DIYHiFi.org

Hi All, I'm from Central Java, Indonesia and this is my first post.

Hi Mr.Carlos,
I'm follow your post about preamp AD815 from another forum. And I'm very veryyyyy interisting. But, never main.. because in my country I can't find opamp AD series. In my country veri difficult to find OPA's, High grade LM(4562 or better),AD's series. There just any cheap opamp like 5532/4,833 etc.
My friends and me from electronic enginering last month ago build amp with yours schematic LM3886 v4 and PSU v3 with cheap part (rubycon general purpose) and sound very good , most DIY'er on my local high school like deep,tight bass with no lost detail mid to high.
I also build standard lm3886 from datasheet and myref rev C with snubbered PSU. I think myref rev C to sweeat to me and untigth/undeep bass but it's good for some kind music.

For everyone and Mr. Carlos any suggestion to upgrade performance my amp LM3886 snubbered with part can be find in my local store??specialy to replace AD815 to another opamp like LM318. I can buy from online store, but money is the problem.
Part can find on local store:

NE5532/34
LM833/LF353/LM318/LF411/2
mosfet IRF610,9610/IRF530/IRF244,9244

thanks for any suggestion. Sorry for my bad engglish.

DIY, never ending...

Carlos, you may have to tell the world those chips are on the way out.

Jocko

_________________
"Because, I hate you guys. I hate you guys so very, very much.

Yours,
General Cartman Lee"

Hi Jocko..
Sorry, maybe those cheap opamp like I write above can't sound good with standard application. So, I build some variation like biased to class a, applied voltage from 9-18 Volt, bypass capacitor, etc. The sound's different, but I'm not like. The bass more thin,little boomy, and top high little harsh at high volume.

I think, discrete preamp the best solution for this problem. And still in progress.

Ehmmm,..I just read viewtopic.php?f=5&t=2007..I look, LM318 on some Musical Fidelity Pre, and this opamp can sound good. On 70's, Mcintosh use NE553/2 and have a good review. I ever clone the C33 (Mcintosh pre's), for preamp and tone control section. Sound very good with cheap component. But, this is DIY..ears never satisfied, always effort to get more!

Thank's

Last time buy:
http://www.analog.com/en/amplifiers-and ... duct.html#

Sorry, I was googling for something else and found this claim from Jocko.

Are you implying the AD815 is not to be made anymore?

I couldn't find anything of the sort at AD's site, even if that doesn't mean the AD815 is not to be killed.

In any case, I don't think too many people did try this CFM good sounding application.


Carlos

It was, and still is out, but AFAIK it should be back soon in RoHS compliant version.

The AD site shows status production for the lead free SOIC version.

I built 1 for a buddy of mine to use as a headphone amp. Works well.

i built on a blank circuit board the Carlos Filipe schematic ( without the offset settings )
The offset at the outputs is -2.2mv and 8.9mv .
First i tryed with capas at the output like the schematic but with mine the results were not good!!
So i removed it and it's better

As you see with this package it's very easy and also fast to do an headphone amp

Serge

This is my first post.I 've build this amp,AD 815,p-2-p solderings.When i power up,it get very hot(large heat sink used,but still hot)The PSU _+15V has gone down to _+1.1V.Can some one help,please.davidho

Am late to the party, but this looks like a cool project. Congrats to carlosfm for figuring it out and submitting the schematic. Only question I have so far is where does the negative voltage regulator (LM337) circuit attach to? Directly to the AD815 -IN1 and -IN2 pins?

Thanks,
Philippe

Hi
The output from the LM 337 is the neg power supply and should be tied to neg power rail of the AD 815 . It should not be tied to -in1 0r 2

regards
kp93300