[Filburt]

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Originally Posted by mb3k Oh boy, that reminds me that I have 2 oscillating PINTs... darn hot. Have you been listening to a different amp for a while, then switched to the PINT?

Do you have C6 installed? While tangent doesn't emphasize using it much on his page, I highly recommend it. My experience has been that it can significantly reduce the probability of oscillation. I installed the AD8058 recently on one of my old PINTs and put the AD8397 in ground so I could run at 6V and it's what I had available (it also has very low output impedance and very high output current, which is useful in this case) and it oscillated (the amp still ran, but it ate current) until I put in C6. I went from ~170mA quiescent to about 30mA just from installing C6 with one of the same caps I used for C3 since I didn't have anything else left in my miscellaneous parts bag.

 

[Andrea]

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Originally Posted by Filburt You could try the AD8058 on L/R or maybe ground as well and see how that goes. Contrary to Andrea, I found the LM6172 markedly better in sound quality than the AD8397 and overall clearer.

Oh yep, artificially clearer, maybe. And seemingly less linear. And how about that greenish tonality...

(disclaimer: my findings are related not to the PINT but to the, admittedly quite similar, Go-Vibe v5; and to the LM6171 Pengamp)

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I haven't found the design inherently lacking in high end extension. In fact, I've found it to be rather good in that respect. I do think I may like the AD8058 the best so far out of the op-amps I've tried with it, though. Although the LM6172 still gets some use.

Not high end extension. If it resembles the Go-Vibe v5 as I definitely expect, it's lacking in transient & treble sharpness/sparkle, which the LM6172 can only accentuate (as opposed to the AD45048 or 8397).

 

[nysulli]

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Originally Posted by IEATTEFLON I listened to both amps with all the headphones that I own. After looking at more pint comments i'm wondering if I have some high frequency hearing loss. quicksilver: they are configured with the mini3 values from what I know. The capacitor positions next to the volume controller is jumpered with some resistors. I broke out my multimeter and measured the output and dc was 0.9-1.5mv on the left and right channels. It did move up to 20ish mv at full volume. Instead of trying to understand it more I decided to return them. I'll stick with my pimeta and build my own when tangent sells the updated boards. The PPAS does seem interesting but I don't see many detailed comments on how they sound compared to other amps.

sounds to me like something isn't quite right with the amp, the dc offset should stay around 1mv even at full volume

 

[IEATTEFLON]

I didn't build the pints. I think every position on the amp was filled by tangents guidelines except that the mini3 values were used. Current consumption was 13-15ma. DC offset was also very low.

I returned the amps already. I cant put my finger on it but it sounded too unnatural for me. I'm sure im probably in the minority but it does seem as if a veil was put over the music somehow especially bass extension. A cmoy that I have sounded more impactful instead of the syrupy characteristics I noticed. All in all the amp was probably not built correctly. Strange was that both sets exhibited this trait.

 

[FallenAngel]

nysulli: Uhm... never had a PINT, (nor almost any other amp) have only 1mV of DC offset, usually ~ 2mV for very stable chips, and around 8mV for the PINT.

IEATTEFLON: Wow, 15mA for a PINT? That doesn't sound right. Mine is like 30mA for a AD8397/LM6172 and closer to 55mA on the dual AD8397.

 

[Filburt]

Quote:

Originally Posted by Andrea Oh yep, artificially clearer, maybe. And seemingly less linear. And how about that greenish tonality... (disclaimer: my findings are related not to the PINT but to the, admittedly quite similar, Go-Vibe v5; and to the LM6171 Pengamp)

Those aren't identical, though. Doesn't the Go-Vibe use a single-channel configuration on the "ground" channel? Pengamp is a different beast as well. I don't know what you mean by artificially clearer, and I don't find the AD8397 particularly linear in tonality.


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Not high end extension. If it resembles the Go-Vibe v5 as I definitely expect, it's lacking in transient & treble sharpness/sparkle, which the LM6172 can only accentuate (as opposed to the AD45048 or 8397).

Hmm, perhaps to some degree, although I find the 6172 gets some of this more right than the 8397 as well. I find the 8397 sounds more artificial overall.

 

[dhp]

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Originally Posted by nysulli sounds to me like something isn't quite right with the amp, the dc offset should stay around 1mv even at full volume

Anything <10mV of offset is normal

and <20mV is ok

 

[dhp]

Quote:

Originally Posted by FallenAngel nysulli: Uhm... never had a PINT, (nor almost any other amp) have only 1mV of DC offset, usually ~ 2mV for very stable chips, and around 8mV for the PINT. IEATTEFLON: Wow, 15mA for a PINT? That doesn't sound right. Mine is like 30mA for a AD8397/LM6172 and closer to 55mA on the dual AD8397.

8620s have very little quiescent draw. On the other hand, the PINT was designed to be used with bipolar, cranky opamps because the PINT is capable of taming these very nice sounding unstable beasts. And its split power supply is very nice too

 

[Andrea]

Quote:

Originally Posted by Filburt Hmm, perhaps to some degree, although I find the 6172 gets some of this more right than the 8397 as well. I find the 8397 sounds more artificial overall.

There's a funny thing I've learnt about the AD8397 -- its sound quality can range form barely decent to delicious.

My first encounter with the chip was when I bought a AD8397 Go-Vibe v4. That amp was claimed to be designed just for the AD8397 to fit - the v4 was all about that. As I bought it in the AD8397 configuration, there were no sockets for rolling.

In that amp the AD8397 sounded just as you describe it -- not linear in balance, dry and artificial in the mids, relatively bloated in the bass, rather cold in tonality... only the treble, though a little boosted, was pretty good.

In my Xenos modded with the AD8397, it's an entirely different beast -- very liquid, more transparent, with controlled bass (not overly so, but that is), and evenly balanced treble. It continued to lack that last bit of fullness with male vocals, which I reckon is a inherent characteristic of it.


So I think we're possibly talking of two different things, albeit with a shared name

So, back to our PINT & relatives - as I said, in the Go-Vibe v5, for my ears it (actually the AD45048) sounds usefully more natural, and more colorful, than the LM6172 for which the amp was designed ...and whose sound obviously I didn't dig in the first place.

The Go-Vibe v5 has essentially the same schematic as a PINT, but with a TL2426 doing the voltage divider part of the job. The rest is basicly the same, save part values only (and layout, obviously).


Oh, that's not to say that I'm all for the AD8397. Not really.

I definitely feel like I'm going to praise my latest AD8066 + 2x LMH6654 combination (in my Guinea Pig, my (1st) Xenos 0HA-REP) more.

 

[Andrea]

Although, I don't know... listening to Leonard Cohen, Ten New Songs, I had the feeling that the AD8066 could be a little flat sounding... Very detailed, very extended, yet smooth, yes. But tonally it doesn't seem the most alive I've heard... Perhaps it's just a momentary "fault" of my hearing?

I'm a little stressed, I need to rest a little & try listening again tomorrow.

 

[Filburt]

I agree that the AD8397 can vary in its output depending on how it's applied. I find, for example, that using something other than an AD8397 on the "ground" on the PINT with the AD8397 seems to give a more balanced sound for it. I'm not sure why this is yet, though.

Currently I'm using an AD8058 w/ AD8397 on G on one of my PINTs. It's probably the most detailed portable I've built yet. I'm thinking I may change the ground channel out for something else, though. Not sure yet. As mentioned earlier, using something other than the AD8397 on ground with the AD8397 IMHO improved sound, but perhaps it's just that two 8397s don't get along. As ground-channel op-amp, the AD8397 is a pretty decent choice though since the output impedance is so low, it's relatively fast, and it has huge output current. Although, it doesn't seem to take well to capacitive loads unfortunately. Oh well.

 

[Pars]

Quote:

Originally Posted by nysulli sounds to me like something isn't quite right with the amp, the dc offset should stay around 1mv even at full volume

Actually, with a mini3-fied PINT, because of the lack of input caps and the bipolar opamp(s), the amp will see a variable resistance from the pot on its input. The offset will therefore climb as the volume is increased (because the input bias currents change with pot level). <20mV at full volume isn't too bad.

 

[Andrea]

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Originally Posted by Filburt Currently I'm using an AD8058 w/ AD8397 on G on one of my PINTs. It's probably the most detailed portable I've built yet.

How does the AD8058 fare in terms of midrange body (fullness), overall dynamics, and power on the lower impedances? Would you classify it as warm in tonality? I'm almost decided to use the LMH6654 in my (awaited) next 0HA-REP, unless you can convince me...


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I'm thinking I may change the ground channel out for something else, though. Not sure yet. As mentioned earlier, using something other than the AD8397 on ground with the AD8397 IMHO improved sound, but perhaps it's just that two 8397s don't get along. As ground-channel op-amp, the AD8397 is a pretty decent choice though since the output impedance is so low, it's relatively fast, and it has huge output current. Although, it doesn't seem to take well to capacitive loads unfortunately. Oh well.

Why not give the THS4052 a try... (if you don't mind the 9V minimum voltage)


Btw, how do you feel about the AD8065/66 ? I remember someone stating that it's not a "rich" sounding op-amp. Yesterday I seemed to hear the same. This evening I'll have a second round of listening...

edit- This morning, in fact. I still feel like yesterday -- the AD8066 + LMH6654 sounds more "powerful", thankfully fuller, and perhaps more detailed than the AD8397; but the latter was more musical-colorful-alive (in the Xenos). I think it's the AD8066's fault.

 

[Filburt]

Quote:

Originally Posted by Andrea How does the AD8058 fare in terms of midrange body (fullness), overall dynamics, and power on the lower impedances? Would you classify it as warm in tonality? I'm almost decided to use the LMH6654 in my (awaited) next 0HA-REP, unless you can convince me...

It's hard to say since we seem to be getting rather vastly differing results with chips. I find it's a rather full sounding chip though probably not as warm as the 6172. However, it has more soundstage and a lot more instrument separation. I'd say it's pretty dynamic overall. At least for me, the 6172 is rather dynamic, and I didn't feel as though I was really losing anything on the 8058 in that regard. The 8057 is the single-channel version by the way.



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Why not give the THS4052 a try... (if you don't mind the 9V minimum voltage)

Ib on the 4052 may be too high to use on a PINT. AD8058 has some unusual characteristics that I think may contribute to its nice performance.


Quote:

Btw, how do you feel about the AD8065/66 ? I remember someone stating that it's not a "rich" sounding op-amp. Yesterday I seemed to hear the same. This evening I'll have a second round of listening... edit- This morning, in fact. I still feel like yesterday -- the AD8066 + LMH6654 sounds more "powerful", thankfully fuller, and perhaps more detailed than the AD8397; but the latter was more musical-colorful-alive (in the Xenos). I think it's the AD8066's fault.

AD8065/66 is OK I guess. The soundstage is kind of compressed compared to the AD825, though it is livelier. I didn't find it very detailed, and maybe less detailed than the 8610 which I don't exactly consider a highly detailed chip. I felt as though the 8065 lost something in the signal when listening to it. It wasn't unpleasant sounding (it was actually pretty decent), but I probably won't be using it in the future.

 

[Andrea]

Thanks for answering. Although it gets even clearer that our respective sonic perceptions are very, very far apart

The THS4051 works perfectly in the ground channel of my Go-Vibe v5. DC offset = 3-4 mV per channel. "Sounds" better than OPA551 & LM6171 in there (for me).