Simplistic NJFET RIAA

[Joao@AltheaMusica]

Originally Posted by RCruz

1. Would you give me a hint about one or two OEM phono preamps that actually use a 4rth pole in the 50kHz ? Today I am atending another Audio Fair and would like to know.

2. Do you mean that building a low impedance iRIAA is more acurate than building the RIAA itself ?

3. I am strugling to reach the optimum curve but it seems there are many ways to reach Rome.....

to 1.
I don't have an overview about phono preamps, OEM or comercial, and the circuits. I prefer using the wellknown designs with 600R LCR-RIAA or an equivalent 600R RC-RIAA. As well I don't care about the 50kHz 4th pole. Maybe I'll do this with my next RIAA design. Anyway I never had the feeling something is wrong with the sound without the 50kHz pole.

Have fun at the show

to 2.
Important in measuring is to know how it's defined and how to do / define. For example, your generator has an output impedance of 600R, then your iRIAA with 600R is a perfect match and the high input impedance - i.e. 10K - of the amplifier results as voltage matching.

To have an accurate iRIAA with perfect measuring conditions allows you to adjust your RIAA perfectly. The sonical result is another point of view but comes from the parts choice and their harmony, another thing is the load from the cartridge....

to 3.
Rome sweet Rome

By the way, Mariza gave another great show here... What a voice!!!

[RCruz]

Obrigado João

I also love Marisa´s voice !

[merlin el mago]

Just for fun, some photos last setup:

Phono RIAA


PS


How different size is the same 10.000uF 63V Jensen 4 pole vs Epcos Sikorel

[Salas]

You organize it better with each step I see. Good job.

[RCruz]

Looking good !

In the psu I see only two rectifiers per channel... Are these double ?

I am quite interested in your opinion regarding sikorel versus jensen....

[merlin el mago]

@Salas
Many thanks, tomorrow I will start the Rs

@Ricardo
Yes the rectifiers are doubles, I don't compare but possible do a new PS for the regs. & phono RIAA with them to compare against Sikorel, but mine opinion is that are better the Sikorels, I will let you know.

I added the silver mica caps & the resistors to the RIAA with exact values as per your suggestion + 2pF to reach 16nF.

Subjective impressions: 1st is the bass control & now can follow him easily, the mids are rich & full, the highs are sweets, in general seems the music less lost like more tight or focused, also seems more soundstage & more separation between channels, the stereo effect is more marked. Very, very good job Ricardo.

If I extract the 2pF what happens with the sound?

[Salas]

Things are evolving well for you. I have posted how to apply Rs on your particular reg sometime ago in the regulator only thread, I think you have no further questions about it? Remember that for the regs to work at all on Rs, the force and sense wire pairs should be connected at the load end.

[merlin el mago]

Let me start the Rs & after I will let you know in the thread Simplistic Salas Low Voltage regulator if I have any doubt

After the Rs I will start with the Hypnotize reg., be sure that I will post something in the correspondant thread but I wait that I not become Hipnotized

[merlin el mago]

A photo to see how is actually mine VTA:



Now seems a little backwards, what do you think?

[Salas]

The 103 has conical tip and much VTF, gets a little less affected than others, normally it gets mellower when looking up. I have seen that vertical tracking force can affect enough. Did the tone change for you now? In what way? Does it track well in general on the Ekos? Is it a Lingo driven deck by the way?