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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  • Christobevii3 - Monday, December 1, 2008 - link

    What about using a dts/ddl sound card to output to a basic receiver?
  • Rajinder Gill - Monday, December 1, 2008 - link

    If going to the nth degree for 2 channel it’s hard to look past USB-I2S in async. For multichannel, a DTS/DDL card is perfectly adequate. Although I’d still use an external solution if I could find one.
  • wolrah - Monday, December 1, 2008 - link

    How do you figure I2S is any better than S/PDIF? S/PDIF supports up to 20 bit resolution at either 48 or 44.1 KHz, so it can carry a CD audio stream natively. The bits on the disc are the bits flowing out the optical port on the back of your gear of choice.

    In theory an I2S signal will be able to take more interference, but when we're talking optical signals in a home environment the kind of interference needed to make a difference would be on the scale that you'd never be able to listen to anything.
  • Goty - Monday, December 1, 2008 - link

    Well that's easy to answer:

    Nope. I'll stick with my Martin Logans, tyvm.
  • wolrah - Monday, December 1, 2008 - link

    In fact it easily can, because plain and simple reading from the disc itself is error prone. A one time rip to WAV or [lossless format of your choice] using cdparanoia on its insane mode output through a high quality sound card will be the same as or better than any silly 4 digit CD player.

    Even playing straight off the disc, there's no reason to believe any "audiophile" gear will play a CD any better than any other CD player unless there's a design flaw like a crappy power supply.


    On the note of power supply, am I the only one who laughed at the bit about the battery vs. the wall wart? Who wants to bet that he's never double-blind tested that one. That's the wonderful thing with A/V gear snake oil, it's very easy to hear what you want to hear.
  • mindless1 - Monday, December 1, 2008 - link

    I've hand-built amps for years and double-blind tested batteries and wall warts. Yes there is a difference. A good (read: overkill for anyone not into building audiophile equipment) localized power filter stage, if not localized regulation, would ideally negate the difference between the two power sources but that can also unnecessarily increase the build complexity, time, and cost.

    PS the battery is almost always inferior assuming the wart has proper shielding or is inadequate in capacity, and generally I refer to a wart as only a transformer and rectification stage, not trying to build an entire high precision linear regulation stage inside of it due to limited space and EMI.
  • Rajinder Gill - Monday, December 1, 2008 - link

    Martin Logan makes electrostatic loudspeakers if I recall.I'm not sure where that fits into using a PC as a transport and for DRC. Unless you're refering to the approval of open baffle design loudspeakers using te supravox drivers?

  • plonk420 - Monday, December 1, 2008 - link

    this is surreal...

    my $20 Chaintech AV-710 just died in the last 48 hours. i've been trying to resist the Head-Fi audiophile talk and try to find cooler heads to verify whether or not i should go X-Fi or DAC (something silly looking like the HotAudio HotUSB1 or Silverstone), or try to figure out if i'm experiencing the placebo effect "falling back upon" my ALC883, which i can swear "doesn't sound as good" EVEN THOUGH i'm fully aware of the power of placebo.

    i'm not sure i liked the mixed bag of positive and negative reports on (cheap) X-Fi vs Xonar vs X-Fi USB vs some DAC vs E-Mu 0404/0202
  • mindless1 - Monday, December 1, 2008 - link

    Choose a Creative card for gaming sound effects. Choose a DIY DAC for highest audio quality at a reasonable price. Buying some cheap commodity grade DAC is a gamble, I'm not familiar with those two products you mentioned but generally in the consumer segment and price range you end up buying an idea, a type of tech but not excellence in that execution.

    MOtherboard integrated audio usually doesn't sound as good including one using ALC883, though someone with poor hearing or gear may notice the difference less and less depending on where the weakest link in the chain is and how bad it is.
  • Gannon - Monday, December 1, 2008 - link

    I have an X-Fi and it's better then my audigy, mind you I got the more expensive version with front panel and the remote. I use it for everything and have never had a problem, though I don't use vista at all just XP.

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