[CaptBubba]

I finaly got my amp all together. Dang it looks sweet, the silver jack and knobs just look so good next to the wood. As for the sound, well, there's a little bit of hiss because I need to ground the POT, but other than that its great. The POT is a problem though, it is nonlinear to the extreme, I think I just got some flux into it, I'll clean it tomorrow.

Finaly, after all this time, its done!!! Yayyyy! Well, now that I think about it, there ARE so many differnt Op-amps that I could, NO,I must have control here, its finished. But I could....arrrg, now that its done I want to upgrade it. Is there any cure for this afull, money-draining affliction? *sigh*

 

[jude]

Congratulations CaptBubba!

 

[Apheared]

Uhm, so, lemme get this straight... you think you're done? I guess this post counts as a version of...

"can I get that in writing?"

Glad you think you're done now, though. what chip did you end up going with for your gainstage, since there's so many opamps out there...

self-control, oh yea, this hobby is FULL of people with that... ehaeha

 

[CaptBubba]

Heh, actualy my post was an attempt at mind over matter. It seems to have worked too, as I don't have any real desire to do any major things, for the time being, just some little things. I hooked the gains up the the wrong order, so it now goes- normal, REALLY FREAKING LOUD, and loud. Neadless to say, that is #1 on the fix-it list.

I went with OPA 134s, they sound great, and coupled with the mosfet follower I don't even know how loud it can get, I simply can't stand to get past 1/3 of the POT when on high gain, and it sounds oh so nice.

I have encountered a problem though, I need a bigger heatsink on my regulator, as the transformer I am using has too high an output voltage, so the regulator has to dissapte a lot of heat (it burnt the crap out of me when I touched it). I'll thow a bigger sink on it, and if that doesn't work I'll slap on a fan( a little one).

BTW, the ones full of self control are also the ones with full wallets, its something to think about.

 

[Apheared]

Bah, that's not true. They still have hobbies, and still buy stuff like commercial headphone amps...
So technically you're SAVING money; you get to do this as your main hobby -=AND=- get to have working electronics out of it. At least, that's the argument I use with the wife. (it works sometimes. Until I buy $300 worth of capacitors)

Well, assuming a 7V swing into just about any load (down to 20 ohm) that's ~1,500 mW into Grados. Depending on input signal level and gain config, of course. Just talkin what's possible... So yea, go figure. VERY LOUD is right. On gain x11 config, my 365mA/ch biased version (with the P2 CPU heatsink) I stop around 12-1 o'clock on Grados. Which is something like 200mW/ch. (eg. pretty f'n loud)

I'd do whatever you can to avoid that fan, but hey that's me. You can go with bigger electronics, bigger heatsinks, even dividing up the work via a separate regulator for each channel (hell, talk to rick and tomo - they'll have you doin dual mono anyway, dissipation problems or not!

)

 

[eric343]

What's wrong with fans? So long as you've got them in a Faraday cage...

Or you could go with the classic Overclocker solution-hook up a liquid cooling solution (I assume this is *NOT* a portable amp)

 

[CaptBubba]

Heh, define "portable", I can pick it up.....

I doubt it will come to using a fan though, that was just a last ditch measure. I have a heatsink that is twice as large as the current one.

hmmm, overclocking audio amps, this opens whole new possibilities I can get my 700Mhz Athlon to do 925, be interesting to see what an amp could do. (But I don't know how the hell you'd go about overclocking it)

 

[ppl]

My recomendation to the Heat problem is to use a preregulator then you can devide the Voltage and Power dissipation of each, as well as improve Performance.

 

[CaptBubba]

I'm giveing the amp its first long term (3+ hour) listening session, and I think I may need to go with a fan, at least until fall or winter

. I can keep my finger opn the regulator heatsink for about three seconds before it starts to burn. I think I may throw in a fan. I'll prob just bring the fan along with me, and if I run into overheating problems, I'll put the fan on the air hole of the amp to circulate air. Water definatly evoporates faster than normal off of the heatsink, but does not boil.

Eric, I may actualy do just that, maybe a small heat pipe system, hmmmmm.

Or am I perhaps obbsessing over the heat issue? It is a class A amp after all...