avr300 said:YoungSC, simplify your circuit by leaving out the gyrator (the transistor, C1 and R1) until you have a stable and usable reg.
I also have seen datasheeds saying BC547 should orientate "the wrong way", but I stick to my childhood learning. Flat side to the left, seen from the top, then you have CBE top-down.
http://www.fairchildsemi.com/ds/BC/BC547.pdf
BTW- what is your feeding voltage ?
edit - YoungSC - Andrew might have said it, your running it 5v.The zeners are drawing to little current. Try the LED trick.
editing myself. I have just tested the circuit with 8v in, 3.3v zener (2 in parallel) and 120R between out and adj. Getting a zener voltage of 3.28 and a output of 4.51. Just as expected. So it works.
I was at my local parts store this morning, I needed a few lytics for my cd67 psu. I wanted Pana FC as thats my usual choice but he had none in stock and offered me Nichicon PW which he says have almost identical specs. I was just curious if anyone has any expereince with these??
I was also thinking maybe we should start some sort of list of what capacitors are good for audio??
I was also thinking maybe we should start some sort of list of what capacitors are good for audio??
AndrewT said:
And lower their impedance. See this excellent article:
http://www.acoustica.org.uk/
"Using 3-pin regulators, part 1"
Hi,
It appears that impedance at the adjust pin is important.
then adjust Zener or LED current for minimum impedance will reward improved regulation.
are two Zeners sharing the current and thus running at half current each showing a higher or lower impedance? Is the resultant impedance lower than a single Zener on the same current?
Alternatively, would a tl431 on the adjust pin help or does that add too much complication?
I just found this reference and see you are pointing me there.
It appears that impedance at the adjust pin is important.
then adjust Zener or LED current for minimum impedance will reward improved regulation.
are two Zeners sharing the current and thus running at half current each showing a higher or lower impedance? Is the resultant impedance lower than a single Zener on the same current?
Alternatively, would a tl431 on the adjust pin help or does that add too much complication?
imperfectcircle said:One other thing, ive been looking through the posts for info on adding regs to the cd67. I want to give the analog and difital section thier own 5v regs and also he clock. I cant seem to finf the info on how to do this, its hard finding stuff among 500 pages
No, it's easy
For a start
http://www.diyaudio.com/forums/showthread.php?postid=1082612#post1082612
http://www.diyaudio.com/forums/showthread.php?postid=1082668#post1082668
no! if one doubles the current into the pair of Zeners then each Zener of the pair will have the same impedance and when you take account of the doubling in number then the resultant impedance will be half.avr300 said:
Just doubling the number of Zeners WILL NOT HALF the impedance. Which is precisely why I asked the question.
AndrewT said:
I didn't double the current. I kept it, and divided it by 2 zeners.
And I do agree - if you dubble the current you end up equal.
Vz = Vz + Rz*Iz
And that's also why one may expect a slightly higher zener voltage if Rz is eq. 20-30R and the current flow is 15mA, you end op .45v over the zener voltage. Not much on a 10v zener, but on a 3.3v it's noticeable.
Thanks AVR, but isnt that for the cd53/63?? Im looking for the cd67 which is a bit differant I beleive. I have these instructions for the cd63
"R511 is supply resistor to Decoder analogue
R508 is supply resistor to Decoder digital
RD04 is supply resistor to Dac digital
RD01 is supply resistor to Dac clock v ref
REMOVE THESE 4 RESISTORS. AND WIRE YOUR WIRES FROM REG PCB INTO THE
CORRECT SIDE (IC SIDE).
U199 is where you solder the wire for DAC analogue (solder onto link)
Cut and remove U200 (near CD15)."
But im looking for something similar for the cd67 and I cant seem to locate it. Any help would be great thanks.
Frankie
"R511 is supply resistor to Decoder analogue
R508 is supply resistor to Decoder digital
RD04 is supply resistor to Dac digital
RD01 is supply resistor to Dac clock v ref
REMOVE THESE 4 RESISTORS. AND WIRE YOUR WIRES FROM REG PCB INTO THE
CORRECT SIDE (IC SIDE).
U199 is where you solder the wire for DAC analogue (solder onto link)
Cut and remove U200 (near CD15)."
But im looking for something similar for the cd67 and I cant seem to locate it. Any help would be great thanks.
Frankie
Anyone else wanna help me out with either a link or some detailed instructions on adding the seperate regs for the dac, clock, decoder for the cd67?? Ive done this mod on a cd53 and it was a big upgrade so id like to do it for the cd67, but it looks a bit differant. I have a pretty good idea, but I want to make sure before I start soldering.
Thanks
Thanks
imperfectcircle said:
Hi,
One possibility: I have a CD67SE and got this advice (see my gif in that post).
My Earlier Post
Ray said yes looks OK (few posts later and added some other stuff I need to do.)
HTH
k,
I was using a 9V battery, now I have used a 12V source from an AC-DC adapter. It actually reads 15V with no load.
It read 4.85V when according to calculations it should show 5.85V. I shorted the 120ohm resistor and got about the same.
I should mention that I've created a dummy circuit across ground and output of 470 ohm. Is this causing the problem? Should I try it with just a connection wire?
It read 4.85V when according to calculations it should show 5.85V. I shorted the 120ohm resistor and got about the same.
I should mention that I've created a dummy circuit across ground and output of 470 ohm. Is this causing the problem? Should I try it with just a connection wire?
I've put together a 12V version using the right parts and connections but didn't attach the gyrator and I'm getting exactly 12V out
I did the same with the 5V version and I still can't get enough voltage out .
Did you suggest the LED's instead of the Zeners because they have lower impedance and therefore less current demand?
I did the same with the 5V version and I still can't get enough voltage out
.Did you suggest the LED's instead of the Zeners because they have lower impedance and therefore less current demand?