Simplistic NJFET RIAA

Hi Lampes, nice work, I’m really impressed. May I ask what enclosures you are using. I have been working on my own enclosure made from birch ply ant Aluminum sheet but had an unfortunate accident with a drill bit recently. I’m ok but the enclosure looks terrible. I’m thinking maybe buying something like yours may be money well spent. Thank you :)

Hi , they are the Italian made Modu, modu
I did a lot of work after that , with a second 6mm base-plate to put the pcb on it , for extra weight and rigidity, also there is no holes-screw heads underneath the units because of that. CNC work on air vents on that fat base-plate and CNC work on the letters and all holes for switch, connectors etc...
I used Kimber 8TC for power and internal connections, special isolation feet underneath
CLC filters with Hammond Chokes instead of just Capacitors
An expensive project...
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Joined 2006
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Technics SL-Q2 / Denon DL-301 MC
FSP MC High Gain
Borbely Class A line Amp (DIY)
Electrocompaniet, The Two channel Audio Power Amplifier (DIY)
Quad ESL57

The silver unit on top of the Line Preamp is an Esoteric E-03 Phono Preamp (SRPP ~$6000) which I use for test/compare my FSP

I really like the FSP phono a lot, it's been a while since the last time I listen to LP (15years maybe) so it was a come back to analogue sound.
After little tuning and break-in period for both Phono and Cartridge it turns out
very nice with powerful dynamic sound with very nice tone , extended stage specially on the front to back, and nice musicality. Compared to the $6000 Esoteric is by far more musical, maybe less dynamic, but E-03 is Very clinical in comparison it's sounds like a bad first generation CD Player
Also I almost forgot, DEAD Silent

Bravo Salas!!

Thanos

Very good build... what are those uge interstage caps ?

I like the red Jantzens bypassed by CD....
 
By the way 600mV pk-pk is 212mV RMS and Bix would have had a big loud hum at the speakers and not some "bit of hum" as he describes. The probe's very high impedance must be allowing more than his amp's input load or there is more mains earth looping between the scope and his handy test chassis. Especially if the probe is not on spring tip short gnd and near enough to that big trafo.

Hi Salas, you mentioned mains earth looping. I’ve been thinking about this and watched a few videos on oscilloscope safety with regards to this. Can I ask you whether a isolation transformer is required for audio work? Safety precautions aside, removing the earth reference from the scope, is this beneficial? What setup do you use to deal with earth loops? Thanks mate hope you’re well :)
 
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I wouldn't lift an oscilloscope's mains earth. The device under test can be temporarily lifted instead for confirmation of a mains ground loop existence or not. But the most noise problems in a measurement setup are of the common mode noise variety usually. Isolation transformers are good for powering devices under test against gross errors when servicing or experimenting on the bench, by avoiding earth loops with the test gear, and providing some HF line noise filtering also. I don't use something special myself because I don't do servicing of unknown equipment anymore or very rarely but that's not wise in general. Isolation is wise to have.

Transformer Isolation
 
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Hi Bix,
You asked the same question in this thread "My new Oscilloscope Keysight EDUX1002G". I responded there, but here it is again :
Hi Bix,
Under no circumstances are you ever to damage the mains earth connection in any way! Whoever suggested that just told you they aren't worth listening too. Wow!

A UPS won't help you in any way unless they are suggesting you unplug it and run "off the grid". I wouldn't if I were you. Most UPS' output a rectangular wave, not a sine wave. This is generally pretty noisy.

I use an isolation transformer, but if there is one piece of equipment that isn't properly designed, it's that piece that is causing your problems. Your Oscilloscope is designed correctly, the signal ground will be referenced to earth exactly as it should be.

-Chris
 
one more question , before going through the whole thread again ..

can someone point out where to install the following pairs of 2SK117GR ( Q2x,Q3x,Q5x on the integrated shunt power supply ? )

pair 1 : 2,96mA/2,97mA
pair 2 : 3,36mA/3,37mA
pair 3 : 3,50mA/3,50mA

I have another pair selected for Q7 , 4,97mA/4,96mA ... just for the records .

Thanks in advance ,
Happy Spinning , Paul
 
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Joined 2002
Paid Member
one more question , before going through the whole thread again ..

can someone point out where to install the following pairs of 2SK117GR ( Q2x,Q3x,Q5x on the integrated shunt power supply ? )

pair 1 : 2,96mA/2,97mA
pair 2 : 3,36mA/3,37mA
pair 3 : 3,50mA/3,50mA

I have another pair selected for Q7 , 4,97mA/4,96mA ... just for the records .

Thanks in advance ,
Happy Spinning , Paul

p1 q5x
p2 q2x
p3 q3x
 
Hello ,

Just assembled the boards plus raw supplies earlier today .
So far so good .

one board passed the bias adjustments flawless .. while the other doesn't seem
to cooperate .
I simply can't trim ( VR2x ) any higher than 30.2 VDC Rail , raw supply aprox. 42 VDC
Leds are working properly !
Any hints ? I assume I must focus on the shunt supply ?

Thanks in advance ,
Happy Spinning ,

Paul