Building the Tiny Giant amp

[Jdansti]

golf cart?! what kinda world do you live in?! hang on - i'll just pop over in my personal jet to see for myself... 

Ummm... Not sure how to answer that, but I'll try. I take it you've never had the amazing experience of riding in one of the most luxurious machines every conceived in this universe or any other.   The golf cart.

I wasn't suggesting he go out and buy one of these comfortable, costly, deluxe, elaborate epicurean, extravagant, fancy, fit for a king or queen, grandiose, gratifying, hedonistic, immoderate, imposing, impressive, lavish, lush, magnificent, majestic, opulent, ostentatious, palatial, pleasurable, plush, posh, pretentious, ritzy, sensual, sensuous, splendid, stately, sumptuous, sybaritic, upscale, and well-appointed vehicles.  All he would have to do is look for a man wearing an ascot and spats, club him over the head, and search the area within a 50-ft radius of the ascottted/spatted/evil/rich guy's body, and surely there will be one of these golf carts that has a battery for the taking. That's all I'm saying.

BTW-please try to limit your personal jet poppings. It's bad for the environment.

[artifus]

icarus was solar powered

[Jdansti]

icarus was solar powered

Aren't we all?

[Moxienator]

Got my TG kit today! Thanks Taylor!

After looking over the board for a bit, I came to the unfortunate conclusion that either the lm338 or the tda7240 can have a heat sink, not both. The board is just too small to accomodate both finned heatsinks. I'm thinking that I'll sink the LM338 with the fins and attach it to the chassis, and the TDA7240 will be attached to the chassis only, with no finned heatsink. Good/Bad?

Second thing- what are the two connection points that are near pin 1 of the TL072 that will be under the socket? one of them has an L next to it. It looks like it comes off the signal input. Do I connect these anywhere??

Taylor- Great job! Love the board! just wish it had enough room for the heatsinks.

I guess there are 4 unconnected turrets, not counting the 12v out. Should there be jumpers? Or do they really not connect to anything?

[bluebunny]

After looking over the board for a bit, I came to the unfortunate conclusion that either the lm338 or the tda7240 can have a heat sink, not both. The board is just too small to accomodate both finned heatsinks. I'm thinking that I'll sink the LM338 with the fins and attach it to the chassis, and the TDA7240 will be attached to the chassis only, with no finned heatsink. Good/Bad?

You should be able to mount both to the enclosure, though be careful that you electrically insulate the LM338 (its tab isn't ground).

[Jdansti]

Second thing- what are the two connection points that are near pin 1 of the TL072 that will be under the socket? one of them has an L next to it. It looks like it comes off the signal input. Do I connect these anywhere??

I guess there are 4 unconnected turrets, not counting the 12v out. Should there be jumpers? Or do they really not connect to anything?

The "L" under the TL072 is actually a rectangular tab indicator showing the direction of the IC. My guess is that you don't need to do anything with the unmarked pads. Taylor or one if the others who have built it should be able to let you know.

[slacker]

The unmarked things that look like pads are called vias. The board is double sided, meaning it has traces on both sides, the vias make connections between traces on the front and back, you don't do anything with them.

[Somicide]

Got my TG kit today! Thanks Taylor!

After looking over the board for a bit, I came to the unfortunate conclusion that either the lm338 or the tda7240 can have a heat sink, not both. The board is just too small to accomodate both finned heatsinks. I'm thinking that I'll sink the LM338 with the fins and attach it to the chassis, and the TDA7240 will be attached to the chassis only, with no finned heatsink. Good/Bad?

Second thing- what are the two connection points that are near pin 1 of the TL072 that will be under the socket? one of them has an L next to it. It looks like it comes off the signal input. Do I connect these anywhere??

Taylor- Great job! Love the board! just wish it had enough room for the heatsinks.

I guess there are 4 unconnected turrets, not counting the 12v out. Should there be jumpers? Or do they really not connect to anything?

Looks like mine should be just around the corner, then!  Anxiously awaiting.

[Moxienator]

@ bluebunny, Jdansti, & Slacker - Thanks guys! Great Info!

I got it wired up, but I think I fried the board. I tried using sockets for the LM338 and TDA, but then they wouldn't stay in them, so I had to take the sockets out. In doing so, one of the turrets on the TDA sort of separated from the board. Hopefully it works, I'll be getting another just in case from taylor soon.

@ Somicide - Yeah, it actually ships quickly, I think he was just waiting for more to come in or something. Once I got the confirmation email, it came like two days later.

I decided to throw a finned heatsink on the LM338 (electrically isolated with the washer and the rubber pad) and insulate its legs, the TDA will have a steel washer attached to it for spacing and both will be mounted to a 4" x 1.25" x 0.25" brass bar as an additional sink, and then mounted to the enclosure. The metal of the enclosure is thin, as its more like a "thin-panel amp chassis" than a stompbox. Even though it's large (12" x 3" x 2.2" ), its very thin (.04" I think), so I'm hoping that the extra precautions will keep everything cool.

Whats the story on the Volume control? Has anyone used a larger Pot on it? I scaled down my tone stack to use 25K pots for treble and bass, and a 5K (should be 1k) pot for the mid control. I now sort of understand how it is usually done - halve the resistors, double the capacitors - which is not how I originally did it, so new parts are on the way again.

With this in mind, can I use a 50K volume control without any ill effects? Or should I stick to the 10k?

[MDK002]

I think this question may have been answered before but I haven't been able to find it in this thread.   
There are 2 point on the PCB under TL072.   Do I need to do anything with these or just leave them alone?

[Jdansti]

I think this question may have been answered before but I haven't been able to find it in this thread.   
There are 2 point on the PCB under TL072.   Do I need to do anything with these or just leave them alone?

http://www.diystompboxes.com/smfforum/index.php?topic=89687.msg909263#msg909263. 

[Valoosj]

You should be able to mount both to the enclosure, though be careful that you electrically insulate the LM338 (its tab isn't ground).

Could you use electrical tape for this? E.g. sticking it on the back of the LM338 and then sticking it against the enclosure?

[bluebunny]

You should be able to mount both to the enclosure, though be careful that you electrically insulate the LM338 (its tab isn't ground).

Could you use electrical tape for this? E.g. sticking it on the back of the LM338 and then sticking it against the enclosure?

I guess that depends on how hot the LM338 gets and at what point the tape prefers to catch fire.      I'd tend to go for a pukka mica or silicone insulator (or whatever they're made of...).

[Valoosj]

A what now? 

[slacker]

If you buy Taylor's kit it comes with isolating pads and washers for both chips.

[bluebunny]

A what now? 

Sorry, "pukka" = "genuine, real" ...

Do what slacker said, and you're sorted.

[Valoosj]

Sorry, "pukka" = "genuine, real" ...

Do what slacker said, and you're sorted.

Ah yes, I should have known. Heard Jamie Oliver say it over and over again   

I've bought the components I need and I always etch my own pcbs, so I need to find a different solution, or find out exactly where Taylor gets his washers (or similar ones).

[Somicide]

Got here yesterday.  I've gotta say, the pictures don't really convey just HOW small this beauty is!  Waiting til this weekend to cook up a mother's day gift with one, and a self-purchased father's day gift with the other.  Need to grab a unibit too.  This is awesome; thanks Taylor!

[Taylor]

Thanks!

Yorick, I just get them on ebay. Search for "to-220 spacer" and/or bushing and you should find them.

[Valoosj]

Thanks Taylor!