Fidelity Research FR-64x

@invictus005 You’re right it’s a buffer, but it has no active gain!

I think you should read this thread first before talking about true passive preamps. Some users sold their $8k active preamps for passive $450 Lightspeed attenuator.

But I’m talking about Nelson Pass gear, i hope you know who it is and maybe you’re familiar with his innovative design of the amps.

We're going off topic here, i'm not gonna discuss it here

About First Watt B1:

"This suggests the possibility of using a high quality buffer in conjunction with a volume control. A buffer is still an active circuit using tubes or transistors, but it has no voltage gain – it only interposes itself to make a low impedance into a high impedance, or vice versa.

If you put a buffer in front of a volume control, the control’s low impedance looks like high impedance. If you put a buffer after a volume control, it makes the output impedance much lower. You can put buffers before and after a volume control if you want.

The thing here is to try to make a buffer that is very neutral. Given the simple task, it’s pretty easy to construct simple buffers with very low distortion and noise and very wide bandwidth, all without negative feedback." -Nelson Pass

Nandric, I don't mind your allusions to what might or might not be my own beliefs and practices, but where did I ever say that I am "trusting the designers by assumption that they know what they are doing"?  I really don't think I ever expressed that sentiment except perhaps in a specific context.  For example, with tonearm alignment, I could do my own geometry, but life is short, so I do rely upon the maker of either the tonearm or the template. As a lawyer, you should expect an "objection" to your generalization which as a judge you would have to "sustain". 

Anyway,  when I purchased my UNItractor from you know whom, he advised me to set the P2S to 231.5mm for the FR64S and then to use the FR64S-specific alignment template supplied with the UNI.  (For those who don't know, there is a separate dedicated template required for each and every tonearm, when you use the UNI; it comes supplied with a few templates chosen a priori by the buyer, and you buy any others that you need, separately.) In the case of the FR64S, I did do as I was advised to do.  Sounds great.

I am guessing the result is Baerwald.

Nelson knows his stuff, I'm not questioning the legitimacy of a buffer. But no way is a buffer better than an active linestage. And believe me, he knows this very well. Buffers are good for amateurs as they are simple to make and don't mess things up too much.

But that Lightspeed passive is nonsense. Putting a volume pot between your source and amp is so mind boggling stupid that I don't even know where to begin to explain why. 

You’d better join the lightspeed thread to get the answer from the manufacturer or from the users.

What i don’t need is gain, even FW b1’s volume control set up no more than 9’oclock in my system, the sencitivity of my full range drivers is 101db. I have killer gain already with my First Watt F2J current source power amp. This is a way different compared to my ex push-pull integrated tube amp.

btw: this FW F2J power amp is not a "voltage amp", but a "current amp" for crossover-less speakers only. I'm blown away by its performance with my Zu Audio Druid speakers. 

Voltage amp current amp who cares? And none of this has anything to do with gain. I don't need answers from the manufacturer or that thread, I haven't lost my mind yet.

Feeding a signal from source to amp through a volume control pot will massively attenuate and distort it. You'll have a major impedance problem. Source output will be bastardized in different manner depending where the volume is set. Things such as cables will have a tremendous negative impact.

Dynamic range will take a crap. There will be no sense of drive. A $10 receiver from the thrift store will sound better.