Hmm... this does not look good

Hmm what does that number mean?

I paid a few bucks extra for this multimeter. For the thermometer function. It has an accuracy of ±5 degrees but that is enough for me - I just want a general idea of the kind of temperature the thing is running at.

And that is in degree Celsius.

Well, actually I was using the linear power supply of the Zhaolu D1.3 to power an amp.

A linear power supply of a DAC powering an amp, so, ya.

"Overclocking" anyone?

Actually, not really. I measured my Yulong T-Amp's power draw to be 4W, and that thing also uses a linear power supply.

Remember I measured the D2.5A to draw 10W.

Nonetheless, it is not good to create something without going through flame-test 3 - long term stability.


How I measured - probe inside closed chassis.

92 degrees is not good, but it's not too bad either, at least it is stable instead of increasing all the way to ∞.

It's just a bit close to the maximum operating temperature of 125°C of the LM317. But that is junction temperature - I'm measuring that of the heatsink. Include junction-to-case thermal resistance, and don't forget contact resistance, consider inaccuracy, and it is darn close to max temperature.

Fortunately LM317 has overheat shutdown. Hooray for integrated circuits.

But I don't like stuff running at near boiling point of water anyway. Maybe 80°C is the max I would go.

So, is this thing so hot because I'm "overclocking" it?

Well it's too unscientific to jump to conclusion at this point. Need to measure temperature of regulator with no load connected.

I got... 80°C.

Screw this design.

RCA couplers have arrived

The last part of the in-line attenuator has arrived.

This thing converts the female connector on the attenuator to a male to save using one extra cable, which has benefits cost and performance wise.

Why didn't I use a male connector on the attenuator in the first place and instead used two female connectors instead?, you may ask.

Well, the dimensions of the front and back are 15 x 13mm. It's actually rather compact for a DIY-ed solution. And it has to be in order to have the most compatibility. These dimensions are pretty tight for a male RCA connector. I did try to use a male connector, but the moment I on-ed the 1cm drill it cracked through the whole thing.

Even for the socket I had to look for one with a really thin body, so that the nut can fit inside the enclosure.


How the finished thing looks.


The thing in action.

So far I've tried it on two systems - the one that you see in the pic, and another one which I shall not disclose now. Lets call it system X for now.

Why am I mentioning this? Well, there are unexpected side findings. Apart from the obvious 20dB reduction in volume.

On system X, it solved a bit of balance issues (due to volume control at too low positions) as expected, at the same time the soundstage opened out/the sound became wide/sue me my audiophile language sucks.

I attributed this to the balance issue being solved - when more sound is coming from one speaker, the image feels less spacious. And/or maybe having two speakers at the same volume brings out mids and some bass better.

On the system you see in the pic, the bass became more controlled and more powerful. Could be due to the same thing as above.

*Note - none of these claims have been blind-tested.

If avoiding channel imbalance issues results in these benefits, there could be some weight in why stepped attenuators sound better than potentiometers (notice the commonalities between claimed improvements of using stepped attenuators vs my thing).

However, again, this is untested, and those who calibrate their speakers to +-0.5dB would know the truth.

RMAA results of 16-bit/44.1kHz MP3 at various compressions

http://wwenze.netfirms.com/mp3.htm

I'm not going to do any explaining... too tired... sucks if you don't know how to read the graphs, go learn.

Incorrect Assumptions

Music Core

- A musical genre that includes everytype of music. This is usually a sarcastic response given when some lame scenester asks what type of music you listen to after listing 20+ genres that may or maynot exist.

Scenester: Yeah so I listen to gothcore, disco ska, plip hop, darkwave, lightwave, gabber, and science rock. So what kind of music are you into?

Source: Urban Dictionary: music core

What I found after trying to find out what exactly does "Slash Core" mean.

http://en.wikipedia.org/wiki/Music_of_DJ_Max#DJ_Max_Portable_3

Big-Oh

Ok sorry about that bye.

That's what he said

"If u supply 150 ohm to the the headphone, other then lack of bass, the mid and high freq is clearly define. in fact it is one of the best gaming headset, if u try to drive with a ipod, well, it's crap."

Me: What happens if I supply 10kohm or 2 ohm to the headphone?

"for 10 kohm, the headphone will be gone.

for 2 ohm, if you are lucky, you can still hear some sounds with the volume at full.

Never use your speaker output to connect to yr headphone."

ragnarok95: Nice question to test someone.

"in fact a lot of people are not aware of it, got hole just plug.

Esp those high end headphone (300 and above), you need to match the ohm in order for it to performance.

From some of the reviews complaining PC350 is cmi, you can see that they just use 64 ohm to drive the headset (which need 150 ohm)."

Me: Okay final question, pardon me noob, you said can see others just use 64 ohm to drive the headset, while you know 150 ohm is good for the PC350, but how do you know how many ohm your soundcard is supplying to the headphone?

"u need a dac or a sound card come with a headphone amp to drive high ohm headphone.

for dac, there is a switch for u to adjust the gain, sound card is control by software."

He didn't answer my question, but that's enough from me.

Source:
http://forums.hardwarezone.com.sg/showthread.php?t=3097327&page=3

[Rant] "WTS: HDMI cable"

Selling brand new premium HDMI cables @ $10 each!

Comes in a classy blue sleeve to match your decor and for better shielding




Ok, seriously, I got it for SGD$4 from eBay, and one without a sleeve would be even cheaper. And my philosophy is, if I can get something, you too can.

So why the f should you let me earn extra $6 for doing nothing?

I'm not going to do anything about what happens in the forums though; there is a rule for documentarists, that an outsider is not supposed to interfere with the course of nature - if you spot a wolf eating a rabbit, you cannot go save the rabbit, even if you like the rabbit. (Exceptions, like endangered species, occur.) If people are stupid enough to pay 200% for the same thing, that is their problem. I believe stupidity is punishable.

Well, I hope none of you reading this blog have been suckered to pay more for less, and if you didn't know about this kind of get-rich-quick scheme (by others) before, well you are lucky.

And if you still don't believe that you can get this for $4 on eBay, and if you want to buy this HDMI cable @ $10, well, we can discuss.

And, I'm not joking about the better shielding part -

Braided for better shielding