B1 preamp and F5 power amplifier

The above is the B1 buffer preamp..

Pictures above are various builds of the F5..

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Both of the above items (F5 & B1)caught my attention this week.

Initially it was the F5. It started someone in the local forum wanna do a group buy to share shipping charges.. I did not realized that the F5's PCBs are 'cheap' and kinda simple to build up.

The existence of B1 buffer preamp I had known for quite sometime, which actually initiate me to build a 'low end' version of my existing buffer preamp.. I think it's time to play with 'bigger' toys..

Here are some pictures of the F5 taken from diyaudio, build by the respective forumer. The copyright of the pictures are theirs.. ;)

More info can be read at diyaudio.com. Get ready to read, at this point of time, a 150 pages worth of postings.. :D

Here's the link for diyaudio wiki: http://www.diyaudio.com/wiki/index.php?page=First+Watt+F5+Clone+PCB+GB++

LDR volume control - A passive preamp aka Lightspeed Attenuator.

I am aware of the above for quite sometime now.. Have read with interest and somehow it (the interest) 'flame out' for no reason.. maybe I'm 'not in the mood' as usual..
The thread at diyaudio.com can be found here.
It so happened that I read the same project at diyparadise.com this evening and somehow it striked me that the circuit is sinfully simple and cheap to do.. why the heck didn't I do it?
Details are here.

There were some problems with channel imbalance and diyparadise solved it by using a digital volume control. Handy of course with remote control.. ;)

What really hit me on the face is that this LDR (passive) volume control is far better than, (read this) : "We found the Light Dependent Resistor (LDR) solution to be much much better than ALL passive preamps we could lay our hands on. This includes transformer volume control, autoformer volume control, shunt/series resistive stepped attenuators, marque volume pots like Black Beauty... "

Damned! I gotta find out! So I have somewhat set my mind that this weekend will be LDR volume control week!

While reading the write up, I was thinking,
1. instead of using LEDs as the light source, why not use a proper bulb? Depending on voltage and wattage, I can certainly get the LDR to drop to a very low resistance.. better than the LEDs, right?
2. instead of using a pot for LED brightness control, why not use a variable voltage PSU? More precise control here.
3. instead of adjusting voltage to control the LED brightness why not keep the LED at a fixed brightness but control the amount of light to the LDR by other means? I have an idea like using something like a camera's variable aperture.. and some other contraption which I have in mind that need to be evaluate... all mechanical means..

Let me 'play' with the idea for a while.. will update this on my final version.
Could this be 'better' than my current buffer preamp? We'll find out soon..!

Cheers.