Greetings.
I'm in need of a simple low power amplifier, preferably with bipolar transistors ( complementary or not ), something between 30 and 50W on 4Ohm speaker, simple or duble power suply, it needs to be made with easy to find transistors, and not verry expensive, i need to built an amplifier like this for someone and i thougt here would be best to search, the net is full of things like that, yes, but not all of them are ok, and knowing here are many experts in the field i need youre advice in this matter, so any imput would be greatly appreciated.
Best wishes to all, Marian.
I'm in need of a simple low power amplifier, preferably with bipolar transistors ( complementary or not ), something between 30 and 50W on 4Ohm speaker, simple or duble power suply, it needs to be made with easy to find transistors, and not verry expensive, i need to built an amplifier like this for someone and i thougt here would be best to search, the net is full of things like that, yes, but not all of them are ok, and knowing here are many experts in the field i need youre advice in this matter, so any imput would be greatly appreciated.
Best wishes to all, Marian.
Maybe i didn't express my self properly so i apologise, what i need is an schematic of the cind of amplifier i have described in the first post here, i will buit the amp, i will desighn the PCB then make it on PNP method, i will do all the work there is on the amp, i just need a good schematic, one that someone had made it and was happy with it, so can anyone help me on that?
Have a look at some power amplifier projects by Rod Elliott.
They have schematics and low cost parts.
ESP Projects Pages - DIY Audio and Electronics
Maybe this fit your request : http://sound.westhost.com/project3a.htm
They have schematics and low cost parts.
ESP Projects Pages - DIY Audio and Electronics
Maybe this fit your request : http://sound.westhost.com/project3a.htm
ESP was my first choice when i have searched, but MJL21193 it's not cheap at all, in fact it costs more than the mosfet's of my high power amplifier so it is not cost efective, as i see it may be possible to change it with BD911/BD912, the same cind of devices but with lower ratings such as max voltage, max current and so on, so am i wright, can it be change with what i sayd?
The original DX, it was guaranteed by the designer.
Or try the latest DX or any of the twenty seven variations that came in between, all but one of which, were guaranteed by the designer.
25W into 4r0 requires 14Vpk and 3.5Apk.
50W into 4r0 requires 20Vpk and 5Apk.
These can be met by single pair output stage powered by a 18+18Vac or 25+25Vac 160VA transformer.
The most expensive parts will be the chassis, the next most expensive will be the transformer.
Replacing an amplifier because it blew up, or was a bad choice, is likely to add no more than 10% to your budget.
Or try the latest DX or any of the twenty seven variations that came in between, all but one of which, were guaranteed by the designer.
25W into 4r0 requires 14Vpk and 3.5Apk.
50W into 4r0 requires 20Vpk and 5Apk.
These can be met by single pair output stage powered by a 18+18Vac or 25+25Vac 160VA transformer.
The most expensive parts will be the chassis, the next most expensive will be the transformer.
Replacing an amplifier because it blew up, or was a bad choice, is likely to add no more than 10% to your budget.
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The Circlophone fits the bill exactly:
http://www.diyaudio.com/forums/solid-state/189599-my-little-cheap-circlophone.html
Compared to other low-cost designs, it is adjustment-free, requires no thermal compensation, is thermally stable, and offers better quality and performances.
It is happy with any parts, requires no selection or pairing, and runs on identical output transistors rather than complementary: the OP devices can be 2N3055 or similarly cheap transistors.
The PCB designed by Wakibaki has been tried and validated by odysseybmx414.
Mike Renardson's amp very detailed project is worth having a look :
MJR7-Mk5 Mosfet Power Amplifier
MJR7-Mk5 Mosfet Power Amplifier
Hi,
Bipolar, low power, not expensive, easy available components...
I suggest a push pull 2N3055 !
this one for example :
http://78.229.172.208/ELEX/ARTICLES_DISPO/1991-01-AMPLI-AUROCK.pdf
Bipolar, low power, not expensive, easy available components...
I suggest a push pull 2N3055 !
this one for example :
http://78.229.172.208/ELEX/ARTICLES_DISPO/1991-01-AMPLI-AUROCK.pdf
Methinks that one tries to be just a bit too simple. No differential pair? Less is not always more. In this case it seems like just a whole lot less.
Methinks that one tries to be just a bit too simple. No differential pair? Less is not always more. In this case it seems like just a whole lot less.
That amp is superb, me thinks you should research and understand a design before commenting. Did you know that a single cfp input stage is more linear than a LTP ???
Understand that design first, in some iterations that amp far exceeds the performans of so called blameless amps and it sounds excellent too,
Keep reading that site, Mike Renardson is a more than capable designer
Methinks that one tries to be just a bit too simple. No differential pair? Less is not always more. In this case it seems like just a whole lot less.
Less is not always more... but may be equal.
At 30 W/ 8 Ohm, the objective performances of this one are on the par with those of the best circuits published all over the world.
Renardson's amp is a wonderful illustration of how good a huge amount of global Negative FeedBack with perfect mastering of frequency compensation can do. It totally disqualifies unsupported comments on NFB such as seen today here : http://www.diyaudio.com/forums/soli...dstage-imaging-transients-15.html#post2659513
I already built a MRJ stereo amp using two mono PCBs and currently assembling two MRJ stereo PCBs, all directly furnished by Mike Renardson.
So there is life outside the Blameless world. Hmmm.....
I built my Blameless in 1974, still working. My current interest with amps having a differential input stage now goes to the push-pull VAS structure suggested by Samuel Groner's in figure 56 of his comments on Self's Book.
I already built a MRJ stereo amp using two mono PCBs and currently assembling two MRJ stereo PCBs, all directly furnished by Mike Renardson.
So there is life outside the Blameless world. Hmmm.....
I built my Blameless in 1974, still working. My current interest with amps having a differential input stage now goes to the push-pull VAS structure suggested by Samuel Groner's in figure 56 of his comments on Self's Book.
This one is tried and proven by me, its been my primary amp for several weeks, uses all cheap components, MJE340/350 can be replaced with BD139/140 and 2N5401/5551 can be replaced with 2N3904/3906 or BC547/557.
TIP35/36 are about the cheapest transistors you can get in complementary pairs.
Schematic: http://i.imgur.com/EQAzh.jpg
TIP35/36 are about the cheapest transistors you can get in complementary pairs.
Schematic: http://i.imgur.com/EQAzh.jpg
I assume it is this one:
http://www.diyaudio.com/forums/soli...r-amplifier-design-handbook-douglas-self.html
Will do so. Thanks.
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