Lamm ML2.1 Tube Life

Jan 10, 2018
61
0
6
Golden CO
#1
I have owned a pair of Lamm ML2.1 mono blocks for about 6 years now and have given me much enjoyment driving a set of Avantgarde Duo Grosso horns. As a matter of contrast to the 18 watts the Lamms produce, the AG's were originally driven by an AG Model 5 integrated amp which put out a whopping 0.5 watt. The AG power was a bit harsh by comparison but I digress...

When I originally purchased the ML2.1's they had a full set of supposedly new tubes. My mode of listening back in those days was dictated by my travel schedule and restricted to weekend only listening. I would typically turn the units on Saturday afternoon or evening and leave them on through Sunday evening. After about 3 years in this mode, one of the V2 6C33C tubes began to become very unstable and I measured high voltage spikes that eventually would cause arcing in the tube and blow the fuse on the circuit board.

Ordered up a new set of tubes from Lamm and the listening schedule was initially much the same. In the fall of 2015 it retired and changed my habits. Since that time I generally will power up the amps an hour or two before listening and then turn them off in the late evenings. The system was now being used almost on a daily basis. A couple of weeks ago, I noted that arcing/voltage spikes resumed on one V2 (BTW, the same amp) so I installed the V2 from the previous set to get me through until the next set is ordered.

Long story short, what behaviors have others experienced with their amps when tubes began to fail? How about tube life? I know that Vladimir is very explicit about using matched sets, especially the V1 and V2 so not sure there are many options other than tubes sourced from Lamm.....
 

Sablon Audio

Industry Expert
May 22, 2015
399
13
18
#2
Such is the way of 6C33 tubes I’m afraid and it is prudent to replace them every year or so on a precautionary basis to save blowing expensive fuses / resistors etc. A cherry red glowing 6c33 reaches @300 centigrade iirc and is truly a site to behold! Fortunately they are fairly inexpensive.
 
Jan 10, 2018
61
0
6
Golden CO
#3
Such is the way of 6C33 tubes I’m afraid and it is prudent to replace them every year or so on a precautionary basis to save blowing expensive fuses / resistors etc. A cherry red glowing 6c33 reaches @300 centigrade iirc and is truly a site to behold! Fortunately they are fairly inexpensive.
Yes it is...hot enough to displace the coating on the top of the tube making it clear (is that a sign the tube has leaked and getter material has oxidized?). Please define inexpensive...a matched set from Lamm is rather pricey. Which begs the question, do many people here disregard Vladimir's advice and install 6C33C from Ebay type sources, which admittedly are relatively inexpensive.

Thanks,

Brock
 

Sablon Audio

Industry Expert
May 22, 2015
399
13
18
#4
Well, don’t know what Lamm or for that matter BAT charge, however inexpensive compared to EML / KR / Elrog / Takatsuki triodes. Is worth speaking with Vlad at Audio Mirror (whose 6c33 amps I used to own) to see if he can help you with matched pairs.
 

Steve Williams

Site Founder, Site Owner, Administrator
#5
Hi Brock

I’ve owned Lamm components now for at least 10 years and when it comes to tubes for Lamm I know 2 things

1. IMO there is no need for tube rolling

2. When it comes to replacing tubes again IMO the only place to buy is direct from Vladimir

Over the years the only tube I have rolled is the 12AX7 on my ML3 Here I use a pair of NOS Telefunken ECC803S. Other than that I always buy from Vladimir. I have an extra set for my amp and ore for each channel. If a tube blows I put in the spare set and take the others out. I send that set back to Vladimir where he replaces the blown tube with a matched version for that channel. When he sends them back I remove my spare set and put in the working set with the replaced matched tube.
 
Jan 10, 2018
61
0
6
Golden CO
#6
Thanks Steve, sourcing from Vladimir makes the most sense to me as well...if one ignores the cost. I have heard that he bought up a number of NOS 6C33C's because he felt that the newer ones are not as well built. And thus my questions concerning longevity of that tube. I have tubes in an old CJ pre and Counterpoint amp that have been on continuously for years and are still ticking and when the 6C33C gives up the ghost with relatively less use I have to wonder....after all, they were the tube of choice for MIG 23's so you would think they were a bit hardier than mine seem to have been.

What is your experience with life expectancy with them?

Brock
 

Steve Williams

Site Founder, Site Owner, Administrator
#7
Thanks Steve, sourcing from Vladimir makes the most sense to me as well...if one ignores the cost. I have heard that he bought up a number of NOS 6C33C's because he felt that the newer ones are not as well built. And thus my questions concerning longevity of that tube. I have tubes in an old CJ pre and Counterpoint amp that have been on continuously for years and are still ticking and when the 6C33C gives up the ghost with relatively less use I have to wonder....after all, they were the tube of choice for MIG 23's so you would think they were a bit hardier than mine seem to have been.

What is your experience with life expectancy with them?

Brock
Hi Brick

I change the 6n30p tubes as he recommends as they seem to blow the quickest.

You just can’t ever go wrong with Vlad’s choice of tubes. When I bought my LP1Signature he strongly warned me against tube rolling.
 
Jan 10, 2018
61
0
6
Golden CO
#8
I know that for the ML2.1 that Lamm is probably the only source for the 6N6P....no rolling there!

Brock
 
May 30, 2010
14,113
78
48
Portugal
#9
I have to say that it something that clouds my engineering views on audio - the absence of defined lifetime of tubes in Lamm products.

I know that Audio Research power tubes should be replaced at 2000 hours and signal tubes every 4000 - the units even have hour counters. I had the same information for VTL or conrad johnson. Why don't we have typical lifetime and replacement cost information for all the Lamm tubes, particularly as ideally they should be sourced from the manufacturer?
 
Jan 10, 2018
61
0
6
Golden CO
#10
I called Lamm this afternoon and talked with Vladimir about my questions concerning 6C33C tube life. I must say that he is very engaging and forthright with his answers. It was indeed a pleasure speaking with him.

So in terms of the 6C33C tube life, he confirmed that he uses NOS for replacements but even then, there are some tubes that don't live up to expectations. In general, he runs his house ML2.1's on the order of 10-12 hours daily and gets between 2-3 years on the big guys. He also confirmed that V2 is the one under the greatest stress and therefore most likely to fail. I recall reading somewhere that someone had tried running their V2 at less than optimum in the range of 0.28-0.29V to extend the life. His comment was that the best sound would be found between 0.31-0.32V and there would be no gain in longevity running at a lower voltage.

So with all that, I ordered up a new (full) set of tubes....

Brock
 
May 30, 2010
14,113
78
48
Portugal
#11
I called Lamm this afternoon and talked with Vladimir about my questions concerning 6C33C tube life. I must say that he is very engaging and forthright with his answers. It was indeed a pleasure speaking with him.

So in terms of the 6C33C tube life, he confirmed that he uses NOS for replacements but even then, there are some tubes that don't live up to expectations. In general, he runs his house ML2.1's on the order of 10-12 hours daily and gets between 2-3 years on the big guys. He also confirmed that V2 is the one under the greatest stress and therefore most likely to fail. I recall reading somewhere that someone had tried running their V2 at less than optimum in the range of 0.28-0.29V to extend the life. His comment was that the best sound would be found between 0.31-0.32V and there would be no gain in longevity running at a lower voltage.

So with all that, I ordered up a new (full) set of tubes....

Brock
Good point, thanks - this means typically around 10 000 hours, an excellent lifetime for audio power tubes.
 

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