Hello, I'm really thinking of going Passive and the LDR3 looks like the perfect preamp. My goal is total noise free, black background. I just purchased a great deal (discontinued--stock still exists) on a new NuForce STA200 class a/b power amp. This amp blows me away on my system. Anyway, I am running ZU omen Defs (ii) which are quite sensitive (101db, plus super tweeter). I hear a slight hiss with sizzle noise (very faint) thru speakers. I took my Peachtree NOVA PRE out of the system and tried my Oppo direct to amp (switched volume to variable) and tried the Bluesound NODE 2 streamer direct (switched volume to variable) and everything was dead quite. On the Nova pre, I bypassed the "gimmicky" tube and the noise was still there. So it seems the noise is coming from the Peachtree. To be honest, the noise is so faint, i only hear up close. However, I know it's there now...so I might as well address as I continue to upgrade my system.
The Schiit Freya seems to have some noise issues as well for some users. Channel Islands preamp looks nice.
Just curious from Tortuga users, is the LDR3 dead quiet?
As others have noted, there's no discernible noise introduced by the Tortuga LDR passive preamps. Of course if there's noise coming in from a source, that noise gets passed through only attenuated. There's no secret to why the LDR3 and our other passive models are dead quiet. Simply put there's no active direct contact between a power supply and the incoming audio signal as there is in all conventional active preamps. The noise you hear to varying degrees from many active preamps is actually the residual noise coming from the power supply. Better active preamps have better power supplies with better filtering and PSRR (power supply rejection ratio) and thus tend to be quieter. Still, when cranked up high, most active preamps produce some level of hiss that can usually be heard with the ear close to the speakers while no music is playing. In this respect passives are usually always quieter with blacker backgrounds and more space between the notes.
One possible exception to this is when mating a passive preamp to certain amplifiers that are DC (direct) coupled. Some direct coupled amps are sensitive to the presence of any DC offset in the signal coming from the amp. A passive preamp doesn't create a DC offset but it doesn't remove an either. If there's a DC offset coming from a source, it gets passed through to the amp. With an active preamp, such offsets are most often blocked via either an input or output coupling capacitor - or both. That same DC coupled amp may also be fussy about connecting to a passive preamp if the preamp's output impedance is too high (too high for that specific amp, not too high for others). The net downside in these instances can be noticeable hum. While Tortuga passive preamps do have adjustable input impedance, the output impedance is inextricably linked with the input impedance and the resulting output impedance will never be flat/constant and may be too high for a particular DC amp.
The vast majority of amps are AC coupled and not DC coupled. Thus, the above exception has proven to be quite rare in practice. Plus with our 30 day in-home buy-try-decide audition policy you'll KNOW after putting one in your system if yours is an exceptional case or more typical. We don't hang people out to dry if our preamp isn't a good fit for your system. Just return it within the 30 day audition window for full refund less your cost for return shipping.