Building Good Guitar Amps For Less Than $100

I would recommend looking at DIY Audio forums and see what members there can suggest.

Thank you Mr. AH. DIY Audio is what I haven't been to. I've seen almost all the links showed up in google except yours. I will definitely look into it. Anyway, I know that I can buy off the shelf fender amps 25W for about $100. I just thought it would be a challenge to build one with more power for the same cost. At the end of it all, it is just the fun of it. Again, thanks all for the helps.

You are welcome!

There are some very bright and informed people on that forum. I used them as a resource to build my HiFi tube amp.

Well you forgot the power supply. The lowest cost power supply will of course be just a transformer, a set of power diodes and a capacitor. You'll certainly need a variety of critical incidental parts like fuses, lne cords and AC plugs.

Doing a brief scan of guitar amplifier kits available for sale I find a nominal price of some $250 and up. This implies to me that the raw parts likely cost around $100. I like the warning here titled "A Word of Caution." In that they warn that almost all kits expect a level of electrical expertise beyond most beginners.

Your problem here is that you are looking at a very small market and production capability. You will be building a prototype. All prototypes are more expensive than the final production run design. In contrast to the $250 kits above, look at this bridgeable stereo 100W/ch amplifier that Amazon sells for $90. I'll grant you that since this is a solid-state amplifier it won't have that desired "warm" distortion that a tube produces when overdriven but it will easily allow one to cheaply make noise in the room.

This brings me to my final point, why do you want to do this? If you want a low cost guitar amplifier, then just buy something like a little Pignose guitar amplifier so that you can hear yourself play. If you wish to learn how to properly design and build a guitar amplifier so you can compete with Pignose then go to school. If you want to just build your own amplifier for the bragging rights that you built it then save your money to buy a kit that fits your goals. If you wish to spend under $100 on a collection of parts so you can learn electronics by building a guitar amplifier of your own design then nothing I or anyone here says should matter.

But I warn you that if you take this last path you will likely spend the most amount of money down this path. I say this because you will never be satisfied with your design. Parts and design configurations that you originally thought were a good idea will disappoint you until you change something. After you correct what bugged you something else will annoy you. You have become infected with the Engineering Inventor's disease. Nothing cures this disease. (Some have claimed that a hot spouse that brings you children can stop this disease, but it only delays the inevitable.)

So be very careful which you choose.

It would be very helpful to know if you plan to build one or two, or one thousand or more.

If you've never done it, and you want to build a quality system, do as AH suggests. He is a very smart person.

There are probably kits that you could purchase from numerous _{Heath/Radio Shack} kit suppliers that would be helpful.

Really, is it a one-off or a business?

Oh, by the way, why don't you register. I very rarely invite "Guests" to join, but you seem like a rather intelligent poster.

Good Luck

I agree, I hope that this guest does register. We always need articulate people.

As has been mentioned, DIY Audio is a good place to start, and there are numerous places doing kits or modules for pre-amps, power amps and power supplies. Bear in mind, the amp/preamp components can be got quite cheaply, but not the speaker and power supply. You could easily pay $100 for these alone, and $20-30 for the rest. The cheapest way to get a reasonable guitar amp is from ebay. Building your own won't necessarily save you money, but will allow you to do something different, or customize to your specific taste & requirements.

This is your answer. i think. http://www.instructables.com/id/Guitar-Tube-Pre-Amp/

In the 70's and 80's I was Chief Engineer for the British sound equipment manufacturer Carlsbro (I had Electronics Engineers to design the circuitry, by the way, so no circuit design requests please). I can tell you that designing and building a guitar amplifier took a lot of time, mainly due to the development of the "sound".

Anyway, tips I can give you from my experience (memory permitting)....

1. The design will depend entirely on the sound that you require. A tube (valve) amp (e.g. Marshall) will ALWAYS sound better than a solid-state (transistor - e.g. Session)set-up, but focussed work on the pre-amp EQ (equaliser) section will help to level the difference.

2. There WILL be problems with earth hum, so persevere with the wiring to eliminate this.

3. Celestion G12 speaker(s) will improve the sound, but whatever you use, don't use PA (vocal) speakers as you'll need an element of distortion from the speakers with plenty of "middle". G12's are ideal in this respect, just look inside a Marshall). And make sure you match the impedance of the speakers to the power amp section!

4. The shape and tuning of the box is close to irrelevant. Most guitar combo's (amp plus speakers in one box) are open-backed. However, if you are building a combo I recommend the use of marine ply to make it as the particle boards (MDF, etc.) are a little weak for the weight involved.

5. You will probably have to learn how to make at least one Printed Circuit Board to fit the components to - messy! If not, a prototype boarding system will be the order of the day for pre-amp and power amp components.

6. Ensure that your Power Supply is adequate, I would recommend at least a 20% "safety margin", e.g 120 Watts for a 100 Watt amplifier.

7. Use a slow-blow fuse in the primary of the transformer as a quick-blow won't take the inrush current on start-up.

8. If you haven't any electronics experience, try some other projects to kick off with - or forget it, you'll kill yourself!

If there's anything else I can help with, just ask.

Excellent points!

The builder should always remember that tube amps have lethal voltages. My amp generates just over 500 VDC. That can be very deadly.

Valve Amplifiers by Morgan Jones is considered the bible for reference purposes.