Recent content by nux
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A Very Compact Hybrid Amp
The flash is from a small bit of thin filament with a low resistance when cold, when heater voltage is applied a large inrush current goes through, the small filament heats up quickly (flashes), increasing in resistance which then allowing the main heater to warm up with the current stabilising.- nux
- Post #1,594
- Forum: DIY (Do-It-Yourself) Discussions
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create LED warmup time with Capacitor
Quote: Originally Posted by cerbie You can drive an LED quite well with a voltage source (LM317+pot+spare DIP socket--try it). However, 20mA is more likely to be the same brightness between samples than 3.0V will be. I like real ones better than text book ones. Things do start...- nux
- Post #18
- Forum: DIY (Do-It-Yourself) Discussions
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create LED warmup time with Capacitor
Quote: Originally Posted by cerbie The thing is, 1ma could be 2V, 10ma could be 2.5V, and 50ma could be 3.5V--not a nice neat voltage scale (it's logarithmic, as is your perception of light). So, with a plain RC circuit, you would be ramping voltage, the LED would appear to turn on late...- nux
- Post #16
- Forum: DIY (Do-It-Yourself) Discussions
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create LED warmup time with Capacitor
Logarithmic, so at first the change in brightness is large, but as the current goes up the change becomes smaller. I would look into PWM circuits, adjusting the duty cycle from 0-100%.- nux
- Post #10
- Forum: DIY (Do-It-Yourself) Discussions
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create LED warmup time with Capacitor
Quote: Originally Posted by nullstring Tridacnid: whats a CCS chip? Punnisher: I want a gradual warm up.. not one that is instant after a few seconds. CCS is a constant current source. LED brightness depends on the current, not voltage. So you cannot simply use a capacitor to...- nux
- Post #8
- Forum: DIY (Do-It-Yourself) Discussions
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Cavalli Audio: Embedded Hybrid Power amplifier (EHPA)
I would be really interested in being in the prototyping phase, can I put my hand up? How much power output would it have?- nux
- Post #2
- Forum: DIY (Do-It-Yourself) Discussions
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Cavalli Compact Tube Hybrid (CTH) Tube & Tweak thread.
Quote: Originally Posted by smeggy Switched it down to 6v, plugged in the 6n6p and off it flew... nice bass increase over the Siemens and the rest sounds damn nice too. I'm very happy with it especially considering how cheap these tubes are. I like how this sounds a lot Big tube...- nux
- Post #157
- Forum: DIY (Do-It-Yourself) Discussions
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A Very Compact Hybrid Amp
Would anyone in/near Australia be interested in a completed CTH amplifier? I made five, and one person pulled out of paying for one.. So I have a spare fully made and tested, with the C3H modification and perforated top (thanks wiatrob!) and the choice between a few different tubes I have...- nux
- Post #1,470
- Forum: DIY (Do-It-Yourself) Discussions
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Wall wart question
Quote: Originally Posted by Jingo Lingo Thanks for the replies. I have a multimeter so i'll try that out. Would you think the power supply needs to be exactly 500mA? Could I get away with using a 400mA or 600mA wall wart? The current rating is its maximum supply current. Hence it...- nux
- Post #10
- Forum: DIY (Do-It-Yourself) Discussions
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diy noob: best sound from my mbp (which dac + amp)
I am using a gamma1 with the optical out of my MBP.- nux
- Post #3
- Forum: DIY (Do-It-Yourself) Discussions
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PSPICE help
R and C should be in some generic library, I think it is 'ANALOG'. A lot of what you have is unnecessary for simulation, get rid of the charge port, iPod dock, 3.5mm jack and switch. Use a resistor of 32ohm (or whatever your headphones are) to simulate the headphone output, use a Vsin (from...- nux
- Post #4
- Forum: DIY (Do-It-Yourself) Discussions
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DIY Bench Power Supply
Here are a few schematics for ideas: Variable PSU 0-30 VDC STABILIZED POWER SUPPLY WITH CURRENT CONTROL 0.002-3 A 0-15 Volt Tracking Power Supply Using a multi-tapped transformer with some comparators and relays would allow you to have the input to the regulator switch to the appropriate...- nux
- Post #39
- Forum: DIY (Do-It-Yourself) Discussions
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Finishing my amplifier design.
Yep he means SPICE (Simulation Program with Integrated Circuit Emphasis). It will allow you to simulate the circuit and analyse voltages/currents at any node, and a lot more. There are a few free ones available. And if you want people to comment on it, just attach your schematics to your post.- nux
- Post #4
- Forum: DIY (Do-It-Yourself) Discussions
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various questions from noob
Quote: Originally Posted by Mizu So if I understand correctly, a Dac will do a better job than the Mini3 on itself when converting digital signal coming from a computer/mp3 player ? A DAC converts digital to analog. The Mini3 does not do this, it takes the analog audio signal...- nux
- Post #5
- Forum: DIY (Do-It-Yourself) Discussions
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A Very Compact Hybrid Amp
Just thinking out loud, would a ripple on B+ cause hum? Has anyone looked at the B+ waveform loaded/unloaded? Of course, make sure your oscilloscope can handle ~100V inputs (or AC couple it). Is VG stable compared to SG? And is it recommended that SG point be connected to anything? I've...- nux
- Post #1,282
- Forum: DIY (Do-It-Yourself) Discussions