[amb]

Quote:

Originally Posted by threepointone i know, but i was just wondering where this magic number 1k came from. a current is forced through the resistors in the noninverting input from signal to ground, so (at full volume) shouldn't the resistance to ground just the 100k resistor and 1k + 10k pot in parallel = ~10k in order to balance the noninverting and inverting inputs? So that would also mean that the DC offset can vary as you change the volume or with different source output impedances.

Yes, in a Mini³fied PINT, the output DC offset will vary a little bit with the volume control.

As for the 1KΩ resistor value, it was computed based on the pot at minimum position, so the equivalent resistance there is 100KΩ in parallel with 1KΩ, which is 990Ω. The R4/R3 values of 6.2KΩ in parallel with 1.2KΩ gives 1KΩ, close enough to 990Ω so that it's balanced. At maximum volume, if the source is direct-coupled, then its output is essentially ground because sources tend to have low output impedance, so the situation isn't much different than the minimum volume scenario. For sources with output capacitors, then the noninverting side's equivalent resistance at max volume is 100KΩ in parallel with 11KΩ (the pot + the 1KΩ resistor), which is 9.9KΩ. This might seem unbalanced from the 1KΩ equivalent resistance at the inverting side, but since the resistances are low, the voltage developed across them (due to input bias currents) are small, so their effect on DC offset is also relatively small.

Quote:

Originally Posted by phobus Is there supposed to be a temperature difference between the "regular" PINT and the minified version?

No, unless something is wrong (i.e., oscillation).

 

[Filburt]

After comparing my first PINT against the second, I have come to some fairly firm conclusions:

1. The Mini^3 dual 8397 configuration definitely has a punchier, more intimate sort of sound to it. It synergises well with sources with lack these characteristics, and also if you just need a bit more kick.

2. These traits come at the cost of some overall refinement, and depth/width to the sound. It doesn't feel quite as holographic as...

3. The AD8397/LM6172 configuration has a more refined sound to it, with greater depth and smoothness. It retains the detail, it just isn't as punched out at you. The little plucks on the acoustic guitar, though, just sound better to me for instance. It just has a more delicate, airy touch to it.

4. I slightly prefer the mids on the dual 8397, though, on some music like old U2. The hybrid's mids are a bit much on The Unforgettable Fire.

Both sound fantastic, but I'm glad I have both configurations as well

 

[fierce_freak]

When you say the mids are a bit much, do you mean they're tipped up a bit? Thanks for your impressions

 

[Filburt]

Quote:

Originally Posted by fierce_freak When you say the mids are a bit much, do you mean they're tipped up a bit? Thanks for your impressions

On recordings that have a bit too much in the mids, it can just become a bit too much for comfort. However, the difference between the two in this respect is pretty subtle. I'm starting to wonder if I'm just imagining it, as the mids on that particular album with either of the amps was a bit much. Keep in mind, though, this is with the MDR-E838 earbuds I was trying it with, which are slightly peaky in the mids anyhow.

I just checked it again, and it does have a bit more presence in the mids, but I don't think it's a big enough difference to base a decision on. The other factors I described are more important, IMHO.

 

[threepointone]

thanks amb, i totally get it now