[jasonhanjk]

I just complete a scale down clone PPA. I felt the chips are a bit warm. Did I do something wrong or is it normal. Sounds very good.

I am using 2 X 9V battery with 47000uF capacitor bank.

 

[jasonhanjk]

Forget to add, this clone PPA brings up the treble of my Senn HD600. Source from my Audigy.

 

[rickcr42]

Quote:

47000uF capacitor bank.

never built the ppa but most buffers get warm so i would not sweat it too much

or you could heat sink them

 

[KurtW]

The chips shouldn't get too warm, certainly not hot. Some oscillation can cause them to get too warm. You can check your supply current and see if that makes sense for the chips that you're using. If its much higher you probably have some oscillation going on.

 

[eric343]

470,000uF?! Yoiks! This isn't exactly a portable amp, I'm guessing..

And you're bypassing the chips with capacitors to prevent oscillation, right?

 

[jasonhanjk]

I still need to get the 6.8uF one.

Will try it with that one and see how.

 

[morsel]

Warm is OK. If the chips are too hot to touch then they are probably about to burn up.

 

[jasonhanjk]

Thanks for replying morsel. Does your PPA IC's starts getting warm a few minutes or so?

 

[aos]

I think HA-5002 does get warm, and I was running it off only +-5V, not +-15V. It operates on higher quiescent current so it dissipates more heat than EL2001. Warm, but not too hot to touch.

EL2009 on other hand uses 40mA quiescent current and it does get too hot to keep your finger on it for more than a second or two. Still runs fiine though.

 

[morsel]

Jason, I'll defer your question to Kurt since he has the prototypes at his place. I don't recall how long they take to warm up.

 

[AIM9x]

speaking of the PPA.... how's the project going? I haven't seen anything posted in the PPA discussion thread for a good two weeks. Still testing the present design?

 

[tangent]

Progress continues apace. Nothing has been posted because nothing truly momentous has happened. You might call this the solidification stage of the design work.

 

[morsel]

Kurt and I have weeks of testing to do, which I have not been doing because I have been busy moving to another apartment for the last 3 weeks. It's a rather grueling process. The new place has about 1/3 of the space. I have been getting rid of tons of stuff. I gave my circa 1976 Tek scope and parts to Kurt. He has been doing some testing without me.

I will also be losing my DSL connection for at least 2 weeks, starting in a few days. So life is a bit rough atm, but should smooth out in a few weeks. Don't expect any work out of me until after I have read "Harry Potter and the Order of the Phoenix" which comes out June 21.

 

[jamont]

Moving sucks. Good luck, look forward to your reappearance on the other side...

 

[jasonhanjk]

See you again in 2 weeks time. Good luck!