The Hundred-Buck Amp Challenge

[Wavebourn]

Originally Posted by hunoz

I can see there are a number of typos in my post. Apologies. I need to learn how to spell check them.

Typos are Ok; we all make mistakes, but making mistakes we learn. It is DIY forum, and I do not see anything wrong in attempts to build some gear from scratch learning real things. You can fix and modify bicycles for most famous sportsmen, you can read tons of articles about world class competitions, but you can't learn to ride bicycle reading warnings about how dangerous and difficult it is, until you try, fail, and try again.

[pinkmouse]

Good post Hunoz, and I think very relevant, if this were the $500 amp challenge. But it's not, and I suspect most building this will be beginners, or failed musicians like me who just want a little amp to noodle around on with some of that valve magic without spending too much dosh.

[hunoz]

Originally Posted by Wavebourn

Typos are Ok; we all make mistakes, but making mistakes we learn. It is DIY forum, and I do not see anything wrong in attempts to build some gear from scratch learning real things. You can fix and modify bicycles for most famous sportsmen, you can read tons of articles about world class competitions, but you can't learn to ride bicycle reading warnings about how dangerous and difficult it is, until you try, fail, and try again.

I was not suggesting that the challenge was bad or that it had no benefit. It has many indeed. Having said that an amp that is an interesting project and one that working on it many things can be learnt from is not necessarily one that is worthwhile to build copies of especially beginners to amp building.

While on that note: the forum members may forgive me for being an old timer and that I grew up with high standards regarding safety while working on a project with high voltages. As such it gave me cringes seeing some of the photos in the posted pics with of lots of loose wiring, loose temporary connections and other unnecessary items on the bench while building and testing amps. (I am not pointing the finger at you, I am talking generally!) I did not even see a safety isolation transformer used on any of the pics. An Isolation safety transformer should always be used when working on any tube amps or where high voltages running in exposed wiring. If there was one somewhere in the pics, I missed seeing it. I think readers who are not aware of the dangers of this beautiful hobby may interpret what they see in the pics as safe practices. Go forbid someone having an accidental shock or much worse!

[hunoz]

Originally Posted by pinkmouse

Good post Hunoz, and I think very relevant, if this were the $500 amp challenge. But it's not, and I suspect most building this will be beginners, or failed musicians like me who just want a little amp to noodle around on with some of that valve magic without spending too much dosh.

Al, If the cheap little amp does not sound right, it will not make nice clean notes or that the distortion will be different than what you want, you will not practice on it. If you can make a riff sound at least similar to your favorite guitar player than you will stick with it and improve. if your amp will sound really thin or muddy then you will stop turning it on.

There are a couple of really nice sounding small amps out there like this one!

YouTube - ‪5 Watt Homemade DIY Tube Amplifier Demo‬‏

Enjoy!

[TheGimp]

Many of us keep our isolation transformers below deck. I've got five of them under my bench running various sections of it.

A 20# (9Kg) transformer just gets in the way on the bench.

[hunoz]

Originally Posted by TheGimp

Many of us keep our isolation transformers below deck. I've got five of them under my bench running various sections of it.

A 20# (9Kg) transformer just gets in the way on the bench.

I did not say that none of you used an isolation transformer. What I am saying that it is not showing and beginners may not know or understand the need for one.

[TheGimp]

Regrettably, I for one will not be keeping my workbench clean and organized as an example to beginners. We have stickies for Safety and best practices.

I don't allow small children, cats or my spouse to touch anything in the garage, so I'm the only potential victim, and I've worked around HV for over 45 years so I am comfortable with my breadboard technique.

[Trout]

Originally Posted by hunoz

There are a couple of really nice sounding small amps out there like this one!

YouTube - ‪5 Watt Homemade DIY Tube Amplifier Demo‬‏

Enjoy!

Sounds like a pretty good amp, but it sure sounds like it had software post effects added.
Certainly its not a 100% dry recording.

[hunoz]

Originally Posted by TheGimp

Regrettably, I for one will not be keeping my workbench clean and organized as an example to beginners. We have stickies for Safety and best practices.

I don't allow small children, cats or my spouse to touch anything in the garage, so I'm the only potential victim, and I've worked around HV for over 45 years so I am comfortable with my breadboard technique.

I was concerned about your safety too, as well as the examples set for beginners. However, as you say it is your garage and I have to say it is your business what you do. I purposefully did not mention yours or other forum member safety as I felt it is none of my business and you all appear to be seasoned professionals. Having said that, I am concerned for any professional who may have an accident due to an untidy bench and loose exposed wiring carrying high voltages. You have obviously have not had a serious accident, because I assume if you did you would not continue with these practices.

As I said it is yours and every other members business here as to what safety measures you / they take. I made my point re beginners and hopefully they will head my advice. Enough said by me on this issue.

I am not here to make enemies, so I apologise if my concerns came across as me telling you how you should work in your garage. It was not my intention.

[tubelab.com]

I did not say that none of you used an isolation transformer. What I am saying that it is not showing and beginners may not know or understand the need for one.

All of the amps here WILL have a transformer for mains isolation. It may not be obviously stated because it is a requirement for discussion on this forum. Posts advocating transformerless construction will get warnings or removal from the moderators, so it is understood as a requirement here. It was stated in the original design criteria that all dangerous points (high temperature or elevated voltages) must be inaccessible to the user, but the enclosure will not count in the final price since presonal preferences differ. Same goes for the speaker.

Musicians are a different: The one and only thing that matters to them is SOUND, whether they are professional or amateurs!

A very valid point, and one that sevreal players here realize.

An amp that will be judged as "ok" for all or many of the styles of music played will be not be satisfactory or really good for any of them! This is fact of life! It is no different from the car we buy. What is the main purpose of the car going to be?.......I/You would buy a very different car for each of these purposes, would you not?

A professional musician would likely have an amp, or multiple amps tailored for his playing style, just as a "car guy" would purchase a car for their driving style. A well off musician or car guy might have several different "instruments" that were not budget priced.

Just as Honda or Toyota will sell many more of their budget priced cars (Civic and Corolla in the US) than the purpose build models, many more budget "practice or beginner" amps get sold than full stacks. The challenege here is to build a mid line model (Camry or Accord) for the budget price.