[Romanee]

Quote:

Originally Posted by Andrea /img/forum/go_quote.gif Not to sound pedantic (just for the sake of correct information) -- be aware that the LT1210 in this 3-channel amp doesn't deliver nearly any current at all (its max current output is likely in the uA range, not even mA). So the 1A output capability is completely irrelevant. What makes it better than the previous BUF634 virtual ground driver, must merely be the near-0-ohm output impedance, unlike that of the BUF634 operated open-loop (like here), which is a few ohms, as such much higher even than the Pimeta TLE2426's typical 0.0075 ohm output impedance.

I don't have the EE education or practical background to adequately answer your note, but I suspect you are making an error in your interpretation of how the LT1210 functions in this system, and in where/what you are measuring. A measurement of uA seems very unlikely to me.

Perhaps you can understand why I am dubious of your results if you read this article by Tangent discussing various virtual ground approaches and solutions, including "I've used Burr-Brown's BUF634 here. It can handle up to 150 mA in the DIP-8 package, and in the larger metal-based packages it can source up to 250 mA..." and "If you need even more than 250mA, the LT1206's big brother, the LT1210, works in a very similar circuit.":

Tangent's Virtual Ground article

If any of our EE-savvy members are reading this, perhaps they can chime in with a little clarifying discussion.

 

[LDMES]

Quote:

Originally Posted by mrarroyo /img/forum/go_quote.gif iMod is in my list. I am waiting for the 120 Gb 1.8" Hard Drive promised by Seagate to do both at the same time.

I am waiting on that drive too.

I asked Vinnie about the 120GB HD and he replied the following:

Quote:

If the 120GB hard drive does work, you can send me back your modded iPod and hard drive and I'll install it at no charge...except shipping.

If you find out about it before I do I'd appreciate it if you'd let me know. Thanks.

 

[Romanee]

I'd also like any new info on the 120gb drive & iMod. Post it here, please! (...as well as in Portables forum...)

 

[Andrea]

Quote:

Originally Posted by Romanee /img/forum/go_quote.gif I don't have the EE education or practical background to adequately answer your note, but I suspect you are making an error in your interpretation of how the LT1210 functions in this system, and in where/what you are measuring. A measurement of uA seems very unlikely to me. Perhaps you can understand why I am dubious of your results if you read this article by Tangent discussing various virtual ground approaches and solutions, including "I've used Burr-Brown's BUF634 here. It can handle up to 150 mA in the DIP-8 package, and in the larger metal-based packages it can source up to 250 mA..." and "If you need even more than 250mA, the LT1206's big brother, the LT1210, works in a very similar circuit.": Tangent's Virtual Ground article If any of our EE-savvy members are reading this, perhaps they can chime in with a little clarifying discussion.

Hmm, were I too delicate, too little assertive, or else what?

Tangent is correct 'course, just that what you quoted DOESN'T apply to our case. There he was speaking of 2-channel amps, where the virtual ground driver is called to sink the ground currents from the 'phones.

In the Portaphile, the LT1210 doesn't source nor sink anything but the reference currents for the feedback loops -- which I've not bothered to calculate but it's reasonable to expect to be in the uA range.


Short version: either trust me already, or wait for Cesar to chime in to deny, which will ultimately result in the same thing.

 

[mrarroyo]

I will gladly post the information when and if it becomes available.

 

[Janus]

Thanks for cool read ASR! I guess now that ceasers making them again, Id better stock up on a backup, in case airport security gets smart, or I finish off the plastic internal switches...

Quote:

Originally Posted by Andrea Short version: either trust me already, or wait for Cesar to chime in to deny, which will ultimately result in the same thing.

Trust is earned, not blackmailed through threats of a flame war.

Quote:

Originally Posted by Andrea I should imagine

The wisest thing that came out of your mouth tonight.

Notice this review is by asr, who is human, and subjective, not unlike yourself. If he enjoys it, and you don't- that doesn't mean either of you are right. To try to use obscure electrical concepts and terms doesn't grant your opinions any more weight than his or anyones.

 

[Andrea]

a) I never really encouraged a "flame war", particularly in this thread...

b) only stated an opinion, a much more temperate opinion than what you black/white guys seem to have understood (prejudice is a nasty beast...)

c) if trust is earned, competence is respected. There's absolutely nothing obscure in my (neutral, anyway) technical insight (which, again, was in no way related to my previous opinion about the sound quality), you may ask Cesar if you don't trust me.

A bit paranoiac, perhaps? Not to worry - it's just an illness of our obscure times.

 

[Andrea]

The affair hidden behind these contradictions, IMO, is not merely trust in this or that person. It's if you're interested in coming to understand things more deeply and veritably, or if you want to remain hooked to your little myths at all costs and go on dreaming. IMO, anyway.

 

[Romanee]

Let's get the thread back on track. I'd like to present an important point regarding this amp and the use of the TL1210 in particular -- as well as a few other personal opinions.

Asr had requested to hear "any Portaphile model", simply to hear how the 8610 opamps sound. I could have sent him a base X3 and he would have been satisfied.

However, I was very interested to hear his impressions of the current amp at its very best, which had to be the Maxxed version with all updates, INCLUDING the TL1210 as virtual ground. I can't emphasize that strongly enough, that if anyone wishes to order the PV2^2 Maxxed, it is essential to request that the TL1210 be included -- in order to hear the beautiful and unique sound it is capable of, after (like the M-Hornet) 350+ hours of break in ("burn in") to reach its optimal sound.

If I had sent him even one upgrade step earlier, with BUF634 as virtual ground, he would only have heard incremental improvements over the original PV2^2.

Cesar's discovery and implementation of the TL1210 as virtual ground in the power supply turned out to be a brilliant application and a very significant improvement. "Out of the box" this final version of the amp literally startled me with the level of improvement (which I expressed to Cesar in no uncertain terms). Based on experience with "burning in" many portable amps, and Portaphile amps in particular, I was literally apprehensive that the HF sparkle, extension, definition and imaging would be subdued and overwhelmed by huge bass when the caps fully burned in -- which did not happen.

I've also experience weird "burn in curves" with various amps, and so I was prepared to tough it out and not be more than a little anxious if the sound quality took odd turns along the way -- which it did.

I've urged a few amp manufacturers to listen to it "just for fun" and with no strings attached -- and they were startled at how good this unassuming and unheralded little amp sounded.

The only small area of reservation or question I have -- hinted at by Asr -- is the frequency range in the mids that involves throat and chest resonances of voices. It's my impression that other portable amps present voices with more warmth and fullness of throat and chest resonance. That aside, I love this amp. I brushed aside my fear of withdrawal symptoms, knowing it's in good hands.

Either the PV2^2 Maxxed-LT1210 has a small dip in this part of the mids, or other warmer amps impart a euphonic warmth to voices. The M-Hornet presents voices with a marvelous warm full character that is wonderful and satisfying to hear. I really would love to have a portable that can combines the best of this Portaphile with the best of the M-Hornet, if that's possible. So far such an amp doesn't exist.

In every other regard, I find this amp to be remarkable and very seductive, so that even though the M-Hornet, as a very good example, is IMO easier to listen to for long periods, and possessed of greater bass punch and overall warmth -- this Portaphile has incredible bass definition/articulation, great HF sparkle and nuance, sometimes startling front-to-back layering of instruments/voices, and great clarity that enables the listener to hear deeper into the sound space with spatial volume around performers with solid placement in space. This is a very transmissive amp that will let you hear much more of the recorded information than portable I know to date. I don't like to use the word "transparent", because every amp I've heard does impart something to the sound, and I don't expect that there will be a truly transparent audio tool for at least a few technological generations.

In terms of timbral complexities, it adds to percussive instruments more of the actual note and complex waveform of each stroke and a greater impression of the material makeup and character of that individual instrument.

Of course if you find this much "detail" overwhelming, then you'll need to choose an amp with a less complex character.

Granted, it doesn't quite create the gorgeous spatial clarity, lush sound or timbral nuance of the best home amps (even the "modest" RKV-MkII with OPA627 upgrade excels in all regards) -- but for a modest little portable I couldn't ask for much more, other than the midrange warmth and bass punch of the M-Hornet, the super micro-dynamics of the SR-71, the great soundstage width, big sound and smooth/well-integrated frequency spectrum of the Headroom Micro+desktop module -- and I'm sure there are a few other specialties that other portables excel at, but I haven't yet heard them all.

All in all -- I believe this truly maxxed-out Portaphile is absolutely a must to hear.

 

[Andrea]

And I'd really love to hear it.

Btw, and to wind up the previous reasoning, I can easily understand how the LT1210 is 'essential'. It's just that...it's not simply that this tweak is very effective, but rather that the previous BUF634 virtual ground driver was suboptimal (even a TLE2426 is much better). IMO but not so much

 

[Andrea]

Quote:

Originally Posted by Romanee /img/forum/go_quote.gif Either the PV2^2 Maxxed-LT1210 has a small dip in this part of the mids, or other warmer amps impart a euphonic warmth to voices. The M-Hornet presents voices with a marvelous warm full character that is wonderful and satisfying to hear. I really would love to have a portable that can combines the best of this Portaphile with the best of the M-Hornet, if that's possible. So far such an amp doesn't exist.

I perfectly share your feelings about the Portaphile midrange, as well as those about the AD8397 midrange (when well implemented).

Just a slight but due correction... Say, for instance... you haven't heard my customised Xenos 0HA-REP (though the AD823 + LMH6654 customisation can be requested to Alberto directly, cost is $122) which notwithstanding the achievements I'm nonetheless planning on improving even further with new chips; I think you haven't heard any Xenos amp for that matter, especially the fresh new 1HA (which in truth you couldn't have).

And, Romanee, what was that Let's get the thread back on track. opening line intended to mean? I ask because, in my eyes, it did just ever-so-slightly taste of hypocritical...

 

[Snacks]

Quote:

Originally Posted by Romanee /img/forum/go_quote.gif I really would love to have a portable that can combines the best of this Portaphile with the best of the M-Hornet, if that's possible. So far such an amp doesn't exist.

Romanee - Have you heard any of XIN's SuperMacro's with rolled opamps?

If you'd like, I could arrange having the one that I have in my possesion sent in to Xin for IV upgrade's and mailed to you for observation. Of course you could pick, whichever opamp I have or one of your choosing to have installed...

Quote:

Originally Posted by Romanee /img/forum/go_quote.gif Granted, it doesn't quite create the gorgeous spatial clarity, lush sound or timbral nuance of the best home amps (even the "modest" RKV-MkII with OPA627 upgrade excels in all regards) -- but for a modest little portable I couldn't ask for much more, other than the midrange warmth and bass punch of the M-Hornet, the super micro-dynamics of the SR-71, the great soundstage width, big sound and smooth/well-integrated frequency spectrum of the Headroom Micro+desktop module -- and I'm sure there are a few other specialties that other portables excel at, but I haven't yet heard them all. All in all -- I believe this truly maxxed-out Portaphile is absolutely a must to hear.

Ditto. Fine piece of equipment; Cesar does great work!

 

[Romanee]

Quote:

Originally Posted by Snacks /img/forum/go_quote.gif Romanee - Have you heard any of XIN's SuperMacro's with rolled opamps? If you'd like, I could arrange having the one that I have in my possesion sent in to Xin for IV upgrade's and mailed to you for observation. Of course you could pick, whichever opamp I have or one of your choosing to have installed... Ditto. Fine piece of equipment; Cesar does great work!

Wow! I have not been able to hear a current Xin amp, and every earlier amp I heard had technical problems. That's a wonderful offer.

For some reason the Xin amps are not popular in metro NYC, Xin has always been too busy to send review samples, and I don't have the resources to buy amps for review.

I'm not sure what would be the "ideal" op-amp in the SM IV. I expect the 627 may be lush and warm, but does it provide excellent layered imaging, separation, air, clarity and definition in addition to liquidity? Perhaps Filburt -- the Xin Maven par Excellence -- has some pertinent recommendations? I wonder if the modified AD744 that Larry & Phil have settled on for their "final" PRII is applicable to the SM IV?

Sorry I haven't kept up with most current Xin threads here.

BTW - do you have the PV2^2 Maxxed with 1500uf BlackGate NX's + LT1210?

 

[Asr]

Quote:

Originally Posted by Romanee /img/forum/go_quote.gif In terms of timbral complexities, it adds to percussive instruments more of the actual note and complex waveform of each stroke and a greater impression of the material makeup and character of that individual instrument.

That reminds me of a point I've been trying to discern during my listening. What headphones are you using to gauge the amp's timbral complexity? I've been using the K701 predominantly but I just don't detect much timbral complexity with it - as far as I can tell it's quite a limiting factor in that aspect. I'm wondering if you're using the DT880 or maybe another headphone, as I don't find the K701 to be very good at micro-detail with aspects such as extremely nuanced timbre (and I'm a musician so I'm used to hearing it live).

 

[Andrea]

Interesting post, Asr.


Romanee, btw, I'm finally awaiting the Faith AMP - I won one on ebay. I'll make sure to let you know my sentiments about it!