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PostPosted: 18 Jan 2009, 12:48 
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Ri's real drill press died a while back. The dremel drill press is rather pricey and would be fairly limited. It is almost as much as a small inexpensive drill press that could also be used for enclosure work. I've used small hand push drills for PCB drilling in the past with good success.

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PostPosted: 18 Jan 2009, 12:58 
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I cant get over the flimsy build of the dremel press and the dremel itself. So, thats why I returned the one I had :)
However my big DP350 Delta Drill Press turned out pretty flimsy to.
Ri

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PostPosted: 18 Jan 2009, 14:13 
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I suppose they've gotten cheaper (china/more plastic?)
The dremel press (older) I have seems of decent quality and is pretty accurate for board drilling.


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PostPosted: 18 Jan 2009, 14:26 
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Ugh, board has a mistake in it. See if you can spot it! The resistors need to be tied and then the series resistor needs to go to output and the shunt goes to ground. I have both going to ground on one half of the board. Well, easily fixed by removing the lead and tying it to the other resistor.
Ri

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PostPosted: 18 Jan 2009, 20:27 
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I hate when that happens :eek:


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PostPosted: 19 Jan 2009, 10:31 
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Posted the following on DIYaudio yesterday while I was working on it..

Well, the first PCB for the lightspeed is goofed up. Notice that one of the resistor legs goes to ground when it should go to the neighboring resistor. I fixed that before trying it out.
My supply works well. I get 4.96VDC with no transformer and powering the supply from mains power. Nice and easy. When I connect this supply to the potentiometer I get 5.06VDC out of the potentiometer for some reason. Odd. I hooked an LED with 100ohm in series to the power supply to test it. It does vary the intensity of the LED. Not super smoothly though, it seems nice most of the way but some places have a quick increase in brightness.
Something went wrong though and its not making sense. Hope you guys can help out although after watching this thread the last week it seems no one is home. Anyway, If you check out the datasheet for my power supply you will see how I made it. Its exactly as on the sheet :
http://www.rohm.com/products/databo...df/bp5034d5.pdf
So, I hooked this up to the pot and then put the DMM on the resistor part of the LDR. I get nothing. Never registers that there is a resistor in there at all as I am varying the current with the pot.
The Silonex datasheet says max 2.5V but we are putting in 5V is this right? Must be.
If somone could look at my layout and figure why the resistors are not getting any light or why the LEDs might not be turning on let me know. I have tested and I do have 5V coming to them. GROUND is actually COMMON/NEUTRAL but 5V is 5V dont think that is the problem.
Uriah

Then this post this morning:
Well, I had polarity reversed. So now the LDRs are varying their resistance while I turn my potentiometer. Sweet I was worried something bad had happened.
Uriah

And finally :)
Hooked it up to my Harmon Kardon that is now only used to test stuff. This way if I had something reversed the HK would make sure that the power was still very low going to the speakers.
It did attenuate the volume when placed between the CDP and the HK.
So I hooked it up to my MYREFC dual amps and placed one junk subwoofer on one of the channels, nothing on the other. Tested and it worked.
Hooked up the Audio Nirvana 12" BR cabs and the MyRefC and the Lightspeed. Works great! Of course my daughter is watching "The Super Readers" and wont entertain a listening session right now. Will have to do that later.
And YES it is very very loud at 1/3 of a turn.
Uriah

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PostPosted: 19 Jan 2009, 11:01 
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Okay,
I usually get pretty excited when something I DIY works. Nothing new today. I am just ecstatic about this pre!
The sound stage is really wonderful. Everything is clear/transparent. Cymbals sound like cymbals as another DIYer put it. Its as if you can hear that there is nothing to hear in between the instuments. Very nice. This one stays! This is far better than any of my carbon pots. Its better than my wirewound, not leaps and bounds better, but definitely better. Better than having the B1 on the amps? Well, yep.. its better. So far the best pre even better than the dale based stepped pots. Loving it.
I like to listen to "I want my MTV" really loud for a new piece of equipment to be introduced to the rest. AWESOME! Always is but today its was amazing as well.
You guys are going to enjoy this pre if you build it.
Ri
Oh, and some people have mentioned that they had less bass with this pre. I admit to having a stunted system in the bass arena recently, but this pre has restored quite a bit of bass. Weird. I dont know why.

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PostPosted: 19 Jan 2009, 13:28 
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Hey Ri, that is great. :up:

Current draw is small enough that one run it off of one side of the chipamp supply with a 5V regulator if they wanted to use it in the same enclosure. Glad to hear it sounds so well too. I have to give some thought as to what I will use for volume control on the MyRefC.

Cheers

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PostPosted: 19 Jan 2009, 13:35 
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True, but I liked building a separate power supply for it. Especially one that uses no transformer and takes power straight from the wall to the power chip.
Neat stuff
Ri

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PostPosted: 19 Jan 2009, 19:39 
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Sounds like Ri got so excited, he must have left a little puddle on the listening room floor. HAHAHA


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