#1
I wanted to get a 1/2 watt Bass Amp. I started looking at Tube amp kits, but was thrown off due to price.

I found a Ruby amp thread from a few years ago:
According to this forum thread the 220uf cap is not doing much tone shaping.
https://www.ultimate-guitar.com/forum/archive/index.php?t-685703.html

But suggested doubling the input .047uf cap and to follow the rest of the Bassman Mod Here:
http://runoffgroove.com/ruby.html
And Checking the LM386 datasheets.

As for Hackaweek and the datasheets:
"An increase in bass frequency can be facilitated by adding a 10K resistor and .033 uf capacitor in series between pins 1 and 5."
http://hackaweek.com/hacks/?p=131

I decided to go with the Mini guitar amp on Taydakits. All components and PCB to build the kit is under $20 USD total.
http://www.taydakits.com/instructions/1-2w-guitar-amp


But with a few mods to make it a switchable Treble/Bass Amp.
And its still under $25 USD with the mods.

Sw1 is a 3PDT to select Electric Guitar or Bass.
SW2 is a Gain cut off. (20 Min Default)
SW3 is a Booster.

So, How much would the 3PDT switch effect the circuits?
How much would the Gain pot effect the bass boost?
Would I want to use the Gain at all in Bass mode?
Would I want to use the boost on SW3 at all in Bass mode?

Still haven't found any info on how many amperes to use as an input power source. Except 4mA?
Would a 12v 1a power supply be safe?
#2
Yes, a 1A 12V supply would work.

To me, it doesn't look very effective to use for bass.
Not much better than the cheapest SS bass amp you can find anywhere.
My Gear:
Fender Classic 50s Strat
Gibson Les Paul Studio
1977 Marshall JMP 2104
1995 Marshall 1959SLP
Silvertone 1481
Yamaha RA-200
#3
4mA is the current it takes when it has no signal - you have the data sheet, that's what Iq means.


Needs a smoothed power supply of about 200mA at 12V, so 1Amp is more than enough - but make sure its smooth - use a 1000uF capacitor across it if necessary. Given its a class B push-pull output it will be about 60% efficient and interrelating between the Pmax for 12V is 800mW so ohms law gives you?

P.