I have soft, low-level hiss in my system with the Lamm L2. Yes, it can be heard from the listening chair 8 feet away. It's very slightly more hiss than I heard with an Atma-Sphere MP1 MK III linestage or Audio Research Reference 3 preamp in the system. It's *less* hiss than was present when using the Atma-Sphere's phono section. The hiss is not audible during quiet passages of music playback (although obviously it's still present).
The hiss goes away when the L2 is muted.
I often wonder if some of us are more sensitive to hiss than others, and were we to listen to the same system at the same time if some of us would object to hiss we hear whereas others would not.
The question is, how do we compare in writing the loudness of the hiss we hear unless we each measure the decibel level with the same model sound pressure level meter, at the same distance from the drivers, and after having established a baseline test tone decibel level? IMO, this is nearly impossible.
To directly answer your question with a few suggestions...
Using the L2 in balanced mode with balanced amplifiers reduces hiss level, as does changing old tubes to new tubes and re-biasing the preamp. Re-biasing according to the owner's manual must be done after tube changes in the L2 power supply. A multi meter, and a small flat head screwdriver is required.
If you still have excessive hiss after you change the tubes, re-bias the preamp, and run it in balanced mode, then perhaps the issue is one of personal preference for less hiss and another preamp is in order. |
Hiss can be annoying, no doubt.
I will add that using different power conditioners and cords has affected the
L2's level of hiss in my system. It seems to be fairly sensitive to power cords
and power conditioning, IMO. You don't necessarily have to spend a fortune,
either. I'm presently burning in an Alan Maher Reference Power Center V2
that retails for $750 including a captive power cord. The hiss level is the
same, or slightly less, than when I was using a Shunyata Hydra 2.
In my system, the L2 is better (more transparent, alive, and lacking
coloration) than the ARC Ref3, despite the ARC being nearly dead quiet.
However, this is likely due to better impedance matching with my amplifiers
than anything else.
The only other balanced preamplifier I'm aware of that has an output
impedance somewhat close to the L2 is the Modwright LS36.5. I'd like to hear
one in my system since Modwright products are famously quiet, but the
price including the PS36.5 power supply puts it out of my comfort zone. |
The L2 Reference is an outstanding match with Pass Labs XA-.5 series.
IMO. |
Interesting about the mosfets.
I owned a Moscode 401HR amp that used mosfets. It's a high gain amp, and I can't say I heard any appreciable hiss.
Not arguing your point. Just making an observation. |
Considering the bad user experiences and opinions being
expressed, I suppose there'll be a glut of used L2 Reference preamps in the
listings soon. Mine won't be one of them, however.
It might be helpful to know the sensitivity of everyone's speakers who are
experiencing excessive hiss with the L2 Reference. Mine are 93dB, and as I've
already written, the hiss is normal, IMO, and certainly within the range of hiss
I've heard in my system in several iterations with other gear and speakers
(89dB).
I have had a few iterations where there was zero hiss...and I mean none. The
amps were NuForce, Bel Canto, and Leben. Preamp was Atma-Sphere.
However, none of the systems were as musically satisfying as the one I have
presently. |
I owned a LL2 Deluxe, which was one of my favorite preamps. In some
respects, I prefer it to the L2 Reference. However, it does not allow for balanced
operation.
In my system, the LL2 Deluxe hissed about as much as the L2 Reference, from
what I recall, and to be fair my system has completely changed in the interim,
so the comparison is not apples to apples. |
FWIW In various tubed preamps I have had good luck reducing hiss by using Rothwell Atennuators at the amps input(s) also they have elimated AM radio leaking through my speakers.
Faziod (Threads | Answers) Depending on the system's resolution, this may not be an ideal solution, IMO, because the Rothwell device adds a layer of resistor that reduces system transparency. The better solution is to have the preamp manufacturer reduce the output gain of the preamp by swapping an internal resistor. I had Lamm do this with my LL2 Deluxe, and the result was perfect. |
Based on typical used prices IMHO the LL2 Deluxe is the darling of the Lamm line-up...
Rgd (Threads | Answers) I absolutely agree. If I did not require balanced operation, I'd likely own another one. 09-26-08: Goldeneraguy
Tvad , I am thinking about lowering the gain on my LL2 Deluxe
If you recall,how much gain in db did you reduce. As I recall, it was reduced to 12dB. 09-26-08: Faziod
Tvad agreed on the loss of transparency with the Rothwells but its the only thing I have found to work to eliminate the AM radio leaking through to the speakers Understood. |
09-26-08: Flyin2jz
how could u possibly deal with a piece of equipment that introduces a hiss to
your system? I am certain that no answer I, or others, will provide will be satisfactory to you based on your obvious predilections. However, I will offer my perspective. I have heard several highly regarded, universally well-reviewed components in my system that have been as silent as a corpse, but the music they produced was sterile, lifeless, and basically sounded like crap. For me, choosing some hiss over the alternative is an easy choice. |
Today, I tried connecting the L2 Reference to my Pass Labs XA-60.5 amps using
the L2's single ended outputs with XLR/RCA adapters. I am still using the Pass
Labs' balanced inputs. I find the sound to be more natural this way. Less
mechanical. I don't discern any additional noise or hiss as a result. In fact, it
may be even quieter.
I did not expect this result, and I'm wondering if any other L2 Reference owners
who run the preamp balanced have tried this experiment.
Does the L2 Reference's signal pass through additional circuitry to convert it to
balanced?
Based on what I hear today, I am likely to convert my interconnects to
RCA>XLR cables thereby eliminating the adapters. |
