SuperTeddyReg - help needed in calculating values

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Hello to everyone,

I am planning to build SuperTeddyReg power supply and I am kindly asking for your help in calculating values in order to obtain +12V output voltage:

1. What voltage on secondary winding of transformer should I have
2. What would be the value of resistors R8 and R8A?

Thank you in advance for your kind asnwers.
Joined 2004
Paid Member
SuperTeddyReg - calculating values

Hi Willi,
1: Minimum 12 vac & max 15 vac
2: The value R8/R8a should be calculated to allow at least 2V dropout as described on the Teddy's site:

The dropout on the second stage (Vdo) can be calculated using the following formula:
Vdo = Vout / ((R7+R8)/R7) -1)
Using 100K for R7
Vdo = 100 * Vout / R8
R8 = 100 * Vout / Vdo
For a dropout of 2.5V
R8 = 40 * Vout
Where R8 is in Kilo Ohm​
Thank you for your kind response and sorry for getting back so late. After successfully built one STR, here are the values of components for +12V DC output, provided that voltage on transformer secondary is 15V AC and cca 21V DC after rectifier:

R1+ 47
R1- link
R2 22 K
R3 10 K
R4 100 K
R6 5K
R7 100 K
R7A 100 K
R8 680 K
R8A 680 K
R11 3,3 K
Q1 2SK363BL
Q2 BC550
Q3 2SK363BL
Q4 D44H11
Q5 BC550
Q6 2SK363BL
Q7 D44H11
C1 100uF/35V
C2 100uF/35V
C3 22uF/35V
C4 0,1uF/63V
C5 10uF/35V
C6 0,1uF/63V
D2 1N4148
Need help designing power supply with super teddy reg

Hello Willi!

I dropped across your post, because I was looking for a decent power supply for my new Furutech ADL Esprit (DC +15V, 800mA, from 220-240V)

There are commercial offers out there, but they cost almost the same as the rest of this DAC. I already had a SupperTeddyReg - Power supply in the past, so my idea was, to build one myself this time.

However, I am in an extreme beginner stage. I don't have the slightest idea on how to design and calculate the thing. I am of course able to buy the components and to solder... but that's about it.

So in case it does not cause trouble, my question would be, if you would be able to provide me with some link, where I can find an easy how-to...

Thanks in advance! Diego
Last edited:
Hello Diego,

you can order a built STR directly from the manufacturer according to the specs you desire (input and output voltages). For this, you will have to build the rectifier and filtering stage by yourself. You can also order just the bare PCB from Teddy Pardo who is very friendly and will gladly help you with calculating values for your power supply. In both cases, you need to specify the output voltage, as well as input voltage that comes into the regulator (usually the AC voltage on your transformer multiplied by 1,414).
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