Have Passive Preamps Finally Come of Age?
1. I believe NPass is speaking to a perfect electronic interface world, which would necessitate building ones system around a PP, as opposed to trying to insert one into a active preamp system I believe it does, and that "perfect electronic interface" is available in systems much much more than not. 1: If the source has more output voltage than the amp has input sensitivity to give full output. This is maybe in 100% of cases. (I have yet to see a source with less output voltage than the amp needs input voltage to make it clip) 2: The ratio of output impedance to input impedance, of the source to passive and from the passive to the amps, are both 1:10 ratio or more, this also would be in at least 90% of cases. Then you have what you call, that "perfect electronic interface" for a passive to work as it should, which is getting the source signal to the amps in the most transparent, undistorted, uncoloured, unhindered way. Cheers George |
I think TVCs are the way to go passively and don't experience the loss of dynamics,TVC's are also great, but they do have their own colouration if you don't mind that, as that poor weak source signal has to go through a "mile" of very thin transformer wire winding and back out again, they are not as transparent to the source as other passives. Plus never get one with "gain" stay with unity, as they do have a tenancy to "ring" from the test we've seen. Cheers George |
When you they want to know several things about what you listen with, so the passive preamp can have its impedance matched to your particular system. If using a ladder network (no.2), the best, this is a bit of a sales gimmick, a 10kohm passive is what’s needed for most. EG: The only time I can see say a 50 or 100kohm passive being needed, is if the source has an output impedance of over 5kohm (yuck!) and the poweramp amp happens to be maybe a Rogue that has 1 megohm input impedance. If they use just a fixed series resistance and vary the shunt resistor (no.3) to ground, which is not as good as the ladder, then yes they can sort of tune it a bit better for different conditions, but this shunt series method varies wildly in it’s I/O impedance, unlike the ladder far more stable. I think you’d be better off just using an Alps Blue Velvet (RK27) or Alps Black Beauty (RK40) at 10kohm. See linked diagram. https://ibb.co/fXy008 Cheers George |
mrdecibel MrD you want a 10kohm passive, as that will serve most situations, as most s/s sources can drive 10kohm no problems, and a 10kohm pot has at worst around 2.5kohm output which will drive almost all poweramps >33kohm input. 1: For the cheapest option, you could go Schiit Sys, for $49 it’s 10kohm with 2 inputs one output. http://www.schiit.com/products/sys 2: Then there the Saga which is 10kohm passive with a better relay pot and it has output tube output select’able if desired 5 inputs two outputs. http://www.schiit.com/products/saga 3: There are a few LDR some passive including mine which mimics a 10kohm pot. I’m sure there are many others Cheers George |
Have Passive Preamps Finally Come of Age? Passive preamps are coming of age, not because of themselves, but because the sources today can do the job 90% of the time without the need of active preamps, and in many cases better, in some cases without the need of passives also if the source has it’s own volume control, which is becoming more and more the norm. I see active expensive pre’s as a bit of a dinosaur slowly becoming extinct, far cheaper more transparent/dynamic passives as an interim move, before all sources have their own volume control. But switching between sources will have to be worked out, but you definitely don’t need a mega dollar preamp to do a source switching job, a $100 dollar switch box can do that. Cheers George |
George always leaves out the rest of Nelson's wordsBecause 90% of systems are a great match for passives, and are the most dynamic /transparent way of getting the source to the amp except for going direct if you can do it without "bit stripping". Here's Wadia take on going direct and Mark Levinson does the same. https://ibb.co/kc4OCo Cheers George |
Just found their site, they have an extensive range, of what looks to be well made products, including a tube one http://www.hattor.com/index2.html#ultimate Cheers George |
These are two Hattor’s. Passive, which I believe you have, which what looks to be Kozmho switched volume control, which I believe is a fixed series resistor and variable ones to ground, which will vary it’s i/o impedance’s at different volume levels, best to me is ladder ones, where the series and shunt resistors work in opposites to each other to give a more constant I/O impedance https://www.audiocircle.com/index.php?topic=145833.0 And the active buffered Hattor which used an opamp. http://mockingbirddistribution.mockingbirddistr.netdna-cdn.com/wp-content/uploads/2018/03/Hattor-Min... Here are some different ways of doing a volume control, quad matched ldr is a ladder https://www.stereo.net.au/forums/uploads/monthly_2018_06/Capture.JPG.93bbd2ce49060300b06abfd1a62ce8f... Cheers George |
The PPs suck dry musical dynamics, timing and related details. That could be true if you weren’t impedance matched. An active preamp can’t "make" these out of thin air, compared to a "impedance matched" passive preamp, it's already there in the music that comes from the source. Remember what Nelson Pass says about passive preamps
Cheers George |
