Lots of general questions from a beginner

[Gwenouille]

Hello everyone !

This is my first post on your forum, and English is not my native language. I hope I can make myself understandable and beg your pardon shouldn't it be the case.

I am new to the realm of Audio DIY and I would like to make myself some boxes and amplifyers.
I've been attracted by electronics for quite a long time now but haven't made significant progress lately: not enough time to spend on the subject.

• Can you recommend a good book that covers the following: basics, capacitors, filters, transistors, Opamps, oscillators, power supplies ?
• I was thinking of the following kits to start with for some boxes I'd make around a Fostex FE127E Loudspeaker:

• SELECTRONIC ::: L'univers électronique :::
• DIY Chip Amplifier Kits, PCB's, Components and Information.
• DIY Chip Amplifier Kits, PCB's, Components and Information.

But I am lost with the power values. The Loudspeaker is given at 15W/8 Ohm (how do you type the symbol ? Ω ?)
Does the amplifyer have to be bigger than that ? Or weaker to protect the box ?

• The source will be a standard CD player or DVD player. I see there are preamps available: I suppose I won't need one, shall I ?
• Symetric/asymetric: symetric is the pro XLR signal connector and asymetric is a standard RCA connector ? When I look at the connection diagramm here i see signal+,signal-,signal Ground. Is it symmetrical, so XLR stuff ? How do I plug a CD player into such an amp ?

Well I guess it is quite a lot for a start !
I'd be pleased if someone could hepl me out !

Thanks in advance !

[livenicely]

Take a start with lm1875 or tda2030a. tda2030a is so much cheap and the pcb for tda2030a can also used for lm1875. Thousands of books available on inter for free. i have downloaded many of them but not yet read anyone. I am thinking to start reading dummy series basic electronics.

[TheSeekerr]

How deep into the hobby do you intend to get? If you intend to remain a casual hobbyist, just searching the internet will serve you well.

On the other hand, if you'd like a deeper understanding, and already have a good background in calculus, I'd suggest Sedra and Smith's "Microelectronics and Circuits". I've been using it for the last year in my EE course, and it's an excellent reference, and very readable provided you're OK with the maths.

Typically, it's appropriate to have an amplifier rated for more power than the speaker can handle. This allows for more headroom, preventing clipping and the artifacts associated with it. 20-50W would easily be sufficient.

(15W into those speakers is good for something like 100dB, which is rather loud)

The easiest way to type Ohms is to use R, eg. 8R. There's not much else for it to be confused with.

[Gwenouille]

Waw, lots of activity on this forum !

Thanks for your advice.

I know how i usually go about my hobbies, and I am the kind of guy always wanting to understand the "why" and trying to do better. In that respect, a good book would be a very nice christmas present !
I can remember having read some chapters of "Art of electronics" from Horowitz and Hill and i liked it. I have read that a 3rd edition was planned. Do you know more about that ? Would you recommend that book ?

@ the Seekerr: I have found a way to type Ω ! Type & #937 ; (without spaces) instead ...

Another question:
I have read some threads here, and I must admit that I am lost with all the TDAxxxs LNxxxs LMxxx. Or they all OpAmps ?
How do they compare soundwise with that:
Hypex - Module amplificateur Hypex UCD180ST 180W

And another round !:
I am often impressed by you guys when you react to a diagramm you see and say: "OMG, C3 is too big ! 4.7nF would do here... Make R4 and R5 100kΩ help the LM3886 cope with ..."
Can you SEE the circuit working ? Can you feel precisely what does what ?
That seems so alien to me...

[mikje]

Here is a link to an electronics course from the US Navy. It should get you started, and it's free!

NEETs Modules

The amplifier does not have to be bigger than 15WPC.

I built an amp similar to the ones you linked to; mine is from Audiosector.com. These are nice little amps and not hard to build. There is a lot of info on this and other forums and the customer service via the website is great too. The LM1875 is probably a good first amp (careful, this suff's kind of addictive!).
Parts Express also offers a Velleman amp with a built in rectifier; all you need ais a 12-0-12 transformer, some hardware, and a way to control the volume. I built one of these too, and it's a nice little amp. I also have the FE127s in a fonken box. I'll have to run them on my Velleman amp and see how they sound.
Whichever one you choose, I'm sure you'll be able to get a lot of help via this forum.

Enjoy,
Mike

[Gwenouille]

Hi !

Once again thanks for your input !

I've recently read things about ALEPHs, and apparently that brand seems to enjoy a good reputation amongst DIYers.

Are they better than TDAs or LMs ?
Apparently GrianGT sells PCB for this chip, but I don't know exactly what it is !
Can you give me some feedback ?

[godfrey]

Hi

My textbook when I studied electronics was "A practical introduction to electronic circuits" by Martin Hartley Jones. I also have "The art of electronics" by Horowitz and Hill, which I got from the second-hand bookshop at a nearby university.

Both books are good. Mine are nearly 30 years old but I still use them for reference. I expect newer editions would be better, though.

I have also spent a lot of time over the years sitting and reading in the university library. Because I was not a student, I could not take books out, but I was allowed to go in and read. They have many more good books and magazines than I could afford to buy!

If you live near a university or college, perhaps you could find out if you can use their bookshop or library.

Regards - Godfrey

[Atilla]

If you want a good book that covers the basics quite well, you can look into "Practical Electronics for Inventors". It's a very good book for beginners. It doesn't cover that much audio-related topics, but it will teach you everything you need to know about electronics so you don't feel in the dark when you read datasheets and articles.

"The art of Electronics" is a legendary book and always a good idea to have. It can be a bit pricey when new however, so you might want to start with something more basic.

A preamp is something you probably won't need, at least not for its gain. My simple LM3886 gainclone can deafen me before it reaches max volume. A volume control is more than enough for making an integrated amplifier. Things like Nelson Pass' B1 buffer are quite interesting to try though, if you need to drive long interconnect cables, or you want to make a power amplifier and keep the volume control and source selection in a seperate enclosure for convenience.

The single-chip systems are a good start and they do have an admirable sound when done right. Don't be afraid of other circuits, but keep in mind they often will require more knowledge and tinkering to get right. I've got a chipamp built with BrianGT boards and I'm quite happy with how it turned out. With the chassis i used it takes a lot less space than the typical power amp. I can even carry it around in my backpack

Good luck and be extra careful with all safety-related topics.

[Gwenouille]

Thanks !
Yes, I have a good rememberance of the "Art of Electronics", but the price tag is, huh, too high !
I can't count on local libraries: I live in the countryside and the nearest library isn't well funded: no choice for electronics. The University is too far away...
I'll find a book on eBay i guess...

So the preamp stage is here for volume control and/or tonal correction?
Or impedance correction ?
I suppose the choice of components is of the utmost importance for the quality of sound as the signal is still weak...?
Are such volume/tonal control passive or active circuits ?
I've seen that some recommend lamps for this job...waw...

I think I will start my project with a pair of speaker on a Fostex FE127E basis that i plan to use as rear speakers on a HomeCinema installation.
Power will not be required: the room is rather small and the Fostex have a good efficiency. I would like a double mono setup. What DIY kit would you recommend ?
BrianGT's 3886 ?

By the way, if someone made a set of speakers with this LS, feedback on the pros and cons of the various charges are welcome !