaking, I could rank the DACs in order according to their sampling characteristics. Doing so, I come up with: (from worst sounding to best sounding)

1. DAC AH Modified – the OP AMP upgrade will only exacerbate the lack of filtering
2. DAC AH
3. DIYEDEN Great March
4. DAC 60
5. DIYEDEN Great March Modified
6. DAC 38
7. DAC 60 Modified
8. DAC 60 + Upsampler
9. DAC 60 Modified + Upsampler
10. DAC 38 + Upsampler
11. DAC 68
12. DAC 68 + Upsampler

In my next BLOG, I will throw away the theoretical and move to the actual. We shall see ..

When they first came out CDs left me cold. Like all audio enthusiasts, I was unimpressed. That is not to say that I did not like some of the early digital artists. Pick up a copy of Fleetwood Mac's Tusk or some of the early Ry Cooder. Okay, the 16 bit conversion voodoo makes it sound a little compressed and cymbals sound like tambourines. But the music was just as progressive as the technology. Probably Lindsey Buckinghams finest work is on the Tusk digital master.

CD players under $800 leave me feeling like I just listened to one of these early works. I listen to them if I must, and I must listen if I want to hear some of my favorite artists without spending $2000 on a CD player. I am stuck in a world of compromises from NAD, Rotel, Music Hall and Cambridge (what I call, the gang of four). Its not that these are bad CD players, they try to do the unthinkable- provide a glimpse into excellent CD sound without costing an arm and a leg.

So we have two DACs here: the Lite DAC-AH, and the Lite DAC AH-M1 from Pacific Valve. From what I am reading about these non over sampling black bricks is that they offer less fatigue along with more detail than one can ever extract from a CD rotating over one of the gang of four's lasers. The DACs keep their promise is by feeding the digital signal from one low price DAC chip to the next and avoid the over sampling hocus pocus. Errors produced as a by product of the conversion process are fed from one converter to the next and so on, until the signal passes through 8 converters and hence 8X oversampling. This is less costly, Lite tells us, than providing the top notch BB PCM-1704UK chip in the DAC 60 along with all the necessary circuitry to produce an accurate analogue signal.

The DAC AH series has a push button switch on the front along with a faint blue light implying that it is to be left on all the time. On the back there is a power plug, analogue out (gold plated), Coax in, TOSLINK in, and a switch to switch between Coax and TOSLINK inputs. That's it!! Quite simple.

The stock DAC AH immediately improves the sound from the gang of four. Comparing the stock DAC AH to the NAD C532BEE one immediately notices some light into the midrange and immediacy in the music.

The stock DAC AH has an excellent midrange presentation sans the harshness. What we also get is some grain on the high end that makes its way into the listening room as the quality of the recording twindles. So good is the DAC AH at doing this that one must re-think their entire music collection while listening to one of these.

What both the DAC AH and the DAC AH-M1 also do is provide a sense of continuity from low end to top end that is missing in the gang of four. CD players on the mid-fi range tend to "bloat" or over-emphasize the midrange and high end and leave the low end, not anemic, but lacking in authority. Not so with the DAC AH(s) whose real job is to bring the detail and tonal balance of $2000 DACs into the hands of audiophiles stuck on price performance.

Enter the modified DAC AH- M1. Pacific Valve, with the help of Lite Audio, desired a price performance modification to the DAC AH with a price under $300.00. The solution was simple, swipe out the stock OP amp for the OPA27M from Burr Brown and wah-lah, price performance.

The only thing that the DAC AH and the DAC AH M1 have in common is the blue light on the front and that's it. Where the DAC AH sounds bright, the M1 sounds smooth, Where the AH sounds harsh and compressed, the M1 sounds open. Cat Steven’s the first cut is the deepest is an example of a recording that cannot be listened to on the DAC AH. Not so on the M1 who tends to be more forgiving in the top end by opening it up and let it bloom into the room. It’s still a so-so recording, but unlike the DAC AH, I am not reminded of it at every crescendo.

The DAC AH M1 is capable of some startling detail at the $250.00 price point. In Harry Connick's When Harry Met Sally Lets call the whole thing off, for example, the plucking of the bass is clearly heard as the bassist makes his way across the strings. In the stock DAC AH, while this is a smooth rendition, it sounds kind of squeezed together and not as clear. And, it is that point, where you can some up the difference between the two. Where stock DAC AH sounds compressed, the DAC AH M1 pours music into room with politeness and detail.

If was on a budget, I just wanted to upgrade my CD player from 1993, then the stock DAC AH will provide an improvement. If I wanted a taste of high end without spending above $500, then the DAC AH M1 fits my bill. If I really wanted an excellent DAC for the money, then the Pacific Valve modified DAC 60 is the one to beat. I differ from other staffers here at Pacific Valve who just love the DAC 68 with its "British" sound. The modified DAC 60 is the one with dynamic punch and low end, and so far, the DAC to beat.


Vic Trola

The Lite CD 15 is the slowest CD player I have ever seen in my life. While Jeff thought that this exuded confidence, I saw it as a minor annoyance that it should take 10 seconds for a drawer to close and another 10 seconds to index a CD. (Okay, after recent soul searching, I am exaggerating - Its more like 1 second in, and 1.5 seconds to find the TOC - but it is deliberate, I mean it does suck CDs in like a vacuum cleaner) All the time, I wonder if it worth the wait.

Well, it is. This has to be the smoothest CD player under $500 and now serves as my reference when the DAC 68 is out on loan. That’s right, I don’t use a DAC 60, even though it has the technically superiors PCM-1704UK chip. I prefer the smoothness and detail that comes across in the multi -tiered sampling of the Lite architecture and AD 1835 chip set. I have not heard the modified DAC 60, what I am told of this mod, is that it brings the DAC 60 more in line with the DAC 68 plus an extended low end. The Lite CD 15 presents a formidable sound stage and I agree with all of Jeff’s comments on its tonal accuracy. It does have a “British” sound as does the DAC 68. Both of these products present like the EL34 tube does – uncanny detail in the midrange, smooth high end and polite low end. The DAC 60 has more of a USA sound, and sounds like a 6550 – articulated in the midrange, nice mid bass and punchy low end.If you cannot afford the DAC 68 and if the noise floor of the DAC 68 bothers you, you will not be sorry with the Lite CD -15 CD player.

My Reference System & Listening Bias

My Reference System includes:

• Lite Audio DAC 68
• Pacific Valve Modified DAC 60
• Lite Audio CD-15 CD Player
• XianSheng D-2020A Kt88 Integrated Amplifier
• Pacific Valve Modified LS27 Preamp
• Lite Audio T62 Amp
• Acoustat Spectra 11
• Infinity 360
• Aurum Cantas
• Various Interconnects

I bias toward the midrange. I favor detail and spatial dimension over tonal balance. So, I favor equipment that gets the midrange right over a tight low end. I am biased toward tube preamps over tube amps. I like hybrid amps. I do not favor a bright top end. The top end for me has to be very smooth otherwise I do not like what I am listening to.