Lamm LL2.1 Deluxe "DC Offset"?

In addition to the previous post about problem with the Lamm LL2.1, It's a brand new preamp, running hour at about 30-40 hour when the problem started occured.

When paired it with McCormack DNA 0.5 deluxe and Totem Model 1 speakers. The Lamm+McCormack Combo produces an unexpected and intermitten movement of the totem woofer cone back and forth. But when the Lamm replaced by other preamps (SFL-1 or Graaf or Mark Levinson 380 preamp), the system going fine.

In the other case, when the Lamm paired with a tube power amp, things also doing fine.

Perhaps, because The DNA power amp is a Direct Coupled design, it passing whatever signals, good or bad, coming from the Lamm directly to the speakers, which then produce a sporadic woofer movement. In the case of highly fluctuated DC offset in the Lamm, this then create problem to the system.

Anybody can help?

Dear Chayro and Syntax,

Many thanks for your advice.

I did contact the dealer as well as the manufacturer. It seem they in difficulties to find out what is realy happen to the unit itself.

I onced sent it to the dealer, they hooked it to their hybrid Audio Research amp and found that things seem just fine. But when I brought it back home, the problem remain occurs. Then I brought the unit again to the dealer when we finally confirmed that there is a Highly fluctuated DC Offset. Not as high as in my home AC, but that might be caused of their using power conditioner in their system.

They suspecting a leakage in the output capacitors, but considering of its sensitifity to the AC fluctuation I suspect a more serious problem in the upstream side of the circuitry, could be in the power system.

The manufacturer strongly suggested me to manage it through the dealer. While I am away, I did text the dealer to check the progress of their observation but no reply. I am affraid they in trouble of finding the real caused of the problem.

Perhaps I need to find the way to manage and repair it by myself, but need in advance advices before start working on it.

Hi Chayro,

Many thanks for your empathy.

It's a hard long story. Iam on the way back to my home-country and curious to check the dealer, again, what is the story, they have been silent since I drop the unit for the second time. Learning from the 2 months strugle of getting their admittance that there is a real serious problem, I have to manage myself to get ready of being disappointed.

Contacting the manufacturer did not give any help, they shift it to the dealer. Seem they rely to the dealer's technician which I doubtly can realy manage in finding the real problem on it.

I agree with Syntax, it is something not common. The issue and challange then is how to find the root of the problem, and this should be managed by the manufacturer who realy know the design and topology of the unit, not leave it to the free-lancer technician.

Charles1dad and P59teitel,

Thanks for your support.

An interesting comment and I wish I could have that luxury of choosing among 1) getting a proper repair, 2) a replacement with new unit, or 3) a full refund. I share same understanding with you on how this mechanism supposed to be well implemented in that manner.

The problem is, the manufacturer will not even respond to my email, you may see it in their email dated 14 June when they finally shift the issue to the dealer and that’s it (I will share it afterward). You also may learn that they don’t even have sincerity in trying to find the real problem, they rather playing the game when the manufacturer shifting the problem to dealer and then the dealer ridiculously asked me to talk directly to their technician, funny.

I can envisage that finally they will leave me alone in the jungle. When I talked to their technician, the result is absurdly unbelievable and you will be amazed when compare it to the explanation made by the manufacturer, it’s totally contradictive statement and conclusion.

Below are my communications/correspondences with the technician and Lamm:

1) Dealer’s Technician Explanation (by phone call on Monday, 8 July 2013):

The Lamm’s, particularly in the power supply system topology, is designed to be simple without (AC) regulator inside, therefore it is sort of common that the fluctuation of AC voltage will “directly and totally” reflected to the DC (offset) in the preamp output, as it is. In other words, to my understanding, a fluctuation of +-200 milliVolt DC offset is the consequence of such typical Lamm design, (so it is common to Lamm?). If I may interpret further, it is typical Lamm design to be a very sensitive unit, even to the AC swing/fluctuation as little as 0.3-0.5V, it will directly generating high DC offset fluctuation to the preamp output. Therefore, the technician stated, the unit no need any repair.

The challenge is then, to find a matching power amplifier for Lamm which can manage high fluctuated DC Offset which generated by Lamm Preamp as affected by even low AC swing. (This actually funny and doesn’t make any sense to my humble logic thinking. How long that so called “matching” amplifier can handle such continuous high fluctuated DC Offset assault that generated by the preamp before it finally get broken or blew up?).

2) The Lamm e-mail (dated 14 June 2013, no further reply to my email afterward):

"Your measurements of voltage fluctuations at the LL2.1’s output are puzzling to us because we’ve been producing this model since 2001 and have not come across the effect you describe. It’s hard to explain.

On extremely rare occasions it may happen that the output capacitor C111 and/or C112 exhibit slight leakage which does not manifest itself at the time when we are burning-in the assembled units at our factory. But even in cases like this the voltage at the preamp’s output never exceeds 50-100 mV. Therefore, we view your measured result of about 1V as not quite reflective of the objective reality (this may have to do with possible low quality of measurement device, method of measurement, etc.)

Since the beginning of production of this preamp, we’ve had three cases that were somewhat similar to yours. In two cases it turned that the owners used relatively inexpensive but quite powerful solid-state amps with DC input and output; these amps were incompatible with LL2/LL2.1. When these people were able to replace their amps with different ones, all problems went away, indicating that the preamp was not at fault.

In one case the problem had to do with leaking capacitors, and the issue was easily solved once the replacement capacitors were installed.

In your case it is difficult to judge what’s going on in reality. If you wish, we can send the replacement capacitors to your dealer. Let us know if you decide to do that. Perhaps, you will have an opportunity to try different amps in your system.

We would like to ask you to abstain from making irresponsible statements about quality control at our facility. Lamm Industries is known for excellent service and unsurpassed quality control. The page with measurements that was sent to you is part of a comprehensive “production report” where we record every step in rigorous testing and assembly processes. This is a confirmation of our statement because each single product that we produce is accompanied by its own production report, which is not the case with many manufacturers.

For your information, we do not usually deal directly with customer – this is the job of our dealers/distributors. Our main function is manufacturing. Therefore, it would be healthier if all questions came to us through your dealer….”

So, that was the strange of comments made by manufacturer and dealer technician.

I agree with P59teitel that I finally have to share this case with any audio forums I can find to wake the manufacturer and dealer ignorance. It may also worth to share it with some High End audio magazine, particularly to those that put Lamm Industries products in their recommended component list. But still, I hope I can manage my frustration and get their sincere attention before I finally come to that ultimate position.

I think I also need Syntax help and confirmation, since is very difficult to get from either manufacturer or dealer about what is really the design of the Lamm LL2.1, whether this true that the Lamm is designed that way.

Any other thought from folks of this forum would be highly appreciated.

Jtimothya

I am not sure why.

Perhaps, the Lamm statement itself did not really confincing about the real problem that cause when they said "But even in cases like this the voltage at the preamp’s output never exceeds 50-100 mV."

I can understand if the dealer and thier technician in doubt to change the Caps. Based on my personal observations, the question should be addressed to the power supply system. Why an abrupt small AC swing (as small as 0.3-0.5v) can generate highly fluctuated DC output? shouldn't it be a tollerance range? says +-2v before this kind of AC swing hits the circuitry and manifested into high preamp DC output?

In this case a full technical support and detail instruction from Lamm is definetly required, they are the only one that really know about the design and topology/circuitry, so that it will not drive dealer and technician to perform a trial and error repair.

Hi Charles1dad,

Following that Lamm suggestion, about ten days ago I dropped the unit to the dealer for observation and necesary repair by their technician.

Amazingly, what they did and feed back me after having their own observation are as follows:

1). There is no repair or parts replacement required to the Lamm. They said this is new unit and no need any repair, only small tightening by reinforcing some solder has been made in and to the power supply area (I am not sure whether this is necessary)

2). The DC Offset fluctuation on the preamp that caused by AC voltage swing is naturally common in Lamm as this is the natural design of Lamm. In other words, the Lamm design will allow such AC swing, even as small as 0.3-0.5v AC, and pass it through the circuitry, to generates high DC milliVolt.

3). They suggesting me to use another power amp that may compatible with the Lamm. They also suggesting me to use stabilizer.

Learning from the above:

1)Should I push the dealer and technician to change the capacitors while they are very confidence that there is nothing wrong with the unit?

2) To my understanding, installing stabilizer and using other power amp is not the right way in solving the root of the problem, it's only curing the symptom while the real problem still exist, beneath. This only creating a time bomb.

I urged the dealer to contact Lamm about this, but they asked me to bring back the unit isntead. They very confidence the unit will be just fine. I can imagine, once the unit back to my system the problem will still exist, and do know what should be the next thing to do except to sell it

Charles1dad,

Welll, that actually a statement coming from the dealer free-lancer technician and His statement is contradictory with Lamm statement.

if we learn from the Lamm email, as a manufacturer who design and pruduce the unit, it's clear that this not their natural design. They said that the measurement of AC fluctuation causing high DC fluctuation was PUZLING them and they never had that experince on such case. They also said that even if there is a leakage on the caps, it will never exceed 50-100 DC milliVolt. So, there are two big questions that they themselves dont have the answer.

I believe they can find the answer, only if they deeply and sincerely and honesty listen, learn and dedicated their time to observe the unit. Further, if I were them, I will have myself to look back and learn the design and then have one or two comparison units put in the bench to be tested. And I believe those unit will perform well, contrary to mine.

If that is the design, does a highly fluctuated +-200 milliVolt DC offset common and acceptable to the industry? Secondly, does the small swing of 0.3-0.5 AC voltage that generates a fluctuated hundreeds DC Offset also aceptable to the industry?. If that the case, then Lamm will have extreem difficulty in finding a matching power amp in the market. They can only be paired with Lamm power amp, which is notbthe case.

There is also the fact that for the first 4 weeks the Lamm work well with my entire system, we did have microphonics problem in one of the tubes but we replaced it by new one and things back to normal.

There is also the fact that before I bought the unit, I firstly contact Lamm whether their preamp will be matching with my system, their answer is: the Lamm LL2.1 will work well with any power amp as long as the input impedance is 10k-ohm or more.

Again, the answer is depend on how serious the dealer, technician and Lamm trying to solve the problem. Not shifting the issue or blamming other products.

Whart,

I dont thing the probelm is in the dealer alone. The tone of manufacturer's email responses was unbelievable. I can say that, both of them, in the way they responding to my case is similar. They are very defensive and tried to shift the issue to somebody else fault.

Iam not realy sure, but I guess something strange on the way they build and arrange the business which refrain the dealer to conduct intensive and frank communication with the manufacturer.

I live in Jakarta, Indonesia.

P59teitel
I agree with you. But the fact is the dealer and their authorized technician do not want to do that. I am not in the position to forced them to do so because, having learn of their attitude from this 3 months struggle, I am afraid they will forced me back to take any consequences. May be, they do know that the real problem is not in the caps.

Lall
I can understand that you already spend your time and thought in considering to buy Lamm product. I spend quite a lot of time and reading some reviews before decided to buy it, and this is the product that I adore to own for at least two reasons: 1) It has good reviews from at least two reputable audio Magazine like The Absolute Sound and Stereophile, 2) Just like Whart said, it’s a one man company product that usually have its own reflection, taste and heritage of the designer. Actually I plan to keep the unit for last, such kind of collection unit.
I do not expect to experience this kind of difficulties and such improper attitudes. But this also gives us a very good lesson learns when contemplating to choose and buy a product.

Whart
I learn 3 important things from your posting:
1) You are very lucky live in NY area, and this gives you an advantage to have a direct contact with the Lamm where they also located in NY. Therefore, this is very easy for you to prove them whenever you experience or find some trouble with your Lamm equipments. There won’t be any arguments and debates on whose observation/finding is correct and whose is wrong, you can simply drop the unit and have them repair it. I can’t imagine if someone across the continent and ocean, with a big spending/investment on the Lamm equipments, experiencing trouble with their equipments…...
2) Your statement of “On occasion, the line stage and amps needed attention….”, give me an understanding and prove that Lamm equipment is not a risk-free or trouble-free equipment. Therefore, a good relationship and trust between the customer-dealer-manufacturer is of mandatory, otherwise people will get lot of bad experiences like mine.
3) “…trust Vlad to do the right thing and also understand why …..he prefers that customers work with his dealers……”. This drives me to concern on a) what if the customers finally getting frustrated from the way dealers treat them? b) what if dealers and their technicians do not know what to do when they facing unusual case, the case that only the manufacturer can handle and give a right and correct direction?. When you invest in the Lamm equipments, though they considered being a small operation, it certainly cost you a big money spending, and you deserve a very good and fair treatment.

Charles1dad
Indeed, I already spent about 3 months facing this difficulties, but so far does not see any clear solution from them……
Again, If I were Lamm, I will contact dealer and :
1) Give them clear understanding what the design of the unit is really.
2) Give them clear and precise instruction on how to observe, find and solve the problem.

Jtimothya

If you learn my previous posts, you may see that the measurement also taken in the dealer's show room. This is to prove and get both side agreements on the method to be taken as well as to get both sides admittance on the result that there is a real problem with the unit. Although they are using power conditioner in the system, the measurement clearly showed a highly fluctuated reading, and the dealer admit it, no arguments.

All measurements was taken using 3 different devices in several different occasions. We are using 2 Sanwa CD800a and 1 Fluke 87V multimeters, those are a well-recognized brands that being used by professionals and audio hobbyist. The dealer itself using local made multimeter (Heles) in comparison to mine.

The dealer does not have another Lamm preamp and power in their stock. So we cannot make any comparison. This is actually what I asked to the dealer.

The suspect is my speakers woofer? or may be my other equipment?. I have 3 other preamps (SFL-1 Signature/Modified & upgraded, Mark Levinson 380 and Graaf, and did comparison test by inserting each of them to the system, one in a time. The result was? Only the Lamm that generates highly fluctuating DC Offset and causing woofer movements. Others showed a very low and steady DC reading, under 2mV DC. I did also connecting my amp with other speakers and in other occasion connecting my speaker to other system, both system work very well.

Yes, Lamm sent that build test report and I immediately sent it to dealer. Unfortunately the dealer did not show their own test result, but I did the measurement and sent the result to Lamm. However, I have to wait more than a week before they finally respond to my email, that might be caused by my attack of suspecting their lack of QC when the unit leaving the manufacturer.

Why using third-party technician? He is actually a dealer's technician and Lamm very well trusted on him, according to their email. But he is not a full-timer or employee which dedicatedly works for the dealer. He is independent and takes work order from others. I only contact with them under dealer consent.

Whart & Charles1dad

Yes, I have already done most of your advices.

The dealer is the only channel I can communicate with. Lamm reject me to directly contact them. They never respond to my email anymore. If I send the unit to Lamm directly, I am afraid they will ignore it. Sending the unit without their consent will even get me into worse situation. In the other hand, I have to agree with Whart about the attitude of dealer, pretending as if my problem.

I did visit the dealer and talk about arrangement to ship the unit to Lamm (yes the unit still under warranty), that also include the shipping cost arrangement, but it seems not workable for them. I also insist dealer many many times to communicate with Lamm and explain our finding, not only my finding. I don’t know how their communication being conducted.

Lall,

I agree with you.
This is not only a technical matters of the unit. Not also a commercial matters. This is more about mentality.

Jtimothya,

Well, seems you missing my previous posts and did not cath-up what reflected on that.

I passed all recommendations Lamm gave to me to the dealer, verbally, face to face, by email, By phone. I've done every necessary things that should be, the way normal and educated people would do.

If the dealer and their technician, whose Lamm deeply trust very very much, then why when they took the other way the blame become in my side?

Lamm shifted the issue to the dealer, they pushed me to talk to dealer, they rejected to answer my email, they assured me that dealer and their technician will and can handle the problem.....then it is Lamm obligation to talk to the dealer and dealer to talk to Lamm.

I've spent my energy and time pushing dealer to talk to Lamm, but if they did not do that.....then why it supposed to be my fault?

Or.....may be,.....may be......,there is some kind of conspiracy between them? So that I can not talk to either dealer and Lamm, and leave me, the customer, in the frustration and solve all thing by myself

Dear Chayro,

No worries.

My Friend teased me by offering to purchase the unit at half price of my original purchased. He may take the unit for an experiment, he jokingly said. So, worse to worse, ithis might be my last resort solution.

Dear all,

This is to update you on the last finding on my Lamm LL2.1 problem.

I finally replaced the output and coupling capacitors by myself and succeed. No woofer movement again and the measurements showing good results.

so, being in audio hobby, we have to be creative and keep trying finding the solution by yourself.

Orpheus 10,

I already loss a big buck on the third week I purchased and owned this brand new unit.

When your dealer not taking their responsibility and treat you badly just like we are a stupid customer, and when the manufacturer ignoring you of being too much proud and confidence of having a realiable product and rather shift the issue to the dealer, what else we can do?.

In that situation, we are no more loosing any buck but our trust to them. Then why we have to relly on them?