Simplistic NJFET RIAA

[alexkosha]

Two red and two green led's are fine.It's what I ended up using.

Opps, I'm not alone using such tandem. Thank you.

 

[alexkosha]

Hi Alex

I used these for the 4.7uf caps

http://www.hificollective.co.uk/components/mundorf_mkp.html

I also ended up using (after re-measuring) one greed LED for the 3 string 5.58V which gets me spot on.

The Cardas solder is superb and great to work with so I’m sure that you are going to be happy with that choice.

Hi shoom,

Thank you for your advice. I'll might order this.
For solder, I used WBT leaded till now and it is an excellent product. However, it is very expansive and I'll probably go for Cardas.

 

[alexkosha]

When I see me referred as "salad" I know its Android.

No, it is my iPhone 5S magic

 

[Salas]

IOS or ANDROID saladise me the same.

 

[BigE]

The folded has a B1 like buffer of its own, maybe you could skip it and couple with small value cap from Q4/R10 node to the general input B1 section of yours through a selector switch.

If the folded has a buffer of it's own, then could you just add a potentiometer to it to make a single source system?

 

[Salas]

Yes, if the -10dBV nominal output level is enough and the amp will like a pot without extra buffer like having a DCB1.

 

[BigE]

Thank you Salas!

What value of pot would be acceptable here?

 

[Salas]

10K even.

 

[RCruz]

I thought that I had found the cause as one of the interconnects was somewhat loose.With different cables all seemed well until 40mins of listening.The crinkling noise doesn't interfere with the listening only being noticeable when close to the speaker inbetween tracks.

Hi Marra

Had the same issues several times on previous builds. Always found the problems related to cold solder joints.... look for connections between the shunt output and riaa amp... look also at the riaa filter components.

 

[Marra]

Hi Marra

Had the same issues several times on previous builds. Always found the problems related to cold solder joints.... look for connections between the shunt output and riaa amp... look also at the riaa filter components.

Thanks RC.I'll hopefully sort things tomorrow.

 

[Erlend Sæterdal]

Yes you can use 7.6V matched between channels. Its we got VR2X & VR1 to still bias right in all somewhat different cases.

I do not really understand the function off VR1 ?



Here is my finnished Build using 2,2 uf 160 V Pept caps instead off the 22 uf.

Touching the box with cover on after 1,5 hour I can not feel it is hot at all. Adjusted to 4 v between. C3 in and Gnd. Adjustement do not change much after the first 5 minutes.

Voltage in is 46 Vdc

Now I am looking forward to hear it somewhere . I do not have a Turntable

 

[Salas]

VR1 is there to help if VR2x is not effective enough and B+ between channels goes too different unbalancing gain. This could be due to different input pairs IDSS or other tolerances. Something like coarse and fine. But not engaged unless needed. A spare.

 

[Salas]

Looking well finished and with stable bias. Congrats. What is the B+ you ended up with by the way?

 

[Erlend Sæterdal]

30,46 v in both channels. My 117 is within 1 %

 

[Salas]

What 369s IDSS and what R2 & R3 values?

 

[Erlend Sæterdal]

Sorry I did not measure the 369. Teabag did it. R 2 and 3 is 10 R

 

[Salas]

Alright. Next move is to find some good TT to hook it up for a session now. It should take some play time for the BGs and NOS in PSU to settle.

 

[Salas]

How you decided R2, R3 will be 10R without knowing the 369s IDSS? Came paired with resistors in some minikit?

 

[presbel]

Hi Salas,
Can I use the attached MKP 4.7uf?

 

[Salas]

Yes its an SCR.