Lambda Pro isn't getting a lot of love here, but in my early Stax days I heard one on a KGSShv and LOVED it! Really fun, engaging sound signature with lots bass impact. Not as detailed and refined as an omega-class, but still had some of the electrostat magic. I would've bought it in a second if the owner had been willing to sell. I agree the vintage Lambdas can have a whole lot of character, and there are gems out there.
There was one I heard after that Pro, maybe the Pro Signatures? Anyways, I didn't like it as much - bright and lean compared to the older Pro. But this is a personal preference thing.
When comparing those two on a Carbon with its power and warmth, the Sig starts to level up. Still bright, but if the brain comprehends that the sound is "good", it starts to adjust to it rather quickly. Casing point is the SR-X Mk3, doesn't have much bass and high frequency extension, but remains strong in whatever is left.
The Lambda Pro is cheap for what it is, one of the most dramatic performances, also improves on the Carbon compared to the standard KGSSHV, starts to get rid of its treble issues - even better without damping when driven by an amp of this caliber. But the Lambda Signature, Lambda Nova Signature and NB Lambda are still higher level with regards to tone and technicalities. (imho of course, they all have different merits and characters and individual flaws needing slightly different matching, etc.)
The 507 + Carbon has the best bass out of any Lambda by far, great detail and definition thrown in for good measure, but the tonality is not better than a Lambda Pro. not everyone seems to be picky about that, or if it can be corrected, it can also be very strong for not a lot of money.
Yeah, i get you. I listen almost exclusively to "classical music" (blanket term, but.. nonetheless) and that of course does colour my view accordingly; granted.
On the other hand, what better headphone brand to listen to classical music
from?
Sad to write this here, but Stax does not make the Sennheiser HE90, which I am still finding to be impossible to match with classical.
The three Lambdas I just mentioned have some characteristics of its sound - but they don't do it as well and also not in one package:
-warmer, richer, weightier tone of the NB
-faster, cleaner, airier, more resolving nature of the Signature
-yet with also the mellow smoothness of the Nova
(And all this with more realism.)
This reminds me why the NB is still my choice of this trio for classical (or just in general). More weight and fullness than the Signature and the high frequency and transient reproduction is better to my ears, speed is less emphasized. I can get by with inferior technicalities, detail above this level might not to contribute to a better sense of realism. Never feels veiled, but also free from excessive forwardness or harshness.
I'd like to think that maybe one day with a T2, I can narrow the selection of this Lambda trio even further. (My bet is still on the NB, but if one prefers a more exquisite ethereal performance, it is the Signature for sure, and the Omega-like underrated subtlety of the Nova is also admirable in its own right)
The Stax Omegas (flagships) can certainly match or potentially exceed the HE90 with regards to technicalities, but the indirect presentation of sound with higher complexity is even farther away than the Lambdas. Less listening to recording, more pure music = in a lot of cases better. (Ymmv.)
To end up on a high note, in a way Stax still prevails over Sennheiser: producing headphones bought by more people (which others can still buy now) and a handul of them were also made much earlier than the HE90.
