Building the Tiny Giant amp

[Skruffyhound]

Thanks Paul, I'll do a bit of research. Starting Monday I'm rebuilding part of the first Danish ship to sail to the Caribbean, and it's a bit of a drive each day, lets see how much free time I get.

[Jdansti]

^ Ship?  I'll bet some teak or mahogany would make a nice cab if you can legally procure some scraps.

[Skruffyhound]

It's oak. There was alot of oak about then.

Funny OT story. A couple of years ago the Danish forestry service rang up the Danish navy out of the blue and said "your order is ready".
To which the navy replied "we haven't ordered anything."   
"Well we have 90,000 oak trees and all the paperwork, ready to ship."
"What? When did we order that?"
" 1806."


Perhaps I'll be able to tell you if that story is the literal truth after the next five weeks working at the National Maritime museum.

[PRR]

> "What? When did we order that?"
" 1806."

I've heard a similar story about an old English school. After 400 years some roof beams needed replacement. The trustees called the usual lumber suppliers but oak that big was a LOT of money if any could be found. After much mulling, somehow word got to the grounds-keeper. He took down a very old ledger and looked something up, took the admins out in the woods, pointed to a very large mature tree, "that one". Apparently when the building was built, they also planted little trees for eventual replacement of all major beams.

[garcho]

FWIW, I built an amp similar to the TG in a tin shoebox with an old iMac subwoofer. For about $20 it made for an amp with a weird EQ and strange, tuned, pangy reverb. If you have a studio or something, or play venues with lots of channels and mics, it can make for an interesting, unique color that would take a lot of DSP/noodle-time to emulate, for the cost of a few pints. My point is, if you're not trying to build a swiss-army-amp, try experimenting. It doesn't get much cheaper or easier than the TG.

[shay1510]

Hey guys, Beginner's question:

I have a 12v 4.2A power supply, and already soldered all the parts to the pcb including lm338t voltage regulator.
If I understand correctly I have to bypass it in order to supply the 12v directly to the board.
What's the best way to do that? (technically - I mean where to connect the +ve wire of the power jack?)

[gcme93]

Hey guys, Beginner's question:

I have a 12v 4.2A power supply, and already soldered all the parts to the pcb including lm338t voltage regulator.
If I understand correctly I have to bypass it in order to supply the 12v directly to the board.
What's the best way to do that? (technically - I mean where to connect the +ve wire of the power jack?)

http://musicpcb.com/wp-content/uploads/2011/02/Tiny-Giant-Build-PDF-rev2.pdf

Look at the last page of the build guide and you'll see a red text box that labels a regulated power out. You can use that little hole with the black arrow pointing to it to attach your +12V supply

[Jdansti]

^That would work. The only thing is that you would bypass one of the 100n caps, but this might be OK. Here's an alternative:

[shay1510]

Hey there,
I used Jdansti's method to connect a 12v PS (omitted the two resistors and the power regulator + a jumper), But I have a problem,
When I connect the power supply the speaker makes a "heartbeat" sound every 3 seconds, wouldn't respond to the volume knob.
Tested with two speakers, same result.

*it also happens when guitar isnt connected.
* it stays the same when I remove the tl072 chip
* when I measure voltage on pin 8 of the tl072 I get a reading of 400mv dropping to 200mv every 3 seconds (which explains the pulsating sound)
does Anybody have an idea?

* Actutally I've noticed now that the PS turn on and off every 3 seconds, once connected. I'll get another PS and report.

[arma61]

Hi there!

anybody tries a DELL PSU, I have the possibility to buy 3 for 25.00 euro, though at the moment I had good results only with an HP one, another one an ASUS didn't work, too noisy also with other pedals, while the HP one is fantastic either in the TGA and with pedals, indeed I have the same HP psu powering the TGA with an additional regulator/filter directly connected to the PSU to power my pedal with 9V.

The DELL PSU model is PA-10 Family Model DA90PSI-00 19.5V 4.62A (as far as I can tell from the zoomed picture I had).

So, is anybody here using this DELL PSU ??

Thanks m8s,
Ciao
Armando

[Jdansti]

Hey there,
I used Jdansti's method to connect a 12v PS (omitted the two resistors and the power regulator + a jumper), But I have a problem,
When I connect the power supply the speaker makes a "heartbeat" sound every 3 seconds, wouldn't respond to the volume knob.
Tested with two speakers, same result.

*it also happens when guitar isnt connected.
* it stays the same when I remove the tl072 chip
* when I measure voltage on pin 8 of the tl072 I get a reading of 400mv dropping to 200mv every 3 seconds (which explains the pulsating sound)
does Anybody have an idea?

* Actutally I've noticed now that the PS turn on and off every 3 seconds, once connected. I'll get another PS and report.

What do you measure at the unused pad next to the "m" where Taylor says you can power external devices?

Also what do you measure on the two pads where you installed the jumper?

Make sure you have your neg test probe on a good ground point.

[shay1510]

I think that the 12v PS was defective, therefore I took a 19.5v PS I had laying around
and everything worked (!). The TG sounds great. Need to put it into an enclosure though.

Thanks again.

[Jdansti]

Glad you got it going!

[potul]

Hi Folks,

Finally, after some months of having it on the table waiting for an opportunity, I had the time to build my Tiny Giant. Populating the PCB was really fast, the task that took me longer was to prepare the Housing for it.

I've used a Heineken mini-Keg and a car speaker I had laying around. Here you have a picture of the final product:



Simple setup, just a volume knob, and input jack and the DC jack. Sounds great, although I can't use it at high volume as it starts to distort in a naghty way (I think it's the speaker....). I might try to fit a Jensen MOD 5 speaker.

Now that I have it built, I'm already thinking on some mods for it, and one of the things I'm interested in is being able to operate it from a battery. It would be so cool to use it with my friends in front of the BBQ...

I've spotted this battery that might work (12v 4500mAh):
http://dx.com/p/ysd-12450-12v-4500ma-rechargeable-lithium-battery-80405
or this one (12v 4800mah):
http://dx.com/p/12v-4800mah-rechargeable-portable-emergency-power-li-ion-battery-91001

But I have some doubts regarding how to wire the whole thing. Ideally I would like to:

-Fit the battery inside the keg (there's plenty of space)
-Be able to run it from battery or from the power supply I have now (19.5v laptop one)

Do you think this battery will work?
Any idea how to put everything together? (the battery should bypass the regulator as it only provides 12 v, while the power supply would use the regulator). Maybe it's better to get an 18v battery instead?
Do you think I can charge the battery from the circuit, or better use the charger that comes with it?

Regards,

Mat

[garcho]

Use the charger it comes with, unless you know for certain what you're doing. Next thing you know, you'll have an expensive battery leaking acid all over your beer. I mean your amp. Sorta dangerous, environmentally hazardous, etc.

I've blabbed a lot about using a 18V 4A cordless drill battery before, but haven't gotten around to trying it out yet. However you do it, you'll want access to the battery, yeah?

Looks good!

[potul]

I'm looking at the option of an 18v battery and kepp it external, plugging it to the same DC jack... But 18v batteries as more expensive than 12v...

I'll think about it tonight while having a beer.

[garcho]

I'll think about it tonight while having a beer.

Good plan!

[Rock_on]

We dont have an LM338T here, what's for sustitute?? Cant find one on google.

[potul]

You can check an LT1084, I'm not sure if it's a one-to-one replacement, but looks quite similar. Check the datasheet. You might need to tweak the resistor values

MAt

[Rock_on]

You can check an LT1084, I'm not sure if it's a one-to-one replacement, but looks quite similar. Check the datasheet. You might need to tweak the resistor values

MAt

That would be a trouble for me... Idk how to tweak anything, i just know how to read a schematic and build it.

How about LM317??