Thanks a lot guys! Anyway, I think I will give it a try to see what I can do. In case the 12V 17Ah is not ok, I will buy a bigger one :p :duh

The reason that I don't wanna use portable power generator is because it is smelly and noisy. Moreover, I have to buy fuel for it. It's kind of troublesome.

First, let me find some time to make the mixer. Probably need to wait till Chinese Lunar New Year.

Quote from: trialabc on January 14, 2011, 12:18:36 AM
For the outputs : at least 2 speakers like in stereo or maybe 4 speakers.

2 speakers for stage (so that we can listen what we are playing) and 2 speakers for audience

Sorry Phatt, I think the word "stage" may confuse you a little bit. I don't need very large power for the speakers in fact. I think two 100W speakers will do. Hopefully this way sounds more practical.

So when it is marked as max 75W, it already counts the lost of transformer?

Thanks for your reply first.

But first, perhaps we can forget about the battery problem first.
Previously I successfully use an inverter to power a line 6 spider III amp (max 75W ) using a battery(12V 17Ah). But due to this kind of configuration, I think there is about 50% power loss due to 2 transformers. Well, at least I can play for 3 hours loudly. It has already achieved what I wanted to do.

As a result, this time I try to power a mixer. However, if I use the same configuration like above, I will still have 50% power loss.
Therefore, I want to make my own mixer for that. As a result, I only required for one transformer, say 30% power loss. Perhaps we can reduce to 2 speakers? Does this sound possible?

For the outputs : at least 2 speakers like in stereo or maybe 4 speakers.

2 speakers for stage (so that we can listen what we are playing) and 2 speakers for audience

At this point, I think it will be required to support 2 mic, and 2 guitar inputs.

Well, if I can have the equalizer like the first schematic you posted would be good, but that's less important.

What I am concern about is the power and possibility of achieving it. I am concerning about the power because it would be powered by 12V battery.

Maybe I should try using a summing up circuit for it?

Thanks for the schematic first.

I see there is a effect out and effect return. In case I don't need any effect, I can just connect the two?

I wanna make a mixer, but not sure how....
What I want is just to combine all inputs (likely to be 4 inputs) and output to two speakers.

Should I consider it as a power amplifier?
Or is it too difficult to a beginner like me?

Thanks in advance!

Thanks, now I get the general idea of it.

Sadly, I don't have instruments to do those testing. Perhaps I should buy the speaker with specification provided.

But for what I have seen, most likely, there will not be db marked on the speaker. Usually I see Ohm and Watts.
What can I do if I can just see the two information marked? Perhaps the size can help?

Please forgive me if I have posted at the wrong place.

I have tried using a car battery (12V 17Ah) to power on a Spider III amp. I use an inverter to convert 12 to 230Vac and turn. For guitar, I used an electric acoustic for testing.
It works, but the problem is that static noise is heard.

When I lower the volume output of my guitar, the static noise is smaller. When increased, static noise output increases too.
I have also tested using 230Vac from wall, it does not have static noise output. So I think at least it is not introduced by the jet and my guitar. And I am guessing the noise is introduce due to the fan on the inverter.
I have tested the voltage for the inverter output. It does not reach 230, but 190 (AMP is turned on). Not sure if this will affect the performance of the AMP.

Is the something I can do except replacing a better inverter? Or is it inevitably noise will be introduced in this configuration?

Fahey, it would be great if you tell me how to make the reverb from scratch. In this way, I can see if I can really make from scratch. If it is possible, I think I will do it. The only problem at hand is just I am quite busy with my work lately...

All I know about the spring tank, are springs with transducers.

Thanks a lot rowdy_riemer !!

Now I really learn something instead of just copying the circuit.....

Hopefully I should have time to start building the amp by this weekend. See if I can finish it, try it and post a picture here. Oh... how to post a photo or schematic?

Guys, thanks for all your suggestions. I have scanned through the schematics of Solo and AmpCan.

Sorry that I am not that keen on circuit design for the moment. Although I would like to learn the behind working principal of the JFET stages, I could hardly understand what you are talking about...

By the way, when I study the schematic of AmpCan, I find diode D1 and D2 are in opposite directions and connecting in parallel. 0.0  Can't understand how it works.... Mind a little more help?

For this moment, I think Op amp will do. Don't wanna mess up the biasing problem.... Seems so difficult....

Oh.... how about the preamp part? What do I need? Which design I can use as reference if I just wanna have clean sound?