Help building my first guitar amplifier

[ShadowSpectrum]

I've been looking into building a guitar amp for the past couple of days because I figured it would be a cost-effective way to get the power I need (I'm going to build an amplifier for live performances, I don't need another practice amp), plus I enjoy DIY projects and I figured it would be fun.

Let me get some things out of the way: I have no experience with electronics, including soldering (I do own a soldering iron, not sure if the quality is good enough to build an amp with though), and I don't know how to read a schematic. I'm an absolute beginner and I know next to nothing. I've already read most of the pinned topics here, but I'm still pretty lost. Any recommended reading for information on schematics, general electronics, soldering, etc. would be appreciated.

The only things I know for sure is that I want something around 100w, +/- 20w would be fine, and I would like two channels, one clean, one for distortion. I was looking at this page: http://www.oliveaudio.com/index.php?page=3, and the second one down can put out 110w with "IRF540N / 9540N". Do you think this amp would be easy enough for a beginner like myself? If not, any recommendations?

Thanks,
Andrew

[joecool85]

First things first, you're going to need to learn how to solder.  A good way to do this is a simple effects pedal.  I would suggest my 5th gear overdrive, its easy to build and will get you on your way to learning how to do stuff like this.

Lets see if you can tell me what any of this is:

[ShadowSpectrum]

Thanks for responding

As far as your overdrive schematic, I see the circles on the left and right side are the line in and line out, D2 is a red LED, and I'm assuming the straight lines are wires. Like I said, I really don't know much, but I'm willing to learn.

Andrew

<edit>After searching Google, I've found out that 1n914 is a small signal fast switching diode, and that MPSA13 is a NPN Darlington transistor. Not that I know what any of this means, but I guess it's progress.

[joecool85]

Thats really good progress!  Transistors are what power a lot of pedals, they provide the gain. 

Here is a good sheet to study:



Capacitors can also be two straight lines (like how they are in my schematic).

[ShadowSpectrum]

Ok, so to build your pedal, I think I would need:

- x2 1/4" jacks
- x2 0.047uF capacitor; what voltage?
- x1 22uF capacitor; what voltage?
- x1 1n914 diode
- x1 red LED
- x1 MPSA13 Darlington transistor
- x1 2k linear pot
- x1 10k pot
- x1 100k audio pot
- x1 9v battery connector
- wire
- enclosure
- knobs


Do I got that right, or am I missing something?

Andrew

[joecool85]

Yup, thats right, except the 10k is a resistor, not a pot (a pot would work if you turn it all the way to one side though.)  For voltage on the caps, anything more than 9volts is good.  I think 16volt is what I used, but it really doesn't matter as long as it is more than 9volts. 

That brings up a good point, caps should always be rated for higher voltage than they are getting put into them, if you have a 16volt cap in a system where it is recieving 30volts, it could explode.

[ShadowSpectrum]

Alright, thanks a bunch for the help. Any recommendations for where I can buy the parts online?

Andrew

[joecool85]

Yup, you should buy your parts from steve at smallbearelec.com, he's the man.  The parts are decent priced, and he's the best guy to work with for buying specialty stuff like this.  If you are going to make it a pedal, keep in mind you will want one mono 1/4 jack and one stereo, that way you can wire the pedal so it's only on when you are plugged in.  Also you will want a DPDT stomp switch and an enclosure to put it all in. 

If you are just doing it for the learning experience, you don't really need an enclosure or the stomp switch, and you could just use two regular mono 1/4 jacks and unplug the battery when you are done using it.

[ShadowSpectrum]

No, I actually plan on using it, so I'll get an enclosure. Two more questions: Does it matter which jack is stereo and which is mono? Also, I don't think your schematic shows the DPDT switch, so how would I go about wiring that?

[joecool85]

Technically you could have either jack be the stereo, but it makes more sense to be the input.  That way you can leave the pedal plugged into your amp and it won't be on as long as you unplug the guitar. 

And for the offboard wiring: http://www.tonepad.com/getFile.asp?id=76

[ShadowSpectrum]

Alright, I'm going to buy the parts probably by this week, but I'm a little confused.

- For the 0.047uf caps, which should I buy? Or does it matter? These are all the .047 caps I could find.

http://www.smallbearelec.com/Detail.bok?no=162
http://www.smallbearelec.com/Detail.bok?no=174
http://www.smallbearelec.com/Detail.bok?no=519
http://www.smallbearelec.com/Detail.bok?no=528
http://www.smallbearelec.com/Detail.bok?no=541

- For the pots, does it matter if it's single or double gang? The pots come in 16mm and 24mm. Does it matter which size I get? For the 10k pot, which type should I get? Linear, audio, reverse audio, etc?

- For the 9v battery snap, does it matter if I get #22 or #24 leads?

- What kind of wire should I get?

Sorry for all of the questions, I just want to be sure I'm getting all the right things when I order.

[joecool85]

- For the 0.047uf caps, which should I buy? Or does it matter? These are all the .047 caps I could find.

I would run the cheapo $0.25 panasonic ones, supposedly more expensive caps can bring better tone, but I haven't seen such results, at least not in an application like this.


- For the pots, does it matter if it's single or double gang?

Single gang


The pots come in 16mm and 24mm. Does it matter which size I get?

24mm is fine, 16mm is good if you are jamming it into a small enclosure, but either one works the same.


For the 10k pot, which type should I get?

The 10k is a resistor not a pot, any 10k resistor will do fine.


- For the 9v battery snap, does it matter if I get #22 or #24 leads?

Either one will be fine, but I find #24 harder to work with, so if it was me, I would get the #22 just to make it easy.  (The bigger gauge number, the smaller the wire...#24 is damn small)


- What kind of wire should I get?

Technically any wire is fine, I'm not sure exactly what smallbear has, but anything from #20-#26 will work real well.


Sorry for all of the questions, I just want to be sure I'm getting all the right things when I order.

No problem, I'd rather have you ask questions now, than ask questions later and have to place another order.

[ShadowSpectrum]

Yeah, the 10k is a resistor, you had already told me and I completely forgot. Alright, thanks alot for the help 

<edit>Forgot to ask you this before, but do the pots, input jacks, etc. from smallbear come with the nuts to secure them in place? How are the LEDs secured in place? I'm pretty sure they use some kind of ring. Also, do you have any sound clips of your 5th Gear? Thanks.

[teemuk]

- "supposedly more expensive caps can bring better tone, but I haven't seen such results"

This is possible but the improvement is very slight and I believe really difficult to actually perceive. The dielectric material of the capacitor causes more differences in linearity: Electrolytes are very unlinear, so are most ceramics, yet they are used in so many applications.

When selecting capacitors I consider more issues like sufficient voltage and temperature rating. I appreciate reliability more than slight tone differences that I can't really hear.

- "What kind of wire should I get?"

Wire is a resistor; the thinner it is, the higher the resistance. For low current systems it really doesn't matter that much but for higher currents and/or long wire runs use thickest wire you can possibly accomodate and solder.

- "How are the LEDs secured in place? I'm pretty sure they use some kind of ring."

Some large models have threaded sockets, the common, small leds often use a plastic collar/socket that tightens them into a properly sized hole. I guess these are called "led mounting clips" in english.
http://www.globalspec.com/NpaPics/97/107159_121920036922_ExhibitPic.jpg

- "The pots come in 16mm and 24mm. Does it matter which size I get?"

It's just a matter of fitting. Potentiometers have differently sized shafts which is really annoying. The diameters as well as the length of the shaft may vary. If you are fitting potentiometers to pre-drilled holes then at least the shaft diameter becomes a parameter of selection.

The diameter of jacks varies as well - even more than of potentiometers. With sealed jacks the variation seems to be a lot larger than between those unsealed ones. When fixing or modding equipment and having to deal with a certain hole diameter this is extremely annoying!

[joecool85]

Yeah, the 10k is a resistor, you had already told me and I completely forgot. Alright, thanks alot for the help 

<edit>Forgot to ask you this before, but do the pots, input jacks, etc. from smallbear come with the nuts to secure them in place? How are the LEDs secured in place? I'm pretty sure they use some kind of ring. Also, do you have any sound clips of your 5th Gear? Thanks.

Yeah, they come with the mounting hardware.  LEDs can be glued in placed, or you can buy LED holders.  I have sound clips of the 5th Gear OD here on the wiki: http://wiki.ssguitar.com/index.php?title=5th_Gear_Overdrive