Ok so I started out trying to make my own amp. So far I have been working on the preamp section.
I based my design off of several designs I found on the internet and the datasheet for the ICs (LM386).
My idea was to use one IC with a drive pot and to be able to switch in the other IC for a "boost" or "high gain" channel.

I am getting weird results. First the gain pot doesn't work, at 0 I get some weird weird artifact noise in addition to harsh metallic distortion. At 10 I get just the harsh metallic distortion. The knob only affects the artifacts.
Also there is kind of a gating effect, sustained notes seem to be cut off after a while in a quick fade out, and playing hard makes it go silent and drop out. Switching on the booster amplifies this effect, I get a second of sounds, then it drops out, then it comes back a second and drops out again, then it dies in the gating effect. Also when playing two strings together I get a "tremolo" effect or oscilation or what you call it

What am I doing wrong? Any ideas?

Schematic is attached,
EDIT: Noticed an error in the schematic C1 is electrolytic!

DocZ

I just found a couple of TIP31 TIP32 transistors, I was thinking maybe I could use them for a power amplifier? Anyone ever tried using those? And anyone who can point me in the direction of a schematic using these that I can study to see if I can use these for guitar purposes?

DocZ

Hello everybody, I'm new to this forum and new to this wonderful world of electronics. I got hooked after I took it upon myself to restore my dads old Teisco 10 tube amplifier from the 50s. After a lot of great help and effort I managed to fix it and restore it to it's original state. So now I got the taste for electronics. Since tube gear is extremely expensive, I started my next project which was building a Ruby Amp. It souds great! A pity it is not loud enough to work as a full band amp.

So I thought I would be able to use the LM386 as a preamp and then get something more powerful to power it. I bought a TDA2030 amplifier board on Ebay, my idea was to use it in a speaker to make it active. And see if it would be good enough to use as a surround speaker. Anyways I ended up getting three boards with a total of six TDA2030s because the first two boards got damaged from shipping.

My idea was that maybe I could bridge a couple or more of these chips to get the power I need to power a 2x12 cab and get the great sound of the Ruby out to the masses. But my first bump in the road is a power supply. This thing needs +15V and -15V as well as 0V. The only transformers I can find with 2x15V and 0V are really expensive! About the same prices as the high voltage transformers used in tube amps. My question is then, is there a cheaper solution to this? If so what can I use? Can I use two 15VDC wallwarts in series to get 15-0-15?  A 15V 4A laptop charger costs like $2 on ebay, compared to the 2x15 toroid that costs $80 it is quite tempting to try it out! But since I have no idea if this will work, I thought I'd ask you guys to see if this is a stupid thing to do.

Cheers,

DocZ