Simplistic NJFET RIAA

[iko]

Oh yeah, thanks salas, I'm totally psyched up now.

Hey, Rcruz, point to point can be quite easy if you strip a thin wire and solder the parts along it, if they belong to the same network branch. I'm not in the mood to etch a board so I'm pretty sure I'll use some of the fine silver wire I got cheap from fleabay and I'll probably stay with ptp. Nothing wrong there.

jonners, can't wait to hear more about the sonics.

 

[RCruz]

Teflons - 2 in parallel for series RIAA caps.

What a coincidence! I just came back with a couple of those! I want to try them for inter stage coupling in the RIAA. You are appointed as the official burn in authority and sonic compatibility reporter before I remove the CCCP Polysterenes and try those. Please let me know if I must do the operation doc!

The pictured caps indicate different values...

In the schematic C1 = 100nF, in the first case we will have 116nF and in the second a little less then 100. Does it mean we can modify C1 value ?
What should be the effect ?

Ricardo

 

[Salas]

With 100nF the roll off is nicely low. The phase won't twist that early.
In case there is a superior capacitor to try, I would advise no less than 33nF for a little less than 10Hz turn. Essentially the same question has been discussed also in posts #597,599. Jonners can tell us if there is any subjective impact, negative or positive, if he will disconnect one 56nF.

 

[RCruz]

Thank you Salas

So it is a coupling cap.

I did not know if it would modify the RIAA curve.

 

[jonners]

With 100nF the roll off is nicely low. The phase won't twist that early.
In case there is a superior capacitor to try, I would advise no less than 33nF for a little less than 10Hz turn. Essentially the same question has been discussed also in posts #597,599. Jonners can tell us if there is any subjective impact, negative or positive, if he will disconnect one 56nF.

Minor cap-ectomy operation was performed as proposed. No audible or measurable loss of bass as a result. Conclusion: Patient is happy and healthy with just 56nF in series.

Dr Jonners

 

[Salas]

Expected medical theory result confirmed by field surgeon.
56nF does safely low for frequency and phase turn in our 1MegOhm second stage load. 56nf turn the phase only by 8deg @ 20Hz. 33nF by 14deg. Both acceptable but 56nF is more correct. If anyone is buying, better look for the 56nF. Also the K71-7 120nF green PP metalized foil and Polysterene separator CCCP military cap that I already use is really good, amongst best metalized caps but cheap. Going to upgrade for K72P-6 too. This film and foil Teflon is even better.

Regards.

 

[nicoch58]

mods

I have some idea to rebuld the AC cable...

for now I have mod one mains distribution blocks ,were are the phono and TT motor

delete the cheap emi filter
delete the cheap thermal brake ,better than fuse but ring ......
add new 0.47mf X2- murata diff/Comm Mode coke-0,1mf X2 for phono

unfiltred for motor

after the stealt mod my test sibilance LP sound a little pronunciate now are ok

can I put this Emi for motor ? (are in my previous amp )

 

[Salas]

I know that it can help amplifiers, I am not sure for motors. I know that isolation transformers help AC motors by experience. You must try and tell us. Best such circuits use common mode choke though.

 

[RCruz]

I was waiting for this oportunity for some time now!

"Filter the motor psu with a common choke."

Hope it works as it is very easy to implement.

My 500VA toroid "Maggeddon" is direcly fed from the mains and feeds 110v (initially220v) to the motor.

Very rewarding as is but I would like to know if filtering the motor psu should bring more noticeable benefits.

PS: Cart loading tests:
After using 464r, 1k 27k and after combining 27k with 4700pf 3300pf 560pf 330pf 120pf and no cap on the cart load, I finally settled on 37k without cap for loading the Benz M. Maybe it likes 47k after all.

VTA is so evident right now ... unbelieavable... (must decide between 15 or 16 cards height )

Ricardo

 

[nicoch58]

the filter idea are only for isolate better amp/phono to motor and 220v wire from pick up rfi ....

but yes can helps the motor , side effect



Jon Risch emi filter

link

 

[nicoch58]

HI Salas as I want put the Shunt in a cheap hammond alu box

how are your pcb size HxWxD of you single b+

thanks

found 40vac trafo

 

[Salas]

Hi,

Unfortunately I did not measure its size. Maybe you can extrapolate from this picture?

 

[nicoch58]

fine ok

thanks

 

[Salas]

Additional inter stage coupling caps to try soon, along with the CCCP Teflons. K40-9 paper in oil 400V 0,1uF.

 

[es44]

I'm finally finished with my first attempt

Did the 36dB version, but need a little more gain, so next one will be the 46dB. It seems i can just lift the voltage 4 volts, and change a few resistors. Should be easy. ( well, at least for some, i always find a way to mess up, hehe )

Thanks for making this possible Salas.

An externally hosted image should be here but it was not working when we last tested it.

 

[Salas]

Hey, nice!

What kind of MM you have and you need more gain?

BTW nice compact PCBs. Are they final to post?

An externally hosted image should be here but it was not working when we last tested it.

 

[es44]

Actually i don't know what pick-up i'm using There's no name on it, so i suspect it's a cheap one, that someone put there long time ago.
BTW, my TT is an Akai AP-306t.
I know i need a new cartridge, but finances are a little tight at the moment, so i have to make the best of it for now.
I'm not really satisfied with the PCB yet. I have some issues with transistors being defined wrong in the library, and some things i have to define myself. Bit of a job, me being into car-repair, and not electronics, hehe.

Best regards
Ebbe

 

[Salas]

Did you notice any better turntable replay with what you already have?

P.S. There are really cheap MM out there, considered very good. Like Audio-Technica CN5625AL.

 

[enzedone]

This what I am using at the moment.

Manufacturer: Audio Technica
Model: AT-110E
Cartridge Type: Moving Magnet
Output Voltage: 4.5 mv
Freq Response: 20Hz - 22kHz
Recommended Load Impedance: 47k ohms
L/R Separation > 25db db L/R Balance < 2db db
Stylus: Elliptical Cantilever Aluminum
Lateral Dynamic Compliance: 15 x 10-6 cm/Dyne
Static Compliance: 20 x 10-6 cm/Dyne
Cartridge Mass 7.2gm

Could this be used with your standard circuit
This is one of those really cheap ones.

Thanks

 

[Salas]

The 110 is a long going favorite indeed. But since you jumped from the extra low budget $30 CN5625AL to the $70 territory, we must also not forget to mention the Grado Black for $60.