GoodSoundClub - Romy the Cat's Audio Site

In the Forum: Audio Discussions
In the Thread: Initial thoughts about new/old Lamm ML2s

Post Subject: Drift, Flux and Tubular LogicPosted by Paul S on: 1/10/2010

Jessie, since I got my amps I have followed Romy's suggestion and recycled swapped-out V2s into V1 service. As it happens, I do not run V2s (or V1s) over a year, but I have had no problems of any kind that I can relate to following the annual V2-to-V1 transfer practice. OTOH, I have never had the problem that you describe, either. I think I paid about $55USD for the current pair of very nice (so far) old Svetlana 6C33Cs I now have in V2 position, but no matter how much I'd paid I would not hesitate to swap out a pair of V2 tubes if one was acting up. First try swapping the V1, and if that doesn't solve the problem, go through the ritual of breaking in a new pair of V2s, as well. But be persistent and systematic, both. I can't tell you how many times over the years I have had ongoing problems either because of multiple, apparently unrelated tube failures at once or due to failures of two (or more!) candidates for the same duty in succession, up to three clinkers in a row! Who would suspect such multiple failures? But you have to be ready and allow for it, or situations like this can drive you nuts! BTW, I have had OK results cleaning tube socket contacts with commercial grade "no residue" contact cleaner and those little, long, round "interdental" brushes that some wack-os (apparently) actually use between their teeth. And just to remind, I have had somewhere between zero and very few problems with the micro-shorts since I started using a little ignition-grade dielectric grease on pre-cleaned tube socket/pin contacts.

Regarding the GE input tubes: I think I spelled out more about the old GE input tubes a ways back, up this thread. The written designations have long since rubbed off my tubes, and now all I remember (I think...) is that they are among the earliest 5751s, older than dirt. But remember that I am using them (and not VTA...) for system-specific tuning. Others might well prefer nice old ribbies (if they can find a nice pair...). This tube position is definitly interesting on the ML2, and what "works the best" would very much depend on what the system-specific demands might be. I think one nice thing about many of the older GE tubes I've tried is good consistency, other factors being equal. But this can never make up for the liars and cheats who deal in the tubes. For this and many other reasons, most people will have to buy and then try the tubes, with no real assurances of anything. This sad state of affairs is just one of many, many reasons why I hate tubes.

Dare I even so much as mention the VTA reference again? Sorry, but it does seem to want some closure, not just to spare myself humiliation (which I think I can deal with in this context), but because I don't want to mislead anyone. Anyway, I certainly hope the VTA stuff I dragged in was clearer to others than it was to Romy. To be clear: I do NOT mean to say that I do (or others should do) tune the system with VTA, because this is not only plain stupid, but it is the worst sort of aimless fiddling that could literally ruin a system if played out too long. Therefore, I actually mean to say pretty much the opposite, that I have gotten a much better handle on system sound and capabilities since I have closed the gap on one more major sonic variable (the VTA), and I was thereby able to take the sound of the ML2s in a pre-determined direction, because I knew where I wanted to go based on a much more solid sense of where I was, using +/- reliable input from vinyl as source material. That's it. I already spent enough time on VTA versus the BEP delta to revisit this; a re-read there ought to put this into context, as well, for anyone who's interested in the "connection".

Lastly, I do not recommend messing with tubes while the amps are on! In fact, I recommend shutting them down and then waiting for the caps to drain before futzing with the tubes. But, to each his own...

Best regards,
Paul S

Rerurn to Romy the Cat's Site