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jessie.dazzle wrote:

Scrolling down to the images of the Lamm ML2.2, I see something that intrigues me... Four ML2.2s are used to bi-amp the Verity Audio speakers; I didn't know they could be daisy chained by using both the XLR and RCA inputs of one pair of ML2.2s (front pair in this case) to output an unamplified signal to a second pair.

I am not sure what makes you intrigued. This is very typical unfortunate/fortunate configuration for Lamm ML2 bi-amping. The XLR and RCA jacks in ML2 are parallel and they run like built-in Y-adaptor. If you have amp very far from your preamp and do not want to run another long ran cable then you might source your frequency section right from LM2’s input. The unfortunate part is that if you still intend to run a dedicated cable to your let say LF section and if you use Lamm preamp then you can’t/ This is one of the most Moronic thing Lamm did. I did pointed it out to him even what we were close but his discarded presuming that his users are anyhow idiots who does not mater do not understand what they do. He was right about it BTW. So, the Moronic think was that his preamps (L1 and L2, I do not know how about L3 but I think it will have it as well) have single ended and XLR outputs and fully balance topology. So, when you flip the absolute phase on Lamm preamp then your XLR output and RCA out become in opposite phase. Pretend how fun it become to bi-amping but as Vladimir very acutetly noted his customers are to idiotic to understand it. Go read all reviews ever were written about L1 and L2 and see if any of those Morons ever noted it.

jessie.dazzle wrote:

Also, I'm curious about that black thing that looks like a tube shield...

This is not tube shield but a capacitor installed trough the amp chassis, similar to what I did in the earlsy version of Super Melquiades

http://www.goodsoundclub.com/Forums/ShowPost.aspx?PostID=1207

What is interesting is that to use this “trough chassis” configuration was absolutely not necessary. There is plenty space at the bottom of the amp to locate a larger snap in cap and there are wide and short configuration of any large caps if the high become a problems. There is certainly nothing wrong in making this trough chassis connection but I think Lamm just wanted to emphasize that his new amp is different from his old versions. I think there is no “claimed” change in input stage in there but most likely the B+ for input stage has a local cap to shunt B+ right next to the 12AX7 anode - the way how it shall be. If that is the” great Lamm improvement” then Lamm is of course is very “unique” engineer.  BTW, I do not have doubts that in context of this compromised PC board assembly of ML2 the move of PS cap closer to load shall be beneficial.

I finally received and installed the new tube sockets for the 6C33Cs. Results: NICE!!!! Rock-steady plate current and voltage. The sockets I used have a solid machined Teflon base with receptacles that each have multiple contacts for the pins.

jessie.dazzle wrote:

Before changing the sockets the sound had gradually picked up some glare (old sockets were probably micro-arcing like hell); the new sockets fixed that and, in the time I've owned them these amps have never sounded better (I'm the second owner). The sound now is now generally more relaxed and natural. I do not attribute the improvement so much to the Teflon, but rather to the pin receptacles and of course to finally being able to properly set the bias; for the past six months (prior to socket replacement) I had been running it at about half the recommended settings in order to keep things from going overboard during drift. With the new sockets, I have not tried listening with the bias turned down to half the recommended setting, but I should, as it would give me a feel for how much this factor alone might be contributing; however, in the past, varying operating points never seemed to make a difference of this magnitude. The sockets did require some serious modification work before they could be installed; I took some close up photos showing the process; I'll post them if anyone is interested (I might not get to it instantly, as I'm neck deep in other stuff).

I did not use those sockets for 6C33C. I use Johnson sockets, love them and never had any problem with them for 6 years as I started to use them. I use the expensive Teflon sockets for my driver tuber and they are very good. Interesting is the material of sockets is very much irrelevant; the configuration of the pin grabbing contacts is the key. I do not know how the contacts are made in the Teflon sockets. For the small currents Teflon is very good as it stress the contacts to be very tight. For the tubes like 6C33C the Teflon that would push the contact to be tight is not good idea as the coals run much hotter and if they are surrounded with Teflon then they would not be ventilated well. Still, I did not play with them and do not know how they made. BTW, there is gay out there who looks like do not like them

http://www.troelsgravesen.dk/AudioMirror-6C33.htm

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