Simplistic NJFET RIAA

[nicoch58]

Our guide should always be one step ahead of us

 

[RCruz]

there is T-network caps at half price if you want burn some money , fortunately you need only two


jensen 4pole (F&T stuff as mundorf....)

he Jensen totally wipes the floor with the other two capacitors. Above 10KHz there is nothing left of the noise. At 5KHz the noise already dips below 1µV (-120dBV).
I don't know about you,but I'll gladly pay €33,- for this kind of an improvement. look

Now we are talking

Where can I get the Jensen caps for 33€ ?

PS: What is a T-network ?

PS2: I recently read about the new Acuphase phono and the French mag quotes it has 2 x 22000uF sommthing per channel.

Should I increase the actual value (10000uF) ?

Ricardo

 

[nicoch58]

better quality then quantity but you can use caps-resistor-caps

the best caps is Epcos Sikorels

4pole-t-nettwork:
http://www.pinkfishmedia.net/forum/showthread.php?t=19871&highlight=jensen

were ...use google

 

[nicoch58]

Ricardo like it ? look better with two 120VA r-core

 

[RCruz]

I like your psu !

Where did you connect the coils ? (after the caps ?)

What are the voltage outputs ?

Do you use it to power a salas shunt ?

Sorry for the questions but I have been reading about the jensen 4 poles and would like to know if this arrangement might improve things in my setup.

Ricardo

PS: I tried bypassing the actual 10000u BHC with some ERO and things improved a lot in high freq... more detail and extension, but the sound became too forward.

 

[nicoch58]

sorry not my phono

 

[RCruz]

Well, it looks very good but I do not see the need for coils after the jensen 4 pole caps.

 

[nicoch58]

Salas ,I search with no luky ,you remember the jfet idss for my dual 45v shunt ? R1 15r



one channel done !

 

[Salas]

6-7mA for all JFets. Did you do it with R6 mod or not? Tested it?

 

[nicoch58]

Thanks!

without r6 mod , tomorrow test after match jfet ,

a lot work at same time,
new trafo driver ,16diode 8caps
power ,16diode 8caps,softstar
4 Salas shunt (2+/2-)...

 

[nicoch58]

one channel

 

[Salas]

Nice symmetric construction.

 

[nicoch58]

TT

 

[RCruz]

Very nice TT

Can you specify the type of caps in your shunt ?

Ricardo

PS: You MUST do the R6 mod.

 

[vgeorge]

Hi,

what kind of cart are you using?
What schematic are you going to use for the RIAA?

Regards
George

 

[nicoch58]

Ricardo ,
I put silmic, pana FC. and 1000mf Kg that is in my amp

Mod ,as for driver ,one for channell ,bc550 need heatsink and I have only 20 2sj74....I see, If I'm luky with match.....


George
the shunt are for driver stage of my amp
Koetsu black

 

[nicoch58]

Salas Helps !

low battery dmm drive me crazy

match jfet , smtp 12,4v (ok),plus MiniReg is a discrete pin-compatible drop-in substitute for the common 78xx from Greg ,but Ihave some problem ie voltage drop 1v on jfet some time

later with new battery I will tray again

if the problem not solved, better use a zener , or resistor to drop to 9v ,and after jfet stabilized set on variabile smtp, 9v across jfet ???

not lucky with j74 match

 

[Salas]

I just use a 9V battery, and the DMM in series between NJFETs (GS together) and +, set for mA measurement. Some crocodile clips, no special rig. For PJFETs I just reverse everything.

You can also use 2SK170 wired with GS together, D towards ground, instead of J74 in the negative regulator. See example.

 

[nicoch58]

thanks but the problem is on test idss

 

[Salas]

What is the problem exactly?