[ZMU817]

Hello all, I'm doing an awful lot of research finding a good USB/DAC amp for a newly purchased pair of DT770 600 ohm, and I've stumbled across this modest looking deal with these specs:

High power operational amplifier (AD8397)
Voltage boost technology
Precision virtual ground reference (TLE2426)
USB DAC (16-bit; 32, 44.1, 48 kHz) (PCM2704)
Poly caps on input signal paths
Ultra low impedance 1000µF electrolytic power supply caps
1% tolerance resistors
Alps potentiometer with built-in ON/OFF switch
Automatic switching between line in and USB port
LED power and battery charging indicator
Rechargeable lithium Ion battery pack (included)
Battery charging via USB port
Strong ABS case - 2.6"(66mm) x 2.6"(66mm) x 1.1"(28mm)

I don't know what much of this means so I'd appreciate if someone could tell me if this was any good. Just around $100 which makes it very attractive at half the price of second hand iBasso which appear to be the same thing in a fancy case (like I said, I don't know much about internals)

Thanks for your help.

Here's the product page

 

[HiFlight]

I have not heard of them, but based on the specs, I hardly see how you could go wrong for the price.

 

[Citizen86]

Bumping, this is an old thread, but looks like a nice portable for only $100 bucks. It's been a couple months, so has anyone heard about this?

 

[episteme]

I've heard of Vivid... no wait.

 

[FallenAngel]

Not sure what the ground channel looks like, hopefully it has an opamp on it and not handled by the TLE. Otherwise, it's really stupid to use AD8397 there, the TLE only handles 20mA. I'd rather make it a resistor divider that can sink any amount of current instead of the TLE, of course a ground opamp would be best. It's also running off a low voltage lithium ion battery, not much voltage swing on it. Meh, for $100, if you NEED a DAC, it's probably OK (as long as the TLE isn't on ground alone), but I'd much rather spend a little more and get an AlienDAC + Mini3.

 

[tdicola]

I just purchased one so I should be able to give some impressions in ~a week. With the live search cashback promotion going on the price was just too good to pass up, only about $76.

 

[jcx]

600 Ohm cans will not be driven well by a amp running on single battery V - the vivid specs are most suitable to 32 Ohm sensitive cans or iems

you should want lots more V, try a line power full sized integrated amp/reciever/CD/DVD player with a separate headphone out, usually they have > +/-10V supplying the op amp and 600 Ohms is a light load for any likely op amp

the difference should be obvious with any truely dynamic recording, maybe not so obvious with "loudness war" compressed pop music

 

[mark10001]

The main power in the V1 is a Lithium Ion whose voltage (V) is around 4.2 volts with a full charge, however the battery output is boosted before going to the opamps. This supplies the opamps with a much higher supply voltage (V).

Mark

Quote:

Originally Posted by jcx /img/forum/go_quote.gif 600 Ohm cans will not be driven well by a amp running on single battery V - the vivid specs are most suitable to 32 Ohm sensitive cans or iems you should want lots more V, try a line power full sized integrated amp/reciever/CD/DVD player with a separate headphone out, usually they have > +/-10V supplying the op amp and 600 Ohms is a light load for any likely op amp the difference should be obvious with any truely dynamic recording, maybe not so obvious with "loudness war" compressed pop music

 

[vivid technologies]

One other thing about to note about the voltage boost is that the amp voltage will always be at a constant high level until the battery needs to be recharged. This is nice since the sound wont change as the battery voltage drops.

Quote:

Originally Posted by mark10001 /img/forum/go_quote.gif The main power in the V1 is a Lithium Ion whose voltage (V) is around 4.2 volts with a full charge, however the battery output is boosted before going to the opamps. This supplies the opamps with a much higher supply voltage (V). Mark

 

[FallenAngel]

Quote:

Originally Posted by vivid technologies /img/forum/go_quote.gif One other thing about to note about the voltage boost is that the amp voltage will always be at a constant high level until the battery needs to be recharged. This is nice since the sound wont change as the battery voltage drops.

Oh cool, a rep from Vivid Technologies

Just one question (most important for me), is the ground channel buffered (or amplified) or are you using the TLE2426 as the ground. The reason why I ask is because obviously the AD8397 can output a huge amount of current (230mA off 5V PSU), but the TLE23426 can only sink 20mA limiting the output current of the AD8397 to a VERY low value. Please confirm how the PSU is set up. Thanks

 

[vivid technologies]

The average power supply current of is less than 20mA. The output current of the AD8397 is peak current. The average current that the TLE2426 sees is also going to less than 20mA.


Quote:

Originally Posted by FallenAngel /img/forum/go_quote.gif Oh cool, a rep from Vivid Technologies Just one question (most important for me), is the ground channel buffered (or amplified) or are you using the TLE2426 as the ground. The reason why I ask is because obviously the AD8397 can output a huge amount of current (230mA off 5V PSU), but the TLE23426 can only sink 20mA limiting the output current of the AD8397 to a VERY low value. Please confirm how the PSU is set up. Thanks

 

[FallenAngel]

Quote:

Originally Posted by vivid technologies /img/forum/go_quote.gif The average power supply current of is less than 20mA. The output current of the AD8397 is peak current. The average current that the TLE2426 sees is also going to less than 20mA.

In a 2-channel amp design the OUTPUT current from each channel (AD8397) returns to the PSU ground and the PSU ground (TLE2426) has to be able to sink it.

 

[vivid technologies]

I did some measurements with the V1 driving a 16 ohm load. As can be seen in the attached scope plot with a peak to peak voltage of 2.4V on each channel the total peak current is 300mA and the ground channel is ultra stable. So it looks like this amp can drive a huge output current without any problems. Note this signal into a pair 16 ohm headphones is ultra load and would probably damage hearing.

See attachment.


Quote:

Originally Posted by FallenAngel /img/forum/go_quote.gif In a 2-channel amp design the OUTPUT current from each channel (AD8397) returns to the PSU ground and the PSU ground (TLE2426) has to be able to sink it.

 

[ZMU817]

Good to see some discussion going on about the amp.

Just some observations after owning this amp for a few months.

-never had a problem or disappointment with the battery life

-it drives my 600 ohm beyers plenty loud, though I understand that there's some difference between high-ohmed 'phones being loud and being powered properly

-sounds especially great with IDM/electronica, can't imagine how it could sound better

-more traditional music generally sounds great most of the time, my recabled KSC-75s are a blast to listen to

-'most of the time' **some artists (Bright Eyes, Play Radio Play come to mind) Are harshly sibilant with the beyers, not as much (but still slightly) with the KOSS

-the DAC seems to be of equal quality to the AV710 soundcard, though don't take my word for it

-it sounds just as good or better than the headphone jack on my late-model Onkyo reciever (one of the more expensive ones, 7x120w speakers, IIRC) so that should clear any worries about voltage hopefully

I think that's about it. Little more than I expected to write, but hope that helps anyone looking at it. Sometimes I absolutely love it, but I confess that I will often look at the next step up looking for something more, but I think that something all Head-Fiers are victims of

 

[Ub3rMario]

so what's the verdict for a starter amp/dac? Buy or pass? It's lookin pretty sexy to me right now (also looking at lyrix and go-vibe petite...so if you have experience with either of those let me know how they compare if you could!)