Can I build an amp to do it all?

This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Hey all,

Looking at building an amp.
I don't want to build one amp for my pc, one amp for my living room, i'd like to build an amp that can be used wherever i decide to put it.

I have been doing the research and can't decide what to build. Or whether it's possible to have all the features i want.

Features I would like
- Min 50w/channel.
- 2 channel with sub out
- Multiple inputs, rca in, optical for tv etc.
- Possibly a usb input to an integrated DAC.
- Volume control
- Low pass filter to sub out

I'm new to amp building and maybe i'm wanting too many features and i'm better off buying an AVR. Not sure, but you knowledgeable might be able to offer some guidance there.

If i do go the avr route, what I would then do is build an amp that would be purely for music. So it would have to be a 2 channel, with sub out, volume control, integrated dac.

There are so many good builds on these forums its hard to know where to start.

Eg. Gainclone, Class d, discrete.

If you were building an amp just for music, min 50w into 4 & 8 ohm,
what would you build?
The problem is many of the features you want are easy to add into a DIY integrated, and others, like the USB input to an integrated DAC are not quite so easy. It also depends on what kind of quality you expect from the final product. Audio is a tradeoff between many things, but the main ones you're looking at are sound quality, power, features, complexity/time to build, and obviously cost. It just depends on what you want. If you're willing to spend 1.5-2k and spend 10-20 hours or more doing research and assembling then you can get everything you wanted in a single box. Otherwise everything else will be a compromise on either lowering cost or making it simpler. One such example is class A/B vs class D. This is an argued topic, but to most people and at least to some extent class A/B sounds better, albeit marginally, but class D is much easier and cheaper to find a board that can just be wired up and ready to go, especially for only 50WPC. So I think you need to expand a little on what budget you have, how much time you're willing to spend on this, and what is most important to you to have. Also one side note, its my experience that digital inputs are harder to do and deal with than making something purely analog and dealing with the D to A conversion outside of the integrated amp.
Happy to build from scratch (kits, pcb + components)

What got me thinking along these lines was the like of the following amp : Buy FX Audio D802C Wireless Bluetooth Version Input USB/AUX/Optical/Coaxial Pure Digital Audio Amplifier 24Bit/192KHz 80W+80W OLED from Reliable usb cable amplifier suppliers on china-audio

But I figured surely I can make a better amp (maybe not at cheap) than buying something from aliexpress.

As for the time factor, I can spend as much time as I like.

And as for the cost, Im not planning an excessively expensive build.
Eg. I know the likes of a kit from chipamp/audiosector will cost me $100, + chassis +toroidal +connections etc. So im expecting a build to cost somewhere in the vicinity of $300. Thats fine.

I guess what is most important in this build is sound quality, thats why I want to build something rather then buy off the shelf. It definitely has to have volume control.
Inputs will be either from a tv, ipod or DAC (raspberrypi or pc)
Obviously if the audio is coming from the tv, im not worried about great SQ, but im trying to make a semi universal amp, so when i do have it running off a nice DAC, the sound quality is really good. So whatever connections are recommended to get that to work.

If i can't manage a subwoofer out and/or a low pass that fine i guess, would have just made it easier if i had it in a bedroom, i wouldnt use a sub, but in the living room watching movies i would.

Hope the update helps
Joined 2010
Paid Member
Before trying to plan a magnificent amplifier with features you still need to understand before messing with, build an available kit as you describe and discover how much more is actually necessary to make it operational and often with no manual or experienced advice anywhere to help you even get started. Look into kits and the extras needed to get an Ebay type kit going. They are only a fraction of the requirements and costs, tools and skills needed to build a useful end product. Many newbies settle for a basic, no-features amplifier because of this.

What is necessary, even before buying, is to know how it works and how the different functional sections fit together first. Many kits are based on very good designs that are cut back to the basics for price and complexity reasons. The added features of digital control, protection management, communication and interface are difficult for DIYs to design and construct and current technologies are usually tied up in patents, copyright and exclusive supply agreements.

If you want recent technolgy features, buy pre-built modules or complete receivers. Otherwise, the learning and skills path is long and expensive. Think microcontrollers, FPGAs, BGA chips and other impossible parts technologies needed in today's connected electronics world. Actually, most of us still live in the 20th century, so we can stick to through-hole parts that don't need optical aids and tweezers for the latest fad tech.

At least with a kit, you will learn a little about audio electronics and manufacturing, maybe enough to plan something bigger that won't be a disaster due to inexperience or lack of education and skills. Audio electronics may look like an easy assembly of simple parts but I imagine that if you wanted to build even a simple one-transistor amplifier that worked to a specification, it would take days to derive a working design unless just copying an existing one from a book, the web etc. :eek:
If by 'better amp' you actually mean 'better sounding amp' then you have a long journey ahead of you - good luck with your travels. That's because there's precious little agreement about what sounds better so you have to find out for yourself what sounds best for you.
Best amp is the one you build yourself. You put so much effort into it, in the end you have conditioned yourself to hear it as the best sounding amp ever. Ugly babies are still beautiful to their parents. Audio is a mind game.. this is what those snake-oil products base their existence on.

As for what amp to build, take any pick from this forum. When something like single ended tube amps with 5% THD still have so many fans, it's no longer fancy figures game. You will find a group vouching for something as simple as Nelson Pass' Zen amp and another group is die-hard follower of something at the other end of the spectrum like Dynaco ST70 tube amp or Honey Badger SS amp, then it doesn't matter what you choose. Just keep this in mind: build an amp that matches your speaker because the other way is harder.
Hi Neo. Some great points have been raised here. You have opened a massive world.

There is nothing wrong with a DIY amp, but are you doing it once-off, or do you build circuits as a hobby?

A few things to consider:
- DIY has an initial cost (which can be mitigated with knowledge)
- DIY amplifiers can very quickly become very expensive if you aren't experienced
- You need to understand and decide on your requirements before you even start to think about building something

Are you going to drive 4 ohms or 8 ohms? Do you want 50 W into 8 ohms, or 50 W into 4 ohms? If you want 50 W into 4, 8 and 16 ohms, then a valve amplifier would do, but otherwise, a transistor amplifier will give different power into different loads.

I've designed and built very many amplifiers, some on request for friends of friends of friends, and I've found that 50 W is actually a lot. Consider this:

An externally hosted image should be here but it was not working when we last tested it.

You can replace cost with complexity, and you can also replace power with decreasing load impedance.

I've found a sweet spot at 60 W. It's ample power for even 89 dB speakers in a large room, it's easy to achieve with few components, gain isn't too much, so possible oscillations are eliminated. Also, in my experience, for higher power requirements, it's much easier to design for 4 ohms than the same power for 8 ohms.

I've built single-ended class A, class A/AB, pure class B, class AB, and the best for me is class AB. You can go class D if you want, but I wouldn't be able to help you there. I find the concept extremely clever and interesting, but I don't have time for class D. A well-designed class D amplifier can sound great, but it's not easy to design. Class AB is by far the best for me - sufficiently efficient, easy to design, limited heat, easy construction.

If you would like a simple design to build, and can't find something here you would like to try, I can gladly send you a design and PCB layout. I'm busy posting a 4 channel amplifier build thread, and I'll put up results and measurements of that.

And there is nothing wrong with single-chip amplifiers like the Gainclone - it's actually a safe and easy bet. Highly recommended.
Last edited:
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.