3 ms·

How to Build the CMoy Pocket Amplifier (2016)

41 points by brudgers 3y ago

green-salt 3y ago
I've had one of these someone else on ebay made for like, 10+ years? Still working good and sounds great.
- ambyra 3y ago
  Me too! Mine was in an Altoids case. They warned me not to bring it on a plane.
- suprjami 3y ago
  So do I. There was a guy in Western Australia selling pre-made ones with a choice of different connectors and charging capabilities.
rainbowzootsuit 3y ago
Anyone interested in the topic should check out the original site / forum, HeadWize, now in memorial mode. https://headwizememorial.wordpress.com/ https://headwizememorial.wordpress.com/
- gfaure 3y ago
  It saddened me to hear about the circumstances: https://headwizememorial.wordpress.com/pow-chu-moys-memorial/ https://headwizememorial.wordpress.com/pow-chu-moys-memorial...
hoosieree 3y ago
Oh wow that takes me back. I originally got into engineering as a career over a decade ago because of DIY electronics (especially guitar stompboxes) and I remember the CMoy making the rounds then too. Thanks for posting, I'm now starting my day with happy nostalgia vibes.
- nrp 3y ago
  Same here! A CMoy amp in an Altoids tin was the first useful project I soldered up while in high school years ago. Part of what made it accessible to a high schooler at the time was that you could sample the Burr Brown amps for free. Obviously the intent wasn’t to give freebies to teenagers, but I’ve since returned many, many multiples of that to Texas Instruments in products I’ve been responsible for!
readingnews 3y ago
Anyone wanting to build that circuit should do a quick search, it has been much improved over the years, and there are even off the shelf PCBs that fit right in the case for cheap. Personally, it is still cool. I think I have three or four of them in the house, and I have built countless CMoy-BB versions for my friends when they were selling the PCBs. It is pretty impressive, I still have one powering my very large Sony headphones right now.
ilitirit 3y ago
Audio is a very interesting and strange hobby. For example, this amp is probably fantastic, but 90% of people probably don't even need one, and those who do can probably get away an Apple dongle or something similar. Some people will swear XYZ amp makes their audio sound better, but that's more a function of taste, the DAC, and/or distortion handling mechanisms inside the amp, and that's itself is an incredibly topic which again 90% of users can ignore.
- p_l 3y ago
  Useful if connecting higher end headphones, not useful if you're only going to connect simple low power in ears. The moment you connect any sort of bigger headphones that do not have their own amplifier to "standard" 3.5mm on most portable devices (even laptops), you find yourself benefitting from such pocket amplifier. The power available on those outputs tends to be quite low, so attaching higher impedance headphones means the resulting sound is quieter, which results in user cranking volume up to compensate, which makes the usable range of volume smaller for adjustments, but also that often quality noticeably falls down because most amps have more distortion at upper ends of power. Depending on devices, sometimes you even get noticeable difference in power drain.
  - ilitirit 3y ago
    My comment stands for over-ear headphones as well - it's just not going to matter for 90% of users. An Apple dongle is usually more than enough. I have several different amps, a tube pre-amp, several DACs and a Qudelix 5k DAC. I regularly switch between an HD600, HD650, HD560s, HE4xx and Audeze Maxwells. I can maybe count on one hand when I thought one combination sounded "better" than another, although I'm sure I could bump up this number if I tried. The problem is 90% of the time it just doesn't matter. There's loads of resources on the net that talk about this, e.g. https://www.youtube.com/watch?v=K8zAko5G6eg https://www.youtube.com/watch?v=K8zAko5G6eg Most of the time the differences are not that important, unless, as the adage goes, you're using the music to listen to your equipment rather than using the equipment to listen to your music. Which... 90% of users don't do.
    - 3y ago
polotics 3y ago
Be very careful that for most people, the first impression of "sounds great" is in reality an "is louder", the loudness wars in audio production have led to less and less significants bits of data being needed to carry music, an objective measure of information loss. Also I will not get started on hearing loss, but... if this was somewhere else in your body than your ears, what DIY project would you accept there?
- deleted 3y ago
  [deleted]
- brudgers 3y ago
  [I am not an audio engineer] Compression was the preferred munition during the loudness wars, not amplification. Recordings producing more acoustic energy were made by reducing dynamic range.
  - tonyarkles 3y ago
    You're totally correct, and just to clarify for anyone who's not into audio/DSP this isn't referring to "data compression" but rather dynamic range compression. Basically quieter sounds get amplified so that the difference between a quiet sound and a loud sound is smaller, and then the whole thing gets amplified so that it's dancing right on the edge of clipping.

41 points by brudgers 3y ago

green-salt 3y ago

I've had one of these someone else on ebay made for like, 10+ years? Still working good and sounds great.

ambyra 3y ago
Me too! Mine was in an Altoids case. They warned me not to bring it on a plane.
suprjami 3y ago
So do I. There was a guy in Western Australia selling pre-made ones with a choice of different connectors and charging capabilities.

rainbowzootsuit 3y ago

Anyone interested in the topic should check out the original site / forum, HeadWize, now in memorial mode. https://headwizememorial.wordpress.com/ https://headwizememorial.wordpress.com/

gfaure 3y ago
It saddened me to hear about the circumstances: https://headwizememorial.wordpress.com/pow-chu-moys-memorial/ https://headwizememorial.wordpress.com/pow-chu-moys-memorial...

hoosieree 3y ago

Oh wow that takes me back. I originally got into engineering as a career over a decade ago because of DIY electronics (especially guitar stompboxes) and I remember the CMoy making the rounds then too. Thanks for posting, I'm now starting my day with happy nostalgia vibes.

nrp 3y ago
Same here! A CMoy amp in an Altoids tin was the first useful project I soldered up while in high school years ago. Part of what made it accessible to a high schooler at the time was that you could sample the Burr Brown amps for free. Obviously the intent wasn’t to give freebies to teenagers, but I’ve since returned many, many multiples of that to Texas Instruments in products I’ve been responsible for!

readingnews 3y ago

Anyone wanting to build that circuit should do a quick search, it has been much improved over the years, and there are even off the shelf PCBs that fit right in the case for cheap. Personally, it is still cool. I think I have three or four of them in the house, and I have built countless CMoy-BB versions for my friends when they were selling the PCBs. It is pretty impressive, I still have one powering my very large Sony headphones right now.

ilitirit 3y ago

Audio is a very interesting and strange hobby. For example, this amp is probably fantastic, but 90% of people probably don't even need one, and those who do can probably get away an Apple dongle or something similar. Some people will swear XYZ amp makes their audio sound better, but that's more a function of taste, the DAC, and/or distortion handling mechanisms inside the amp, and that's itself is an incredibly topic which again 90% of users can ignore.

p_l 3y ago
Useful if connecting higher end headphones, not useful if you're only going to connect simple low power in ears. The moment you connect any sort of bigger headphones that do not have their own amplifier to "standard" 3.5mm on most portable devices (even laptops), you find yourself benefitting from such pocket amplifier. The power available on those outputs tends to be quite low, so attaching higher impedance headphones means the resulting sound is quieter, which results in user cranking volume up to compensate, which makes the usable range of volume smaller for adjustments, but also that often quality noticeably falls down because most amps have more distortion at upper ends of power. Depending on devices, sometimes you even get noticeable difference in power drain.
- ilitirit 3y ago
  My comment stands for over-ear headphones as well - it's just not going to matter for 90% of users. An Apple dongle is usually more than enough. I have several different amps, a tube pre-amp, several DACs and a Qudelix 5k DAC. I regularly switch between an HD600, HD650, HD560s, HE4xx and Audeze Maxwells. I can maybe count on one hand when I thought one combination sounded "better" than another, although I'm sure I could bump up this number if I tried. The problem is 90% of the time it just doesn't matter. There's loads of resources on the net that talk about this, e.g. https://www.youtube.com/watch?v=K8zAko5G6eg https://www.youtube.com/watch?v=K8zAko5G6eg Most of the time the differences are not that important, unless, as the adage goes, you're using the music to listen to your equipment rather than using the equipment to listen to your music. Which... 90% of users don't do.
  - 3y ago

polotics 3y ago

Be very careful that for most people, the first impression of "sounds great" is in reality an "is louder", the loudness wars in audio production have led to less and less significants bits of data being needed to carry music, an objective measure of information loss. Also I will not get started on hearing loss, but... if this was somewhere else in your body than your ears, what DIY project would you accept there?

deleted 3y ago
[deleted]
brudgers 3y ago
[I am not an audio engineer] Compression was the preferred munition during the loudness wars, not amplification. Recordings producing more acoustic energy were made by reducing dynamic range.
- tonyarkles 3y ago
  You're totally correct, and just to clarify for anyone who's not into audio/DSP this isn't referring to "data compression" but rather dynamic range compression. Basically quieter sounds get amplified so that the difference between a quiet sound and a loud sound is smaller, and then the whole thing gets amplified so that it's dancing right on the edge of clipping.