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sagi4422 10th December 2012 01:44 PM

DIY AMP start project - Help choosing one
Hi .

I am new in this field of building an amp or other electronic devices but I have the enthusiasm to do it as a hobby.
I am reading some details about the circuits but I am lack of knowledge in how each component contribute to the sound/circuit and whats its porpouse. Does anyone can link me to a good guide ? Anyway, I though a good way to start is to take a well known schematics and build it and on the way to understand the inside of the amp.
I was suggested to start with low voltage amp rather high voltage as the lack of experience so I found the below kits (unfortunately they are headphones amps):
Bottleneck Crack $280
Project Sunrise II $200
The Starving Student Millett hybrid $130

Of course that any other suggestions will be welcome but I was wondering if any of this can run even in low volume , a nice Paradigm speakers instead or headphones as I am hearing using speakers mostly.


sagi4422 10th December 2012 06:38 PM


DF96 10th December 2012 07:01 PM

Valves don't work too well on low voltages. Speakers don't work too well on a headphone amp.

Start with a simple chip amp kit. Safer, and less to go wrong.

sagi4422 10th December 2012 07:13 PM

any suggestions for a kit which gives high details in low volume?

Jack Caldwell 10th December 2012 07:18 PM

Perhaps you could consider starting with a pre-built amp board such as the ones sold by and then selectively replacing onboard caps and inductors. You would be working with a very good sounding amp to begin with, and then hear the differences as you swap out components. And it would give you a great starting amp to compare others against. These amps, in stock form, will outperform 98% of what's out there, and for very little money.

Then you could start building a tube-amp kit, such as the ones from Transcendent Audio. They have some wonderful OTL amps.

And at that point, if you come up with something that sounds better than either of the previously mentioned amps, I'd be interested in hearing it!

sagi4422 10th December 2012 07:29 PM

Hi. I saw the site you suggested above . Although itched details you supply are interesting , I think it will be more complicated to change caps/ resistors on pcb like this . It is very dense in this case ( in compare to point to point ).

kingbabytank 10th December 2012 07:36 PM

yo bro. i can kinda help you out.
tubes are basically used for two purposes. rectification or amplification.
rectification is basically converting ac to dc. amplification is increasing a signal in volts, watts, or current.
there are 5 basic types of tubes: diodes, triodes, tetrodes, and pentodes.
diodes are made of a filament (cathode) and an anode. they are only capable of rectifying and cannot amplify. AC passes through the filament (the thing in the center) and it heats up. When it is hot, it starts releasing electrons into the vacuum which hit the anode. The power coming out of the anode is dc since the electricity only flows from the anode instead of back and forth as it did in the filament.
a triode is the most basic amplification device. basically it is a diode with a "control grid" that surrounds the cathode. your audio signal flows through the grid causing it to release different levels of levels of electrons. as electrons come out of the grid, they repel some of the electrons coming from the cathode, making the electrons that actually reach the anode a stronger copy of the signal that passed through the control grid.
tetrodes and pentodes do basically the same thing as triodes, but produce different levels of distortion and have slightly different sounds. i can explain these more if you want me to.
a power transformer is used to change the voltage ac voltage that comes out of your wall to make it usable to your amplifier.
an output transformer decreases the very high impedance from inside the amp to a low level that your speakers can use. all tube amplifiers have these since they operate at such high voltages, but most solid state amplifiers don't since they work at lower voltages.

dagerman 10th December 2012 11:07 PM


Originally Posted by sagi4422 (Post 3279007)

It's always good to give it a day when waiting for a response, otherwise people may think you are impatient... ;)

Here's my suggestion based on my own path. Let me preface this with saying that I have no good feel for what your level of general experience is with electronics, specifically those that involve high and potentially lethal voltages (like tube circuits of any kind) or if you can solder and so forth. There's always the other aspects of an amp build which involve putting everything into an electrically safe enclosure that may require intermediate 'crafts' skills, depending on how fancy you want to get.
If you have no good working knowledge of electricity and associated safety, I would probably recommend not picking a tube amp as your first endeavor.
But if you do...

I did a good amount of research when I picked my first amp build and ended up with the Tubelab SimpleSE found here: Simple SE board
What appealed to me was the fact that...
  1. it was a proven design
  2. I could order a PCB
  3. Lots of others here have built them
  4. George is extremely helpful
  5. The documentation is second to none of any kit I've looked at
  6. The total price point of the resulting amplifier was right
  7. it works with a multitude of different tubes and transformers, depending on what you like [to spend]

The build is very straightforward and it makes all the difference in the world if your first build actually results in an amp that sounds really, REALLY good.

I have since built another one with equal results.

I don't have the skills to design my own circuit yet, but I am studying Morgan Jones' book, which is often quoted as a good reference.

If you have no experience, I would definitely recommend reading up first and getting a working knowledge of what's involved and - more importantly - what NOT to do.

There is a really good 'sticky' thread here about electrical safety, which you should read, print, read, memorize and always remind yourself about if you decide to embark on the journey. Respect for what you are dealing with is in my mind one of the best safety mechanisms...

Good luck!

Midnightmayhem 10th December 2012 11:53 PM

DIY ECC802S (12AU7 / ECC82) Vacuum Tube SRPP Preamplifier

I had great luck with this schematic. I used some different parts, such as tube rectification and it still turned out fine. If you are handy and can build an enclosure (or find a cigar box) it is a great first amplifier, that sounds respectable and looks as good as you build it. I think when all is said and done I had less than $100 into the amp with my time billed out for free and most the parts being recycled. One of the main reasons I chose this is because it is a tube amp that does not require output transformers. Once built it can be used with all types of power amplifiers both solid state and Tube. Not saying that there are not other good designs out there but I had great success with this one. It is well explained in the text and should turn out great should you decide to build it. Good luck

sagi4422 11th December 2012 05:53 PM

Thanks for the suggestions.

Although hands-on is my preferred way to start, the above schematics are for high-voltage amps. Do you have any good starter kits for low-voltage ?

kingbabytank - thanks for the info. I read good info on the discussed issue in this site : Fun With Tubes but after explaining very good the basics, he jumps to a full schematics. This part of understanding how each component influence the outcome is much important to me than to build on blind. Any good books/sites to recommend?


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