Tuesday December 27, 2022; 1:49 AM EST
- (6 min read)#
- #
- I am finally sitting down in the good chair, between the big speakers. It's been a few weeks of learning about cassette decks and how to set them up properly, and then doing it, over and over, until I get it right. I'm listening to a recording of Norah Jones from a Maxell XL II tape recorded from a Super Audio CD directly from the Oppo BDP83-SE to the NAD 6300 I've finally declared ready to listen to. #
- The speakers are being driven by a pair of Class A amplifiers based on the Nelson Pass F-4, which I built myself several years ago, and refer to as the Wild Side and the Weasel Side. Class A means they sound great until they get hot to the touch, at which point they sound amazing. They're my winter amps. They don't provide any gain, just current, lots and lots of current, so I have the Parasound P/LD-1100 Line Drive to swing the volts required to make the big speakers sing. They are six feet tall and just two inches thick, like great golden monoliths, and they are Magnepans, and listening to them is like wearing headphones that are six feet tall.#
- The audio on the Super Audio CD is recorded in DSD, which is not like ordinary PCM audio at all. You can get the digital output in PCM form, it's 88.2 KHz and sounds great, but it's not what's on the disk. DSD audio runs at a clock rate in the megahertz, and it doesn't sample the voltage, and convert it to a binary number corresponding to the scaled value, which is what you normally think of when you think of how a DAC works. DSD just records stream of ups and downs. Is the voltage rising, or falling? There's your ones and zeroes. You don't need 16-bit words. What you do need, is a special player. You cannot listen to a Super Audio CD on a regular CD player. There may be a regular Red Book audio layer for your regular CD player, but you will not be listening to the DSD version. #
- You also can't rip a Super Audio CD to a digital file. You can intercept the digital audio going through the HDMI output, and get that 88.2K stream, but you cannot get the DSD bits. That's because we're all dirty filthy pirates, of course. We brought it on ourselves. #
- So the only way to listen to these discs is on the Oppo, which they stopped making because making great DVD and Blu-Ray players was distracting from cellphones. And since the only thing you get as output from a Super Audio CD is actually analog audio, why not record that to a cassette tape, and then listen to the tape instead? This sounds insane. The entire point of digital audio is absolute fidelity to the original source. No distortion. #
- But actually, we like distortion. Nelson Pass has noted that about half his customers preferred a little second harmonic, and the other half preferred a little third harmonic. And because he is a genius at this, he can tune his amps to produce extremely pleasing flavors of distortion. The F4's are mainly second harmonic, which is generally considered warmer, versus the more crisp sound you'll get with the third-harmonic variants. They don't have much distortion anyway, and running them as mono blocks cuts that by another 3 dB.#
- Audiophiles, at least those of a certain nervous sort, focus on short signal paths, purity and low distortion. Even tone controls, your regular treble and bass knobs, are considered bad, because they change the sound, on purpose. The fewer changes, the better. This is what is referred to as the "absolute sound", which is precisely how the music literally is, which is a real thing that you can totally reproduce, or get at least keep as a shining beacon on the horizon, as you perpetually upgrade your gear, and settle down for some critical listening. Discrete circuitry, no chips, no op-amps even. The less, the better. (This basically describes the F4's actually. They are nothing but a handful of transistors, the power supply, and lots of heat sinks.)#
- The thing that cracks me up, though, is just how mangled the sound was on the way to that recording. There are so many op amps in pro audio. Everything's been filtered, and boosted, and cut, and panned, and impedance matched, and run through so many transformers and coupling capacitors, and resampled, and reclocked. And that's before you even get to the mastering part, where everything gets another sheen of tiny boosts and cuts and feather touches of compression, and finally it sounds like natural, pure music.#
- Using a cassette deck can be considered a way of adding distortion to a recording. In fact, several of the steps in the recording studio rely on the specific distortion added by tape recording, so there are digital plug-ins that apply this distortion right in the DAW, lots of them. (And, I haven't looked, but they probably all model the same handful of classic tape machines. There is magic in using the exact same equipment used to make famous recordings. Maybe the luck will rub off.)#
- When I get new equipment, which usually is actually old equipment, from eBay, I like to fix it up so it matches the factory specs. Test equipment generally has great documentation, with step-by-step instructions for getting it back into spec. Follow the steps, and it will perform as it should. This, for me, is one of the fun parts.#
- The NAD 6300 has hundreds of little fiddly parts, and dozens of fiddly steps, to get it working properly. I am still trying on the wow and flutter. Wow is slow changes in tape speed, generally below 6 Hz, flutter is the faster stuff, generally up to around 200 Hz. It's basically the analog version of jitter. You can really hear it with piano, if it's bad. This deck should be able to do 0.025% weighted JIS, which is really quite good, and it's at 0.05% right now, which is really only excellent. So there's still room for improvement there.#
- But the electronics are on the dot, they have been dialed in, and dialed in, and gone over, the entire 25-step process, repeated several times from scratch. The entire purpose of this device, now, is to add distortion, but as carefully and precisely applied as possible. So some steps you just do over and over, seeing if you can get a difference down to 0.01 dB, even though it was in spec back when it was 2.5 dB, ten minutes ago. #
- And while I already had the HP 8903A distortion analyzer, and the Meguro MK-668D wow flutter meter, and the Keithley 2015 THD multimeter, and a bunch of other really quite neat, and not boring at all, test equipment, I did not have an Information Terminals M-300 alignment gauge, nor did I have a bunch of test tapes with various precise signals recorded with precision, nor a torque meter cassette, so it was fun getting that stuff, and learning how to use it, too. #
- It's been several weeks of evenings and weekends, and now I'm finally sitting in the good chair, listening to Thelonius Monk, and his gorgeous piano. It sounds pretty good. I did good. I am happy.#
Tuesday December 27, 2022; 1:49 AM EST
- (6 min read)#
- #
- I am finally sitting down in the good chair, between the big speakers. It's been a few weeks of learning about cassette decks and how to set them up properly, and then doing it, over and over, until I get it right. I'm listening to a recording of Norah Jones from a Maxell XL II tape recorded from a Super Audio CD directly from the Oppo BDP83-SE to the NAD 6300 I've finally declared ready to listen to. #
- The speakers are being driven by a pair of Class A amplifiers based on the Nelson Pass F-4, which I built myself several years ago, and refer to as the Wild Side and the Weasel Side. Class A means they sound great until they get hot to the touch, at which point they sound amazing. They're my winter amps. They don't provide any gain, just current, lots and lots of current, so I have the Parasound P/LD-1100 Line Drive to swing the volts required to make the big speakers sing. They are six feet tall and just two inches thick, like great golden monoliths, and they are Magnepans, and listening to them is like wearing headphones that are six feet tall.#
- The audio on the Super Audio CD is recorded in DSD, which is not like ordinary PCM audio at all. You can get the digital output in PCM form, it's 88.2 KHz and sounds great, but it's not what's on the disk. DSD audio runs at a clock rate in the megahertz, and it doesn't sample the voltage, and convert it to a binary number corresponding to the scaled value, which is what you normally think of when you think of how a DAC works. DSD just records stream of ups and downs. Is the voltage rising, or falling? There's your ones and zeroes. You don't need 16-bit words. What you do need, is a special player. You cannot listen to a Super Audio CD on a regular CD player. There may be a regular Red Book audio layer for your regular CD player, but you will not be listening to the DSD version. #
- You also can't rip a Super Audio CD to a digital file. You can intercept the digital audio going through the HDMI output, and get that 88.2K stream, but you cannot get the DSD bits. That's because we're all dirty filthy pirates, of course. We brought it on ourselves. #
- So the only way to listen to these discs is on the Oppo, which they stopped making because making great DVD and Blu-Ray players was distracting from cellphones. And since the only thing you get as output from a Super Audio CD is actually analog audio, why not record that to a cassette tape, and then listen to the tape instead? This sounds insane. The entire point of digital audio is absolute fidelity to the original source. No distortion. #
- But actually, we like distortion. Nelson Pass has noted that about half his customers preferred a little second harmonic, and the other half preferred a little third harmonic. And because he is a genius at this, he can tune his amps to produce extremely pleasing flavors of distortion. The F4's are mainly second harmonic, which is generally considered warmer, versus the more crisp sound you'll get with the third-harmonic variants. They don't have much distortion anyway, and running them as mono blocks cuts that by another 3 dB.#
- Audiophiles, at least those of a certain nervous sort, focus on short signal paths, purity and low distortion. Even tone controls, your regular treble and bass knobs, are considered bad, because they change the sound, on purpose. The fewer changes, the better. This is what is referred to as the "absolute sound", which is precisely how the music literally is, which is a real thing that you can totally reproduce, or get at least keep as a shining beacon on the horizon, as you perpetually upgrade your gear, and settle down for some critical listening. Discrete circuitry, no chips, no op-amps even. The less, the better. (This basically describes the F4's actually. They are nothing but a handful of transistors, the power supply, and lots of heat sinks.)#
- The thing that cracks me up, though, is just how mangled the sound was on the way to that recording. There are so many op amps in pro audio. Everything's been filtered, and boosted, and cut, and panned, and impedance matched, and run through so many transformers and coupling capacitors, and resampled, and reclocked. And that's before you even get to the mastering part, where everything gets another sheen of tiny boosts and cuts and feather touches of compression, and finally it sounds like natural, pure music.#
- Using a cassette deck can be considered a way of adding distortion to a recording. In fact, several of the steps in the recording studio rely on the specific distortion added by tape recording, so there are digital plug-ins that apply this distortion right in the DAW, lots of them. (And, I haven't looked, but they probably all model the same handful of classic tape machines. There is magic in using the exact same equipment used to make famous recordings. Maybe the luck will rub off.)#
- When I get new equipment, which usually is actually old equipment, from eBay, I like to fix it up so it matches the factory specs. Test equipment generally has great documentation, with step-by-step instructions for getting it back into spec. Follow the steps, and it will perform as it should. This, for me, is one of the fun parts.#
- The NAD 6300 has hundreds of little fiddly parts, and dozens of fiddly steps, to get it working properly. I am still trying on the wow and flutter. Wow is slow changes in tape speed, generally below 6 Hz, flutter is the faster stuff, generally up to around 200 Hz. It's basically the analog version of jitter. You can really hear it with piano, if it's bad. This deck should be able to do 0.025% weighted JIS, which is really quite good, and it's at 0.05% right now, which is really only excellent. So there's still room for improvement there.#
- But the electronics are on the dot, they have been dialed in, and dialed in, and gone over, the entire 25-step process, repeated several times from scratch. The entire purpose of this device, now, is to add distortion, but as carefully and precisely applied as possible. So some steps you just do over and over, seeing if you can get a difference down to 0.01 dB, even though it was in spec back when it was 2.5 dB, ten minutes ago. #
- And while I already had the HP 8903A distortion analyzer, and the Meguro MK-668D wow flutter meter, and the Keithley 2015 THD multimeter, and a bunch of other really quite neat, and not boring at all, test equipment, I did not have an Information Terminals M-300 alignment gauge, nor did I have a bunch of test tapes with various precise signals recorded with precision, nor a torque meter cassette, so it was fun getting that stuff, and learning how to use it, too. #
- It's been several weeks of evenings and weekends, and now I'm finally sitting in the good chair, listening to Thelonius Monk, and his gorgeous piano. It sounds pretty good. I did good. I am happy.#