Okay,I go back to where it worked,the original CCS 300v/15mA,worked fine.My idea besides CCS for the Led´s(Do you have a suggested dessign-NPN-?)was direct coupling,that´s why the higher voltage 495v.
Will an RC filter be enough to bring the votage down to safe level(300v)or shall I use a SS regulator?
4.
Will an RC filter be enough to bring the votage down to safe level(300v)or shall I use a SS regulator?
4.
Ryssen said:
The NPN design is with the others in the earlier thread about CCS PCBs. A correctly-designed RC filter will be adequate to bring the voltage down to <300V (I would suggest 250V).
I repeat that you need to learn more about theory before attempting to modify designs. You can learn about "boring" theory or you can live with "exciting" explosions/smoke and destruction of expensive components. The choice is entirely yours...
hi ryssen,
please visit duncan amps website for the models of the different devices. the site also has instructions for using a tube model.
When you click on Component from the toolbar, you selected a diode and it was labelled D1 D.
Now, insert the model entry for the diode, example 1N4004:
.MODEL D1N4004 D(IS=2.55E-9 RS=0.042 N=1.75 TT=5.76E-6 CJO=1.85E-11
+ VJ=0.75 M=0.333 BV=400 IBV=3.95E-5 )
Copy this text, press S on LT Spice to insert a Spice direcftive. Paste the text.
Then Right Click on the D label of your diode and type D1N4004 into the text box.
That's my OT answer
please visit duncan amps website for the models of the different devices. the site also has instructions for using a tube model.
When you click on Component from the toolbar, you selected a diode and it was labelled D1 D.
Now, insert the model entry for the diode, example 1N4004:
.MODEL D1N4004 D(IS=2.55E-9 RS=0.042 N=1.75 TT=5.76E-6 CJO=1.85E-11
+ VJ=0.75 M=0.333 BV=400 IBV=3.95E-5 )
Copy this text, press S on LT Spice to insert a Spice direcftive. Paste the text.
Then Right Click on the D label of your diode and type D1N4004 into the text box.
That's my OT answer
EL34 might be pushing things because of the high bias voltage requirements, but it could be done. If you've got 34V requirement, that's 20 red LEDs per string. You'll need 10 strings to handle the current. Let's see, for a 6 ohm per-LED impedance (you can do better, but it takes some searching), that's 120 ohms per string. 10 in parallel gets you to 12 ohms impedance, a bit higher than you might want, but not unreasonable (Dynaco used a 15.6 ohm resistor in that spot). So, it's possible, but with 200 LEDs per channel, perhaps slightly over the top.
Or maybe not so over-the-top. At surplus, I've been getting my LEDs-of-choice for a little under 5 cents. So that's $10 per channel for a stable and reliable bias supply. Hmmmm......
Or maybe not so over-the-top. At surplus, I've been getting my LEDs-of-choice for a little under 5 cents. So that's $10 per channel for a stable and reliable bias supply. Hmmmm......
Maybe when I get the time to do the individual testing and compiled 400 red LEDs, I'll do this.
Right now, there's no looking back for me. I changed my WE396A preamp to use LED on the cathode, and while it sounded good already with RC on the cathode, the LED puts it in a different league. I substituted the 2C51 and it sounded so good.
When I get back my 12B4, maybe I'll attempt the first step. I'll change its LM317 cathode current source with LEDs and check the difference. If I hear it then, I know what's the next step
red LEDs, I'll do this.Right now, there's no looking back for me. I changed my WE396A preamp to use LED on the cathode, and while it sounded good already with RC on the cathode, the LED puts it in a different league. I substituted the 2C51 and it sounded so good.
When I get back my 12B4, maybe I'll attempt the first step. I'll change its LM317 cathode current source with LEDs and check the difference. If I hear it then, I know what's the next step
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