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Messages - ozzu2000

#16
Well, I'll have to dismantle it, draw the circuit, hopefully get any ideas on how to mod it, then order the components, and only then mod it. All this takes time, and as I only have this amp I wouldn't have any amp in the mean time ;)

Think I'll try to build the MXR distortion + as suggested by Fahey, or maybe just a simple booster could do the trick :)
#17
I'll try to make a schematic, it's take some time because this amp is dificult to gain access to the lower part of the pcb (I have to desassemble 6 buttons and 2 jacks in order to remove it from the metal panel).
I'll post photos as soon as I can :)
#18
J M Fahey: Thanks for the idea, that MXR  seems actually similar to the overdrive circuit on my amp (there's a dual opamp and two clipping diodes).

Teemuk: I've looked into that cr15 schematic, and it looks very diferent from what I have. I guess the clipping circuit on the first opamp is the same as what I have.

The idea was to keep the original circuit of the amp, but it might not be worth the effort. I guess I'm thinking about this just as a fun project ;)
#19
Hi!

My small practice amp is an orange crush 12w (CR12L), and although I like it's sound, it lacks a footswitch, or even an overdrive on/off button.
So started thinking about a way to add a footswitch to it.

This amp only has one channel, so the pedal would have to do 2 things:
- Enable the overdrive (clipping stage)
- Lower the master volume a bit (to avoid that when the overdrive is on, the volume getting much louder as well)

The footswitch would activate a relay, and the relay would then connect or disconnect the bits on the circuit.

Any ideas on how I could accomplish this?
If anyone has a schematic for this amp it would help a lot as I cant seem to find it anywhere (I guess the CR10 will be the same).

Thanks :)
#20
Plugging in an mp3 player for example  :)
#21
Hi!
I'm thinking about buying an small 12W amp, (orange crush). The thing is that, unlike it's bigger 20W brother, this one does not have a line-in jack (aux input).
Do you have an idea of how hard is it to add one?
I'm guessing it's just a jack and a couple of resistors in the right place...  ;)

Any help will be appreciated  :D
#22
Quote from: rowdy_riemer on December 07, 2010, 02:09:39 PM
Ditto what JM said. LM386 is great for not too loud (though I can still manage to piss my wife off with a ruby amp, especially with a 2 x 12 cab). If a single lm386 doesn't do it for you, go with a more suitable chip.
:D

I like that description ;)
Think I'll stick to the single ruby with 12+ volts eheh

I tried to connect one of my hi-fi celestion 100W 8ohm speakers to the ruby (still on breadboard) and it is much more louder than the other 5w 3.2 small speaker I have.
Though on that large speaker I seem to have lots of bass and little treble...  ???
#23
Hi!
I've found lots of LM386 simple amps, and almost all of them have some sort of gain or drive potenciometer.
But these amps have a rather small output, so I was looking for the TDA2003, that has a higher output and still can be run with 12v.
Problem is that all the TDA2003 designs I've found have no drive control...
Do you know any schematic for one?

Regards! :)
#24
I've just found that when bridging amps, the amp will "see" a speaker with half the impedance. So my 3.2ohm speaker will become a 1.6ohm speaker to the bridged lm386, not good!
On the other hand, a parallel amp will see a speaker with the impedance doubled, so a paralleled 386 would see my 3.2ohm speaker as a 6.4ohm speaker.

Any ideas on how to to this?
Or the benefits of doing it?
#25
I've found that little gem mk2 a while ago when searching through google ;)

Well, I still have the power amp that used to drive that speaker (LA4597), thing is I have no idea on how to use the ruby as a preamp, or how to add a volume potenciometer between the ruby and the power amp :P
Can anyone enlighten me?

The "grace" stompbox on runoffgroove has a 100k potenciometer on the output, can this be used as a preamp instead off a stomp box?
Maybe I could connect it directly to the power amp I have?
Grace (lm386 based distortion):
http://www.runoffgroove.com/grace.html
#26
I don't need much power... and for the power it has, the little gem mk2 is as simple as it gets ;)
I just need to know what will happen if I connect the 3.2ohm speaker to the bridged 386.
On the Little Gem mk1 (single 386 and no preamp jfet) it seems to sound fine.
#27
My knowledge of electronics is somewhat limited.
I went for the 386 because I can have simple amp with distortion and it has schamatics readilly available at runoffgroove.

I tried to use the power amp that used to power that 5W 3.2ohm speaker, (LA4597 iirc) but I couldn't figure out a way of adding a volume pot between the ruby and the power amp...
#28
Hi!
I'm building a Little Gem MK2 (bridged 386), using 2 LM386-4 chips, and about 15 volt supply. (15v when running on an AC adapter, 12v when on batteries).
I'm planning on using a small heat sink for the 386 chips.
Everywhere I read it states a 4+ ohm speaker, but the one I have is a 5W 3.2ohm unit from a sony portable cd player.

What will happen? Burning amp, burning speaker, bad sound?

Thanks for your help :)