Thank you! If only I can get the PCB done... I'll have to send some boards out to people to see what they think.
Iko - Good idea [but...]
My CD player sucks in the utmost. It injects all sorts of HF trash. What's strange is that I picked it because I really liked the sound - it does sound good, to add insult to injury. But, it is audibly distorted so I can't use it as a source.
Trying to install 3rd party drivers... I've heard too many good stories about 3rd party X-fi drivers and too many bad ones about the creative drivers...
- keantoken
I suspect it didn't make it into the first box, but somewhere in the second.
Assuming I ever get round to sending it, pair of Stromberg Carlson 600:600
2H:2H transformers. I've used successfully for isolation between PC sound
card and amplifier under test. Very flat and wideband into higher than 600
ohms, especially when driven from less than 600ohm. Potted in metal cans.
Bad amps regularly used to blow out the sound chip on my PC motherboard
till I got smart about isolating DC. When you test hundreds of Class-D amps
every day, some bonehead is sure to have mis-oriented at least one part...
Usually through hole electrolytic, as stuffing those is not easily automated.
If DC or ground loop is the problem, they will fix it right pronto. But more to
the point, prove weather or not that is indeed what you are fighting...
Assuming I ever get round to sending it, pair of Stromberg Carlson 600:600
2H:2H transformers. I've used successfully for isolation between PC sound
card and amplifier under test. Very flat and wideband into higher than 600
ohms, especially when driven from less than 600ohm. Potted in metal cans.
Bad amps regularly used to blow out the sound chip on my PC motherboard
till I got smart about isolating DC. When you test hundreds of Class-D amps
every day, some bonehead is sure to have mis-oriented at least one part...
Usually through hole electrolytic, as stuffing those is not easily automated.
If DC or ground loop is the problem, they will fix it right pronto. But more to
the point, prove weather or not that is indeed what you are fighting...
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Ken, those transformers sound awesome! Can't wait to play...
The filtering I think had an strong effect. I can't validate it yet since I'm trying to install new drivers. Before the sound was fine, but something was very off, I couldn't place my finger on it. There seemed to be something in the air that caused my body to have a fit; the back of my neck tensed up and I started feeling sick. I started to suspect it was the HF noise in the amplifier, since I've heard of discomfort caused by ultrasonics. I tried turning off the monitor and most of the tension released. Go figure, most of the time the signal was buried in ultrasonic noise, and I had no filtering! High-KHz tones of the lower amplitude than that noise are intolerable from any amp or speaker. Ultrasonics are still there, but there is much less fatigue.
One of my goals for this amp was to have clean reproduction into the ultrasonic range, so that it might be used with analog sources or test equipment capable of this, since test have shown ultrasonics to have a significant effect on the perception of sound. Of course for digital sources, all this needs to be filtered out...
- keantoken
The filtering I think had an strong effect. I can't validate it yet since I'm trying to install new drivers. Before the sound was fine, but something was very off, I couldn't place my finger on it. There seemed to be something in the air that caused my body to have a fit; the back of my neck tensed up and I started feeling sick. I started to suspect it was the HF noise in the amplifier, since I've heard of discomfort caused by ultrasonics. I tried turning off the monitor and most of the tension released. Go figure, most of the time the signal was buried in ultrasonic noise, and I had no filtering! High-KHz tones of the lower amplitude than that noise are intolerable from any amp or speaker. Ultrasonics are still there, but there is much less fatigue.
One of my goals for this amp was to have clean reproduction into the ultrasonic range, so that it might be used with analog sources or test equipment capable of this, since test have shown ultrasonics to have a significant effect on the perception of sound. Of course for digital sources, all this needs to be filtered out...
- keantoken
It wouldn't surprise me if you glow in the dark kt
LOL! I'll remember this trick if I am ever in need of a flashlight...
Well, I installed the new drivers, and the sound seems very laid back. That or I've just lost much of my HF hearing. I kind of miss the edginess. What do I know though, my ears change drastically every day... Everything always sounds different... Especially if I stay up for 2 days in a row...
- keantoken
Indeed.
Well, I went to bed, and when I got up it sounded the same. Confirmed! The sound of my soundcard with better drivers is... Softer!
Maybe my doubt in my ears was misplaced.
Up until this point I was using 1uF film caps for local filtering, but I looked up the specsheet and was reminded that lower values don't mean better decoupling... I'm soldering in some cannibalized Panasonic HFQ. These showed flawless impedance until 500KHz.
- keantoken
Well, I went to bed, and when I got up it sounded the same. Confirmed! The sound of my soundcard with better drivers is... Softer!
Maybe my doubt in my ears was misplaced.
Up until this point I was using 1uF film caps for local filtering, but I looked up the specsheet and was reminded that lower values don't mean better decoupling... I'm soldering in some cannibalized Panasonic HFQ. These showed flawless impedance until 500KHz.
- keantoken
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I don't know what did it, but the resolution has increased a LOT. I'm not sure if this is my amp or my soundcard drivers, quite possibly both, but I like the change. It's as if you can sort of feel around the contours of the instruments in the frequency domain, and "tune in" to specific instruments easily.
The input and feedback caps are bright green electrolytics, rated 200V each, and labeled "HXBP". I got them out of old ultrasonic air fresheners, I think they were used in a flyback type circuit to get the voltage necessary to actuate the piezo tranducer thing... I think they are similar to photoflash electrolytics. I should probably increase C3. Schematic as implemented.
- keantoken
The input and feedback caps are bright green electrolytics, rated 200V each, and labeled "HXBP". I got them out of old ultrasonic air fresheners, I think they were used in a flyback type circuit to get the voltage necessary to actuate the piezo tranducer thing... I think they are similar to photoflash electrolytics. I should probably increase C3. Schematic as implemented.
- keantoken
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After some time of tweaking, I began to think that it couldn't get much better than my speakers. But now I'm hearing things I simply don't hear with my speakers. It's the amp, not the soundcard. On my speakers, someone saying "yeah" in the background just sounds like a quiet breath, but with my headphone amp, it is clearly audible.
Listen at 00:16. "Jingle all the way", track 13, "Coffee with the crows"
Bad Dudes - Video Game Remixes, Albums and Free EPs
I need some tracks in digital format that will help me resolve fine detail for testing purposes. I'm not sure if my source material is suitable for this. Know of any good ones?
- keantoken
Listen at 00:16. "Jingle all the way", track 13, "Coffee with the crows"
Bad Dudes - Video Game Remixes, Albums and Free EPs
I need some tracks in digital format that will help me resolve fine detail for testing purposes. I'm not sure if my source material is suitable for this. Know of any good ones?
- keantoken
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