Building the Tiny Giant amp

[Taylor]

Did you do all of the stuff mentioned in the PDF to do before powering it up? Checking for continuity, etc.? Have you looked over your board for shorts across solder pads?

[guitarplayer83]

Yeah I checked everything.    I will double check everything in the morning and go get a new tda7240. It is possible I overlooked something.

[kinski]

Hey All, I'm very interested in this little amp. For those who have built and used the amp for a while, what do you think? Does it sound good built stock plugging a guitar direct (or using foot pedals) and then direct to a speaker cab?

Even better, if you have some audio of the amp in use, that would be great. There is not much available on the internet. Thanks!

[zuk16l]

I think I need a new hobby.  In my efforts to build the Tiny Giant, I have been practicing with some easier builds in order to boost confidence.  Unfortunately, I have not been able to build anything that works at all.  I don't know what it is, but I'm ready to quit.  I'm so bad at this, I can't even get a smokey clone op amp to work.  One chip and two caps with a couple jacks and a speaker.  How flippin hard could it be.  Needless to say I'm frustrated.  Any tips or advice on how to get this right?

Travis

[Taylor]

I think I need a new hobby.  In my efforts to build the Tiny Giant, I have been practicing with some easier builds in order to boost confidence.  Unfortunately, I have not been able to build anything that works at all.  I don't know what it is, but I'm ready to quit.  I'm so bad at this, I can't even get a smokey clone op amp to work.  One chip and two caps with a couple jacks and a speaker.  How flippin hard could it be.  Needless to say I'm frustrated.  Any tips or advice on how to get this right?

Travis

First, I'd recommend starting new threads for builds other than the tiny giant, but, here is a good place to start:

http://www.diystompboxes.com/wiki/index.php?title=Debugging

When something doesn't work, probe through it, starting at the input with an audio probe. This is easiest with effects rather than amps of course. Post photos of your builds - maybe somebody will see something glaring that is causing you trouble. Perhaps your soldering technique needs some help.

[garcho]

For those who have built and used the amp for a while, what do you think? Does it sound good built stock plugging a guitar direct (or using foot pedals) and then direct to a speaker cab?

yes! mine is going straight into a jensen mod 10" in a faux train case, works perfectly for rehearsals I have in a group with an upright, violin, accordion, and drum set (quietly played). I normally play out of a hotrod deluxe, but am too lazy to haul it to every bands' rehearsals I have. Built it a few months ago. I could post some examples in a week or so, but none right away, sorry.

I'm so bad at this, I can't even get a smokey clone op amp to work.

Ever watch a 3 year old try and write their name? Nothing is easy at first. We can get that smokey clone to work. My advice to you is to start a thread "Total noob can't make a smokey clone". Take pictures of what you have done. Look through the trouble shooting guide here. Do a lot of site:diystompboxes.com google searches, then ask every single question you might have. Give every shred of information about the components you're using. Once you get that to work, do the same thing for the next project. The Tiny Giant will be your friend after a build or two. You'll be making modular synths in a couple of years. Give or take. 

[drezdn]

For the output jack, does it matter which wire connects where? From the schematic, it looks like it shouldn't but I'm trying to narrow down my possible mistakes.

Secondly, could powering it up without a load cause problems?

[Taylor]

The speaker wires can go either way.

Powering it up without a load will not damage the amp, but of course it won't make any sound with no speaker connected. I'm sure you know that, just pointing it out for clarity's sake.

[mr_deadmaxxx]

i was thinking of adding an mp3 input to this so i could play some music while playing the guitar. so do i just connect the mp3 input straight to the output of the opamp buffer, just before the power amp? or would i need a mixer?

thanks..

[Taylor]

You would need a mixer. You can do a really simple resistive mixer, but these don't perform very well. You should be able to find a simple active mixer schematic on google.

[mr_deadmaxxx]

so output of the mixer is connected directly to the input of the power amp? after the opamp buffer?

[Taylor]

That's probably the best way, yes.

[n4vgm]

Just joined as I stumbled on this forum from the Tiny giant page. You folks sure are having fun! I looked through the posts and did not see this but has anyone created a "stereo" version - two TG's controlled by a double volume pot? I was thinking of this since I have both guitar and bass muti-effects pedals that output in stereo. A stereo 40w head for either bass or guitar with separated speaker cabs would sound cool for chorus/phase effects I bet.

You could run two TG's on one laptop PS right???

Thanks, Bob

[Taylor]

Yes, a friend of mine has built one just like that. He runs it off of a single power supply and it works well.

[mr_deadmaxxx]

is the buffer on the tiny giant suppose to make the guitar signal stronger?

i tried building the power amp section only without the buffer and the guitar signal is really weak as compared to my iPod signal.

[Taylor]

The input of the TG is a booster. It doesn't have a huge amount of gain, though. The output of an iPod is going to be way larger than that of a guitar. Did you build the mixer you were planning to do? Part of a mixer's job is to balance levels from disparate sources.

[mr_deadmaxxx]

I haven't built the mixer yet. I just swap inputs to check which was louder and the guitar was really subtle.

Can I swap another booster of the TG something like AMZ mini booster? Or should I just retain the TG's booster and run AMZ booster before it as a pedal? I wonder which would sound better on clean signal. BTW, is 11.6V really necessary for the booster and the amp itself? I was using exactly 12V for the power amp section.

Thanks.

edit:

Found this on google. The right part looks like a buffer or a booster I think. If I use this on the TG, will I still need the TG's booster? Or should I just connect them all to get more gain perhaps?
I noticed, TG's input was fed on the + side of the opamp and in this mixer, it's fed on the - side. Is that good?

[d.watson08]

hey guys! great little build taylor and the quality of the board is top notch.

Ive completed the build but the amp seems to break up at around volume 3. Only way to describe it is a farty type sound and its effected by how hard/soft I play.

any ideas what could be wrong or is that the sound I should get?

[Taylor]

What are you feeding into it?

I hit it with an ipod sometimes and can crank it up way past 3 without distortion. Could possibly be that the biasing on the input to the TL072 is dodgy (bad solder joints on the 10k resistors?) or that your voltages are not right. Can you post voltage readings for the ICs?

[Avulon]

Finished up the offboard wiring last night and finally, after much fiddling cursing and dropping of screws, nuts and spacers managed to fire it up for the first time.  Was in a bit of hurry as time was getting on so only managed to put it through my small 5w elac speaker but sounded pretty good (the speaker is in my 5w ax84 P1 amp, another thumbs up from a tube afficianado!).  I hope to get it hooked up to a pair of 10 inchers in a 70w cab asap.

I'm using a scrounged PSU from a defunct laptop that gives 20v at 3.5A (Dell) so set it up using the 1.5K resistor on the regulator and got 16.69v on my meter.  Two niggles when building, the ic socket had got it's legs mangled in the post, pity it wasn't stuck into the other side of the foam the tlo72 was in, and one of the screw and nuts wouldn't go together I figured a damaged thread: replaced both the socket and the screw/nut and had no further problems: except how small and fiddly it is to solder up ( hey I'm over 40 and my eyesight isn't what it was!

Plan now is to build a stompbox type preamp to run off the regulated 16.69v and put in the same case, any recommendations for one which will clean right up, but still get to a decent classic rock sound?

Oh yes, you can also chalk me up as one who'll have to file down the lip on the case lid to make sure it doesn't contact the ic tabs, doh!

Avulon.