[Filburt]

PINT #1 - Not "mini^3ified", AD8397 on L/R, LM6172 on ground, gain 4.

Sound - Smooth with great detail and rather good soundstage and imaging for a portable. Has a nice amount of depth, relatively speaking. The sonic 'feeling' is that of the LM6172 keeping the aggressive 8397 in check.

PINT #2 - "mini^3ified" with AD8397 on both. Gain is still 4. More aggressive sound to it, and more forward. A bit brighter as well on upper mids it seems like. Soundstage and depth seems to be less than on PINT1.

I can try to elaborate more if necessary, but perhaps this will help. I prefer #1 for classical and jazz, and prefer #2 for rock and metal.

 

[kwsuh]

C1 1K, R3 1.2K, R4 6K, AD8397 on L/R, LM6172 on ground.
L1 in the loop for L/R and ground.

There was no sign of oscillation. I checked with lab power supply and scope.
DC offset was below 10mV.

 

[The Monkey]

Are you guys getting hiss with the non-mini^3fied PINTS?

 

[Teerawit]

Quote:

Originally Posted by The Monkey Are you guys getting hiss with the non-mini^3fied PINTS?

Yes.

 

[blueworm]

Quote:

Originally Posted by The Monkey Are you guys getting hiss with the non-mini^3fied PINTS?

Yes with HD497 32 ohm cans.
No with HD595 120 ohm cans.

 

[Filburt]

Quote:

Originally Posted by The Monkey Are you guys getting hiss with the non-mini^3fied PINTS?

Both of my amps lack input caps, but only one of them has the mini^3 mod which involves cutting a trace and moving R4 onto the C3 pad and stacking C3 on top of it. Neither amp has hiss.

My resistor configuration is 1,33k for R3, 4,02k for R4, and 1K axial resistors in C1 L/R in place of input capacitors.

 

[nysulli]

fully minified, ad8397 for both op amps, L1 as stock value listed in tangents build guild, 1k resisters at c1, r3 1.62k, r4 3.3xk, gain = 3, running 16.8v battery and 24v wall power via elpac wm-1224 wall wart, no hiss powered in either way, maybe a tad quieter backround with wall power, but i really can't hear a difference between wall or battery power (elpac is plugged into an isobar, so some power filtration before the elpac) dc offsets for all 3 channels are under 1 mv, 63 ma drain with led

sound is very detailed, widened the soundstage noticably with my hf-1's, mids and highs are clearer, more detailed, low end has a bit more punch to it.

 

[cire]

fully mini'fied with a gain of 6.

when amping ksc75 with the volume at full blast, the hiss is barely audible and completely gone with even the slightest amount of music. when amping E4c, there's a bit more at full tilt, but still much quieter than a mint at full volume.

this amp makes me want to sell my millett. its that good.

 

[headchange4u]

What exactly is mini^3ified?

 

[BavariaBarbarian]

Nice thread!

What I'd really like to know is if the AD8397's performance scales with the supply voltage.
It'd be great if it could be used with 4 AAA rechargeables because that's what one can fit into a mint tin.

Has anyone actually tried that?

 

[Filburt]

Quote:

Originally Posted by BavariaBarbarian Nice thread! What I'd really like to know is if the AD8397's performance scales with the supply voltage. It'd be great if it could be used with 4 AAA rechargeables because that's what one can fit into a mint tin. Has anyone actually tried that?

Yes, increased voltage will probably improve performance. 4 NiMH AAAs will probably only give you around 5,8-6v at full charge, and it'll drop down to 5v and below as the batteries discharge. That'll probably run the PINT on low impedance cans, but I think tangent's site had something like 6,4v as the clipping point for a 330 ohm load. In general, though, performance does improve with more voltage even if you aren't hitting the clipping point. I run my PINT with 2 9v batteries in a MINT tin.

 

[BavariaBarbarian]

If I did the maths correctly 4V will give me at least 1.1V voltage swing, which is ample for all my cans.
I already have a nice fast charger for 4 AAA / 4 AA that I'd prefer to trickle charging plus AAAs exist up to >800mAh which would allow for significantly more runtime.

But if sonic performance is noticeably lower, I'll have to use 9V batteries....

Could you please elaborate on the difference in sound? Have you actually gone as low as 4-5V?

Cheers!

 

[Filburt]

Quote:

Originally Posted by BavariaBarbarian If I did the maths correctly 4V will give me at least 1.1V voltage swing, which is ample for all my cans. I already have a nice fast charger for 4 AAA / 4 AA that I'd prefer to trickle charging plus AAAs exist up to >800mAh which would allow for significantly more runtime. But if sonic performance is noticeably lower, I'll have to use 9V batteries.... Could you please elaborate on the difference in sound? Have you actually gone as low as 4-5V? Cheers!

I haven't tried it on the PINT, as my encounters thus far with the AD8397 is that it's a fickle beast and I've done enough experimentation already that my wallet is starting to put up a fight.

However, my experiences with other chips has been that the performance starts to get a bit sloppy. I lost impact, detail, response, and as you get closer to clipping, some distortion can crop up. Tangent and amb probably have more experience with this than I do, so they'd be good folks to ask.

It may work with 4 AAAs, but I wouldn't bet on great performance or long battery life if the cells don't keep their voltage high enough through the discharge cycle. You'll probably have to omit the diodes on the power section to keep from losing voltage there, which means you'll also have to omit the battery charging section. You could actually fit 6 or 8 AAAs in with the PINT in a mint tin, if you really want to use AAAs. I prefer the extra voltage, so I use 9v batteries, but 6-8 AAAs would probably provide enough power to give acceptable performance.

 

[blueworm]

Quote:

Originally Posted by headchange4u What exactly is mini^3ified?

See http://headwize.com/ubb/showpage.php?fnum=3&tid=6096
Then for a complete explanation see:- post #81
http://www4.head-fi.org/forums/showt...=173192&page=5

 

[threepointone]

for everyone with mini^3-ified PINTs, I was just wondering--what DC offset do you get (ignoring any source offset)? does it change with the volume control? I'm just somewhat confused about how the gain resistor values were chosen--how exactly do you calculate the resistor values without the input cap? It seems from tangent's calculator that the gain resistors should be a bit higher, optimally--were lower values chosen for lower noise?