Amplifiers


Again a little out on a limb, I'm a fan of Single Ended Triode amplifiers.

Welborne Labs had a pair of Yote 300B amplifiers in need of a little TLC listed in their bargain bin at $1000. The simple addition of tubes and a couple of plate chokes was enough to get them both working again and they sound sublime. The 96dB sensitivity of the Supravox driver marries in well enough with the 8W output of the 300B tubes. While 8W does not sound like a lot compared to the power output of most solid state amps, it's more than enough to drive the Supravox drivers to ear splitting levels. I seldom need more than 85dB or so at the listening position, so can barely account for 1W of power from the amps.

The remarkable simplicity of SET amplifiers means that they reveal every nuance of detail from the source and throw an utterly convincing soundstage that's full of texture and tone. While SETs are not everyone's cup of tea, partnered with the right speakers they manage insight and dynamics that other topologies seem to smear. I have found the addition of these amplifiers driving the 3D Sonics speakers to be revealing of almost every change I have made to upstream components, making them a perfect base to use as a test system.

A Stevens & Billington transformer volume control provides volume attenuation rather than using software level volume controls in Vista. Unfortunately, software based volume controls attenuate the signal in the digital domain by dropping bits, which can lead to a loss of resolution as soon as the volume is moved below maximum output. I've found transformer based volume controls to be very close to sounding neutral, even outperforming shunt volume control made up entirely of 0.1% tolerance laser-cut metal film resistors.

Lastly, I suppose I should mention cables. Despite my attitude towards other components, I don't do funky high-cost cables and all the fuzz associated with them. For speakers, I use a single strand of solid core 24-gauge silver covered in a simple cotton jacket. The whole shebang costs a few dollars per foot from most good audio DIY outlets and sounds fine to my ears. Interconnects are made up using either Cat 5 cable or suitable solid core coax. Power cords are all generic off the shelf types, no special plugs or dielectrics needed.

The PC

There's nothing remarkable here: a Gigabyte X48T, 4GB of OCZ Platinum DDR3, a Corsair modular PSU, and an X6800 dual-core processor. A 250GB Western Digital Caviar hard drive stores audio files in WAV format. The operating system is Vista 64, which is not ideal for audio due to some of the open source software failing to function properly if at all. There have to be compromises somewhere and current study requirements keep me on the Vista coach just to keep up to speed with its administration. Anything using a dual-core processor running at over 2GHz is likely more than sufficient for an audio server. 4GB of memory is pretty much mandatory for Vista 64 to work efficiently when placed under any kind of load. Another caveat is that I have not managed to locate any USB-ASIO drivers for the Vista 64 platform. ASIO drivers are preferred to help lower latency by routing signals directly to hardware where possible. Vista 32 and XP are fully supported by USB-ASIO, so that's something to bear in mind if you'd like to keep latency as low as possible.

The Test System Outboard DAC solutions
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  • goinginstyle - Wednesday, December 3, 2008 - link

    I agree, while I might argue about some of the conclusions or have a different opinion, the author knows what the hell he is talking about. It is obvious from a lot of the comments that people stopped reading on page two and brought out the guns. It is fine to agree to disagree but some the comments here apparently came from five year olds and not adults. Sound quality is subjective, get over it. I appreciate a different opinion than my own and found the article to be thought provoking at times. Something an article should do when covering a hot topic like audio quality. Being an old hippie myself, I still love the tubes but digital has its place now. I vote that he does another article on this subject and lets see where AnandTech takes this in the future.
  • strikeback03 - Tuesday, December 2, 2008 - link

    How do you live in a rural area and not own a car?
  • royboy66 - Tuesday, December 2, 2008 - link

    hi I have been into audio and music for many years it is my hobby, computers are my business and hobby. I commend you guys for covering this topic -i will download the software you have used and give it a try.
  • Wastral - Tuesday, December 2, 2008 - link

    Well at least he talked about SOMETHING to do with the PC!

    DAC talk was good if really really wordy. Nothing like breaking points down into something someone can read.

    Not one review of sound cards of sending analog output out from the computer and its actual quality... You know the main component needed in a PC... What a stooge.

    Most People can't even hear over 16khz and the very rare person can hear around 20khz. I tested out at 18.3khz with a wave generator when I was 16. Now? Probably no more than 14khz at the age of 30. Not to mention the dB sensitivity of the ear over 16khz is next to nothing. On top of that, as I pointed out with a little thing called age your hearing decreases to 10khz by age 60 or so.

    Of course If we really want this right, it has to be decoded at the amp, which won't happen, due to there being a million and 1 codecs around. Thus, we are stuck with analog.

    Its all about your speakers and amp. That part of his article I won't complain about too loudly.

    Just his BS about tube amplifiers. 10 years ago that was true. Now its only because old Hippies are retiring and tube amps were top of the line then and they have too much money and time on their hands to burn, with nostalgia hot in their blood.

    Try recording something and then play it back with a tube amp or a Digital amp and compare the sound. No one uses Tube amps in studios. Why? Because it CHANGES THE MUSIC and is not as PURE as one can get with Digital amplifiers. They say they like it... wonderful, its not as true of a sound though, the HYPOCRITS!!!

    Everything else was typical Audiophile BS ignorance. Hell, I have even installed an outlet for an "audiophile" pointed North-South for better "power" to his amp. No joke, he whipped out a compass.

    Comments like, "I only use silver 24 guage wire." DUMB shit!! Go another guage larger in copper is a hell of a lot cheeper and gets better results.... IDIOT. Not to mention its your CONNECTORS THAT COUNT.

  • Rajinder Gill - Tuesday, December 2, 2008 - link

    Where did I sue the word 'only' in that statement about wire?

    Seems you've done the typical thing and read what you want to read.

    My entire cable setup costs less than $40, including the interconnects and mains cables. No north-south compass in my house either.

    Connections are direct soldered where they can be and if it's practical enough. No expensive connectors used.

    I'll aslo refrain from using the derogatory language you seem so comfortable with.
  • Rajinder Gill - Tuesday, December 2, 2008 - link

    correction meant 'use'..
  • Geraldo8022 - Tuesday, December 2, 2008 - link


    Mr Gill is trying to do some of you a favor by cluing you in, but some of the denser posters come back with talk about receivers, headphones, soundcards, measurements, double blind testing, Class D, etc.
    Someone once asked Satchmo what jazz was and his reply was, "if you gotta ask you don't get to know." I guess some of you here aren't gonna get to know. Just keep your head in the sand, or elsewhere.
    I have been into HiFi for almost forty years and it is about things like sitting in the dark at one o'clock in the morning with Sarah Vaughn. If that doesn't make any sense to you, then you don't get to know.
    Mr Gill, I thank you for this article. You keep on keepin' on.
  • Beefmeister - Tuesday, December 2, 2008 - link

    Great choice on the Opus DAC; the Twisted Pear Audio guys do great work. I've built myself a Buffalo DAC.

    That being said, I would strongly suggest you look at replacing your Ballsie with IVY modules. IVY is capable of zeroing the DC offset from the DAC, thus allowing you to jumper the output coupling caps on the Opus. It also gets rid of the dual and quad OPAMPs of the Ballsie, which apparently don't measure as good as the single and dual variants.
  • draak13 - Monday, December 1, 2008 - link

    Starting off with reading the article, I was getting quite pissed about how much this was going into the usual audiophile BS, where their 'prowess' of electronics goes so far as, "the resistor says 1000 ohms, but really, it TASTES like 992 ohms. There's such a huge difference." I was half expecting there to be talk of putting sandbags around the room to 'enhance the musical quality of the room setting.'

    Reading further, I found that this article was quite good, and was even moderately scientific as I have come to expect from Anandtech. The choice of the recording microphone was EXCELLENT; I looked up the spec sheet for that, and the response on that mic is absolutely incredible, and is a total steal for the price you pay. Kudos to anandtech for finding and using it. The very objective comparisons of two different dacs was quite excellent, as were the multiple recordings.

    I absolutely loved your analysis of an addition of a subwoofer into the system to compensate for the range of the main speakers. I have always been curious about how well that would actually work. Lastly, I was blown away by your DRC analysis. That's an INCREDIBLE algorithm that you have there; I love it.

    There are a few things that I could say about the choice of components, and the squabbling going on about what components "perform better", but there is an end-all test that you could do to prove what is and isn't BS. First, I can flat out GUARANTEE you that your microphone is as sensitive or more sensitive than the human ear AT LISTENING VOLUME. That is, anything that you can hear, that microphone should be able to hear as well. So, if you wanted to turn your subjective listening tests into objective listening tests, then play back those songs you were testing your setup with, but record those songs at listening position with your microphone using all of your different setups. Record them multiple times, as you have been doing in your tests. Next, using MATLAB or whatever other software, overlay the recorded waveforms and determine the differences between the two. If there truly is a difference between the different hardware setups that you were using, I guarantee that this will be sensitive enough to detect that difference, and will do so quantitatively.
  • DeepThought86 - Monday, December 1, 2008 - link

    At the end of the day, is all this expensive tomfoolery just to listen to music? Why pay extra and turn your brain to jelly to boot?

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