Newbie's first amp - Where to start?

So I discovered the diyaudio forum a few days ago, and all I can say is - OVERWHELMED.

I've been an enthusiast of electronics, gadgets, and DIY in general, and have a few years experience installing audio professionally. My electronics background, however, is limited to playing around with a couple of radio shack electronics kits when I was a kid.

One thing I've discovered is that the learning curve for anything complex gets a lot easier the more interested you are in the subject. I have been self-taught in creating things from computer programs, to telescopes, to loudspeaker designs. Now, I've been bitten by the amplifier bug and I want to get one under my belt. I believe I can tackle this and come away happy.

So I'm looking for someone to point me in the right direction. Here are some things I'm looking for in my first project:

* Quality - I want the amplifier to "get out of the way" of the sound so that the liveliness of the music can shine through. I don't believe this requires large amounts of power, or necessarily really expensive components. I won't be needing loud volume levels or to create a lot of bass. For me, it's balance, neutrality, openness, airyness, and lack of fatigue during long listening. I want the sound to be a clear cut above the standard stuff you find in a major electronics store, and for it to be apparent that no important corners were cut in the design.

* Simplicity - I'm looking for a tried-and-true, simple, proven, and basic amplifier design without a lot of gotchas, tweaks, frills, unnecessary gadgets and doodads. Large fancy regulated power supplies, elaborate feedback schemes, debatable features, and silly hard-to-prove improvements are things I want to leave out. This will be my first build, so I want to start with the basics but I also want to get the basics right and not leave a lot of room for improvement for what it is, being simple.

* Price - I'm looking for the "sweet spot." I'm willing to lay down a few hundred bucks to do this right, even better if it's less, but do not find it worthwhile to spend a lot of time or cash pursuing hard to find or expensive parts. My guess is that for somewhere between 150 and 500 bucks I can end up with an amp that will really sing and make something of comparable price from an electronics store seem like junk.


So, there it is. If there's a kit out there that fits the bill, great. If all I can hope for is a schematic, and I have to hunt down all the parts, that's okay too. But I guess my biggest fear is not finding a project that fits my above three criteria. So, for you experienced ones out there, has the above description brought anything to mind?

I'd love to hear it.
 
Well it depens on what do you expect...
I can suggest the D class amps of 41Hz Audio - News I have build two of the AMP 6 by my self. Sounds nice but I dont know if 20W are suficient for you. You find some nice amps there with decent price and good quality and a lot of reference on the web.

For solid state there are a lot of AB class amps with 100W power out.
For exmaple Module Amplificateur - Module amplificateur stéréo SAP15 2x100W ClassAB
its a french site but I buy there and trust theyr product will be decent.
cheers
 
Peter Daniel's implementation of the Power Amplifier is DC coupled and is designed to particularly to suit a high efficiency speaker.
These are not intended for Beginners or Newbies.

I highly respect your opinion/info Andrew but I'm not sure I'm following. As a newbie, I built the LM3875 with no problems. It only took a few hours and works well. I run a pair of Fostex FE127s and they sound great.
Mike
 
Hi Mikje,
are you blissfully unaware of the risks you are taking using a DC coupled amplifier?

If you are aware and have decided to accept those risks, or have taken steps to ameliorate those risks, then you are not a beginner.

Hi AndrewT,
Uh oh :eek:... not aware of what is meant by DC coupled, nor do I know the dangers. Care to enlighten me? It would be much appreciated.
Thanks,
Mike
 
As I read about DC coupled amplifiers, it seems the danger would be in applying DC to the speaker. Noob questions: If that's the case, is there away to add a high pass filter?
yes, that's one of the reasons for building AC coupled amplifiers. They can only pass on AC signals. The only time the speaker sees DC is at start up or shutdown or failure of the output stage. Hopefully supply rail fuses protect against output stage failure.
 
Murphy's law says a $10 transistor will always fail before a 10 cent fuse breaks. Not always the case, but the fuse can protect the speaker from DC if the transistor fails. Also a relay to connect the speaker only after a simple logic circuit determines there is no DC at the output of the amp, at startup and shutdown. Many people dismiss an output coupling cap because of the sonic effects.
 
Hi there,

I think I started the same journey about two years ago, from about the same starting point :)

It's been a lot of fun, and good lord have I learnt a lot. and the more I've learnt, well, the more I clearly don't know (yet!). For my first proper build I did a dual mono set of chipamps from DIY Chip Amplifier Kits, PCB's, Components and Information. Pretty easy to build, sound great, cheap and convenient to buy a kit and parts in one hit. Lots of stuff on the web to so if learning is your bag then god knows theres plenty of info. It taught me the lesson I'm still learning - the chassis is the hardest part, if you want a nice looking 'lounge room' unit in the end. Have a look at DIY Chip Amplifier Kits, PCB's, Components and Information. for some lovely enclosures for that sorta amp.

I followed up that build with a tube preamp/stepped attenuator/channel selector, and there you have it, the amp I still use most today. I'm looking to build a B1 shortly (Pass Laboratories for the pcb's, and to lob some cash to one of the best supporters of this whole audio diy scene) and see how that works out for me.

If you want to push the boat out a bit further, then give the F5 (check the first watt website) a go. Your big cost here is transformers and heatsinks - I still cant believe the size some of those end up being...

My final reccomendation? Build yourself a B1 Preamp, and a chipamp, and see how you like it. Both are easy, low part count and quality performers. And when you budget, make sure you leave quite a bit in the kitty for nice enclosures/switches/lights have a look at DIY AUDIO PROJECTS - Do-It-Yourself Hi-Fi for Audiophiles for the good the bad and the fugly in diy builds...

All the best, and watch out! This is addictive, and I probably now have a coupla grands worth of uncompleted projects scattered about... Good luck!