Sonic Impact Tripath amp-->AkG K1000?

Sep 28, 2004 at 6:34 AM Post #2 of 86
No, it won't work properly. Digital amps have a nonlinear shift in their frequency response as the impedance of the load they're driving changes. Most digital amps are most neutral when driving a 6 ohm nominal load, but the tonal shift is not major when driving a 4 ohm or 8 ohm load. The AKGs present a 120 ohm load and will sound excessively bright if you use this amp to drive them. It will be loud enough though.

For this reason, most (all?) digital amps that have headphone jacks use a separate headphone amp section (usually an op-amp) rather than the main amp section for the headphone jack.
 
Sep 28, 2004 at 1:49 PM Post #3 of 86
I bought one of these things in July.
I bought it mainly to use for background music outside on the patio. For what I bought it for, it sounds fine and is a great bargain. Fed by a portable cd player, driving cheap speakers, it sounds FAR better than any boombox, self powered loudspeaker, Bose Wave, etc. that I have heard. It may be a good foundation for a cheap 2nd system or dorm room system. For laughs, I hooked up a CMOY to it as a "preamp", which sweeted up the sound a little and filled in the bass. But, I think it needs to considered in the mass market electronics arena and not as a high end audio product.
I wouldn't use it to drive anything as revealing as a pair of high quality headphones and if connecting headphones to it makes it sound brighter or leaner than it already is, I would avoid it for that application.
I think this is a product that you can have a lot of fun with if used in the right application as long as you don't take it too seriously and expect it to do things that would be ridiculous for $30. It's kinda like buying a hot dog at the ballpark-great cuisine as long as your expectations are set at the right level.
 
Sep 28, 2004 at 2:14 PM Post #4 of 86
I asked about this also and somebody said it wasn't good with K1000.

For home use, I tried kartik's sharp digital amp and it was great. My Panasonic XR25 wasn't bright with K1000 so I don't know if all digital amps are weird with the K1000. If you can get a free trial from Target, I say just try it.
 
Oct 1, 2004 at 8:06 PM Post #9 of 86
mb: It might work, but it sure won't be the optimum - because 9,6 W input power will certainly not generate real 2x 15 W output power...

Greetings from Hannover!

Manfred / lini
 
Dec 16, 2004 at 8:39 PM Post #11 of 86
Quote:

Originally Posted by Wodgy
No, it won't work properly. Digital amps have a nonlinear shift in their frequency response as the impedance of the load they're driving changes. Most digital amps are most neutral when driving a 6 ohm nominal load, but the tonal shift is not major when driving a 4 ohm or 8 ohm load. The AKGs present a 120 ohm load and will sound excessively bright if you use this amp to drive them. It will be loud enough though.
For this reason, most (all?) digital amps that have headphone jacks use a separate headphone amp section (usually an op-amp) rather than the main amp section for the headphone jack.


Do you know whether Creative TravelSound uses the same D amp for both speaker and headphone, or a seperate op amp?
 
Dec 17, 2004 at 8:37 AM Post #12 of 86
Wow, thansk for revival of an old thread. Since I started the thread with the questionr regarding SI-->K1000, let me answer it.

SI in no way, shape, or form sound "exceedingly bright" with AKG K1000, not any more than my 300B tube amp and "normal" Marsh SS amp.

Just another lesson confirmed. Theories are nice, but what counts is what happens when you actually try it.
 
Jan 18, 2005 at 10:43 AM Post #13 of 86
In the thread Sonic Impact Tripath amp-->AkG K1000? Wodgy wrote,

Quote:

No, it won't work properly. Digital amps have a nonlinear shift in their frequency response as the impedance of the load they're driving changes. Most digital amps are most neutral when driving a 6 ohm nominal load, but the tonal shift is not major when driving a 4 ohm or 8 ohm load. The AKGs present a 120 ohm load and will sound excessively bright if you use this amp to drive them. It will be loud enough though.


In the thread Hmmm, 39$ digital HIGH-END amp....!?!? , sluggo wrote

Quote:

The Tripath reference design includes the low-pass filtering. There is also a Zobel (at 80kHz) to quell any peaking of the LC at no-load.


So the HF junk is being filtered out by the LC filter. The chip doesn't see a raw load impedance of 4 (or 8 or 120) ohms, but a more complex load including the LC filter, the zobel, and a 0.01uF cap paralleled with the speaker load. Since the load at high frequencies is dominated by the choke in the low pass LC filter, the speaker/phone load resistance won't affect the high frequency response as described by Wodgy. So this amp could be used to drive high impedance phones without any extra brightness -- as long as the phones are rewired without a common ground, of course.

Please correct me if I'm mistaken about this.
 
Jan 18, 2005 at 12:38 PM Post #14 of 86
Quote:

Originally Posted by eweitzman
In the thread Sonic Impact Tripath amp-->AkG K1000? Wodgy wrote,

In the thread Hmmm, 39$ digital HIGH-END amp....!?!? , sluggo wrote

So the HF junk is being filtered out by the LC filter. The chip doesn't see a raw load impedance of 4 (or 8 or 120) ohms, but a more complex load including the LC filter, the zobel, and a 0.01uF cap paralleled with the speaker load. Since the load at high frequencies is dominated by the choke in the low pass LC filter, the speaker/phone load resistance won't affect the high frequency response as described by Wodgy. So this amp could be used to drive high impedance phones without any extra brightness -- as long as the phones are rewired without a common ground, of course.


Would anyone try Sennheiser HD580 without a common ground, maybe by cutting the cable and sticking the bare wires into the amp output?

I tried it with a common ground. The result has no bass.
 
Jan 18, 2005 at 3:49 PM Post #15 of 86
I have been using a Sonic Impact T-Amp with K-1000 for about a week. For those who said it wouldn't work, I'd strongly advise against talking about something that you don't know anything about. This is a very nice sounding system. I use batteries (NiMH rechargeables), which in theory reduces the output power, but not enough to affect the K-1000. Bass in K-1000 is very strong. The T-amp takes about 30 min to fully warm up, and can be slightly dull until it does. I'd rate the T-amp as just under my modded SHA-1 as a K-1000 amp. Clean, clear, brings out the imaging of the K-1000, and does not skimp at the low end. Weakness is probably thinner mids than I'm used to. As far as battery-powered portable systems go, the Creative NJB Zen, T-amp, and K-1000 may be the best I've heard. Not a lot of isolation, though
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