My Building Plans: Comment and suggest...

Ok, I'm going to make a stereo IGC with the following features....

-stereo out
-3 inputs
-volume control
-front power button
-front source selector button

Implimentation...

-RCA Inputs
-Discreet Transistor Buffer as shown on Decibal Dungeon w/ BC547 transistors
-- Question: Should I buy a bunch of these transistors and run a test circuit to find the 3 best matches?
-Big input caps, I'm thinking 4.7uF solen poly's
-alps blue 50k log pot for volume
-Analog SSM2404S to control audio switch
-Wood Casing with copper foil for shielding of signals
-320VA 22+22 secondary torroid transformer from parts express
-Quantum Research QT110 capacitive buttons for front panel (to keep a nice clean front) through wood
--1 button per input
--Single Power Button to turn off and on
-Led's behind power knob glow when the amp is on, letting light leak out from behind the volume knob.
-Passive Heatsinks with slots in bottom of casing to vent heat
-Soft Power on (delay) to minimize power on thump and buzz
-Discreet Rectifier bridge
-Snubberized Power Supply
-Seperate power supply & small shielded transformer for logic chips
-Seperate power supply for buffer (fed off main torroid)
-Shielded Input Line Filter (inductors, caps, and resistors)

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These are just ideas I've been plinking around with. If you have any recommendations let me know. Also just so you know, the first pair of speakers this amp will see (other than my disposable crappy test set) are a pair of Paradigm Atom v.3's. So the load is pretty easy, but I want to make this amp power most speakers.

Question: Is there any merit to the T-Feedback setup? I read about it, but there isn't too much talk on it.

Question: Can I just setup my pot in front of my buffer as I normally would?
 
I plan on making the whole face flat. Then a volume knob sticks out on top of that. Then drill 3 holes equally spaced near the volume knob center (lil ways out) in the casing. Install normal brightness LEDs pointed straight at the knob but recessed so they don't stick out at all. Finish the back of the knob in a high gloss finish. Then just let the LED light hit and bounce back and forth between the knob and caseing, making a nice smooth, not harsh light.
 
Stocker said:
Stand by for three points of light around the knob. Unless you do some further surface treatments, you will have a good deal of a point-source effect from each LED, I think.


I think with 3 LED's spaced 120 degrees off from each other around the shaft it would be pretty even, maybe a slight off glow. And don't forget the light will be diffused behind a pretty large knob. Plus the given light is purely from reflecting back and forth from the knob. I have a feeling it will work. Maybe I'll get some scrap and do a test run before I go all out on the casing.

I'll post pics of what I find.
 
i think the closer you place the leds to the shaft, the better it will look.

also, i would caution you against a high gloss finish. i personally will be use a very bright white paint finish on the back of my knobs. think about it, a mirror finish will reflect light precisely and laser like. it wont diffuse it, a white finish is still reflective, but will tend to diffuse more.
kind of like seeing a led through saran wrap versus through waxed paper.
 
homer09 said:
i think the closer you place the leds to the shaft, the better it will look.

also, i would caution you against a high gloss finish. i personally will be use a very bright white paint finish on the back of my knobs. think about it, a mirror finish will reflect light precisely and laser like. it wont diffuse it, a white finish is still reflective, but will tend to diffuse more.
kind of like seeing a led through saran wrap versus through waxed paper.

Point taken, high gloss white finish it is.
 
also, from what ive been thinking, look to buy large angle LEDs. there is something called a viewing angle usually specified in the datasheets. the wider, usually the less bright and led is, but you dont care, you want the light to be spread. i got 70 degree ones, that are also HI brightness.

just some stuff i came up. also thinking, test matte paint too, or semi-gloss, if you get spotted diffusion.
 
I'm leaning toward using the mauro Penasa version as previously suggested. Seems like a nice setup and for toppers the PCB has already been designed and tested. piece of cake.

That means I just need to design the logic portions now. :) I just ordered a bunch of copper clad (2 and 1 sided) off ebay so PCB's will be sure to follow.
 
another ideas for the backlighting would be like this....

take the face. Cut a circular hole...say 3/4" diameter. Now cut a piece of circular lucite 3/4" diameter. Now drill a hole 1/4" diameter for the shaft of the pot to fit through. Put LED's shining on the lucite and it should diffuse everything quite nicely...plus you could bring out that shaft of lucite a bit to help throw the light out a bit too.
 
asgorath said:
I'm leaning toward using the mauro Penasa version as previously suggested. Seems like a nice setup and for toppers the PCB has already been designed and tested. piece of cake.

That means I just need to design the logic portions now. :) I just ordered a bunch of copper clad (2 and 1 sided) off ebay so PCB's will be sure to follow.


glad to see you like my suggestions :)

if your quick i think you can still tag on to this group buy and save some money on the parts:

http://www.diyaudio.com/wiki/index.php?page=Mauro+Penasa+GC+Parts+GB
 
homer09 said:



glad to see you like my suggestions :)

if your quick i think you can still tag on to this group buy and save some money on the parts:

http://www.diyaudio.com/wiki/index.php?page=Mauro+Penasa+GC+Parts+GB


I'll just make my own PCB, I already own some of the parts, and I need to make an order to the suppliers for other things anyways.

I'm really looking forward to this and have put alot of thought into it. I think you guys will be impressed with my first gainclone.