Well, I wouldn't call it "complete", but it's close, and it only took 3 years, and that doesn't include the time researching and ordering parts. So here it is: a basic LM3875 inverted GC, ala Nuuk. With exception of two Black Gate Caps and a couple of resistors, all the parts, including the case materials, are from the local surplus shops. For the time being, I'm just running it in my shop off a cheap CDP with a passive vol. and cheap speakers, but I'm really impressed so far. Dead quiet and <20mV DC output. In hindsight, I wish I had sourced the components a little more carefully. Maybe I'll rebuild it with quality components.
Here's the first channel in May 04:
And the second channel was added in Aug 04:
I spent some time listening in my shop with a portable CD player and realized this had some real potential. It took a couple years popping into the machine shop on lunch breaks to put together a case:
And here is the result with the passive pre:
Is it complete...well, not really. I 'd still like to remove the dykem, buff the scratches out of the aluminum, build a new bottom since it's a little like swiss cheese after moving parts around and counter-bore the SHCS on the face plate. I guess that's next years project.
Dave
PS Thanks for the help of the board members along the way.
Here's the first channel in May 04:
An externally hosted image should be here but it was not working when we last tested it.
And the second channel was added in Aug 04:
An externally hosted image should be here but it was not working when we last tested it.
I spent some time listening in my shop with a portable CD player and realized this had some real potential. It took a couple years popping into the machine shop on lunch breaks to put together a case:
An externally hosted image should be here but it was not working when we last tested it.
And here is the result with the passive pre:
An externally hosted image should be here but it was not working when we last tested it.
Is it complete...well, not really. I 'd still like to remove the dykem, buff the scratches out of the aluminum, build a new bottom since it's a little like swiss cheese after moving parts around and counter-bore the SHCS on the face plate. I guess that's next years project.
Dave
PS Thanks for the help of the board members along the way.
Nordic said:Looks very nice!
Those exposed fuses bother me though, can't say I've never been shocked by them.
Nordic-
The primary AC fuse is mounted in an enclosed holder just above the IEC power socket, the exposed fuses are on the low voltage DC legs. I plan on removing the low voltage fuses once I'm sure everything is working properly, but I don't think they pose any danger.
Thanks for looking,
Dave
Re: I likey!
And there are two categories of these: 1) the ones I keep tweaking, and 2) the ones my wife reminds me about that really are NOT finished.
Thanks. Yep. the case is actually what took so long. I sneaked into the machine shop on lunch breaks when I could afford the time. It's pretty much a copy of the work others have done and posted on the galleries.
Dave
lgreen said:A lot of my projects take multiple years to make. But the truth is you are never quite done, are you?
And there are two categories of these: 1) the ones I keep tweaking, and 2) the ones my wife reminds me about that really are NOT finished.
markiemrboo said:I like the case! Did you build this yourself too?
Thanks. Yep. the case is actually what took so long. I sneaked into the machine shop on lunch breaks when I could afford the time. It's pretty much a copy of the work others have done and posted on the galleries.
Dave
case time
Great looking project! I completely understand about the swiss cheese bottom.
I'll bet for something like a GC the case will always take you far longer to complete than the circuit layout. I used an old computer case (IBM PCjr) and it took me a couple hours every night after work for exactly a week to get everything right. ( I kept changing the internal layout around also) I'm still working on it as I just got the parts to build the AD815 based pre and it also will be housed in the case.
Great looking project! I completely understand about the swiss cheese bottom.
I'll bet for something like a GC the case will always take you far longer to complete than the circuit layout. I used an old computer case (IBM PCjr) and it took me a couple hours every night after work for exactly a week to get everything right. ( I kept changing the internal layout around also) I'm still working on it as I just got the parts to build the AD815 based pre and it also will be housed in the case.
Audio_idiot said:My 1st GC, in 2005, using a PCB a friend made, took a saturday afternoon to complete.
An afternoon! What's the fun in that? I spent more than an afternoon cleaning off the dust between the down times! Just kidding, AI, that is a really cool case!
Dave
Hi Hewie,
I'm the impatient type.... My philosophy "A lousy singing amp is better then any silent amp"
Glad that you like the box, it was originally a tissue box, I replace the bottom ply with an 5mm thk aluminum plate (with some holes drilled) for better mechanical strength and double as the heatsink...
It was a LM1875, since the chip has very good PSRR, the power supply section was a breeze...
Cheers
I'm the impatient type.... My philosophy "A lousy singing amp is better then any silent amp"
Glad that you like the box, it was originally a tissue box, I replace the bottom ply with an 5mm thk aluminum plate (with some holes drilled) for better mechanical strength and double as the heatsink...
It was a LM1875, since the chip has very good PSRR, the power supply section was a breeze...
Cheers
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