Simple amplifier

hobbit

Member
2007-02-04 9:39 pm
Udine
This is my first post. My english is bad.

I want make a amplifier that must to be:
- simple and fast to assembly (good kits or universal board, ....);
- have good sound (better of my Nad 302);
- good for listen classic, spirituals, country, ....;
- working with 89-90db speakers (I don't know the power necessary);
- very cheap;
- well bjt, fet, chip, t-amp, .tube, ....

Give me an idea?

Bye,

Francesco
 
Hi,
using cheap as the most important criteria, then you can remove tube from your options.
Chipamp or very simple BJT could get what you need.
For 89 to 90db/W/m speaker try for 50W to 100W.
If your speakers are 8ohm then lm3886 might be your solution.
Small PCB and low component count= cheap, kits= easy to build,
Have a look at some of the chipamp threads, Nuuk's Decibel Dungeon and look at the ESP site.
 

tinitus

diyAudio Moderator R.I.P.
2005-11-24 1:47 am
I use 40-50watt...but there are different kinds of 50watt, and my small monsteramps are no doubt much more powerfull than a small chipamp

"41hz" have some interesting amp kits, and quite cheap...personally I dont know them

The 100watt from AussieAmp may also be configured as a 60watt, lowering the voltage
 

hobbit

Member
2007-02-04 9:39 pm
Udine
Originally posted by hobbit
.............- working with 89-90db speakers (I don't know the power necessary);...........Give me an idea?

Originally posted by hobbit ........ I don't need 100w, is excessive for my listen.
Hi,
do you want or need assistance?
I think that 20-30w is sufficent because my Nad 302 has 25w and it's sufficient for me. Bur I don't sure.

I use 40-50watt...but there are different kinds of 50watt, and my small monsteramps are no doubt much more powerfull than a small chipamp

"41hz" have some interesting amp kits, and quite cheap...personally I dont know them

The 100watt from AussieAmp may also be configured as a 60watt, lowering the voltage
Thanks. 41hz is interesting. Which is best amplifier of 41hz? (good sound)

Best regards,

Francesco
 
i found simple, and low cost.

http://www.audiosector.com/lm3875.shtml

the dual mono classic: $57 (can be run off a transformer with dual secondaries)

add appropriate transformer(s), available from various places, something local. look for ones with 24v taps and between 150 and 300VAC (if these numbers are wrong, someone correct me please)

the rest is the basics. potentiometer, power switch, Mains jack, RCAs, etc. and case, obviously.

-Jared
 
hobbit said:
Thanks.

I'm undecided, T-amp way or gainclone-way.
Which is better? Which has better sound?
I don't know t-amp and gainclone sounds.
Bye,

Francesco

They're both better, in their own way. T-amps are so cheap to build, as are the gainclones (unless you upgrade to premium parts) that you should build one of each. It'll likely be when you start upgrading to premium parts that you notice the most changes in sounds, so...

a) build them cheap
b) then upgrade as money allows
c) learn a lot along the way

You'll even be able to experiment with different upgrades to the same thing, like hearing the difference between caddock, riken, and Kiwame resistors in the signal path, for example. You'll be able to hear how different values of capacitors in the power supply and at the chips affect response, and all that. Make sure you build them to be easily upgraded and you should have lots of fun with them. It'll be like the electronics equivalent of LEGOs.

and then theres always tubes, but I make no promises as to finding a kit as cheap as the T-amp or chip amp kits.

-Jared
 

tinitus

diyAudio Moderator R.I.P.
2005-11-24 1:47 am

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If you want cheap and simple, go for a Gainclone.

I'd steer clear of T-amps now simply because Tripath have gone bankrupt, and although Cirrus Logic have bought the T-amp technology rights, they aren't producing parts. National will probably keep the LM3886 going for quite some time.

I'd say that a well constructed Gainclone will easily better the sound of the NAD amp. My Gainclone keeps up with an Arcam Alpha amplifier costing at least 3 times what the Gainclone cost me to make :)
 

hobbit

Member
2007-02-04 9:39 pm
Udine
Thanks for all replies.

Searching in diyaudio I have found this project:

http://www.diyaudio.com/forums/showthread.php?threadid=55621

This project seems simple to realize in universal board. It dosen't need preamp because has active regolator:

http://www.diyaudio.com/forums/attachment.php?postid=622225&stamp=1113832139

I have a pair of op285 do they works in this circuit? Which is the better opamp for this stage?

For the power stage I am thinking to sostitute LM3886 with LM3875 or LM1875 (the same power of my Nad).

Is this a good idea?
Bye,

Francesco
 
I think that, like most of the Gainclone designs, it should be a good amp. honestly, I haven't heard them all to compare, so it's naturally going to be subjective. Your speakers/room/source will determine how the amps sound, obviously, so what sounds good in one persons system might sound too sweet or bright, or muddy, etc in yours. try a few with different configurations, and see what you like.

-Jared