The Magical Tube Amplifier, Affordable DIY HIFI

in #technology6 years ago

carina.jpg

I flip the green power switch. It's solid, like something you'd expect to find on a 1960's space ship console. In an instant, I am bathed in the soft glow of four stereo vacuum tubes. I can't help but smile. I connect with people, ideas, and technology from the past.

This is not an i-Pod. This is an honest to goodness tube amplifier, based on technology from the Marconi Company, dating back to the early 1900's.

Ever since solid state amplifiers started taking over music reproduction, a large and vocal group of musically oriented people have staunchly defended the older tube technology. Centering arguments around concepts like "full analog" and "better tone", advocates for tube amplifiers and other analog stereo gear refuse to be persuaded by the benefits of modern technology. Sacrificing power efficiency, technical capabilities and other aspects, analog enthusiasts eschew it all in favor of "better sound."

Acoustic music sounds unbelievable..

Tube amplifiers (especially lower power ones) are known for their strong performance at reproducing acoustic instruments. Warm. Silky. Buttery. Crystal. Defined. Incredible. These are the kinds of words people use to describe acoustic music player over a good tube HIFI system. Country music can take on a whole new tonal quality, and delicate (or booming) vocals sound incredible. Tube amps have a hard time keeping up with more modern equipment for rock music, electronica, and things of that nature. For everything else .. tubes are hard to argue against.

"It just sounds better, somehow ..." is something you'll hear from a tube enthusiast.

Tube amps come in all sizes, flavors and budgets. From single-tube systems all the way up to thousand watt monsters, there is a tube amp for every taste and budget. It is not hard to get started with tube amplifiers, and low cost models can be found for several hundred dollars. Of course, those with larger budgets have a world of possibility.

Although my particular amplifier, a Vaugh Audio Carina, is a modern build, it is based on very old design principles. Engineered for premium sound and reliability, it's overbuilt and is not moved lightly. Surprisingly, and to the shock (shock, I tell you) of people who hear it, it puts out only two watts. However.. when paired with ultra high efficiency speakers, it delivers incredibly clear, rich sound, that, if pushed, will make your ears bleed.

Quality recordings take on entirely new aspects the first time you hear them. Inhalations. Callused fingers on fresh guitar strings. Recording studio chatter. Truly, music takes on a new dimension when it is reproduced well.

I should note that good sound comes down to three things, basically: good speakers, a good amplifier, and a good source. You must achieve these three primary things if you ever want to make sound that you can disappear into. Throughout this article, I'm going to tell you how to do that, even if you're on a tight budget. Quality HIFI is achievable for very little money: the key is to spend the money on the right things.

record-336626_960_720.jpg

Vinyl: The Perfect Mate

Scotch and cigars. Champagne and Orange Juice. Certain things go well together, and this is very true when considering vinyl and tube amplifiers. There is a technical reason for this, which I'll do my best to explain.

When recorded music (analog) is converted to a digital format, the sound is sampled, and turned from an analog signal into digital format. This is done by recording the frequency of the sound, many times per second. The resulting data can then be reproduced.


Analog-and-Digital.png
An Analog Signal vs. a Digital Signal.

As you can see, the signal on the left is perfect: this represents the analog signal recorded from the initial playing of the music. The signal on the right is what happens when you convert that analog signal into a digital one. The jaggier the line, the more inaccurate the musical representation.

When you hear things about "sampling rate", this is often what they are talking about. The higher the sampling rate, the higher the number of samples over a given time period. This results in higher accuracy. The graph above would be a very crude sampling: modern sampling is much higher resolution, and from a distance, you'd not see much difference between the two signals. Zooming into the graph, however, would reveal one chart with perfect curves, and another with jaggy lines. However, no matter how high your sampling rate, you are never going to get better than the original analog signal.

This concept explains, simply, why vinyl/analog advocates swear by records and tube amplifiers.

If you introduce a solid state amplifier, or a CD player, or a computer, you are ruining the analog chain, and introducing a digital element. If you are ever converting between analog and digital, you're losing the benefit of going all analog.

Get yourself an Affordable System

If you want to get yourself real HIFI for reasonable dollars, you need to be smart about it. If you adhere to these ideas, you'll find you're able to get yourself a gorgeous sound system that easily outperforms anything you'll find in a big box store, and in fact, many custom stereos. Leveraging a few concepts, we're going to get you something that sounds like it should be more expensive .. maybe WAY more expensive, depending on how smart you are!

Two speakers ONLY

Base the system design around a single, full range driver: one speaker that can reproduce a broad spectrum of frequencies. You're doing a 2.0 stereo system. Two speakers only. No sub, no center channel, certainly no rears. Old school.

What about home theater?

Put simply, a HIFI 2.0 system will often outperform a 5.1 or even 7.1 system. Two excellent quality speakers usually sound better than five or seven low quality ones. I used to have a twelve foot wide home theater screen, and was able to fill the room with sound (spatially accurate sound) with two speakers on two watts (and it sounded almost magical.) You are not missing much by sticking with 2 speakers.

"Normal speakers.."

When you look at most speaker enclosures, they typically have two or three speakers: one to handle the low end frequencies, one the middle, and one the high end. Subwoofer? Mids? Tweeters? These are specialized speakers, meant to reproduce relatively small frequency ranges. We are going to avoid the cost of multiple speakers as well as the added complexity of crossovers by selecting one speaker that can reproduce all of our frequencies.

ONE SPEAKER TO RULE THEM ALL.

Buy High Quality Full Range Speakers

There are many, many options out there: you can buy a speaker and cabinet, ready made .. or you can buy the speaker itself and build your own enclosure. The trick is, whatever you do, buy a HIGH QUALITY DRIVER that is capable of reproducing a full range of sound. Features of high quality full speakers will include extra large magnets, super light cones, great power efficiency and a good frequency response throughout the important sound ranges. Typically the more expensive the speaker, the better its range. Equally sized speakers can perform very differently, depending of the quality of components. Also, each speaker has its own voicing .. no two sound the same .. so do some reading on which speakers are better for which types of music.



If I was building a high budget set of speakers, personally, I would start at lowtherloudspeakers.com. They are renowned for making some of the finest loudspeakers on earth, and are often used as the basis for lavish, amazing speakers. If you want the best, you have to have the best ingredients .. and Lowther is up there with the best. Pricey though, they sure make you pay for it!

When you buy storebought speakers/enclosures, you tend to get a nice looking enclosure that contain relatively poor quality drivers. When you are building your own, you can afford to spend more on the speakers themselves: so make sure you do that. Personally, I have experience with The Fostex FE168 Sigma series, as well as the Hawthorne Audio Iris units. I've recently found out that Hawthorns audio is no more, so you can't get their speakers anymore. The idea is to base you speaker around a full range drive .. so find one, and go from there.


fe168ez.jpg
Fostex FE168 Sigma Series. A wonderful full range speaker that will fill most rooms with sound. It doesn't do the low end very well though, so if you want the boom, look at something bigger.

Don't make the mistake of buying "too much speaker." You want to be able to, ideally, crank your amplifier to full power and have the speaker reproduce the output without distortion, and not disturb anyone. At full power, your amplifier may start to distort, but you don't want your speaker to .. so make sure they are sized for your space, and for your amplifier. If you live in an apartment or a place where loud volume is not going to work, get speakers that won't annoy the neighbours even when they are turned right up .. and a flea sized amplifier. The Fostex above, for example, would not be suitable for an apartment. You'd want something smaller with less sound output.

aasinger.jpg

Put the Speaker in a Box

Once you've selected your speaker, you're going to need to decide on a box, or, enclosure. You will probably have several options here. Almost always, the speaker manufacturer will distribute plans for their "ideal enclosure". This can often be a good option, though alternatives should be evaluated. For example, I put my Fostex speakers in a "Bigger is better" enclosure, and it went swimmingly. If you search for "bigger is better speaker box", you will see what I mean: it's an alternative enclosure for a specific speaker, and such designs exist for many speakers. These can be superior to the manufacturer designs and are often simpler .. so definitely check that out. The more popular speakers have entire communities devoted to their use, so make sure to avail yourselves to the resources of the Internet.

Once you decide on a box, you need to decide how to build it. On-line kits are available for many speaker sizes, and depending on the speaker you choose, something might exist. If so, assembly is easy: put the pieces together! If not, you need to have the box built: you can hire someone to do this for you, or you can do it yourself. If you have no carpentry ability, and no desire to learn, you're probably best off ordering something, or having it built for you. If you are at all handy with tools and not looking for a show piece, you can bang off a set of functional, great sounding speaker boxes for very little money: they don't have to look great, they just need to be of the correct size and material. You can build some very good sounding speakers with the cheapest of materials.

... and if you are good with woodworking, and want to pony up for some nice wood .. well, the sky's the limit ...

The following site may be useful to you, at least to get an idea of what you can order as far as speaker kits.

http://www.commonsenseaudio.com/fostex.html

In addition to speakers, you'll need some speaker connectors, and some wire: when you put your speakers in their box, you'll run a wire from the back of the speaker to a set of outputs you put in the back of the speaker. Pick good quality connectors and wire: there are many choices .. pick one you like. Madisound.com is a great site: they have a good selection of everything you'll need to build your own stuff. If they'll ship to you, they are a good option.

Now .. the Amplifier

The tube amplifiers available to you will vary wildly, depending on your locale. The best way to get started is to start reading a lot about tube amplifiers .. and find one that matches your speakers. See if you can find it in your area. One site that is absolutely excellent is tnt-audio.com: this place is an encyclopaedia of knowledge and should help you to familiarize yourself with what you need to know. Just read review after review, and try to find something you like.


amplifier.jpg
This is not a tube amplifier -- note the lack of tubes! Congratulations if you noticed!

If you cannot find a tube amplifier in your price range, check out Class T Tripath amplifiers. These always come in at lower prices than tube amps, and while they are solid state, some of them provide wonderful audio quality for their relative cost. The Sonic Impact, for example, is about a $50.00 amplifier that can run with $1000+ units, no problem. I ran a Super-T (a slightly upgraded model) and had great success with it: wonderful sound! It's not a tube amplifier, but hey: the goal here is to get you an awesome system for cheap, and some of the T. Amps provide incredible sound quality for what they cost. I know it's hard to believe, but that $50.00 amplifier, with the right set of speakers, will outperform conventional multi-thousand dollars systems, easy. Easy! You won't get the volume, but in terms of sound clarity and overall quality .. they are hard to beat.

Now, the source.

A decent quality record player (check out MMF) would be nice, but if you're not into vinyl, the key to coping with digital is to make sure that your DAC (digital-analog-converter) is of high quality. Your ipod? Your sound card? Odds are, it's putting out a poor quality audio signal. This means that your speakers will never get the chance to reproduce many of the nuances of the music, as it is lost .. to all sorts of things. What you really need is a high quality DAC, a device that has been specifically designed to properly convert the digital signal into analog. You can buy USB DACs, or external DACs, which take a digital signal (usually via optical or coax cable), and output stereo (analog.) A USB DAC is a very handy way to get great quality sound output from a computer or laptop, and a wonderful way to get HIFI sound without sacrificing modern convenience.


audiolab_m-dac_01.jpg
An example DAC, from Audiolab.

Your setup might look like this:

Computer -> USB -> DAC -> Amp -> Speakers
CD Player -> Coax -> DAC -> Amp -> Speakers
DVD Player -> Optical -> DAC -> Amp -> Speakers

The key thing to note here is the DAC is what tells your amplifier what to play .. and a good one will do a lot better job of that than the "pennies each" DACs that make their way into consumer grade stereo equipment. You can use any old digital source you want .. as long as you can output it to a decent DAC, which can then take that digital stream and turn it into something GOOD for your speakers.

Personally, I use a Monica2 DAC from diyparadise.com. You can read a review on it here:

https://www.tnt-audio.com/sorgenti/monica2_e.html

It was the hot thing at the time, and I've been very happy with it. It does provide a noticeable improvement in sound quality over lesser quality sources. As with amplifiers and speakers, huge amounts of information is available on all of your options. Do your reading, and find a DAC that works for you, and integrates well with your existing equipment.

In summary:

High Quality, Power Efficient, Full Range Drivers
High Quality Audio Source, via Quality DAC
HIFI Amplifier, Low Power, Tube or Class-T

Your checklist to go from zero to audio hero IS:

(1) Get high quality speakers that are very efficient, enabling you to use low power (and lower cost) amplifiers.
(2) Put them in boxes, according to the manufacturer, or based on vetted, expert hobbyist designs.
(3) Connect them together with wire and connectors from a place like Madisound.
(4) Pick a HIFI amplifier of suitable power level, matched perfectly to your speakers.
(5) Figure out your source: where are you going to get music from, and how can you turn it into a high quality signal for your amplifier. You'll probably want a audiophile grade DAC.

I hope you've enjoyed my little foray into tube amplifiers and HIFI stereo. Hopefully I've given you the tool to create your own magic little music system. It's a hobby I truly enjoy. I've been doing it for a good number of years, always with an eye towards "bang for buck." If you follow the general ideas herein, and do just a few hours of homework, I can pretty much guarantee you'll end up with something that will bring a smile to your face, and outclass pretty much any stereo you are likely to encounter in the wild.

Good luck, we well, and take care!

P.S. I would be remiss not to mention "open baffle speakers", one of the simplest, most cost effective ways to house a full range speaker. Basically you cut a hole in a board, bolt the speaker to the board, and you're done. There is no back, no "chamber" .. it's just a speaker hanging off a board! It's not quite that easy, but basically it is. This type of speaker has unique sonic characteristics, and is also kind of nice because it takes up less space than a conventional speaker enclosure. If you decide to build yourself a system based on this advice, do yourself a favor and read about the open baffle designs. You'll be glad you did!


obspeakers.JPG
Some fairly basic open baffle speakers. Although they get much more elaborate, this image shows you that you don't have to be fancy. Excellent results can be had with MDF or cheap plywood.

Image Credits
@walkerland
https://pixabay.com/en/record-player-disk-turntable-vinyl-336626/
https://byjus.com/physics/difference-between-analog-and-digital/
https://www.madisoundspeakerstore.com/approx-6-fullrange/fostex-fe168ez-6.5-full-range-sigma-series/
https://pixabay.com/en/microphone-boy-studio-screaming-1209816/
https://pixabay.com/en/stereo-amplifier-music-event-play-1208090/
https://www.whathifi.com/advice/dacs-everything-you-need-to-know
http://theartofsound.net/forum/showthread.php?54189-My-personal-Open-Baffle-speaker-project


[ @xwalkran ]

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