Amp, the sequel

[CaptBubba]

Ok. My amp is now retouched and working (and looking) better than ever. The right chanel was gone because of a bad solder joint. Also the regulator heatsink was getting too hot because I had it too close to the side if the box. Also there was about five feet of wire that I threw out. My szekeres is better than when I first made it.

Ok, here's the list of stuff I did.

Unchanged

basic szekeres with gain
panel unchanged
big Athlon heatsink still there

Changed
selectible gain removed, fixed at 11
different impedences selectible on the input (so loud stuff isn't too loud)
board moved to allow better heat dissapation
You can see the board, wires obstructed it before


Ok, nuf talking, here's the pics.

The front, I think it looks good...

The wireing for the front panel. Not as good looking as the veiw from the ouside.

The whole thing, believe it or not, it actualy works! Actualy, it works very well.

Well, that's my amp. I'm happy that it works. But here's the best part, it doesn't pick up as much interference as it used to. I can actualy listen to it without turing off everything electrical in the room.

CaptBubba

 

[Budgie]

Sounds like your pretty happy with the results. What chip did you decide to use for the gain stage?

 

[rickcr42]

Hmmmm.....seems to be a trend here--big ass heat sinks and wooden enclosures.
I was part of the :"big ass heat sink brigade" up until last week,but then my version ran at 750ma per channel at one point

I then backed off to a "sane" 500ma,which sad to say is now down to around 250 ma per/ch.
Could change though,winter is coming !!!!!!!!!!!

 

[Possum]

750 mA!!!

When I used 500 mA, my steel case would burn your skin if you left your hand on it for too long (a few seconds), and the 5 heatsinks I had in the case were "free-floating", maybe 2-3 were lightly touching the case with an edge. I went back to 250 mA since my air conditioning at home wasn't on. But 750, another

 

[Tomo]

hey,

haha. Me too. I ran mine at 750mA too before I realized that I can cook egg on top of my heatsink.

Tomo

 

[CaptBubba]

As far as the big heat-sink wood case thing, I've had this case and heatsink ready and in use since early August (when it was needed because of the heat). Actualy that heatsink isn't that big when you consider that it is being used for both mosfets. It's only slightly larger than some of the others I've seen.

I am using BB 134A's in it. I would like to experiment a bit, that is the next thing. Any suggestions? More importantly, any person want to donate the parts?

Dang, 750mA?? Wouldn't that require 15-20W of dissapation? Mine runs at a paltry 350, just enough to get that heatsink warm (burning hot electronics worry me). I can't go any higher or the regulator would go nuts, it is currently getting 22V down to 14V, so there is a good bit of heat created there. Still, at 750mA, you have a small space-heater.

Tomo, the egg may not be a good idea, but if someone made an amp that could perc up some coffee, I'd be there!

CaptBubba

 

[paulb]

So, have any of you who have tried the whopping big currents noticed an audible difference? I was all set for 350 mA but I can run more (got space for a fan...).
On the wood note, I never thought about it before I started looking at this site, but a wood case is looking pretty cool. I happen to have a brother-in-law who is a finishing carpenter...
Capt. Bubba, are those nails in the panel? See, I never would have thought of that...looks rustic and high-tech at once, kind of a reflective look at the inner struggle between the never mind I'll shut up now.

 

[Tomo]

Hello,

I did not hear any difference btw 750mA, 500mA, 250mA. What I did was to change resistor values in the constant current source (CCS). Note in original design, you are using a resistor in place of CCS. This resistor value does not show actual quiescent current values.

Personally, I do not like the amp to heat over the boiling temperature. I should be able to touch it without burning my hand. Note the IRF510 will operate a little over 125 celsius degrees. I would not push it since it can denature. Not to mention thermal damage to surrounding passive elements like capacitors and resistors.

Note with CCS, MOSFETs will emit more heat since you are forcing the current though them no matter what resistance the MOSFETs have. This almost means that CCS will be pretty hot too.

Tomo

P.S. UHC-MOS are hot in Japanese audiophiles and enthusiasts who choose to go solid state.