Category Archives: audio

Parasound Zamp v.3

I like small amplifiers. As you can see in the pictures below, I have a few of them. I also have TA2020 board in need of a chassis and a Gainclone waiting to be assembled. Other “hobbies” have these two projects on back bench for now.

For a while I have been using a Topping TP21 (TA2021 based) amplifier to drive my main speakers. Since it’s only about 12-15 wpc RMS into 4 ohms, I find that it doesn’t quite have enough power for when I really need to rock out. Being a fan of Tripath and class D based amplifiers, I set out to find a more powerful one. Unfortunately, the higher power class D units tend to be expensive. I’m not quite sure why that is. Maybe it has something to do with convincing audiophiles that class D is fine for more than just sub amps.

Instead of overpaying for a 50 wpc class D amp, I bought a $300 Parasound Zamp. This thing is tiny and beautiful. I haven’t taken the lid off yet, but it appears to be a standard class AB using bipolar output transistors. I won’t regurgitate the specs and features, you can read all about it on the Parasound web site. For those concerned about the country of origin of their gear, it’s made in Taiwan.

I used my kill-a-watt style power meter and found that the amp measured 8 watts when “off” and 13-14 watts when on and idle. Blame it on the big-ass toroid in there I guess.

MP3 streaming with MPD in Ubuntu 10.04

Nov 13, 2010 update: 0.16 alpha3 build
mpd_0.16~alpha3+git20101108.46ab8d1-0ubuntu1~ripps1~lucid_i386.deb

I have not tested this build! My mpd box is now on 10.10 and I haven’t rebuilt mpd for it yet.

Sept 11, 2010 update: 0.16 alpha2 build
mpd_0.16~alpha2+git20100803.68c02fc-0ubuntu1~ripps1~lucid_i386.deb

June 13, 2010 update: an updated build mpd_0.15.10+git20100608.53f08a9-0ubuntu1~ripps1~lucid_i386.deb

As of mpd 0.15, there is built in support for http streaming as an output.   Rather than using Icecast, mpd does the streaming itself.    By default 10.04 uses mpd 0.15.4, however I had problems getting the built in http streaming to work.   Also, the build included in the repository does not have lame support so it could not stream mp3, only ogg vorbis or possibly flac which many players don’t support. For example, I’m using a Roku Soundbridge with does not decode ogg.

I figured a recompile was in order. The first thing I did was add the mpd trunk PPA to /etc/apt/sources.list

deb http://ppa.launchpad.net/gmpc-trunk/mpd-trunk/ubuntu lucid main
deb-src http://ppa.launchpad.net/gmpc-trunk/mpd-trunk/ubuntu lucid main

After that, I downloaded the source deb and modified debian/rules and changed DEB_CONFIGURE_USER_FLAGS to include –enable-lame-encoder.

DEB_CONFIGURE_USER_FLAGS += $(WITH_TREMOR) --enable-sqlite --enable-un   
--enable-ao --enable-openal --enable-wildmidi --enable-sndfile --enable-pipe-output --enable-lame-encoder

A rebuild required about 800MB of dependencies. The result is the latest version of mpd with built in support for mp3 streaming.

You can grab my .deb here: mpd_0.15.9+git20100520.8945736-0ubuntu1~ripps1~lucid_i386.deb

My mpd.conf has an output section that looks like this:

audio_output {
        type                    "httpd"
        name                  "mpd stream"
        port                    "8080"
        bitrate                 "192"
        format                 "44100:16:1"
        encoder               "lame"
}

To get your device or player to stream properly, you may have to give it a playlist file. This can be hosted on any web server or can even be a local file.

mpd.pls:


NumberOfEntries=1
File1=http://myhost:8080/

I’m done giving Apple Inc. money

Despite having owned way too many Apple products, I’ve never considered myself a “Mac user”.   Partly because I use Windows and Linux just as much and also because it’s just an operating system and not a drug, I’ve never put myself in the category.  I may buy another Apple computer at some point in the future, but generally I’m going to try and avoid it.  Even though I’ve never owned an iPhone or an iPod touch and I’ve never even thought about developing applications for them, the iPhone Developer Program License Agreement has certainly made me think twice about even buying another Apple product.

http://www.eff.org/deeplinks/2010/03/iphone-developer-program-license-agreement-all

So what now?  Sansa Clip+.   For $49 it’s pretty hard to go wrong.   The nice smooth integration with desktop software isn’t there, but it works pretty well with gpodder.    It’s so tiny and has a beautiful screen.  It is also very popular with the head-fi audio-nut forum guys.

Shure SE102 are the same as the E2C/SCL2!

I mistakenly bought some Shure SE110’s after my E2C’s finally bit the bullet.  More correctly, the cable finally gave out after a few repair jobs involving solder and heat shrink.  Conveniently, my wife left my SE110’s on an airplane.  While shopping for yet another set of headphones, I noticed that the SE102’s were the same shape as my old E2C’s.   An old thread on head-fi (http://www.head-fi.org/forums/f103/new-se102-old-e2c-rebranded-393597) lead me to believe it might even be the same driver inside.

I didn’t even bother comparing the specs (gasp), I just took the plunge and bought some SE102’s.   Sure enough, they sound just like the E2C’s.   One thing to note is that the SE102’s don’t come with the foam ear pads or the round zipper case.

Teac PD-H300mkIII

My search for a small expensive CD player kept leading me back to this Teac unit.   If you want a nice small amplifier, there are probably hundreds of choices, not so for CD players.   I was unable to check it out locally so I took a chance and bought it online for less than $200 CAD.  Thankfully, it does everything right.   It’s very quick to load a disc and change tracks.  All the buttons do exactly what you think and it doesn’t have a lot of extra crap no one uses.  It will read MP3 CD’s which I’d normally file under “extra crap” but that doesn’t get in the way of playing a CD.   I was concerned that it might impact the load time of a normal CD, but if it does, it’s not noticeable.  The only thing I can complain about at this price is the lack of a detachable power cord and maybe a dedicated headphone jack and level control.

How does it sound?  Good, like a CD player should.

Other notes of interest:

  • It’s made in China like every other mass-produced piece of electronic equipment under $1000.
  • The matrix LCD display is very nice but you can’t dim the display.
  • All normal operations for playing a regular CD are accessible on the front panel.  You don’t need the remote for any of it.
  • There is no CD text support.
  • My pictures don’t capture how nice looking this thing is.

Shure SE110’s are disappointing

A few years ago I bought some Shure e2c in-ear monitors which I use basically every weekday on my commute to work.   After two warranty replacements for cracked cables, I  had to buy some new headphones.    The SE110’s seem to occupy the same space in Shure’s product range previously held by the e2c’s.   Even though they’re around the same price, the SE110’s are no where near as good as the e2c’s.     The isolation they provide is as good, but there is just something wrong with the midrange and high frequency with these headphones.    It’s just not there.

The clear headphones with the cracked cable are the e2c’s and the black ones are the SE110’s.    I’m going to try replacing the cable on the e2c’s.

Bit perfect audio with Linux and mpd

What is bit perfect sound?

Bit perfect sound is about sending the exact bits from a sound file to a digital to analog converter without re-sampling.  Think of it as dumping the bits directly from a (decoded) file to the digital output of your sound card.  In both Windows and Linux, this not the default behavior.  In many cases, all digital audio is re-sampled to 48KHz before being sent out the digital output or to the onboard DAC.  On Windows the culprit is KMixer and on Linux it’s ALSA’s dmix.

Why is this important?

To be honest, it isn’t unless you’re one of those people that is obsessive about getting the absolute best sound possible.

OK, I’m one of those people, what do I need?

I’ll describe the basics of what you need for a Linux based setup.   If you want information on doing this on Windows, go here:   http://www.mp3car.com/vbulletin/faq-emporium/88852-faq-what-bit-perfect.html

If you’re like me and you think in pictures, this is what we’re doing.

setup

Ok, here are the words.

Hardware

1.  A sound card capable of bit perfect output.

This is the trickiest part.  The good news is that most of the cards that are capable are cheap no-name brands.  If you have an Audigy or something like that, throw it out.   Also, I didn’t have any luck getting any of the Intel HDA or AC97 codec based cards to work.   These are common with onboard audio.  The most widely available bit perfect capable cards are VIA Envy24HT cards and Cmedia (CMI) 8738/8768 cards.

Check here for a list of CMI cards:  http://code.google.com/p/cmediadrivers/wiki/SupportedDevices

I personally use this one:  http://www.tigerdirect.ca/applications/SearchTools/item-details.asp?EdpNo=3180419&Sku=D15-9060 (Diablotek 7.1 Tremor Digital Optical Sound Card – $30.99 CAD). I’ve successfully used it for 96KHz/16bit audio.

If you want to check if your current card supports bit perfect sound, the best way I’ve found is to use the ‘speaker-test’ application that should come standard with alsa.     For example:

44.1KHz/16 bit:

speaker-test -c2 --device cards.pcm.iec958 --rate 44100 --format S16_LE

96KHz/24 bit:
speaker-test -c2 --device cards.pcm.iec958 --rate 96000 --format S24_LE

If you get the following message, it means that your hardware doesn’t support the bit or sampling rate.

Setting of hwparams failed: Invalid argument

2.  A good outboard Digital to Analog converter.

There are tonnes of good DACs.  Some are cheap, some are not.  If your preamp or receiver has digital inputs, you probably don’t even need one.

I personally use this DAC:  http://www.obadimports.com/catalog/item/4377355/4684274.htm

(“DAC In the Box” Super Pro – CS-4398 24-192khz, $79.99 CAD)

3.  A decent stereo system.

Specifically, you should buy an Arcam FMJ and ScanSpe… yah just kidding.  Get whatever you want.

Software

As shown in the picture above, I use mpd (Music Player Daemon).  It has a clients for every platform and works quite well if your music isn’t tagged consistently.

Only a slight modification to /etc/mpd.conf is required.

audio_output {
        type                    "alsa"
        name                    "SPDIF"
        device                  "cards.pcm.iec958"
}

Restart mpd and away you go!   One small warning about the configuration above.  Specifying the hardware device directly like this will shanghai the sound system and no other systems sounds will be heard while mpd is playing.   Other applications may even hang if they try and play sound.   Flash player is one example.

Veneering with paper-backed veneer and wood glue

I put this together based on using materials you can easily find in Canada.  I got everything at Home Depot except the veneer which I got from Lee Valley, however I’m sure I’ve seen Cedan veneer elsewhere.  This was my first veneering job ever and basically the first time I ever used a router, so you don’t have to be an expert woodworker to do this.

You can’t be in a hurry to do this either.  This process took a couple of days.  I’d highly recommend only doing one side at a time.  I did the bottom, sides, top, back and then the front in that order.  Ignore the driver, cup and port holes.  That gets done last.

Here is what you need:

  • Paper backed veneer (Lee Valley 41A05.24 – http://www.cedan.com)
  • Sponge brush
  • Elmer’s PROBOND glue (I think this is PVC glue)
  • Green painters tape
  • Very sharp utility knife or scissors
  • Router with flush trim bit and a rabbeting bit if you countersunk your drivers
  • 150-200 grit sand paper
  • Iron (the kind use to iron clothes)

Supplies

1. Cut the veneer to the desired size.  You’ll want about 1/2 inch of overhang on each side.  I used sharp utility scissors to cut the veneer sheet.

2. Tape the veneer down to a flat surface.  I used a piece of lexan I had kicking around.

Veneer taped down to a piece of lexan

3. Mask any veneer already applied to the speaker.  Avoid getting glue on the finished side of the veneer.

Masked

4. Apply a thin layer of glue to both the MDF and the back of the veneer using the sponge brush.  Make sure you get right to the edges.  You’ll want to mix a little bit of water into the glue just to make it easier to brush on.  Some recipes call for a 10:1 glue/water mix.  Mine was more like 20:1.  Not enough water is better than too much.

Spread it as thin as you can on each surface while still having a nice even coat.

Glue on the box

dscf0015veneer

5.  Let it dry for about 50-60 minutes.  I got the best results when the glue was just dry enough so it didn’t stick to my finger.

6.  Heat up your iron.  Put it on the highest non-steam setting.

7.  Carefully place the veneer on the box.  Since the glue is still wet, the two surfaces will stick together right away.  I never had to, but it might be tricky to reposition the veneer once the two surfaces touch.

8.  Put a thin cotton sheet (pillow case, dish towl, etc) on top the veneer and iron the veneer on.  Apply quite a bit of pressure to make sure the veneer flattens out nicely.  Make sure you get the edges nice a flat.  There shouldn’t be any bubbles whatsoever.

9.  Let the glue dry for another hour, then use a flush trim bit on your router to trim off the excess.  If you have a steady hand, you could probably use a utility knife, but a router works so much better.  Lightly sand off any jagged edges left by the router.

10.  Repeat for each side.

FrontBack

When doing the driver and cup holes, drill a pilot hole in the veneer big enough for your flush trim bit and then trim the hole.  To do the counter sink, use the exact same rabbetting bit that was used to make it.

For a better explanation of this trimming process, see this page:  http://www.speakerbuilder.net/web_files/Articles/ventut/ventutmain.htm

It’s been two years since I did these boxes and there is no sign of the veneer coming off or cracking!

Zaph’s Inexpensive Mini MTM build

These speakers were built in the summer of 2008.  The design is very old and Zaph no longer distributes it, but I had the parts and the plans around.   After almost 15 years of building speakers, this was basically my first really successful speaker project.

This design is based on the MCM 55-1855 5″ midbass and Seas 27TFFC tweeter. I used Bondo and drywall compound to fill cracks and edge seal. The finish is 3 coats of sealing primer, Rustoleum Painter’s Touch Dark Grey, and some Rustoleum clear gloss.

Just a note about this project.  Please don’t email me asking for the plans.  I’d like to help you out, but they aren’t mine to distribute.