I stand corrected guys..it's clearly not a digital volume control...merely a poor and cheap one.
I got my info on it from an informative Feedback Letter to 6 moons.com a couple months ago about the configuration with an analog preamp.. have not looked inside, but thought I remember it was a digi volume control. Nope, just cheap it is...whaddya' want for $39 list, eh?
I have a Scott Nixon battery powered DAC/preamp coming later this week, so I'll have my personal CDP, the Scott Nixon and the SI all on battery power. Vinnie, I bought the 7 aH battery from Battery Mart...no grain at all I can tell with that running it.
Kurt, Dmason also liberated the SI guts and placed in a nicer looking cabinet...but I like the looks of this thing just as is (and plastic, as wood, adds no additional EMI/RFI). I tried a strip of ERS cloth underneath, but more than half a pinky sized and it robbed the little guy of dynamics. Can you beleive that a $39 amp has dynamics than can be robbed
From 6moons.com:
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Hello Srajan,
You guys must spend a lot of time lurking on the Asylum and Audio Circles to have picked up on this amazing little amp [Sonic Impact - Ed.]. For what it's worth, I have a couple of suggestions I hope you will pass on to the reviewer to maximize the quality of sound from this little hummer.
First of all, the cheap volume control is the weakest part of this amp which sounds a lot better if you just crank the thing all the way up and use it as a basic amp with a good preamp. I have had good results using a quality passive preamp (inexpensive custom made by Scott Nixon) and even better results with several tube preamps, especially one without a cathode follower/buffer stage.
While the amp works well on 8 x AA batteries, you can improve the sound by using an inexpensive 12V battery booster as a power supply (I use a $30 one from Target that also happens to be color-coordinated with the amp). Another option is to use a 13.8V/3-5A regulated linear CB radio power supply which will give you an extra watt or two. Tripath's published maximum voltage for this chip is 13.2V but they told me that a tightly regulated 13.8V supply is okay and I have had no problem goosing the amp to that level. Some of the Audio Circle crowd use a $20 Pyramid linear power supply sourced from Parts Express. However, I recommend a higher-quality power supply made by Astron which costs about $10 more. As you can tell, I am a "spare no expense" type of guy. I recommend against using a switching power supply as Tripath chips put out a healthy dose of RF hash which doesn't need to compounded by its power supply.
Keeping with the theme of amazing bargains, I suggest the reviewer try using a Home Depot 14-gauge outdoor extension cord (the orange and black one) for speaker wire (an Audio Critic recommendation from a couple of issues back). Just twist the bare wire tightly and jam it into the cheapo spring connectors (careful or you will snap the plastic levers if you reef down on them too hard). A $4 Radio Shack stereo mini to RCA converter will allow the use of decent interconnects (Nordost Solar Wind in my case).
I use one of my Sonic Impact amps to good effect with my 93dB Loth-X BS-1 speakers. Sonic Impact markets this amp as 15 watts but it only puts out about six watts into 8 ohms so efficient speakers are a must. However, I have also had good results using two of these suckers in a bi-amped configuration to drive my 83.5db LS3/5As. In that set-up, I use the Astron AC power supply to drive the midrange drivers and the battery booster to drive the tweeters, which cuts down the high frequency system noise.
Obviously, you cannot tweak this amp into Bel Canto eVo territory but a little inexpensive DIY setup can produce remarkable results in a small room system. Hell, I enjoy listening to it in my main system but I am not a head banger or a bass freak. For the ultimate low-cost system, just add a Toshiba 1350 or 1360 DVD player for RedBook playback and you've got a very musical, satisfying el cheapo system. By the way, you can get this amp from Target Online for a mere $19.95. Is this a great country or what?
Thanks for reading these ramblings. I appreciate that you are open-minded enough to review something as offbeat as this amp. It has certainly increased my interest in your web 'zine and I predict it will help broaden your readership.
David Dye
Bethesda, MD
Hello David,
Jeff Day is the moonie responsible for landing this catch and I forwarded your loaded-with-tips note to him this morning. Thanks very much. This is exactly the kind of "audiophile community" type exchange I enjoy the most. The hobbyist underground element is what created hands-on excitement in the 'olden' days of HiEnd. Arguably, as the mainstream developed, some of that has receded or, at least, lost visiblity in the mainstream press. We're just as guilty as everyone else for being ignorant about some of the current trends in DIY and thus really appreciate folks like you 'working with us' by providing tips we otherwise might never come across. Thanks for giving us this opportunity!
Cheers,
Srajan
