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Phono Card MB

A question about how to adjust voltages in the manner recommended by Neil above: 18V (or 19) front end, 27V back end. My DC voltage source (a 200VA toroidal transformer and a Hackercap) provides 35.3V Raw DC.

Assuming R1 is a 5K trimpot, what are the ideal values for R2, R3, and R4? FWIW, I do have the following values on hand: 1Mohms for R4, 93.1 Kohms for R3, and 140 or 158 for R2. But just as happy to place an order if these won't work.
 
These are the values that I used, R2-160R, R3-120K, R4-1M, trim pot 5K. If you need any of those values I have plenty. You could always put in what you have and try and adjust the voltages without the phono board fitted.
 
timH said:
Teddy explains all here http://www.teddypardo.com/diy/teddyreg.html
Click to expand...

So here's what I think Teddy says one should do to calculate Voltage:

Vlr (which, I gather, is the output voltage of the linear regulator) = (R2/R1 +1) x 1.25. Using the 3rd example from Neil's spreadsheet (R2=240 and R1 = 5600 and Raw DC = 34V) I get this:

240 ➗5600 = .0429.
.0429 + 1 = 1.0429.
1.0429 x 1.25 = 1.30V.
34V - 1.30V = 32.7 Vout

But Neil says Vout = 30.42

I'm guessing Neil is right. So what am I doing wrong?
 
The calc doesn't have anything to do with the Vin as such (except that the lm317 has a max drop of 37v). You've transposed R1 and R2 values. Try 5600/240 + 1 then x 1.25 to get 30.42
 
Argh. Well, I was going to say this originally but it is difficult to overstate how clueless I am about the pretty much everything with respect to how electronics work. The only thing I can do with some degree of competence is identify capacitors, resistors, transistors, etc. And I can solder. Not always well, but I can do it. With everyone's help I have been able to put together a B4 and a NJMB and even do some mods to a NAP250, but I really don't understand the inner workings of these things. So the truth is I just need someone to say what the R values should be.
 
I did say what values I used in post 103. Three of us have built stages using those values and they all work fine.
 
Right. I guess because Neil provided different R values for different raw DC voltage input, I thought that perhaps my R values may need to be different than the ones you are using (even though I know that Tim said that Vin doesn't figure into the calculation). But if they don't, I'll just use the values you used.
 
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