Fidelity Research FR-64x

Raul, i have various tonearm and some of them designed with Baerwald like my Reed 3p "12, some of the others i can readjust easily with my Feickert. But as i said, i trust manufacturers. For example SONY PUA-7 has its own geometry and its own protractor, look here. I’m not so paranoic about distortion level in my system, but i want to learn (and i want to hear) why one geometry is better than another one. I have time to learn this process slowly with different arms and cartridges. If it’s clear for you it’s not clear for me yet.

Have you ever read Stevenson’s explanation about his method ?

P.S. Passive amps is easy to check for coloration, we can simply connect our source directly to the power amp to play some quiet tune, then we can add preamp in between to compare the sound signature. If we don’t need a buffer to solve impedance mismatch then there is even simplified device like the LightSpeed Attenuator. Using devices like First Watt B1 or LightSpeed Attenuator with a proper power amp we can save at least $2000 on active gain preamps. I like this concept, but i never tried the LightSpeed Attenuator, i use First Watt B1 passive buffer preamp. 

It’s not a passive preamp. It’s a buffer. Passive preamps are horrendous. They have massive distortion and completely bastardize the original signal. They are complete and utter nonsense. Connecting source directly to amp will sound horrendous. In all honesty, you should really get a real preamplifier as buffers only are not the best either.

There’s nothing transparent about passive preamps as the potentiometer will have a significant impact on sound. And most of these potentiometers are worthless garbage. Especially today. Good stuff is no longer made and eBay pots are all 100% fake Chinese trash.

Passive preamps are made by people who know 0% about electronics and how circuits work.

@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.