I have 400W transformer 11.8V-5V-0-5V-11.8V AC
And i want to ask for some power maybe SE amp for this voltage... I'm made DoZ, and i experiment with this trasnformer, but voltage is so small for correct sound.
Please give me some amplifier ideia for this transformer..
....
Second question is that i have almost 1Kw transformer, but with 7.5-0-7.5 ... what about sheme for amplifier with this transformer?
...
I preffer Class A etc...
Thank you in advice...
Best reggards! / Niki / Bulgaria
And i want to ask for some power maybe SE amp for this voltage... I'm made DoZ, and i experiment with this trasnformer, but voltage is so small for correct sound.
Please give me some amplifier ideia for this transformer..
....
Second question is that i have almost 1Kw transformer, but with 7.5-0-7.5 ... what about sheme for amplifier with this transformer?
...
I preffer Class A etc...
Thank you in advice...
Best reggards! / Niki / Bulgaria
Those are pretty odd sizes. To get much use out of either the first thing to investigate is a voltage doubler. For the second one a voltage trippler. I suggest you solve those problems first since the voltages quotes 11.8V and 7.5V are too low to do much in audio except preamps, headphone amps, and signal processing of one kind or another. And for those uses the wattage/VA rating are way more than you need.
I would say the second transformer with a voltage doubler could be used for a moderate (30W?) class A amp. The 1kW rating may even allow you to drive 4 or 5 amps, in case surrouind sound interests you.
The first one doubled might do for a stereo 30W or so class A.
But before you commit to a particulasr amplifier project, checkout voltage doublers & tripplers and decide if that is something you want to consider. When you know the rail voltages you will have available it will be easier for people here to suggest an amp project.
Maybe someone else here has a better idea.
I would say the second transformer with a voltage doubler could be used for a moderate (30W?) class A amp. The 1kW rating may even allow you to drive 4 or 5 amps, in case surrouind sound interests you.
The first one doubled might do for a stereo 30W or so class A.
But before you commit to a particulasr amplifier project, checkout voltage doublers & tripplers and decide if that is something you want to consider. When you know the rail voltages you will have available it will be easier for people here to suggest an amp project.
Maybe someone else here has a better idea.
bezobraznia said:
I would have thought using 11.8 and -11.8 giving 23.6 volts would have worked OK for the DOZ. I was intending to use a 12-0-12 volt toriod for a DOZ after Rod said it should be OK.
What rectifier are you using and what is your DC voltage?
BTW: I run various LM1875 and LM3875 GCs from a 12-0-12 300VAC toriod and they work OK.
How about this amp.
Easy to build.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=3075&highlight=jlh
Serosmaness
Easy to build.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=3075&highlight=jlh
Serosmaness
If you end up using a voltage doubler (or tripler), you might want to use a capacitance multiplier to help with filtering, because the ripple voltage from a multiplier circuit is very high.
There is a suitable circuit at www.sound.au.com
There is a suitable circuit at www.sound.au.com
thank you
Thank You for Your replyes...
I consider that i don't want doubler or tripler
I have already DoZ and i want another chalenge for me
DoZ is ok with more voltage - above 40V...I'm not a fan of Capacitance Multipler , I preffer big capacitance (abouve 100mF) and riple filter on AC voltage before transformer..
I will think about LM1875... hm... i will experiment with low power voltage for LM3875 - i have four of these... but i think that for 4 or 5 channels home theatre lm1875 will be ok with 7,5-0-7,5 (1kw) transformer...
About JLH- I want more than 10W... soon i will build SE (or maybe push-pull) with 2xEL34+ECC83 and this will be my low Watt-age amp
What kind amp is this Le Monster?!
Best Reggards!
Niki / Bulgaria
Thank You for Your replyes...
I consider that i don't want doubler or tripler
I have already DoZ and i want another chalenge for me
DoZ is ok with more voltage - above 40V...I'm not a fan of Capacitance Multipler , I preffer big capacitance (abouve 100mF) and riple filter on AC voltage before transformer..
I will think about LM1875... hm... i will experiment with low power voltage for LM3875 - i have four of these... but i think that for 4 or 5 channels home theatre lm1875 will be ok with 7,5-0-7,5 (1kw) transformer...
About JLH- I want more than 10W... soon i will build SE (or maybe push-pull) with 2xEL34+ECC83 and this will be my low Watt-age amp
What kind amp is this Le Monster?!
Best Reggards!
Niki / Bulgaria
Importand Correction
Hello I have importand corection about second 7.5-0-7.5 transformer
It is not voltage above, but correct voltage is:
Two independant windings with
15-0-15 AC (but with so thin wire)
and importand is 10-0-10 AC - hard wire!
...
And i see Le Monstre... good design , but now i know - I want Class A SE with this transformer
...
and the trasnformer is not 1kW but - onli 400-500W
...
sorry for annoyances about scales...
Best Reggards
Hello I have importand corection about second 7.5-0-7.5 transformer
It is not voltage above, but correct voltage is:
Two independant windings with
15-0-15 AC (but with so thin wire)
and importand is 10-0-10 AC - hard wire!
...
And i see Le Monstre... good design , but now i know - I want Class A SE with this transformer
...
and the trasnformer is not 1kW but - onli 400-500W
...
sorry for annoyances about scales...
Best Reggards
Exactly... one transformer , here is almost 1/2 of my month salary..
but anyway... i want amp for this transformer , because transformer is really good - made for military technology by ibm , i think...
A friend of mine say that for this transformer i only build Aleph-X , but low-voltage version... with 2 x 8-10W for channel... this is good idea... but i don't know ... the only low voltage Aleph that i found is for 18VDC...
For DoZ everybody say that will work with any voltage, but my experience say that for DoZ 42VDC is minimum for good orking amp... i'm afraid that with Alpeph will be the same situation?
Best reggards!
Niki
For a 300Watt project we got 45-0-45V 9A toroids made to almost mil specs for INR1200 (US$27 aprox) a piece. I wonder what price you have to pay in the US for this?
Actually, in my 25 years or so experience with sophisticated instruments from all over the world, I find transformers made in India are far more rugged than the ones from Europe and US. The probable reason is that they are designed to withstand the local grid conditions which are far from friendly.
If you are looking for a few extra US$'s, you might consider the potential business oportunity that is implied. Electronic components PCBs come in duty free, transformers may as well.
One of my two favorite North American sources for transformers in Plitron in Canada. Unfortunatly, the current exchange rate is making them a lot more expensive (in the US) than previously.
Anyway a transfformer such as you described costs US$60 -- $US120 at the moment. That's with no bells and whistles. Make it "medical grade", encapsulate it, shiled it, etc and the sky is the limit.
One of my two favorite North American sources for transformers in Plitron in Canada. Unfortunatly, the current exchange rate is making them a lot more expensive (in the US) than previously.
Anyway a transfformer such as you described costs US$60 -- $US120 at the moment. That's with no bells and whistles. Make it "medical grade", encapsulate it, shiled it, etc and the sky is the limit.
uh...
Only for final of "price-store" i would say that this transformer cost to me 50USD and my month salary is about 100USD, so
Don't dodge a question from above please!
I would like to make some good quality amplifier and i like Class A SE... so pls, i want idea about similar amplifier, not economical and theritorial particularity of market, ok?
Thank you & best Reggards
Niki / Bulgaria
Only for final of "price-store" i would say that this transformer cost to me 50USD and my month salary is about 100USD, so
Don't dodge a question from above please!
I would like to make some good quality amplifier and i like Class A SE... so pls, i want idea about similar amplifier, not economical and theritorial particularity of market, ok?
Thank you & best Reggards
Niki / Bulgaria
Sorry to get off track.
The transformer that you describe as two independant 15-0-15 may be configured in series as :15-0-15/15-0-15. If you cap-off the 0V leads and connect what I called "15/15" wires as the center tap point, then you end up with 30-0-30 which is much more useful. This assumes I understand correctly what you are describing.
You will need to do some checking to see if you have identified which wire is which -- both winding have to endup the same direction. If you wire them in opossing directions the cancel and you get zero volts! If this happens just reverse one (not both as I stupidly did one time!).
If you truly end up with 30-0-30, this is suitable for about 80W in Class B. Class A will be somewhat less. The most popular Class A amp seems to be one of the Pass Labs Aelphs. This has the advantage that there are many here who have built it so help will be easy to find.
The transformer that you describe as two independant 15-0-15 may be configured in series as :15-0-15/15-0-15. If you cap-off the 0V leads and connect what I called "15/15" wires as the center tap point, then you end up with 30-0-30 which is much more useful. This assumes I understand correctly what you are describing.
You will need to do some checking to see if you have identified which wire is which -- both winding have to endup the same direction. If you wire them in opossing directions the cancel and you get zero volts! If this happens just reverse one (not both as I stupidly did one time!).
If you truly end up with 30-0-30, this is suitable for about 80W in Class B. Class A will be somewhat less. The most popular Class A amp seems to be one of the Pass Labs Aelphs. This has the advantage that there are many here who have built it so help will be easy to find.
ok
Again, My both independand voltagees on transformer is:
10-0-10 and 15-0-15... and the second (15-0-15) is less than 50W
but, Stocker it is imposible for rewireing second because it is independant and transformer is welded outside ...
there is some pictures on this transformer:
Again, My both independand voltagees on transformer is:
10-0-10 and 15-0-15... and the second (15-0-15) is less than 50W
but, Stocker it is imposible for rewireing second because it is independant and transformer is welded outside ...
there is some pictures on this transformer:
Attachments
I'm not sure where you got the +-18V rail figure, but I designed both the Mini-A and the Aleph-X to run off 15V rails. The Mini-A puts out 10W or so with 15V rails, and the Aleph-X (assuming sufficient bias) will put out nearly 40W.
I have run those circuits as low as 12V and as high as 22V, at which point it starts making more sense to build a "real" Aleph, such as the 3. With a little adjustment, you can run them even lower than 12V, albeit with slightly higher distortion.
That's not to say that there aren't other fine amps out there that you could build, I just thought I'd fine tune the numbers posted above.
Grey
I have run those circuits as low as 12V and as high as 22V, at which point it starts making more sense to build a "real" Aleph, such as the 3. With a little adjustment, you can run them even lower than 12V, albeit with slightly higher distortion.
That's not to say that there aren't other fine amps out there that you could build, I just thought I'd fine tune the numbers posted above.
Grey
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