GoodSoundClub - Romy the Cat's Audio Site - 6C19P, tube paranoia and grounding

12-10-2006

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Paul S
San Diego, California, USA
Posts 2,672
Joined on 10-12-2006

Post #:	21
Post ID:	3288
Reply to:	3282

Sticking with a winning strategy

Your points about "better" versus "correct" and "tactics" versus "strategy" are well taken. You are pretty good at saying things I have thought about for some time but never articulated, perhaps because there was no one to tell. I have no wish to "improve" on the ML2's native capabilities (strategy) at this point, if only because I am not sure yet exactly what sorts of parts and what sort of a whole I'm dealing with. So far I am having a blast, and I am NOT in a hurry. I am mainly pleased so far that the old tubes I have replaced have allowed the amps to do what they do best even "better", and I do mean "strategically" as well as hi-fi sense. I use one tube over another not to alter my/amp's strategy but to voice the system, ie, it is a hi-fi tactic. My drivers are not as "hard" as yours, of course, and the ribbies give just the right edges when it's called for, and they also kick things down a couple of Hertz, getting pitch/tone/timbre pretty close to perfect in this system. Some of the beloved-by-audiophile Amperex are very "revealing" and "air-y" at the expense of a certain "weight", and this is not something I wanted here and now. I "like" the nice Amperex, too, but not here, now.

Well, if you couldn't find "good ones", then I suppose I will try the Ukranian on e-Bay for 6N6P, unless you have a better idea.

Any ideas for sources for 6AK5 and 5651A? Seems like most of the ML2 tubes are "hard to find" from local sources.

I am also going to finally break down and try some Herbies, at least on the ribbies, even though the ribbies are among the "calmest" 12AX7s. Again, tactics, not strategy. Strategy-wise I aim to continue to play to the ML2's strengths.

Best regards,
Paul S

12-10-2006

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Romy the Cat

Boston, MA
Posts 10,184
Joined on 05-28-2004

Post #:	22
Post ID:	3289
Reply to:	3288

Other tubes for Lamm ML2

Paul S wrote:
Any ideas for sources for 6AK5 and 5651A? Seems like most of the ML2 tubes are "hard to find" from local sources.

I do not know why you say it. Both 6AK5 and 5651 are very common and very inexpensive tubes. The 6AK5 are penthode and dozens and manufactures made them. I had few or them, perhaps a half dozen of different brands, and I did not detect any huge differences in their sound. As I understand Lamm uses it as aerial amplifier in his B+ regulator to drive with 6AK5’s plate the grid of the 6C33C regulator. It is HF penthode and it is fast, nothing more requires from this tube, so it is no surprise that it did not affect sound tangibly. I ended up to catch a party of Western Electric 6AK5. Honestly they did not sound better or worth then anything else and I used them juts because the sexy yellow Western Electric letter across the tube. I think I paid for them a few bucks per tube…

5651 is also is very common tubes. It is actual not a tube but a low current gas regulator on 80-90V. You can use in there absolutely any type of gas voltage reference diode that could regulate near 85V and can handle under 3.5mA. There are many substitutions for 5651 and many different manufacturers made them. I also did not detect any big difference in Sound in those tubes.

Do not confuse the Gas tubes that Lamm used in his regulator and the gas tubes that Melquiades uses. If you read the thread from my bookmarks:

http://www.goodsoundclub.com/TreeItem.aspx?PageIndex=2&postID=2792#2792

They you might be under impression that gas tubes do affect sound, however Milq and ML2 use them differently. In ML2 the gas tubes are juts the voltage reference for stabilizer but in Milq the gas tubes supply bias, driving the grid of driver stage. Evan it took place via a large resistor but still it is way more mending duty. If I had ML2 I would change one resistor and would try a 35mA gas regulator instead of 3.5mA. In Milq the 35mA-type were better but it not necessary would means that they might be better in ML2. Those gas tubes are also a couple to few dollars per tube and they are good for years. The good part about the 3.5mA-type gas tube that there are practically not fake tubes among them…

The cat

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche

12-30-2006

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Paul S
San Diego, California, USA
Posts 2,672
Joined on 10-12-2006

Post #:	23
Post ID:	3407
Reply to:	3289

6AK5: bass, feedback, organization

I did find replacement tubes OK (online), just not locally, like I had hoped. I have now recieved, installed and tested all new tubes but the 6N6Ps, which have been delayed in St. Petersberg by Christmas mail jamb-up. I think I already talked about sonic differences wrought by the other tubes not mentioned here.

So: I have replaced with NOS each tube type one at a time to hear what, if any, difference each type makes. New 5651s "leveled" the sound somewhat (Less "jumpy"), helped the sense of "timing", and they also helped somewhat with bass. New 6AK5s made quite a dramatic difference. Bass is now getting serious; not "fast" or "tight" in the tipped-up sense referred to by single-driver nuts, but real fundamentals with drive and articulation. I have never had bass like this in my own system before, ever.

Another thing I noticed with new 6AK5s was much greater clarity, on one level, and much better "organization" on another level. Music became "fearless", meaning no matter how crowded, condensed or loud it gets, it keeps the same quality, with no sense of strain or confusion. This gives the impression that there's always plenty more where that came from, and it helps me to listen better. It is especially great for close vocals that always overloaded my systems in the past. Now lyrical expression (when it's there) is available through the entire piece rather than tapering off as the sound overloads or confuses the system. I am more excited than ever to get my turntable going again so I can hear cleanly clear through the wonderful tenor/baratone duet from La Boheme (Jussi Bjoerling and Robert Merrill) that always did such a number on my system. In fact, I'll be looking for another copy of the original mono EMI, which is brittle/scratchy, but with killer dynamics.

It is strange having this much clarity and HF extension with no real sense of "HF". Previous SETs have always had that slight "glitter" or "shimmer", which some people just love, although it's not something I notice in live music. It never bothered me, but I don't miss it, either, and it's absence certainly allows more room for music. In fact, one might simply say that new (properly functioning) 6AK5s make for less noise.

Also since new 6AK5s, the sound has pretty much lost all relationship to the speakers. This is very cool. When sounds suddenly errupt now they appear totally without warning, and they can seem to come from almost anywhere but from the speakers. This makes music so much more spontaneous, when appropriate, and more natural overall.

Romy, do you know the value of the input resistor on ML2? Is ML2 input impedance really only 41k Ohms? All my other amps have been from 100k to 200k input impedance.

My AI M3A pre-amp is obviously too strong for the ML2, with 30 dB line gain, and it also has 1.4k Ohm output. I think I would rather just get another pre-amp than try to throttle the natural gain with resistors, and it would be absurd to try to lower its output impedance. I have looked at the Herron VTSP-2 and thought this might work better with ML2: 100 Ohms only out, 15 dB only gain, and still suitable input and switching for phono stage.

Best regards,
Paul S

12-31-2006

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Romy the Cat

Boston, MA
Posts 10,184
Joined on 05-28-2004

Post #:	24
Post ID:	3409
Reply to:	3407

Lamms ML2 input impedances

Paul I slightly surprised about your comments. The regulating aerial amplifier tube affected sound very mildly, if ever, at least it was my experience. I had a few different 6AK5 but changing them was not a highly notable effect. I still have left a dozen of so of Philips Miniowat 5654SQ “Special Quietly” tubes, if you wish I might send them to you, as I have no use for them. BTW, be advise the all this tubes need to be burned in and they will change sound after then…

About the input impedance - I do not remember the values now. I have the calculation sheets for my crossover somewhere and I might look for it… if I did not trash it… It has a voltage divider with I think slightly under one 1K in series and the shunt resistor that makes it 41K… Anyhow, why are you planning to drive the ML2 input to higher impedance? Your preamp can’t handle R41K? I usually peruse opposite and try to drive input impedance as low as possible with objective to load cables with current. I love drive cables with current, even with active bias current. If it were up to me then I would run 1A of DC though all system interconnects…. In fact I will do it sometimes…

Anyhow, the 41k is perfectly kosher impedance. As I understand Lamm made it to use with his line level preamps. His preamps are weak in output and they have difficulties to drive anything under 35K. In fact I make quite few experiments loading L2 with different values, even put there a very high quality trimmer and eventually I came up in my completely blind listening assessment with the best values…. To my satisfaction it was exactly near 40K…. Of course when I used 4 ML2 I was forced to increase the impedance as I paralleled the inputs. I use 80K in one amp and 105K in another. Do not ask me why they were not identical as it is VERY complex subject. Theoretically the balance loading should not affect anything but it did…

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche

12-31-2006

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Paul S
San Diego, California, USA
Posts 2,672
Joined on 10-12-2006

Post #:	25
Post ID:	3410
Reply to:	3409

True values, true colors

I think the key to understanding this case is that it is beginning to look like the tubes that came with the amp all were over the hill, electrically. Since I have no way to test them other than by ear, that is what I have done. So far the only "special" tubes I have used are the input tubes, as I mentioned before. And of course that change was quite audible; not "strategically", but "tactically", and I am enjoying the results. Again, the original input tubes were shot, electrically, too, so the new ones were of course an improvement in that sense, too. The 6N6Ps I bought are nothing "special" as far as I know, but they are all tested and to spec, according to the seller, so I will also replace my current 6N6Ps when the new (NOS) batch arrives, and I will note any changes in sound then, too.

I would be pleased to accept your offer of the 6AK5 variant. I will send my info (if it isn't already there) and I hope you will at least allow me to reimburse you for shipping. Although the new (NOS) 6AK5s I used made profound differences (all significant improvements, by the way), I would not call these changes strategic differences, either, in the sense you apply the term, but I would say the new tubes simply allow the amp to better realize its design potential, electrically. I have been changing other things around, also, homing in on the heart of the ML2s, and I am just amazed by what I am hearing. I think I can tell already why you might try for NFB SET with your particular "dedicated", "narrow-band" set-up, but it is really hard for me to imagine that anyone could do better than the ML2s with any sort of conventional ~HE set-up. However, as great as the ML2s are turning out to be, I am very sceptical now about using them with speakers any less efficient than mine (96 dB), despite all the ecstatic hyperbole I've read from many audio reviewers who use them that way.

Despite your explanation, I can't understand how 1.4k Ohms out from my pre-amp could be optimum with 41k ohms input to the ML2s; that doesn't make sense to me. And now that you mention the shunt, etc., it sounds like it would be wise to leave the ML2 input resistors as-is.

Best regards,
Paul S

12-31-2006

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Paul S
San Diego, California, USA
Posts 2,672
Joined on 10-12-2006

Post #:	26
Post ID:	3412
Reply to:	3409

Burned-in 6AK5 finds the music (just the music)!

Well, I thought I'd heard some nice hi-fi at times in the past, but this is something else, altogether! As the new 6AK5s burn in the amps have become truly uncanny music makers. The "highs" are now such that it has become unimportant where I sit in relation to the speakers, and I have just listened to some of what I always thought were poor recordings of some performances I love rendered not only "listenable" but downright, bloody musical. Somehow, in sync with the "missing" HF, these amps seem to pay attention only to the music, and they are otherwise silent. I don't know how to put it any better than that. This is simply not like hi-fi as we have known it before now. Yes, it is much "better".

I will follow Romy's lead and stop short of a blanket recommendation, because any tool can be misused; but at the same time, I never really imagined reproduced music could come literally so close in every respect to live, without the accompanying noises, etc. that have up to now invariably tagged along as part of the price for a "ruthlessly revealing" system. In this case, just take out the "ruthless" part and add a significant chunk of new-type information to what you have heard to date in terms of "revealing". It's music, but not at all in the same sense as all the PRAT-oriented mid-fi stuff that always gets that citation from reviewers. I mean MUSIC!

If new 6N6Ps add anything substantial to what I'm getting now, I'll have to be tethered to keep my feet on the ground!

Happy New Year,
Paul S

12-31-2006

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Romy the Cat

Boston, MA
Posts 10,184
Joined on 05-28-2004

Post #:	27
Post ID:	3413
Reply to:	3412

It’s not necessary all on surface.

Paul S wrote:
Well, I thought I'd heard some nice hi-fi at times in the past, but this is something else, altogether! As the new 6AK5s burn in the amps have become truly uncanny music makers. The "highs" are now such that it has become unimportant where I sit in relation to the speakers, and I have just listened to some of what I always thought were poor recordings of some performances I love rendered not only "listenable" but downright, bloody musical. Somehow, in sync with the "missing" HF, these amps seem to pay attention only to the music, and they are otherwise silent. I don't know how to put it any better than that. This is simply not like hi-fi as we have known it before now. Yes, it is much "better".

I will follow Romy's lead and stop short of a blanket recommendation, because any tool can be misused; but at the same time, I never really imagined reproduced music could come literally so close in every respect to live, without the accompanying noises, etc. that have up to now invariably tagged along as part of the price for a "ruthlessly revealing" system. In this case, just take out the "ruthless" part and add a significant chunk of new-type information to what you have heard to date in terms of "revealing". It's music, but not at all in the same sense as all the PRAT-oriented mid-fi stuff that always gets that citation from reviewers. I mean MUSIC!

If new 6N6Ps add anything substantial to what I'm getting now, I'll have to be tethered to keep my feet on the ground!

Happy New Year,
Paul S

Paul, it is might not be what you think. This holiday week many companies are slowing down and I have heard from others that electricity have got better the last few days. My playback for instance during this week does very well but the previous two weeks it was unbearably cruel and harsh. So, it is very much possible that the positive results that you observe are not the 6AK5’s contribution but rather those your ML2 re-tubing coexisted with the period of good electricity. In any case - enjoy the ride….

Have a good Year….
Romy the Cat

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche

12-31-2006

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Romy the Cat

Boston, MA
Posts 10,184
Joined on 05-28-2004

Post #:	28
Post ID:	3414
Reply to:	3410

Vertical/diagonal change vs. horizontal change

Paul S wrote:
The 6N6Ps I bought are nothing "special" as far as I know, but they are all tested and to spec, according to the seller, so I will also replace my current 6N6Ps when the new (NOS) batch arrives, and I will note any changes in sound then, too.

I would not trust any seller who clamed that they tested them. What they tested: transcendence, cathode emission, at which current? Come on, no one test those tubes and partially as “expensive” as $2 worth tubes. There are two options. First: your 6N6P that you got in the ML2 was good to begin with. Considering that I know the person from whom you bought your ML2 I might assure you that the amp did not work in his home at all. Second possibility is that you juts did not “catch” the change. You see, when people re-tube amps they look for the changes in Sound that I characterize as vertical or diagonal change. It is true for ML2’s input stage but with the driver stage it works differently. Changing the driver tube in this amp affects something that I call “horizontal change”. The horizontal change has less to do with “sounds” and has more to do with accentuation of rhythm and dynamic emphasis in “fundamentals range” (presumably if a playback can hands it)… As the side-evidence of the worn of the 6N6P you might look for the dark amalgam in sides where the electing bombarded the glass. That would be a good indication how much tube worked. The dark sided are not necessary indication of the bad tubes, you need tube tester (and the skills to use it) to say anything more or less defiantly. Still, with 14 cents per tube that I paid I changed it each six month when a gray coloration of the side juts tube to brown. Ironically, even then I did hear the “horizontal change” in the sound when I employed the new 6N6P..

The caT

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche

12-31-2006

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Paul S
San Diego, California, USA
Posts 2,672
Joined on 10-12-2006

Post #:	29
Post ID:	3415
Reply to:	3414

Once a whore...

You are correct, I neither know nor expect, really, that the person from whom I bought the 6N6Ps tested them in a way that will make any difference to me, and I certainly did not buy them with any particular sense that this was the case. I am just hoping for at least some of the 10 I just bought to be useable. If a reasonable percentage of them work, I'll get more and stash them. I am not saying the 6N6Ps I'm using now need replacing, of course, because I have as yet no frame of reference, what to expect or aim for with that tube in this amp; but the amps are sounding mighty good just now. I'm really just in the process of getting to know the amps, after all. Basically, so far, so very damn good! If these benefits stick, these might even make me lazy!

As for the power grid (and/versus the "new tube benefits"), I hope the benefits stay and become a new mind-boggling norm, wherever they came from; but I am also entirely prepared to simply enjoy the performance for what, and when, it is. I have often said that I would go with strings running between soup cans if it "worked", and nothing has changed in this regard; no brand loyalty and no meaurable expectations. If I'm not exactly a whore, I'm at least very easy; just give me performance. Plus, I have had no success to date with power conditioners on amps (and basically mixed results with other components). I was recently looking at the type that isolates ground noises, like the Cinepro, etc., but I have not yet tried one of those. And right now I am running the crappiest possible power cords to the ML2s; the cord to my printer is bigger and better! I should go to the parts bin and whip some up; I think I need some braided copper sleeve...

Best regards,
Paul S

01-04-2007

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Paul S
San Diego, California, USA
Posts 2,672
Joined on 10-12-2006

Post #:	30
Post ID:	3435
Reply to:	3414

Truer words...

"I would not trust any seller who clamed that they tested them." -- R.B.

How annoying that your words were prophetic, Romy. The 6N6P tubes just arrived from St. Petersberg in a plastic mailing bag rather than a box, and one tube was totally smashed in the bag. The other tubes look NOS, all right, to the extent that there is still loose manufacturing crud all over all the tube pins. So the next question is, just how did he "test" them (since he says outright that he tests them all carefully) without some of the crud rubbing off when he put them in the tester socket?

I have not really looked at the 6N6Ps that came with the amps, but the tubes that just arrived do look pretty "cheap" in terms of quality of internals and pins, although the glass looks good (but thin). Of course, all the 6C33Cs I've seen also have those horrendous, rough steel pins, and they seem to do all right.

You have said that there are no "good" 6N6Ps; but are some physically constructed better than others?

Right now the only other seller of this tube on ebay is the Ukranian. i know of no other sources except BOI (if they are for real), and they want 17/tube!

I'll get back to tell about any changes to the sound these new tubes make, apropos.

Then I'll be adding decent, DIY power cords.

Best regrds,
Paul S

01-05-2007

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jessie.dazzle

Paris, France
Posts 456
Joined on 04-23-2006

Post #:	31
Post ID:	3436
Reply to:	3435

6N6P and Grounding

Paul,

I have an L2 that uses this tube (at an alarming rate!), so I try to keep a stock of them... While sniffing around, I came upon a deal on eBay that may interest you (since you are in the US)... Check out item number: 150077022964 (end time : Jan 09 @ 10:04 PST).

Regarding power cables : In my case, grounding made a difference. Since you are making your own cables, you may want to consider "lifting the ground" and taking advantage of the chassis grounding lug Lamm provides, connecting your ML2s (and ideally the rest of your equipment) directly to a dedicated ground (using one of those long copper-coated grounding rods just outside the house).

Thanks for sharing your experience with these amps.

jd*

How to short-circuit evolution: Enshrine mediocrity.

01-05-2007

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Romy the Cat

Boston, MA
Posts 10,184
Joined on 05-28-2004

Post #:	32
Post ID:	3437
Reply to:	3435

6C19P, tube paranoia and grounding

Paul S wrote:
You have said that there are no "good" 6N6Ps; but are some physically constructed better than others?

Nope it was not what I said. I said the all 6N6P are equal, at least among those that I have seen and there are no reasons to pursue different production versions. (Some Russian tube from 60 generally better then form 70-80) There is a deviation on tube tester there between the new different tubes but it is hardly auditable.

Paul, also, I my suggest that you a little bit too “violently” took the ML2 and your recent obsession with re-tubing of this amp is not good thing, at least it’s how I see it. You got a new amps and it looks like you like it. It is fine but what makes you to be fascinated to change tubes in it? Are any specific problems with sound while you use your current tubes that from you point of view makes the ML2 to sound bad? I do not think it is how you feel. So, if you have normally operating ML2 then spend a month of two juts living with it and getting accustom to it sound and then VERY SLOWLY buy some spare of the tubes. This approach will save you a lot of money, lot of nervousness and will prevent you from immature decisions.

jessie.dazzle wrote:
I have an L2 that uses this tube (at an alarming rate!), so I try to keep a stock of them..

Yep, as the person who was the very first who alarmed public about the L2’s 6C19P-sysndrome I very much concur with what you said. Lamm keep shameful silent about the issues, in fact I did not even know if he knew about it 5 years back and eventually the numerous companies made him to make an announcement that the tube should be changed once a year. Yep, right – one a year my tail!!! I remember at the best times I was clearly able to distinct the 6C19P that worked for a week (!!!) in Lamm L2 preamp. I really do not know if it is the problem with 6C19P of with the way how Vladimir uses it. Theoretically it should be very simple – juts a common regulator but I did not look further into L2. In my headphone amp the 6C19P sits at near 170V, 20ma with -33V at bias… It works fine with huge microphones (1 out of 10 is suitable) and it looks like it still work there “faster” then It would be expected. Still, I do not use that headphone amp too much to make more definitive conclusion…

jessie.dazzle wrote:

Regarding power cables : In my case, grounding made a difference. Since you are making your own cables, you may want to consider "lifting the ground" and taking advantage of the chassis grounding lug Lamm provides, connecting your ML2s (and ideally the rest of your equipment) directly to a dedicated ground (using one of those long copper-coated grounding rods just outside the house).

Jessie, it has nothing to do with Lamms. The use of grounding that come from the “wall” should be absolutely prohibited for means of high end audio. The entire audio installation MUST be listed form the wall’s ground. It is very basic and very essential requirement.

Rgs,
The Cat

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche

01-05-2007

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Paul S
San Diego, California, USA
Posts 2,672
Joined on 10-12-2006

Post #:	33
Post ID:	3440
Reply to:	3437

No, not about the tubes

Actually, Romy, it is simply that the tubes that came with the amp were not "good" in the sense that they were not doing their jobs. Period. You may remember the pulses through the speakers and how new input tubes cured the problem?  So, no surprise then that the new input tubes also improved the performance/sound. So far all the tube "rolling" has been about nothing more than a systematic attempt to be sure that the amps are operating to spec; that's all. But of course I figure I may as well get 'good quality' tubes while I'm at it, if there is such a thing. Why not do something right the first time, if you can? And who should I ask to find out about these things?

You expressed surprise that new 6AK5s made such a profound difference. Well, please don't think that I think it is the brand or cryogenically treated pins that made the difference. At this point I do not believe that the brand of 6AK5 influenced the sound.  But it certainly appears at this point that properly-functioning 6AK5s had a hand in subsequent performance improvements, which were not at all subtle, and in fact brought my amps closer to what others have described, that I up to now could only intuit. Am I pleased with the results? You betcha!

Like I said, the 6N6Ps presently in the amps are the last tubes that came with the amps, and I have absolutely no reason to suppose that they are woring to spec. I will try the new ones I got and listen to the results. And since I know they will need regular replacement I am stocking up, so I don't have to deal with it later.

And don't worry. I do not think I am listening to "tricked-out" ML2s. Rather, I figure I am hearing the amp running ever closer to spec. Pardon me if I am agog. No, these amps are not "perfect". But they are so much better in every way than anything else I have heard in 40+ years that it just makes me wonder how they even happened.

In writing my ML2 impressions I am: 1) Trying to take advantage of your extensive experience with these amps. 2) Re-capping my experience in simple, rote terms. 3)  Sharing my personal impressions/reactions as I go along.

With respect to the ground issue: Romy, as you know, in most residential/commercial installations the "neutral" wire of the pair powering the gear runs back "unbroken" to the same main ground bus/rod as the "ground" wire. Code (and common sense) absolutely demands a whole-system ground at/near the main electrical service.  A first-class installation will use separate neutral and ground busses at any secondary panels and just join neutral and ground wires at the main panel ground bus. When we use a dedicated ground for the "ground" wire from our hi-fi systems most of us are really using 2 routes to ground: the original neutral-to-main-panel ground and any "dedicated" rod for the system ground. I also do the dedicated ground trick, by the way.

Best regards,
Paul S

01-05-2007

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jessie.dazzle

Paris, France
Posts 456
Joined on 04-23-2006

Post #:	34
Post ID:	3441
Reply to:	3437

Grounds for Paranoia

I'm probably just paranoid, but...

You are operating in a zone where the "Theory of Natural Selection" has been rendered extinct by the "American Legal System"...

I fully agree with your take on lifting the ground, but for the above-mentioned reason, SUGGESTING its benefits is about as far as I wanted to go.

Even though manufacturers like Lamm make it really easy to isolate the ground, I am always surprised to see expensive systems, complete with expensive mains cables, and in some cases even so called "dedicated circuits", sharing the electrical ground with the microwave oven !!!

The heavy-duty disclaimers audio manufacturers include in the operators manuals probably de-suade quite a few from ever considering an isolated ground.

Having said this much, there are of course "approved" ways of isolating the ground.

I can already imagine a nice polite Romy the Cat disclaimer...

jd*

How to short-circuit evolution: Enshrine mediocrity.

01-05-2007

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Romy the Cat

Boston, MA
Posts 10,184
Joined on 05-28-2004

Post #:	36
Post ID:	3443
Reply to:	3441

The ML2’s input power filters and everything else…

Jessie,

Actually the tendency of manufactures to isolate ground becomes almost common among any more or less serious manufactures nowadays. The main’s ground is so polluted in US hat it is scare… or even dungarees. I remember a few years ago when I was setting up AC polarity for my playback I was measuring some VERY ugly sings on the ground side….

I have my cooper poll drive in backyard but also, and do not try it home; I had a few years ago a period when I was driving the entire single ended system completely flooded. At that time I was e4xremeting with active basing of the cable and I remember I got some very crazy setting. I had for instance a couple weeks the system running 110V in one wire and 220V in other wire… of course completely lifted…. and it was 11 components. It was interesting time…

Anyhow, since it is Lamm ML2 thread I’m jumping off the subject of grounds. The only thing that I would add on the subject of the thread would be that on all 4 of ML2s that I owned removed the input filters filters. Vladimir used in ML2 power entry modules that combined fuse, power receptacles and common mode rejection filters. What I did was broken off the filters from the power pins and lifted the ground cable form the unit to the power entry module. It was possible to order to $6 the identical power entry module but I decided do not bother. I personally feel that even the discreet, build with the best possible parts, with the best possible techniques, make to the very specific and very exact current common-mode and EMI filters do eat dynamic, among the other thighs. However, in the ML2 used $11-worth cheap filter that I thought should be removed. Frankly speaking the effect of removing was much less notable then in some other components (I toss it always everywhere) but it was auditable. Though I admit I do not spent a lot of efforts to confirm it but instead I juts bite the filter off and forgot about them….

Rgs,
The caT

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche

01-06-2007

Post does not mapped to Knowledge Tree

Paul S
San Diego, California, USA
Posts 2,672
Joined on 10-12-2006

Post #:	37
Post ID:	3446
Reply to:	3443

Another plug for the ML2

Well, I hope that Romy is the only one who still thinks I'm tube rolling, because this post is even farther afield (although it is almost a spin off from the previous posts about AC/grounding).

I finally got around to adding not-terrible power cords. I had been using some little peices of crap I had in a box with some cast-off computer stuff, but now I have nice fat solid 12 gauge copper, and yes, Virginia, there is an audible "difference", and the difference is an "improvement", and the improvement is in the "ease" of the performance. The amps are now, paradoxically, at once both more free and more in control, if that makes any sense. Music does not feel at all squeezed or pushed but it is yet more dynamic, more sudden and spontaneous, and there is still less background HF whatever-it-is that ties the music back to the speakers. This was not a "big change", because the amps were already tending like this, but it was significant enough to suggest that the AC cord does "matter" with the ML2. One really cool audiophile tidbit was to hear for the first time with my system the proper sound of the air from a trumpet, consistently rendered when the miking warranted it. (Sorry, Romy, it is true, but I said it just to tease you...)

Although I have had audible reasons to believe that the amps have not up to now been running true to spec, I am ready to accept that they are presently operating to spec. However: I still plan to try new 6N6Ps. Again, this is because I want to be as certain as possible that I know how the amps sound with the properly-functioning tubes they were designed around. I will begin evaluating my system in ernest once I am sure the amps are up to speed.

By the way, all the things I was excited about earlier are still in effect without the "Holiday Power Grid", so I hope this means that I am flipping over this amp while it is working "normally".

Best regards,
Paul S

01-08-2007

Post does not mapped to Knowledge Tree

Paul S
San Diego, California, USA
Posts 2,672
Joined on 10-12-2006

Post #:	39
Post ID:	3456
Reply to:	3450

Failed experiment a success (What ho, peasants?): another gusher

Too bad I had to continue today with the original 6N6Ps! LIke I care right now!

I imagine there are people who read these posts and wonder if the ML2s are "worth it", as I did for a couple of years. If by "worth it", you mean do they truly kick ass, then yes, they are worth it. But I will also hedge like a mother and say "it depends", because it does depend on whether the rest of your system can make good use of the ML2's capabilities, and it also depends on your tastes, expectations, and hi-fi acumen.

Getting the tubes closer to spec has worked just the sort of improvement I wanted along with lots of other benefits I never saw coming when I first used the amps. But I would also hazard an educated guess that these amps, although used when I got them, yet needed some "break-in" time, simply running with loads, to stabilize and begin to give their best. Although this has required but a modicum of patience, it has taken some time and attention to details to get the amps where they are now.

Where they are now is by far closer to live music in a very literal sense than I ever even imagined hi-fi could be, because up to now my expectations were limited by my (rather extensive) experience, which up to now did not include these amps. Circular, but true. Although you have heard about "holographic imaging" rendered by other amps before, I have heard them and they simply do not do it the the way the ML2s do it, and they do not do it as well as the ML2s. These amps just hinted at this for a while, but it is now part of the regular program: the uncanny, unshakable aural impression that the music is coming from the singer(s) or instrument(s) rather than from the speakers or the "sound field". This might seem like a fine point, but it isn't, and it has to do with the way the sound travels (especially the incredible "non-existent" highs) and in turn is percieved by a listener. The way the ML2s put it, the musicians and vocalists are making the music and the "sound field" rather than vice-versa. Which wouldn't mean a thing to me if everything else wasn't so well done, too; but it is.

I want everyone to know that I kept my old amps because I was not going to keep the money tied up in just another pair of amps, no matter how "good" they were in terms of my former understanding. But I want to encourage you fence sitters that if you care about music and you are prepared to go the distance to get it, then the ML2s should be on a very short list (of, perhaps, 1).

I would wait to post this kind of drivel, but I am too excited to stay quiet. I'll try to be more coherent (and less of a little kid) as the amps settle in and I get my TT up and running again.

Best regards,
Paul S

01-13-2007

Post does not mapped to Knowledge Tree

Paul S
San Diego, California, USA
Posts 2,672
Joined on 10-12-2006

Post #:	40
Post ID:	3488
Reply to:	2941

Skinny pins and cheap-o sockets

Have you tried these with skinny-pinned versions of your tubes? I just bought a bunch of 6N6Ps that have pins so freaking skinny that the sockets on the ML2s won't connect with them. These 6N6Ps have the "up arrow" printed on them, so next time I will avoid that version of the tube, if I can.

I was thinking: Maybe crappy Russian tubes need crappy Russian sockets; but then I remember you making fun of the Russian "two-point" "built-in short" sockets.

Years ago I used needle nosed pliers to try to tighten some socket pin clamps. I was pretty careful, but I wound up breaking the first one I tried. I was amazed that they would use such crappy metal for connecting to tube pins, and I started looking around in the amp. Then it got funny as I realized that for all the time I spent making things OCC copper, "six nines" silver, "direct gold sputtered", etc., I was just connecting the exotica to the corroded steel IEC socket and double-plated "Tiffany" sockets , ad nauseum, on the amp, not to mention whatever terrible, pitted metal the Russians use for tube pins.

Anyone know if there is a good reason (other than, "it's cheaper") why such apparently-crappy metal is used for tube socket clamps? If you tell me it's actually good stuff I'll be happy to believe you so I can quit thinking about it. At least I'll forget about it once I find sockets that will hold the skinny-pinned tubes, too (or maybe I'll go on a tear and root out all the cheap parts from my gear...).

Got a link to those sockets (I'm afraid you may have blown the "Best In The World" connection for all of us...)?

Best regards,
Paul S

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	Target	Threads for related reading	Most recent post in related threads	Forum	Replies	Views	Started
»	New	A quest for a better SET...	Still, there is something in it....	Melquiades Amplifier Forum	3	64586	02-05-2005
»	New	The Silence of the Lamms!..	Well, Lamms are not exactly fun anymore. ...	Audio Discussions Forum	7	90337	06-12-2005
»	New	Romy, how does the original ML2 sound in regards to acc..	Modification of Lamm’s SET...	Audio Discussions Forum	5	67819	06-20-2005
»	New	Lamm Industries: a special interview with a special com..	Lamm now is Active...	Audio News Forum	106	1333215	09-18-2005
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»	New	The short "6C33C Survival Guide"...	Ac filament.....	Melquiades Amplifier Forum	20	375556	12-18-2007
»	New	Amplification and Consciousness...	Freedom of expression vs. something to say...	Playback Listening Forum	15	114363	01-07-2008
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