Second gainclone...

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The first was built in a Radio Shack plastic case with Radio Shack parts less the chip and toroid. Initially it had hum which went away with time. It is now in amp heaven. This is my second with BG caps and Riken resistors. 50k Noble 31 step pot. The transformer is the 160va 15+15v (hammond) from Digi-Key & MUR860. Listening to it for about two weeks now and I have to part with it (gift). Which is a good reason to build a new one!!!

I posted the copper pipes a while back so I figured it only proper to follow through and pot the finished amp.
 

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Yes 4" copper pipe cut to about 2 1/8" to 2 1/4" long. I took it to a local hardware store and the guy cut it on a miter saw with a huge (12" or so, round) abrasive blade ($6 for 3 cuts). The heatsink is a flat piece of aluminum, 1/4" thick, cut to fit snuggly into the inner diameter of the pipe. It is held in by nothing more than its tight fit. The copper and heat sink are then countersunk into the bottom piece of wood. I would've liked to countersink the top as well but it was such a pain to countersink the bottom with layman tools that I didn't bother.
 
Hi

Have couple of questions:

- I can see you used liquid silicone to hold parts in place and dampen their vibrations. What if the chassis would go hot and the silicone will melt? Did you consider this situation? I have some silicone that looks just like that (used it to seal speaker cabs), do you know what kind of temperatures it can withstand and still be solid?

- I found the outlook of this one very original!
Now that you have to part with this one, what are your plans on the parts and schematic that you will use on the next one? if you dont mind me asking. I assume you had experimented with the values and brands of the passive components and trafos to make a decision for your next design.

Thanks
Alex
 
About the silicone it is GE Silicone II and the reverse reads:

NOT FOR: Surfaces that willl exceed 400´F (205´C)...

When the amp warms up it dosen't get close to this temp. I've had the amp on for periods of 2-3 days and it dosen't get warm at all if no signal is going through it. I run it between 10-15 (vol. pot) and it runs slightly warm. It is on practically all the time. Prehaps I am running a fire hazard or doing something wrong, but up until now it is ok.


About another one. I don't think so. Not until I can get some space for a shop or get cheap access to better custom work. Thinking about standard 19" rack chassis next.


About parts and stuff. I don't know. I didn't do much if any experimenting. All I know is that the better stuff Riken, Black Gates definitely have a much more detailed, quiter sound. Much bassier as well.

I'm not techincal about this stuff. I just build it. I have no clue what DC offset it. I don't even know what a capacitor does. For me the BG caps look better than the Panasonics, also feel better in the hand. Like a better, more solidly, built cap. I just enjoy building things and I love music (sound). If a cap looks and feels better it has to sound better/perform better. Actually I liked the leads of the 1000uf BG the most. Massive relativley speaking to cheapo 1000uf's. Very nice stuff. So now when I listen to the cap that I enjoyed looking at and feeling it sounds better.

I am 99.99% sure that the 3 to 8 (22k) resistor is a 1/4w Riken. I wish it was shorter that would have made me much happier with the construction. Also I should've added the zob. stuff at the output. Other than this it was a nice put-together experience. Everything seems easier the second time around.


No PCboard as hard wiring is very simple especially with solid silver wire. no stripping or twisting or anything but solder one end, find/bend the wires path, snip and solder.


Those are actually mute switches.


About the sound: My Philips DVD712 is spinning some Beatles HDCD discs into the amp into Energy XL-25 floor standing speakers. I am very, very impressed with the sound. Totally blows away my Onkyo home system and I feel very strongly about it leaving the Linn Majik in the dust as well. I also listened to it using a pair of Decware RL-2 radial speakers. The Decwares have a very serious sound-stamp. Very sharp sound. Like its using a super tweeter or something. Can get a bit unbearable if you ask me. The tweeter is connected seperately in the Decwares and a volume control can be used to adjust the tweeters volume. This is too much of a pain in the behind (adjusting for everything I listen to) for me.
 
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