[Mullet]

So I'm finally done with my reworked errr re-terminated Apheared 47. I ended up using the suggested parts by Holland and others. Also, Fred sent me a few LED kits. I picked a green one to match the creme de menthe theme. The plastic jacks worked fine and no more heat or loud buzz. I tested it out with different power supplies and definitely noticed the ground hum with an un-regulated supply. With my regulated supply no hum at all. So now all is good. I'm going to enjoy this puppy for a bit with my SR-80s and then try maybe a Szekeres or move up to a Cavalli-Kan Kumisa III or M³.
 
Some impressions: The drivers of my SR-80s seem to be being pushed harder? Perhaps, this is because there is more current being pushed through these puppies. Anyways the result is more fatigue on my ears, faster. I dig the sound and everything seems a little tighter than when un-amped.
 
I still plan on testing DC offset and how much current this thing is pulling. Overall, I enjoyed this project and learned a great deal. Still have way more to learn. Thanks everyone for your help and guidance.

 

[Mullet]

Oh and just for completion's sake... I ended up measuring the voltage of a shunted 1.3 ohm resistor and got .064 volts, which in the end translates to 49mA. This is exactly the current draw that is expected. Yippee!!! 

 

[holland]

congrats.

 

[Avro_Arrow]

Good job!

 

[nikongod]

Sweeet!

 

[Mullet]

Here's another issue that I'm running into now that I've had the A47 running for about a week or so. My - (negative) power supply cap runs hot when I'm using my regulated 24v power supply. If I use a 12v unregulated supply that runs around 18v it's a little less hot. I haven't tried it with a 12v supply that runs close to 12v. My buffer and rail splitter are running correctly because I'm getting +12v and -12v measurements from ground to the positive or negative sides of the power supply with a DMM. I know that caps should not run hot and that they will die sooner if this is the case. My LED is getting hot as well. I'm thinking that the resistor needs to be on the negative side of the LED. Any thoughts? Here's a pic...
 

 

[nikongod]

It dosnt matter which side of the LED the resistor is on.
 
Are you 100% sure the cap is in the right way around? They usually just explode if you put them in backwards, but its good to check.
 
Can you replace the cap? Sometimes they are just bad.

 

[Mullet]

Yeap, I'm pretty sure the cap has the right polarity. I'll double check tomorrow when I have the amp in front of me. If worse comes to worse I'll replace the cap. I could just let the cap eventually fail or dry up as they say and replace it then. For all intents and purposes the amp functions correctly. I have the voltage splitting properly ie +/-12v. I have the proper quiescent current ie 50mA. I could pull it apart and reflow the joints around that cap and see if that makes a difference. The only caveat is that pulling it apart would be a little bit of a pain being that all of my jacks are mounted from the inside. Also, could the hot wire connected to the LED be emitting heat and the cap is absorbing it?