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In the Forum: Audio Discussions
In the Thread: Initial thoughts about new/old Lamm ML2s
Post Subject: 6AK5: bass, feedback, organizationPosted by Paul S on: 12/30/2006
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 SRerurn to Romy the Cat's Site