Here is my first impression of the Sonic Impact T-Amp Gen 2 that I received today.
I ordered the T-Amp Gen 2 from Parts Express on February 29. Cost was $50 plus $9.18 shipping. It arrived in 7 days.
What’s in the box: The T-Amp Gen II, a 12v 3A switching power supply (BI Model BI42-120300-E2), a female RCA (L&R) to mini-jack adapter, Male RCA (L&R) to minijack cable (looks like 3 foot), a very brief manual.
Physical Inspection: The new model is significantly smaller than the old in height, and is much easier to stack with other small products. The volume knob pushes in to turn off (the old one clicked off when turned to the left). The new model looks nicer in my opinion. It has the same cheap push-pin speaker connectors, the same mini-jack input, the same 12v adapter input, and the same capability to run on 8 AA batteries. The manual says it outputs 10 watts with the AA batteries, and 15 watts with the AC adapter. The only new connection is a mini-headphone jack on the right side.
Cost Comparison with Old T-Amp. The Old T-Amp sold for $35 without a power supply. The power supply retailed for $15. So the price with a power supply would have been about $50. The price really hasn’t changed between the old and new models if you account for the 12 v 3A power supply. In addition, I believe the former SI power supplies were 2A and not 3A supplies. So the power supplies appear to have been improved. I’ve read a lot of carping on the internet about the “higher price” of the Gen 2 – the commentators don’t seem to notice that the Gen II includes the power supply and the Gen I did not.
Headphone Amp. This is an entirely new addition to the Sonic Impact line. The prior versions did not include a circuit for headphones. Moreover, adopting the speaker outputs for headphone use was problematic. According to web resources, the T-Amp chip was designed to work with 4 and 8 ohm speaker loads using special digital filters. It produces noise and artifacts when used outside of the filtered range. Moreover, the amp is bridged and cannot be used with headphones that share a common ground without causing damage to the headphones or the amplifier. Therefore, one would have to cable the headphones for dual mono use. Presumably, these issues have been addressed in the design of the headphone connector. But read on.
Headphone Output
The headphone output sounds pretty good with my Koss KSC-75s, which have a 60 ohm impedance. But high impedance headphones don’t work right at all. The sound completely fell apart on my big Senn HD-580s (300 ohm impedance). I got really bad and strange distortion artifacts even at modest listening levels. The same music on the KSC-75s sounded fine. I suspect the problem with the 580s was the lack of proper digital filtering designed for high impedance phones. I don’t know what impedance range the digital filtering of the headphone output is designed for. It seemed to work fine with my low 16 ohm impedance Shure E2cs. No hiss, clear sound.
So, what do I think of the sound quality with low impedance headphones? Well, I think it’s fine. Nothing great or earth shattering, but it’s an adequate sounding convenience. It’s not a world beater by any means. I’d say the sound is similar to your average dap. I would not recommend this to someone looking specifically for a headphone amp. Still, having essentially free headphone output thrown in with such a great sounding little speaker amplifier is a big plus. One warning. Make sure you turn off the power before plugging or unplugging your headphones. The shorting noise is a real killer on this amp.
Speakers
I played the same music through both the old T-Amp and the new T-Amp Gen 2 using Kef Chorale speakers. Based on my initial comparison, I couldn’t tell any difference. The Gen 2 sounded virtually identical to the old. That’s not a bad thing, because the T-Amp in my opinion sounds terrific – very musical. My guess is that the so-called “bass rolloff” problem has not been fixed – although I’m basing this on listening to organ music through relatively small Kef Chorale speakers, so it’s possible that the Kefs just don’t go low enough for me to notice any difference. I have neither the test equipment nor the skill to do a scientific test. I’m sure there will be detailed reports on this from others more capable than I. However, I can say that the amp sounds just beautiful with speakers. Delicate, quiet, detailed, and musical. It’s still shocking to hear such great sound from such a light and cheap amplifier. So I continue to recommend the amp most highly for people on a budget. There is nothing I know if in this price range that can compete with it for sound quality with a set of bookshelf speakers.
I ordered the T-Amp Gen 2 from Parts Express on February 29. Cost was $50 plus $9.18 shipping. It arrived in 7 days.
What’s in the box: The T-Amp Gen II, a 12v 3A switching power supply (BI Model BI42-120300-E2), a female RCA (L&R) to mini-jack adapter, Male RCA (L&R) to minijack cable (looks like 3 foot), a very brief manual.
Physical Inspection: The new model is significantly smaller than the old in height, and is much easier to stack with other small products. The volume knob pushes in to turn off (the old one clicked off when turned to the left). The new model looks nicer in my opinion. It has the same cheap push-pin speaker connectors, the same mini-jack input, the same 12v adapter input, and the same capability to run on 8 AA batteries. The manual says it outputs 10 watts with the AA batteries, and 15 watts with the AC adapter. The only new connection is a mini-headphone jack on the right side.
Cost Comparison with Old T-Amp. The Old T-Amp sold for $35 without a power supply. The power supply retailed for $15. So the price with a power supply would have been about $50. The price really hasn’t changed between the old and new models if you account for the 12 v 3A power supply. In addition, I believe the former SI power supplies were 2A and not 3A supplies. So the power supplies appear to have been improved. I’ve read a lot of carping on the internet about the “higher price” of the Gen 2 – the commentators don’t seem to notice that the Gen II includes the power supply and the Gen I did not.
Headphone Amp. This is an entirely new addition to the Sonic Impact line. The prior versions did not include a circuit for headphones. Moreover, adopting the speaker outputs for headphone use was problematic. According to web resources, the T-Amp chip was designed to work with 4 and 8 ohm speaker loads using special digital filters. It produces noise and artifacts when used outside of the filtered range. Moreover, the amp is bridged and cannot be used with headphones that share a common ground without causing damage to the headphones or the amplifier. Therefore, one would have to cable the headphones for dual mono use. Presumably, these issues have been addressed in the design of the headphone connector. But read on.
Headphone Output
The headphone output sounds pretty good with my Koss KSC-75s, which have a 60 ohm impedance. But high impedance headphones don’t work right at all. The sound completely fell apart on my big Senn HD-580s (300 ohm impedance). I got really bad and strange distortion artifacts even at modest listening levels. The same music on the KSC-75s sounded fine. I suspect the problem with the 580s was the lack of proper digital filtering designed for high impedance phones. I don’t know what impedance range the digital filtering of the headphone output is designed for. It seemed to work fine with my low 16 ohm impedance Shure E2cs. No hiss, clear sound.
So, what do I think of the sound quality with low impedance headphones? Well, I think it’s fine. Nothing great or earth shattering, but it’s an adequate sounding convenience. It’s not a world beater by any means. I’d say the sound is similar to your average dap. I would not recommend this to someone looking specifically for a headphone amp. Still, having essentially free headphone output thrown in with such a great sounding little speaker amplifier is a big plus. One warning. Make sure you turn off the power before plugging or unplugging your headphones. The shorting noise is a real killer on this amp.
Speakers
I played the same music through both the old T-Amp and the new T-Amp Gen 2 using Kef Chorale speakers. Based on my initial comparison, I couldn’t tell any difference. The Gen 2 sounded virtually identical to the old. That’s not a bad thing, because the T-Amp in my opinion sounds terrific – very musical. My guess is that the so-called “bass rolloff” problem has not been fixed – although I’m basing this on listening to organ music through relatively small Kef Chorale speakers, so it’s possible that the Kefs just don’t go low enough for me to notice any difference. I have neither the test equipment nor the skill to do a scientific test. I’m sure there will be detailed reports on this from others more capable than I. However, I can say that the amp sounds just beautiful with speakers. Delicate, quiet, detailed, and musical. It’s still shocking to hear such great sound from such a light and cheap amplifier. So I continue to recommend the amp most highly for people on a budget. There is nothing I know if in this price range that can compete with it for sound quality with a set of bookshelf speakers.
I was hoping the bass situation had been addressed in the V2. Hopefully, someone will be able to check that part out soon.
