Hello folks, Im new here! I have a couple of quesrions.

[manisfive]

I would love to get into building and moding pedals and amps but i have no knowledge of any of this stuff. If i was wanting a crash course in diy electronics where would i look? Also, I was looking at buying the fender pro jr 5w. I read that it had an output for an ext cabinet. What is the biggest extention cab i could run with it? I have a fender blues deville 4 by 10 combo, could i just unplug the speakers from the 4byten and run them to the pro jr?

[M Fowler]

Manisfive,

Welcome and here is some reading material for you.

Mark

https://tubeamparchive.com/viewtopic.ph ... e+material

[Structo]

You pretty much have to have a good understanding of basic electronic theory to do much in electronics.
This includes AC & DC theory, Ohm's Law, Component familiarity, soldering, etc.

As for the speakers, the total impedance is what needs to match up.
So if your amp has an 8 ohm output, the speakers in whatever combination should total 8 ohms as well.

Mismatches are possible but you need to know what you are doing to do it safely.

So if the 4 x 10 speakers total what the Pro Jr. output is, then it is completley safe.
Most amps, if they have more than one output jack, have it wired in parallel with the other jack so the load is distributed between those two jacks.
So if an internal 8 ohm speaker is connected and you plug in another 8 ohm speaker, the total load is 4 ohms.
Ohm's Law.
In series resistance adds.
In parallel resistance has a formula
R = 1 / (1/R1+1/R2+1/R3)

Many times it is best to unplug the internal speaker on the combo then plug in the extension speaker.
The totally depends on the amp in question though and does not apply to all amps.

Good luck! now it's time to hit the books!

[GibGa]

I'm still learning but have done a few scratch builds to date now with near 100% success - minus a probably bad to begin with Ebay Grundig SE OT, and cooked a small PT that I got free along the way ... all advice is to read read read and read at all the amp forums like here, hoffman, weber, metro etc, and then it starts to come together well with a simple practice amp to mod on like valve jr etc.

I found excellent electronics books when I first got interested at the local library, and bought a basic guitar amp book and tinkered on my then stock Mesa Subway, which is now a MHuss 5V6 1987 fixed/cathode biased...and will stay that way - Thanks Mark for the infos on the build is a great little amp now.