Baby Amp Is Born...

[Paul Marossy]

Just for fun, I built the Little Gem from ROG. Here is a little picture essay of my project: http://www.diyguitarist.com/GuitarAmps/LittleGem.htm

[thomas2]

sweet  

[Sic]

thanks paul, always a pleasure reading your stuff.

[MartyMart]

Thats great Paul, very neat build/cab  ( as ever ) LOVE the covering !
I'm just about to build the "Little Gem" so its very inspiring !
It would go very well with my "Tiny Tube Reamer"  LOL
Cheers,
Marty.

[Peter Snowberg]

Very nice build!

[guitarhacknoise]

cool! looks like a heavy duty, ready fer "action" amp.
-sorry, just had to !

[remmelt]

very cool, i love the photo essays!

one question: why the little gem and not the ruby? i'm thinking of building one of these and to me it looked like the ruby was the gem's successor.

[Steben]

I should think more of a big daddy actually.
The sounds are very similar though.

Putting a fet stage and not a buffer (big daddy) in front of the 386 will add more transparent sounds when more cleanish. Yet I should use a fet stage without decoupling cap at the source for not to much heavy metal gain there.

[remmelt]

i own a smokey and that's a little too dirty for effects testing, although it sounds great one on one with my guitar.

am i right in thinking the ruby is the cleanest of the rog pack? (sorry for hi-jacking the thread, by the way)

[Paul Marossy]

I'm glad that you guys like it.  

I could always change out the circuit if I decide that I don't like it...
I tried to look at the page, but something is going on with my website again.  :evil:

[Marcos - Munky]

Really beautiful, Paul.

[Paul Marossy]

I had a thought for a mod that could be done: Instead of connecting the input to Pin 2 (inv in), you could connect it to Pin 3 (non-inv in) through a 10K pot to ground and have Pin 2 connect directly to ground. This is what it shows for a gain of 20 application right on the LM386 data sheet. It probably would sound a bit cleaner. Or you could even use the gain of 50 or 200 version, which is the same thing as described above, but with a cap or a cap and resistor in series between Pin 1 & 8. The Little Gem is almost just like the gain of 20 schematic on the data sheet except fo the input arrangment and the addition of a gain control.

Anyhow, just some thoughts. I like it like it is, if I roll the volume back on my guitar, it sounds pretty clean, and I can get distortion by turning it up. So far I like it just like it is...

[littlegreiger]

Hey Paul, what's the rating on those speakers?

[Paul Marossy]

It says on the back of the speakers "50 watts maximum". You could use almost any speaker with this circuit - it's only 1/2 a watt...

BTW, I have been playing this for a couple of days now, and I think it sounds pretty good with those speakers.  

[video_dude]

Nice amp ! Speakers look like Kewl JBL's

[Paul Marossy]

Yeah, I like the way that those speakers look, too.
Thrift stores can be a great resource for some things. I have had really good luck finding small speakers and all sorts of wall warts to use with various projects I have made, for very little out-of-pocket.  

[travissk]

That looks really useful - the "fake cab" plate is great

[Paul Marossy]

You mean the fake chassis? That worked out kind of cool considering that this whole project was kind of thrown together, so to speak. I started with the speaker baffle, and that mostly dictated what size the enclosure should be. I built the enclsoure without really knowing how to do the "chassis", until I had a thought to do something similar to my Fender Hot Rod DeVille. So that control cutaway was done "after the fact", after I figured out the chassis part. It's not perfect as it will pick up radiated 60Hz hum if you point it at a computer for instance, but it's not very noticeable. A little bit of shielding on the inside could eliminate that. Anyhow, the rest of it was pretty straight forward - I just used my experience from the three tube amps I have built so far and applied it to this project. I even had a thought tonight that one could build a two-channel version of this - one channel would be the Little Gem and the other channel would be the Ruby. I took probably about 7-8 hours to build the entrire thing. Building the cabinet is what took most of the time...  

[Michael Allen]

I used a similar approach when I built my Ruby. It was a piece of steel used for fencing i believe. Check it out here in the projects section.

http://photobucket.com/albums/v368/soma_hero/

[Paul Marossy]

Great minds think alike, eh?  :lol:

Seriously though, I was playing my Strat through my Little Gem this morning, and with the Strat it sounds very clean. I have to turn the gain almost to max. to get some distortion. With either of my humbucker equipped Ibanez guitars, it has much more distortion. I think I still like it just like it is...