Which "light" Chipamp project with which power supply

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Heya!

I am quite new to DIY, except for building Speakers and the electronics necessary for those.

I have some experiences in soldering, I can read wiring diagrams and the main point, it is so much fun to me!

But I am well aware of the dangers and traps one can tap into, so I decided to open this thread, although one or another person may think that there are at least 1k threads like this. But I have some specific questions, which could be answered quite fast by some people with own experiences (at least I hope so :p )

1. The Amp:

For the start, I would like to build a nice and clean sounding Chipamp. The Chipamp does not need to have much power, it should be able to drive 2 small 1 way speaker for a desktop solution and not more.

What is important for me, is that the amp has a neutral charakter and does not do much to the sound, except for amplifieing.

I took a closer look at the 3886 Chip, but I saw there are many many other Chips out there, and the 3886 may even be a little bit oversized for my needs. Now I am a little bit confused, as I do not know the other Chips, and I do not know which one of them falls into the categorie "good and neutral sound quality".

2. The Power supply

I am aware of the fact that most of the people here build their own power supplies, but to be honest, I am not 100% sure if I also should go this route. Everything I know about electronics is out of books and the internet, and handling a power supply can get dangerous if you are not 100% sure about what you are doing.

At the end to big questions remain open:


1. Which Chip should I use, or preferably which DIY kit and where should I buy it (I am in the UK at the moment)?

2. Can I buy a discrete power supply for the project? If so, which one and where?


Guys, thank you very much for your support, remember, everybody started somewhere, and I am very thankful for you guys sharing your knowledge.

Cheers!

Schlumpfpeter
 
Thanks Mark,

I did not really find something for the PSU, most of them did have a PSU Board which you have to solder yourself, add a transformator (which you have to choose by yourself) and then put it into a case including grounding etc.

.... I was just thinking, maybe there is a boxed plug and play solution for that with decent quality.... I may be daydreaming.

Cheers!
 
amplifiers
neutral charakter and does not do much to the sound, except for amplifieing
so do we know chip amps that do otherwise? as your post implies.
are they more numerous to make a list of just the "good" ones.

Im not sure part number matters as much as the whole design around the chip amp part that determines "goodness"
then probably a commercial amp kit with PS and chassis included makes more sense, less design choices to go wrong?
 
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In my opinion, I wouldn't worry about the power or size of the chip or it's amp. The 3886 may make more power than you need, but it doesn't hurt to have the power.

For a first project, I would concentrate on something simple to build, they all would meet your requirement of not coloring the sound.

The MyRef projects have excellent sound but the MyRef is a more complicated build than others. Also, those are hobby projects and boards are not always available.

Don't worry about selecting a transformer. You should build the power supply (sometimes on the amp board, sometimes a separate board). It's easy and you will get recommendations for transformers and other components from the seller.

If I were in your position, I would probably build the Chipamp.com or the AudioSector LM3875 Gainclone . They are straight forward to build and have good building instructions.
 
I am fairly experienced in building electronics gear, although mostly HF gear. More recently I have branched out to AF amplifiers and associated equipment. For a starter project I built the Chipamp.com LM3886 dual-mono amplifier kit (~$100) with all PCB's and good quality parts to build working units.

Even though I have built gear for 25-years I still went with a kit from an established vendor in Chipamp.com for my first entry into high-end audio. The manual was solid, the PCB's of good quality and all parts were included along with a few extras, just in case. I am told the support from Brian is good, although I did not need any.

I would not hesitate to purchase from Brian at Chipamp.com or Audiosector (though I have not personal built his gear, others rave about the quality and sound of his kits). As for PSU, it really is best to build your own. The Chipamp PSU boards are easy to populate, easy to build with the assembly manual (online only, I believe) and the selection of a correct transformer is clear in the manual or here on DIYaudio.com. I went with the AnTek Inc. shielded transformer with dual 30V and 15V secondaries. It was about $80 with the transformer shield (not required, although I recommend it) plus shipping. AnTek Inc. is good to deal with and more importantly they shipped very quickly. I suspect you can find a similar vendor closer to you for your transformer.

As for the PSU, double-check you work and then check it again. Follow the assembly manual closely and ask questions if you have them. Always exercise caution when working with mains voltage and you will be fine.

Best of luck.

Darren
 
Wow, thanks guys for all the answers. You really helped me a lot.

So LM3886 it is!

Now the question is, which kit to go for. I really like the chipamp.com kits, as they are reasonably priced (actually, seems like quite a bang for the buck) and I can easily reach somebody here to ask questions about it.

What bothers me a little bit is that there is no volume control and no heat sinks included.

Where can I buy heat sinks that will fit and how hard is it to include a volume control into the 3886 stereo amp kit?


Cheers guys!
 
I see, the idea behind the pcb price is that you pay the development through that... sounds ok to me.

But for the first project this is a little bit overdimensioned for me i think. I would rather go with a chipamp or amp-yourself.de kit first. I think I will go for a 1875 Chip based amp, and afterwards I will build a bigger LM3886 kit, good chances that it is going to be the modulus one, as it seems to have accelent reputation here in the forum.
 
Go with the Chipamp.com gear. It really is close between the various kits based on the LM3886 so any would do. As for heat sinks? I salvaged many from old thrift-store receivers or from yard/garage sales. If you foot shipping I will send you one, cheapest shipping method possible to make it a reasonable value prop for you. It should do the job cooling the Chipamp.com kit with room to spare.

Wow, thanks guys for all the answers. You really helped me a lot.

So LM3886 it is!

Now the question is, which kit to go for. I really like the chipamp.com kits, as they are reasonably priced (actually, seems like quite a bang for the buck) and I can easily reach somebody here to ask questions about it.

What bothers me a little bit is that there is no volume control and no heat sinks included.

Where can I buy heat sinks that will fit and how hard is it to include a volume control into the 3886 stereo amp kit?


Cheers guys!
 
Where can I buy heat sinks that will fit and how hard is it to include a volume control into the 3886 stereo amp kit?

A good supplier in Europe for this kind of things is reichelt.de.* Prices are very good and shipping honnest. A 0.9K/W heatsink, 160mm wide and 75mm high, is only 9.81€. I'd use one per lm3886. For lm1875, you could use only one (they have wider ones too for similar prices).

They also carry the alps blue potentiometer at about 12€, if you want a good volume control.


*The only caveat is that if they don't specify explicitely the manufacturer, it's probably a cheap part from China.
 
scrap it, grab an STA540 chip and you don't even need a pcb to make it into a verry decent amplifier. Schematic is in the datasheet.
for heatsink salvage a computer cpu heatsink of an older computer.
as for powersupply you need something around 5A and rectified near 20 volts.
build the bridged version, it runs for pocket money, and the sounds is pretty good even compared to more expensive ones.

for a first project it should be more than decent enough.
as a powersupply you can use a laptop charger if you have any around.
just make sure its not going to pass over 20 volts, and you should be fine.
 
scrap it, grab an STA540 chip and you don't even need a pcb to make it into a verry decent amplifier. Schematic is in the datasheet.
for heatsink salvage a computer cpu heatsink of an older computer.
as for powersupply you need something around 5A and rectified near 20 volts.
build the bridged version, it runs for pocket money, and the sounds is pretty good even compared to more expensive ones.

for a first project it should be more than decent enough.
as a powersupply you can use a laptop charger if you have any around.
just make sure its not going to pass over 20 volts, and you should be fine.

Same goes for the LM3886. I built a LM3886 without a PCB based on 3 resistors and 2 capacitors per chip and a unregulated PSU with 20k capacitance. It performs as good if not better (in some respects) than the kits I have purchased/built. Although I have pound the PA03 PCB/design to be about as good as it gets even when compared with my LSA Premium commercial amplifier at 20x the price of the PA03 including parts and enclosures. Building the amplifier without a PCB may simple for you and me but as a first-time project I would not recommend it, unless extremely proficient and solders and layout. It often requires very good construction and layout. Not to mention the likely possibility of additional troubleshooting without help from a supplier or dealer.

I believe there is a version of the LM3886 simple, 3 or 4 resistors, 2 capacitor (per chip) design on Decibel Dungeon. I cannot remember the page directly but if you search for simple 3 resistor LM3886 amplifier you should find it.

I do agree that you can build great amplifiers based on basically any chip or transistor and no PCB with superb results. I would not consider it a beginners project, though.

BTW: I had not given the chip you mentioned much thought for use as a non-PCB solution until you mentioned it. I checked the datasheet (as you referenced) and some posts online and (thanks to your mention) decided to order some and build up the circuit. Thanks.

Darren
 
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well, if you take a look at the bridged veraion of STA540 You will find that all You need basicly is supply bypass/filter/reservoir caps, input caps, and mute/standby circuit, really only a few components. You don't need to solder the gain setting resistors.
7 components, really not a lot. 8 if you have ground lift resistor installed.
 
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