Sonic Impact Tripath amp-->AkG K1000? - Page 2

Awesome, Hirsch! Is it better than the Xin Super-Mini ?

I'm going to have to do a comparison. No smiley here, incidentally, because I'm not kidding. The Xin SuperMini has driven the K-1000 very nicely the times I've tried it, and may have a better midrange than the T-amp. I don't remember it having the same low-end extension, though.

Guru and I compared the Sonic Impact-T amp. (powered by a Radio Shack 12.8 volt supply) to an ASL AQ-1005DT amp. for driving a K1000, and we heard no difference. I'm now using the Impact-T amp. to drive the K1000 in one of my setups, and it sounds great.

Slightly off topic, I know, but hey... Im considering setting up a small bookshelf system with one of these. What speakers would you guys recommend? I've heard good things about wharfdale and their ilk...

i am using a pair of the athena as-b1.(best buy, on sale for $100)

You should be able to use any high sensitivity speakers(paridigm atom, a few mission m series, etc)

If you do a search with either the atom or mission speakers mentioned, you will find a wealth of information.

I had originally intended to buy the K1000s with an RKV MKII but after seeing all the buzz about the Sonic T-Amp, I picked one up and just ordered the K1000s. My idea is that this set-up should provide a good basis of evaluation for the headphones - comfort and general audio presentation. And I'd get the RKV if I was happy with the cans. (hmm... can I call them cans?? They don't look like cans...)

A couple of questions: to folks who've heard the K1000/RKV combo as well as the SI (glancing at Hirsch), is my strategy a sound one? (I love quality sound but am not really an audiophile - have trouble identifying differences in good digital sources, wires, etc. though I believe that things *I* can't "hear" or describe can definitely make a difference to my long term enjoyment of music.) I'd hate to feel that I didn't give the K1000s a fair shake during the 30-day return period if there would be a significant difference with the RKV - or another expensive amp.

Second question: I'll be using the SI with alkalines - and an on-hand RS 3-12V 800mA regulated PS that, fortuitiously, has the correct adapter. (This combo is powering a 20-year-old set of Boston Acoustics bookshelf speakers very nicely as I type.) The wall wart that SI offers is rated at twice the current level as my RS and folks are recommending 13.8V 3A supplies. Do you think my PS is adequate to do justice to what the SI presents to the K1000s? Among the options I'm entertaining is to put off buying the RKV for a while if I'm very happy with the K1000/SI combo and, at that point, I'd invest in one of the higher current linear supplies that have been suggested. But for now, I'm interested in making sure that I'm getting something close to the best I can get from the SI in order to properly evaluate the phones.

Will sure appreciate any guidance you can provide!

Thanks much,
Beau

I think the strategy is sound. The T-amp will give you a good taste of the K-1000, and in some cases that could actually be the end point, with no further upgrade needed. It really is that good. Several people came by last weekend, and I liked watching their jaws drop when they listened to the T-amp. If the K-1000 is what you like (and it's definitely a headphone that I like), then you can look at other amps, if you want to. A tube amp such as the RKV, Melos SHA-1 (at least in my case, some Melos amps may not have the same output level), etc. provides a bit more midrange warmth and a bit more impact. But not always, and you might actually lose some detail as a trade-off. I sense some sort of paradigm shift coming on. When you can get performance that's competetive with $1000 amps out of something that costs $30 (OK, list price is $40), then change is in the air...

I use NiMH rechargeables, and have stuck with them. I tried the Radio Shack adapter (mine is adjustable, and can do 12v @ 800 ma) and it seems to work fine. However, I do prefer battery operation, and have not pinned down why. Also, I believe that the T-amp needs warmup. With K-1000 it can sound thin and undynamic (OK, downright boring) on first turning it on. 30 min later, it's singing beautifully. I suspect that a regulated adapter, with more amperage, will do more justice to the T-amp than the Radio Shack adapter, but have not done the comparison. Note also that using an AC adapter will in theory allow the T-amp to produce more output power, but I haven't felt that I've needed it. IMO battery power is so much cleaner than what comes out of the wall that I use it whenever possible.

I'm looking into modifying the SI amp for phones. The big hurdle is that the lowpass LC filter is designed to run into a particular load. Tripath's spec sheet shows two values for the C in the filter for each of a 4 or 8 ohm load. A 120 or 300 ohm load would drastically alter the filter's characteristics. Coming up with a new filter shouldn't be difficult once I know the output response of the chip. The Zobel would probably also need to be changed.

Those of you running your phones on this amp now are possibly risking damage to your phones, since they're being exposed to a large amount of ultrasonic signal. As Wodgy wrote, many class D amps depend on the speaker filtering out the HF garbage. This amp has a filter built in, but if it's "defeated" by a load that differs from expected, the load -- your phones -- will be absorbing the HF garbage. I don't know the amplitude of the HF noise, but if it's large, your phones will be absorbing a lot of HF power even though you can't hear the sound.

- Eric

Beauregard - I use the Radio Shack 12.8 volt 3.0 amp. power supply to power the T-amp. No warmup is needed; i.e., the K1000 sounds great right from the beginning. I've compared the sound from the T-amp. to that of a 300B tube amp. setup that costs in excess of $1.5K, and could not hear any difference. I suggest that you get the more expensive amp. with a 30 day return option, and also get the Radio Shack power supply, which costs about $40. You can return this power supply to Radio Shack after trying it in the system. My guess is that, after testing and comparing, you'll be fully satisfied with the T-Amp., and possibly also with the Radio Shack power supply, and that you will return the more expensive amp. As for the K1000, I'll bet that you'll always cherish it.

Sonic Impact's site has a blurb that says the amp has an "input for optional AC Adapter 12 Volt/2 amp power supply." They have a link for a power adapter that "will provide a continuous power supply of 12V and up to 1.5A to your Class T amp." So it appears to need a 1.5 amp supply.

Did the tube amp have a dedicated headphone jack? If so, what type of circuit was used to drive the phones? If not, did you somehow compensate for the high headphone impedance?

- Eric

I'm with Hirsch and mikeg. The SI is a great little amp to drive the K1000's, and does a LOT right. I think the midrange is very neutral, though tubes CAN give thta lushenss that is likely colored, but very musical.

I have also owned the RKV Mk II in the past, and it is also great with the K1000's (and also the Senn 650's!!). But for $30 +/-, you may never find yourself moving away from the SI. I wish I had them for a side to side comparison, but I don't...just relying on memory.

And like mikeg, I use the Rat Shack 13.8V, 3amp PS. While the amp spec's a 12V input, the Tripath chip can take more - but it should be regulated, so as not to have power spikes that can fry the amp/chip.

I don't use mine for travel, it sits in a second bedroom (my "escape pod") along with a nice mod'd Pioneer universal player. SWEET sounds abounds!

Availability

I ordered a SI amp in early December and the vendor never sent it. I have been fighting to get my money back.

I just Froogled the SI 5066 and every place that comes up is out of stock. The only place that seems to have it in stock is SI. They however want $39 plus $6.50 shipping. They want to make the manufacturer margin, and the retail margin, and charge me for shipping to boot. I don't think so.

I'll wait.

I was one of those people and I couldn't believe it either. Now, I haven't spent a lot of time with the K1000 (don't own a pair) but the few hours I spent at Hirsch's listening to this amp makes me want the K1000s. We had two fine setups going (the SI/K1000 and another) and while the second amp was a great sounding amp...I kept wanting to go back to the SI/K1000. I hooked up my iPod to it and played Gary Peacock and Ralph Towner's album A Closer View (ripped as Apple Lossless files). I'm having a hard time listening to that album now at home, because that little amp and the K1000s made it so much fun. It was a blast to listen to. I can't comment on specifics as I have not spent any serious dedicated time with it, but the combo made a great first impression indeed.

Quote:
Originally Posted by Hirsch
It really is that good. Several people came by last weekend, and I liked watching their jaws drop when they listened to the T-amp. If the K-1000 is what you like (and it's definitely a headphone that I like), then you can look at other amps, if you want to.


finally -- a portable k-1000 amp that sounds very fine.

i was amazed when i heard it. it is an excellent untethered portable amp for the k-100 & sounds great with the ipod mini & zen jukebox. put a belt clip on it & you are good to go. finding a t-amp is the hard part. everyone is sold out & back ordered. and cheap! as low as $20.

It was an ASL AQ-1005DT power amp., with a SinglePower SDS amp. serving as preamp. The K1000 was connected to the 16 ohm speaker posts.