[Andrea]

Quote:

Originally Posted by tigger A somewhat misleading conclusion. The LM6172 in a simple two channel design bares little resemblance to a properly implemented 3 channel version such as a V5 with LM6171 driving the output ground.

IMO the chips are what creates the basic sound signature (which the 3 channels help worsen, especially for the LM6171/2).

Funnily, the only instance I remember where I liked the LM6172 was when I put it in a Practical Devices XM3 (2 channels with TLE), and that was with a too high DC offset (but the op-amp was running perfectly stable) !

 

[tigger]

Quote:

Originally Posted by Andrea IMO the chips are what creates the basic sound signature (which the 3 channels help worsen, especially for the LM6171/2). Funnily, the only instance I remember where I liked the LM6172 was when I put it in a Practical Devices XM3 (2 channels with TLE), and that was with a too high DC offset (but the op-amp was running perfectly stable) !

As you point out here Andrea, you liked the LM6172 in a two channel amp. Isn't this a contradiction of your statement that the chip "creates the basic sound signature"?

Anyway, my point in the above reply to Kugino's post was that he apears to be comparing a 2 channel LM6172 based amp to a 3 channel PINT amp and implying all LM6172 based amps will carry the same sonic signature.
Your statement above actually re-inforces my point.

In my opinion, if Kugino had the chance to hear a V5, he would find it closer to a PINT than the other LM6172 based amp mentioned.

 

[Andrea]

Quote:

Originally Posted by tigger In my opinion, if Kugino had the chance to hear a V5, he would find it closer to a PINT than the other LM6172 based amp mentioned.

Yup, this looks reasonable.


I only compared the LM6172 to the OPA2134 in the XM3. In some ways the LM sounded better -- visceral bass, softer treble -- but for accurate tonality, and atmosphere, I thought I preferred the OPA. The DC offset was too high so it didn't stay long enough to draw conclusions.

 

[MisterX]

Quote:

In my opinion, if Kugino had the chance to hear a V5, he would find it closer to a PINT than the other LM6172 based amp mentioned.

The amp he is reffering to does in fact have an active ground channel but there is no overshoot in the square wave responce from the left and right channels so draw your own conclusions to how it compares with the V5.

 

[mrarroyo]

Quote:

Originally Posted by MisterX The amp he is reffering to does in fact have an active ground channel but there is no overshoot in the square wave responce from the left and right channels so draw your own conclusions to how it compares with the V5.

Would you please explain the comment? I have no idea what it means!

 

[kugino]

Quote:

Originally Posted by tigger As you point out here Andrea, you liked the LM6172 in a two channel amp. Isn't this a contradiction of your statement that the chip "creates the basic sound signature"? Anyway, my point in the above reply to Kugino's post was that he apears to be comparing a 2 channel LM6172 based amp to a 3 channel PINT amp and implying all LM6172 based amps will carry the same sonic signature. Your statement above actually re-inforces my point. In my opinion, if Kugino had the chance to hear a V5, he would find it closer to a PINT than the other LM6172 based amp mentioned.

as misterx has already stated, the 6172 amp i am referring to has a 6171 in the ground, so is somewhat similar to the PINT's and GV5's 3-channel designs, though not in every respect. i have not heard a LM6172 PINT, but i think i may prefer the AD8397 simply because it's punchier and more engaging. i think tangent was right to base the PINT around the AD8397 simply for its beautiful sonics.

 

[DDF]

I seem to remember Andrea hating the 8397?

Anyway, I've been designing op amp based preamps for over 15 years and the implementation makes a huge difference. You just can't generalize from one design to the other, or one layout to another. Reading Bob Pease's or Walt Jung's op amp design articles make you quickly realize that there are many subtleties to getting op amp gain stages right. How is thermal managed? Are the inputs compensated? What is the source impedance? Is it inverting? NI? Capacitive load compensated? etc etc

FWIW, I grabbed two AD797s when they came out around 10 years ago and they were horrible. The 5532s I have from 1983 blow them away. But I read here that some think they're the be all and end all. Horses for courses as always.

DDF

PS I may buy a Xenos Rep, try Andreas mod and report back, but I'm not sure at this stage if it'll drive the DT770-600s with its 12V supply. I could probably use the extra 6 dB of a 24 supply. When I wrote Xenos to inquire about their voltage o/p into 600 ohms, I never heard back.

BTW2, I built my first LM6172 preamp over 10 years ago and it sounded OK, but I eventually kept blowing them up. Stability margin on it is pretty darn low, and I couldn't guarantee stability with my point to point wiring.

 

[episiarch]

I may wind up regretting it, but I am going to add my two cents to the debate.
Quote:

Originally Posted by kugino i find the LM6172 uninteresting and uninvolving. it's warmer, if not muddier, and while i do like it with some vocal-rich music, it's not my favorite

This is a reasonably fair description of my reaction to the Porta Corda II, which IIRC is an LM6171 amp. Because of that I was hesitant about ordering a Go-Vibe 5, but went ahead because the early reviews were so positive.

Well, I'm glad I did. The GV5 sounds nothing like the PCII (or kugino's description). Its sound is sharp (to write it "sharp!" with an exclamation point would be more descriptive) clear and clean. It is far from muddy, has no warmth that I can discern, and its main vocal characteristic - besides clarity - is that the non-vocal highs and lows are so nicely defined that they take over a bit of the vocals' accustomed degree of focus and attention.

In other words, having heard the LM6171 in a two-channel amp with a reaction not much different from kugino's, the GV5 is about the last thing I expected from this chip series. Its sound is very different from what my earlier experience with that heritage would suggest.

 

[kugino]

Quote:

Originally Posted by episiarch I may wind up regretting it, but I am going to add my two cents to the debate. This is a reasonably fair description of my reaction to the Porta Corda II, which IIRC is an LM6171 amp. Because of that I was hesitant about ordering a Go-Vibe 5, but went ahead because the early reviews were so positive. Well, I'm glad I did. The GV5 sounds nothing like the PCII (or kugino's description). Its sound is sharp (to write it "sharp!" with an exclamation point would be more descriptive) clear and clean. It is far from muddy, has no warmth that I can discern, and its main vocal characteristic - besides clarity - is that the non-vocal highs and lows are so nicely defined that they take over a bit of the vocals' accustomed degree of focus and attention. In other words, having heard the LM6171 in a two-channel amp with a reaction not much different from kugino's, the GV5 is about the last thing I expected from this chip series. Its sound is very different from what my earlier experience with that heritage would suggest.

then i might have to try the GV5!

 

[Andrea]

With the premise that as the new, bigger Panasonic FM cap (installed a couple of days ago, together with 2 new tantalums) burns in, I'm appreciating the sound the amp produces (with the new chips, once again) more and more,

Quote:

Originally Posted by episiarch Its sound is sharp (to write it "sharp!" with an exclamation point would be more descriptive) clear and clean.

I hope you didn't mistake me. By saying that transients were too softened, I never said it sounds muddy (really)

Quote:

has no warmth that I can discern,

Certainly, in fact it has the opposite


Quote:

and its main vocal characteristic - besides clarity - is that the non-vocal highs and lows are so nicely defined that they take over a bit of the vocals' accustomed degree of focus and attention.

Let's say that vocals are (were) too nicely defined to sound real. They sound(ed) a bit synthetic, dry, lacking that "material presence" to me. That aside, a certain excess of midbass (not muddy at all, though) choked them a bit.

 

[afobisme]

how much of a difference does having the 9.6V battery vs. the 9V battery make? trying to decide if i should get the 9.6V+charger. if the improvement is marginal, then ti might be too hefty a fee for me.

if i buy 2 9V batteries+charger from all-battery.com, it'll be about $21 shipped.

if i get 1 9.6V battery+charger from maha, it would cost me roughly about $45

then again, i only see a "9V" charger on the maha website, so does that mean i don't need a specific 9.6v charger?

 

[tigger]

Quote:

Originally Posted by afobisme how much of a difference does having the 9.6V battery vs. the 9V battery make? trying to decide if i should get the 9.6V+charger. if the improvement is marginal, then ti might be too hefty a fee for me. if i buy 2 9V batteries+charger from all-battery.com, it'll be about $21 shipped. if i get 1 9.6V battery+charger from maha, it would cost me roughly about $45 then again, i only see a "9V" charger on the maha website, so does that mean i don't need a specific 9.6v charger?

I just revised the battery advice on the Go-Vibe website. I realize now that a $40 battery charger combo doesn't make a whole lot of sense on a $75 amp. Yes there is a marginal improvement with a 9.6V NiMH battery, but not nearly as much improvement as spending a similar amount on an Elpac power supply.

 

[afobisme]

thanks boss.

time to go shopping

 

[facelvega]

just a bump to this mammoth thread to give due credit to Norm's customer service. I had a problem with a faulty volume pot/switch; Norm took care of this within hours, and has taken the time to answer several emails I've sent him about power supply and gain issues. Buy with confidence, people.

 

[*645-k701]

Well i placed my order today.
can barely contain my jizzself..

My k701's have had close to 400 hours.
so they are good 'n'ready..

I'll get back to this post a few days after my GV5 arrives ..

Itching myself silly...YeehaW!!