Positive Grid Spark EDGE Portable 4-Channel Smart Amp & PA Black

I bought this amp to use with an electric nylon string guitar. I have a Spark Go and have been pretty happy with it as a headphone amp. I was primarily interested in using it as an acoustic guitar amp. But I also own steel string electric guitars - both passive and active - and evaluated it with them. The amp is usable, but I found some fairly serious flaws. If you plan to play acoustic and sing simultaneously you're out of luck. Only channel 2 supports "acoustic" sound. You can use it for your guitar, or your vocals, but not both. Channel 1, though it sports "acoustic amp" choices, is really just voiced for electric guitar. The built-in tuner only works on channel 1, so if, like me, you bought this for your acoustic guitar, then you can't use the tuner. On channel 2 the headphone output and speaker output sound pretty close. On the electric guitar channel (Ch 1) the headphone output sounds good (but see flaw 4), but to my ears the sound of the speaker output is far inferior. On Channel 1 I noticed a tone (parasitic oscillation) at about 8 kHz. It's hidden by the noise gate, but once you notice it, it's there even while you're playing. If you put a buffered pedal in front of the amp, the oscillation quits. If you set the pedal to "true bypass" and turn the pedal off, the oscillation returns. It doesn't occur with an active guitar. With no input, the oscillation is there. With a shielded passive guitar with NO PICKUPS, the oscillation is there. My educated guess is that the preamp ahead of the A/D converter oscillates if the source impedance is high, as in a normal passive guitar. Buffers in pedals or active guitars provide a low source impedance and kill the parasitic oscillation. I suspect this is not correctable with a software update. So, if you want to sing and play acoustic, you should look elsewhere. If you play electric, then be prepared to use a pedal in front of the amp, which kind of defeats its purpose.

this unit is good for guitar not for vocal. it sounded terrible vocal .Since it is called live, it should have better sound for anyone wanna perform live with a guitar and vocal mic to sing at small venue .for guitar it is good