[Ikon]

Quote:

Originally Posted by Filburt /img/forum/go_quote.gif What is the projected battery life on this amp? Does it have a DC-DC step up converter or does it just run on 3V?

Microshar says 230 hours, IIRC. It runs on 2.4V (two NiMH cells) and I don't think I saw a step-up-converter in there.

 

[Filburt]

Quote:

Originally Posted by Ikon /img/forum/go_quote.gif Microshar says 230 hours, IIRC. It runs on 2.4V (two NiMH cells) and I don't think I saw a step-up-converter in there.

Hmm, hopefully it has more than 2.4v. 1vRMS (common output of portable devices) is ~2.828vpp sine wave (e.g. you need >2.828v supply just to get a unity gain buffer out of this).

Hmm...230 hours? Okay, so then they're figuring 10mA quiescent or is that figuring in projected average draw while driving headphones?

 

[Ikon]

See for yourself: http://amp.microshar.org

"up to 230 hours [battery life] with one full charge (normal use)"

 

[Chris_Himself]

im listening to the Black Rain album by Ozzy and it sounds really really warm.

it does naturally dude to the nature of the Grados but the amp further accents this attribute.

the AKGs just sound even more AKG but a more bassy and refined high end. nothing happened to the mids though. i think its because my AKGs were meant to sound this way the whole time when properly powered.

 

[minkling]

They say that you can specify the gain. I am new but am thinking about ordering one. What gain would I want to use with a motorcycle intercom system? Two helmets, input is a Sony MiniDisc or an MP3 player. Thanks.

 

[Dara_D]

Quote:

Originally Posted by minkling /img/forum/go_quote.gif They say that you can specify the gain. I am new but am thinking about ordering one. What gain would I want to use with a motorcycle intercom system? Two helmets, input is a Sony MiniDisc or an MP3 player. Thanks.

We have had lots of customers buying this amp for the same Purpose, they have all been very happy with 19db (default gain).

 

[minkling]

Thanks!!

 

[Zorander]

I won't be able to hear this amp until Saturday (when I have the time to pick it up). I'm mighty curious though on what sonic character this amp has. Chris?

 

[Filburt]

Quote:

Originally Posted by Chris_Himself /img/forum/go_quote.gif im listening to the Black Rain album by Ozzy and it sounds really really warm. it does naturally dude to the nature of the Grados but the amp further accents this attribute. the AKGs just sound even more AKG but a more bassy and refined high end. nothing happened to the mids though. i think its because my AKGs were meant to sound this way the whole time when properly powered.

Which AKG and Grado headphones?

 

[Chris_Himself]

AKG K240 Studio and Grado SR-80 soon to be 225 if i can find a good one on ebay

 

[MonkeysAteMe]

Is there any kind of warranty and/or return policy?

 

[Chris_Himself]

Quote:

Originally Posted by Dara_D /img/forum/go_quote.gif These are the answers to recently questions asked about uAMP107B : uAMP107 have a Money Back Guarantee for 10 Days (10 days from the time you receive the product).

yep.

10 days is a bit short though.

there is one thing that bugs me a little bit. the blue charging LED is mounted kind of far back or something so it looks dim the whole time. but other than that im pretty happy.

 

[Ikon]

Quote:

Originally Posted by Dara_D /img/forum/go_quote.gif We will be Releasing Some new Technical Details about uAMP107 and uAMP107B this week.

Dara_D, can you elaborate on that? You have a couple of nerds on your hands that are desperate for more technical details

 

[Filburt]

Quote:

Originally Posted by Chris_Himself /img/forum/go_quote.gif AKG K240 Studio and Grado SR-80 soon to be 225 if i can find a good one on ebay

I won't use less than ~6V supply for a headphone amp and, even then, it does cut it close. 3V IMO is not suitable unless all the amp is doing is, at most, acting as a unity gain buffer to a low-amplitude source. 3V supply would not even allow unity gain out of many CD decks and dacs. So, you end up with distortion as you reach the rails. So, maybe your impressions are due to distortion?

I think it would be helpful to know whether there is something like a DC-DC converter in this so we know what voltage the output stage is actually seeing at its rails.

 

[Ikon]

Quote:

Originally Posted by Filburt /img/forum/go_quote.gif I think it would be helpful to know whether there is something like a DC-DC converter in this so we know what voltage the output stage is actually seeing at its rails.

I can make photos of the PCB, but I'll give Dara_D some time to respond. Need to recharge the batteries of my camera first, anyway.