Sonic Impact Super-T Amp.

It's here!

SI-5, the makers of the well known Sonic Impact amplifier, have just come out with a new version of the amp, the Super-T. This new model is designed with the audiophile in mind.

Though this new versions uses the same Tripath chip as the first little amp, that is where the resemblance ends. The new amp is much larger, much heavier in an all metal chassis. It comes with a switch mode power supply and a cord to connect to a battery. There is also power filtering onboard.

On this page I will have a look and listen to the new amp.

Is it worth $100 more than its little brother?
How does it sound?
Can it be made to sound even better? (Like the original)
How hard is it to modify?

A first look.

The new amp is heavy! It is in a all aluminum case with a very thick front plate. Just a large volume control knob, LED and power button on the front. While it won't win any beauty contests, but it is a least fairly sober looking and should blend in well. A black anodized version would be nice.

The rear panel holds the connectors; RCA inputs, Banana outputs, coaxial power connector. All good quality and gold plated.

My unit came with a "line lump" style switch mode power supply. It is rated at 12 volts, 3A. Also included are a stereo RCA cable, 2 short speaker cables, and a battery cable. The RCA and speaker cables are certainly not "Audiophile" quality, so use what you like. The stock cables are probably just included as a convenience. The battery cable will come in handy for those of you who like battery power. It has a coaxial plug on one end and 2 rather large, gold plated eye terminals on the other end with an inline fuse in the middle.

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A first listen

This is not the old Sonic Impact. The new amp has balls. No more lack of bass or thin sound. Gone also is the harsh high end. A good start. The new amp seems to have about the same gain as the old, judging by the position of the volume control, the new amp sounds much fuller.

The new amp reminds me of my first modifications the little Sonic. At first listen it also is as full sounding as the Fenice board or the 41Hz AMP6. I will try to get some more listening and comparing done thru the week.

A second listen - Any Bass?

A lot of people want to know "does this amp have enough bass?" The original Sonic was very bass shy. This new amp is not bass shy.

I have an old Pioneer integrated amp that must be early 80's vintage. It's a big honking thing, very heavy. It would never win any audio quality awards, but it is solid with a big power supply. About 90 WPC and not faint of heart. I've always been surprised at how much more bass this amp has than any other I've heard - so much so Ii thought is was bass heavy. The amp is used at work to power big 2 way speakers (about 93dB/watt 4 ohms). They can play loud down into the 30s no problem, or even lower. BIG room too. 40x45 by 20 feet high! In a room like that, the bass gets soaked up pretty fast.

So I took the Super-T to work for a listen. Not a fair test, putting this little 11 watt T-amp up against the big brute Pioneer in that huge room. But you know what? The Super-T had just as much bass! Maybe more. Astounding! This is stock, no power supply upgrades. The Super-T had all of the Tripath magic, as much bass as the big Pioneer, and more dynamics. Sure, the Super-T will not play as loud as the 90 watt brute, but that is only because of the power difference. At the same power (max for the T-amp) -- no difference.

Bottom line? No bass worries here. The problem has been fixed.

A Third Listen

Tonight I fired up the 41HZ AMP6 to have an A/B listen with the Super-T. Levels were measured and adjusted to be exactly the same.

The two amps sound much alike, which isn't too much of a surprise. The AMP6 takes the edge, though. The AMP6 has more space and a feeling of ease compared to the Super-T. Going from one amp to the next the difference is subtle, but consistent. The AMP6 sounds more open, more spacious. The sound of the Super-T is more pulled in toward the center and a little heavier, thicker, in the mid bass. Switching form the Super-T AMP6 the sound seems to spread out and also sound smoother. The effect is the same on all types of music.

So. Why? I don't know yet. Both amps are stock. The AMP6 is running on its 14V linear supply, the Super on the 12V SMPS that came with it. Both amps use electrolytic input caps. The 41HZ has 3.3uF Panasonic caps, the Super has 2.2uF caps of unknown type. There are a few differences in the other caps too. The output filters are very different. A 2nd Order filter with toroid indictors on the AMP6, what looks like a 4th order filter on the Super with shielded bobbin inductors.

Conclusion? The differences are subtle, but real. The Super seems a little more focused at first, the AMP6 more expansive. But I feel that the "focus" of the Super is coming from a lack of micro detail that defines the recorded space. It will be interesting to see if new, better caps in the Super will recover the lost sense of space. Work to be done!

Modifying

This amp should be easy and rewarding to modify. I will begin to do so soon. At 1st glance I would say that the basic mods should be as follows, and would cost you about $25US in parts, plus a few hours time.

Basic mods.

1) Replace the input caps. Nice film caps here will help a lot. e.g Solen or Jantzen.

2) Replace the onboard electrolytic caps with Panasonic FM series or other good low ESR caps. The Pannies are inexpensive and work really well, fast and good sounding. This would be for the amp decoupling as well as in the power supply.

3) Add a good 100uF cap on the power jack. This will help lower noise coming from the switch mode power supply.

4) Maybe remove the reverse polarity protection diode. That will give a 0.6V boost, Can't hurt.

5) Add a stiffener cap. 10,000uF. Gives a tighter, stronger bass and wider sound stage. Use to taste, a lot of guys don't like the tighter bass, better damping factor.

6) Better wire on the inputs and outputs.

7) Add a heat sink.

Advanced mods: around $100-150 in parts.

1) Do all of the above, except use expensive film/foil caps on the inputs.

2) Replace connectors with high quality models, e.g. Vampire, Cardas, WBT.

3) Bypass volume control if you have a pre-amp.

4) Replace coaxial power plug with something sturdier. Maybe 1/4" phone plug.

5) Modify output filter. TBD.

Technical.

A quick examination reveals that the new amp is quite a bit different from the old. Same Tripath TA2024 chip, but most everything else is different. The potentiometer is a 50K model made by CTR (don't know the brand). There is a good bit of power filtering onboard, including an LC filter. A big diode is near by, most likely for reverse polarity protection.

The input caps appear to be ordinary electrolytics, value of 2.2uF, so no bass roll off. Better caps will be tried here.

The output filter is completely different.
First, it uses shielded bobbin type inductors. And it uses 8, not 4, so the filter is most likely a 4th order low pass. The filter caps are thru hole polyester types. Why SI-5 chose to go with a 4th order filter, I don't know. I do like the idea of shielded inductors and good polyester caps.

There is a bit more circuitry around the input side of the chip, too. Perhaps a larger 5V decoupling cap. There are 3 SMD transistors on the PCB, Don't know yet what they are for.

Mechanical

There is plenty of room in the case for adding things. The case is a typical project type case with grooves inside for PCBs. The amp PCB, however, is screwed to the front panel. The back panel has ventilation holes. The 50K volume pot is soldered to the PCB, as is the power switch.

Alas, no chip cooling. No heatsink nor even a solder slog under the chip. Too bad, I think cooling helps the chip. Maybe at 12 volts it will be OK, but if you push it to 13 volts or more, well... might be "Good-bye Mr. Chip."

Thin shielded cable runs from the RCA connectors to the board. Nice to see shielded cable here. The speaker output wire is thin "zip cord" - an odd choice, but as good as the wiring in a lot of commercial units.

Conclusions so far.

Nicely done, a big, bolder amp than the first. Still has the Tripath magic, but with a more "manly" sound. Looks like it will be easy to modify for those ultimate tweaks. The sound could use some improvement, but it's a good start, much better than the original Sonic Impact.

Is it worth $100 more than the original? So far, I think so. If you wanted to modify the original Sonic Impact, put it into a nice case, buy or build a power supply and connectors, you might be able to do it for a few dollars less than the new version. But that doesn't count the time and aggravation spent modifying the little guy. =)

Stay tuned for more updates.

Photos