I am so appreciative of your circuit. Thanks for designing something that truly sounds good while being easy to build. The ubiquitous '386 designs, while simple, sound terrible and I don't understand why others aren't more interested in finding newer more flexible, inexpensive, better sounding, and easy to build designs like yours. I built one Stella and after playing through it for a week, I ordered another so I'll have it handy when I find that "perfect enclosure". Am finding myself playing more through the Stella now than my primary amp. A couple of things I can suggest that may help other builders with their Stella build...
1) publish the thread length for the pots and the jacks - I had to do some creative Dremel work on the wooden cigar box I had because the walls were too thick to allow the threads to stick through to the other side. The threads on the supplied parts will probably work nicely on cardboard cigar boxes but are more challenging on wooden boxes - no showstoppers for sure but letting buyers know in advance will certainly help.
2) list sources of speakers on your web site - I had not bought a speaker in years - I thought you could go down to your local electronics store like I did as a kid 30 years ago and buy a single decent speaker - no such luck. I had a mild panic attack and was wondering what I was going to do for a speaker. I then saw your mounting speakers pages and saw what you used - then I picked up a BRS40 for 8 bucks (plus tax and shipping) on amazon.com. Works great!
3) tell us a bit more about how to use the hacks leads. I sense there is more I can do with the Stella but not much documented beyond the amp.
Overall, you've created a surefire winner. Thanks again for this gift!
Well, I'm totally flattered!
Well, I'm totally flattered!
1. I thought for sure that I had pictures of me building an amp from start to finish in a wood box, but I guess I never uploaded them! I'll have to dig around now and find those pics.
Anyway, I usually use a wood chisel to chip away enough wood to make the pots fit.
I spent two weeks looking for pots, those are the longest threaded shaft pots I could find without having some custom made (which would be ridiculously expensive).
2. I thought I had a page up for speaker selection too! But I guess I don't. I know I wrote a whole bunch of stuff on which speaker to use. (Maybe it disappeared in my site crash a few months ago.)
I will say I have a big box of BRS40 speakers sitting in my closet. I can't sell them on my store because I can't change the shipping cost on a per-order basis. This is a software problem and I'm trying to fix it. Last thing I heard from the guys who wrote the software is "we don't really understand why this is happening."
3. Info on the Hacks output will be forthcoming. I thought I had a surefire awesome tone hack and after a few weeks of messing about I had to completely give up on it. I have no idea why it didn't work.
I'll look into all that stuff. To be honest I have been putting a lot of work into some DIY synth stuff and a photography project, and not so much work on the website.
I'm glad you like the Stella! My main amplifier completely crapped out on me, and I haven't even bothered looking into how much it would cost to fix. On the other hand, I never play with a band or anything like that, so I don't need anything more powerful than a little practice amp.
Best open hardware audio amp circuit design
Very nice design. I just ordered the kit and I just can't wait for it to come in ("I'm so excited, and I just can't hide it" http://www.youtube.com/watch?v=rQqwG_rQx7A ). I've built at least 2 beavis audio Dual Power King circuits and while it could get loud, I just could not get a very clean tone. I'm working on other projects at the moment and really did not want to take time away from other things to research and develop a new audio amp design. I'm extremely grateful for this awesome design. Very nice work.
Kenneth: I checked and I don
Kenneth: I checked and I don't have any pending orders for a "Kenneth Matthew". Please send an email to crazybutable at gmail dot com with your order number if you want to confirm that I have your order. If you do not have an order number, then definitely email me and we'll see about straightening this out.
Re: I checked and I don
I greatly apologize for the confusion. The order was placed under the name David A Overcash. Just checked the form today and saw the reply. That person has confirmed that my order has been shipped.
Thanks for trying to verify my order. Very good customer service. I'll defiantly buy from you again in the future.
Need a higher voltage capacity
3 to 12 volts won't be enough for me and I've blown a few chips on other circuits during trial and error. The circuit I purchased will most likely be powered by 3 (18650) rechargeable batteries with (3400) mAh and the total voltage with all batteries on a full charge will be 12.6 volts.
Please recommend a decent opamp model so I may achieve 3-16 volts.
Thanks & Happy Thanksgiving ^_^
I did a little digging around on the web for opamps. The pin layout appears to be the same on the MC33178PG.
The slew rate on the MC33202PG is 1 V/us
and the MC33178PG is 2 V/us and seems to support voltage between 2-18V on the dual rail.
Would the MC33178PG work OK in the circuit?
I'll use what ever opamp you recommend.
Everything looks good
I've received the amp in the mail a couple of days ago and have began to slowly build the circuit. This is my first electric kit ever so I apologize for the over excitement. My soldering skills or soldering iron itself is a little below average I think but I'm not sure. Most of the soldering points I've done seems to be good enough. I'm taking my time on each solder point to ensure a solid working circuit.
Next time I will try to order a kit that has already been soldered because I hate when solder gets on other parts of the board or my skin. Sometimes either myself or someone else would trip on the cord to the soldering iron and when it falls it starts burning up everything in its path leaving a trail of smoke and destruction.
That opamp you found should
That opamp you found should work great! Once you replace the opamp you should have a kit that will operate safely up to 16 volts, well within the 12.6 volt range.
If you have not yet ordered your opamp and you want to get this thing working now, head over to Radio Shack and pick up a TL-082 (or is it TL-072?). That will also work fine at higher voltages, although it won't work as well at the lower voltages, especially with the clean tones.
As far as the soldering goes, I completely understand. I used to hate soldering, even though I really wanted to learn it. Everyone said it was so easy but it always seemed like I was burning pcbs, myself, components, and the solder would never work right. The iron would be super hot but the solder wouldn't melt until it did ALL AT ONCE, and then it would get everywhere, fusing all of the parts together. I'm not ashamed to admit I broke down in tears on several occasions.
That all changed when I picked up a really nice temperature controlled soldering station. I fired it up, and prepared myself for soldering something that I expected would take about 40 minutes. I was done in two minutes.
So if you have one of those little pencil irons, the problem might be poor equipment. The temperature of the iron is going to depend on the voltage of your household electrical supply and the tolerances of the heating elements, so there are all sorts of things that can go wrong. It's bad if the iron is too cold and it's bad if the iron is too hot, and either of those things will make soldering very difficult.