Simplistic NJFET RIAA

[RCruz]

Nice build Botte.

Where did you connect gnd from output RCA´s ?

Are output RCA´s GND connected together ?

[Botte]

Originally Posted by Salas

Botte:

Plain, effective, excellent. Congrats. What you had before?

I have an Allen Write FVP that I built many years ago. I lent it to a friend and he lent me his Pearl and the Pearl was more dynamic. So I figured I would make one. Then I was looking at your thread and realized that yours was more elegant with the shunt regulator and I had all the parts. So I threw it together and played around a little bit with the caps, it’s now voiced similar to the Pearl but I would say it’s a little more open and ambient. The Pearl was a little more focused and forward, but it’s very close. I’m sure you can go much farther with better caps; I had the MIT’s sitting around and bypassed them with polystyrene to get to the values matched. I’m quite happy with it.

Thanks again.

[Botte]

Originally Posted by RCruz

Nice build Botte.

Where did you connect gnd from output RCA´s ?

Are output RCA´s GND connected together ?

The RCA grounds are tied across the input resistor and the output resistor since this is the closest reference for the input and output. The chassis ground lug goes to the ground lug of the shunt. It’s very quiet even on my 98dB horns.

[vgeorge]

Seems like you have shunt regulator V1. You could try a BIB or V1.2 for a little bit better performance.

[mns80]

Over christmas I bought myself an old old Thorens TD150 mkII including a Shure M97xE cartridge and was in need of an MM phono, tried a couple of simple versions (pacific and similar) and found this thread.
As I already was trying different ones and they were so simple I tried the simplistic too, 37dB MM version as in the evolution pdf, some components to add and some to change and done. I played a little with R1, had a 100k pot there, and found that it sounds sweeter with it at higher resistance so at the moment I have it at 100k on the breadboard.
When testing out I started with a CRCRC+317 but it was too noisy so I tested Salas V1.2R shunt regulator and it was much better. Still some noise when cranking up the pre fully but I think this will get better with proper cabling and enclosures.
I like the combo so much that I am in the process of making some more permanent solution than in the pictures. Plan is to have powersupplies in one box and phono+pre in another.
First picture is the phono, second shuntreg and third the Thorens deck (somewhat halfway through some cleaning and cableswaps).

[Salas]

First time I see one done all the way on breadboard. Still some noise when cranking up fully he says...ain't that a something in such a prototype? Watch the 1.2R with oscilloscope on the power rail, it can oscillate in various layouts.

[Salas]

Originally Posted by Botte

I have an Allen Write FVP that I built many years ago. I lent it to a friend and he lent me his Pearl and the Pearl was more dynamic. So I figured I would make one. Then I was looking at your thread and realized that yours was more elegant with the shunt regulator and I had all the parts. So I threw it together and played around a little bit with the caps, it’s now voiced similar to the Pearl but I would say it’s a little more open and ambient. The Pearl was a little more focused and forward, but it’s very close. I’m sure you can go much farther with better caps; I had the MIT’s sitting around and bypassed them with polystyrene to get to the values matched. I’m quite happy with it.

Thanks again.

Very good results. Yes there may be more in special parts and regs versions, but I think you did very well already. Z foils for the load and the series Riaa resistor are two minimum hassle upgrade points, is a tip.

[dimkasta]

Awesome thread... I hope to read it from start to end at some point... Still working on it

I plan on building one for my 3,6mV Clearaudio Virtuoso (47k, 100pF load)

Will the HiMC/MM version be ok? My guess is that some less gain should be more suitable?

By the way, is there any store where I can get the matched JFets in Athens?

[Salas]

You need the MM setting that you will find explained in the PDF. Fanos store in Solomou Street maybe gets you K170BL on order or has some extras readily available if lucky, but matched isn't something stores offer. You buy many and you match yourself.

[df_genius]

I got my V1.2R regs debugged this morning (I tried to keep the layout as compact as possible), and have finished the phono section. I wanted to keep the regs as close as possible to the the phono section so used one board for everything. Using my old 15Mhz BK scope I can't detect any oscillation at all, I just get the noise of the scope itself at the highest frequency setting. I'm going to start installing into my pre-amp (using the baseplate as the heatsink) this evening, and have short a connection as possible to the input sockets. Here is a (bad quality) photo