Hallo allemaal / Hello everybody

[edm]

I am Emiel Metselaar and live in the Netherlands. Three quarters of year ago i made my home build speakers and got infected with the 'audio' virus. Currently they (the speakers) are running passively, but i am in the process of converting them to active ones. For this project (which am taking very slooooowww) i am already passively following this forum for a some time now.

At the moment i have 'designed' the pcb's for the active filters, which are based on the info from the Linkwitz webpage. The initially planned LM3886 amp chips for this project are already cancelled, thanks to a friend of mine who convinced me that a discrete design would/could be 'better'. He also provided a discrete alternative, which i am going to try. So that part is also covered, what needs to be done is the preamp section.

I got an ok from my girlfriend to proceed with this audio stuff (luky me ) if i created something she also could use and it was not to big/scary/etc. So the idea was that the preamp should be the heart of my system. Some things it should do/have:
- a remote control
- switch the amps on/off
- switch between the various input sources
- control the volume (duh)
- mute function

I was very happy to see the 'Son of Dork' project from which i hoped to 'steal'some ideas, but I have the impression that the project died a slow death, dorkus????? The 'design'of the preamp is in a state that the digital board with the microcontroller is done, the programming is done. And a test board for the input swithing, volume control, amplifying is almost done. I already opened a topic about the volume control part in the solid state section, so that i can finalize it.

With this board I would like to do some comparisons between opamps, and discrete opamps. And based on that info make a finalized design.

O yeah something about my background, I have an Applied Physics degree and learned some of the basic electronics stuff. But since i started trying to compose a working preamp I found that there is a large difference between being able to measure and understand the basics and cooking something up that actually works. The difficulties I alread encountered:
- finding the parts you need by yourself,
- reading technical document (the information is there, but the documents are soooo compressed), etc...
- finalize something

So all in all i am an electronic noob willing to learn, living by the motto "why, because we can" and sometimes suffering from "If all you have is a hammer, everything else looks like a nail".

emiel

O yeah i have searched the forums, but before i did that i already was convinced that i did not introduced myself before .

O yeah2: Since everybody in the pass section are always thanking Nelson Pass, i would like to thank the person(s) providing this great forum.

[pinkmouse]

Hi Emiel, welcome to the forums

Don't write off chip amps totally, you can get some very good results, as I am finding out with the LM3875...

It sound like you are well hooked on DIY audio already, it will be good to have your input to the forums.

"If all you have is a hammer, everything else looks like a nail"

I used to know a Lighting Designer who had a special flightcased toolbox for site, on the top, in a tray, was a pair of white silk gloves, on the bottom was a selection of hammers, from tiny tack hammers to 4lb lump hammers!

[ststone]

Hi Emiel, welcome to these fine forums.
You will find lots of info down here.

btw heb je je schoen reeds gezet ?

[edm]

Don't write off chip amps totally

I won't, i am going to use them in a first prototype (free samples ). The reason is that the discrete alternative is finished schematic wise but the pcb layout is not completely done.

The filters and the preamp will/can be completed first and tested with the chip amp. I hope to etch the pcb's next week.

And i hope i have improved my soldering skills when i start with the discrete amp, because my friend decided that the BC847BS and BC857BS should be used in the differential section. And since i have seen the picture Peranders has on his webpage i got a little bit freightened

An externally hosted image should be here but it no longer works. Please upload images instead of linking to them to prevent this.

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[peranders]

Originally posted by edm
And i hope i have improved my soldering skills when i start with the discrete amp, because my friend decided that the BC847BS and BC857BS should be used in the differential section. And since i have seen the picture Peranders has on his webpage i got a little bit freightened

Yes, this isn't for everyone! But still, you can solder this if you have a solder iron with a fine tip and a steady hand. See what I have done and I'm normal "handy".

[peranders]

See this picture also.

[edm]

Peranders what about etching, can this be done using the standard diy pcb brewery (print on sheet, put sheet on pcb, apply uv light etc)? I can imagine that these fine traces are hardly do-able in the home setup. We planned to give it a try last weekend, but stuff came up so it will be later...

[fdegrove]

Hello Emiel,

got infected with the 'audio' virus

Not a very unique desease here.

Still beats a flue hands down,donnit?

Cheers and enjoy,

[ststone]

Talking about the flue, there is no such thing around here, just herons and alligators

hup, holland hup laat de leeuw niet in zijn hempie staan

[fdegrove]

Hi,

I think that on average a new dutch guy signs up every week.

Hello Belgium,what's gong on?

Dag Steve,