I have spent months trying to get my chip amp to sound better.
Been doing a lot of reading. When I cam across this sentence.
Measure weather the positive and negative output voltages are symetrical.
They should be within 0.6 V of each other. This test is done under zero load.
So I tested all the transformers I have. Some EI some toro all have more than 0.6v variation on the output.
Maybe they just make shitty transformers in my country.
Another friend told me it does not matter what the difference is. It just means that one side will clip sooner than the other when pushed to the limits.
Other than trying to import a transformer how do I fix this. Do I need to worry about it ?.
I have tested direct output from the transformer and also after the voltage is passed thru the PSU board.
This pertains to my tda7294 and lm3886 builds.
Been doing a lot of reading. When I cam across this sentence.
Measure weather the positive and negative output voltages are symetrical.
They should be within 0.6 V of each other. This test is done under zero load.
So I tested all the transformers I have. Some EI some toro all have more than 0.6v variation on the output.
Maybe they just make shitty transformers in my country.
Another friend told me it does not matter what the difference is. It just means that one side will clip sooner than the other when pushed to the limits.
Other than trying to import a transformer how do I fix this. Do I need to worry about it ?.
I have tested direct output from the transformer and also after the voltage is passed thru the PSU board.
This pertains to my tda7294 and lm3886 builds.
How much deviation?
How good is your meter?
You are supposed to check on load, I think.
Find out who supplies transformers to BEL for their military stuff, contact them.
They do make good transformers in this country, the customers dirty their pants at the price...
How good is your meter?
You are supposed to check on load, I think.
Find out who supplies transformers to BEL for their military stuff, contact them.
They do make good transformers in this country, the customers dirty their pants at the price...
Try measuring into a reasonable resistive load (maybe 10%of full load) rather than into a DC supply.
Schematic ?. A transformer plugged into the mains and a multimeter on the output leads ? x-0-x the Xs don't match. As per the statement I read this test is to be done on zero load even before you hook it up to a DC supply / rectifier board. I have tried it in all combinations they very rarely match.
On a side note I checked the oem transformer in my akai amp. The voltages dont match under load or just measured at output of transformer.
I guess this is why people build fancy and complex PSU circuits to get the voltages on both rails to match.
On a side note I checked the oem transformer in my akai amp. The voltages dont match under load or just measured at output of transformer.
I guess this is why people build fancy and complex PSU circuits to get the voltages on both rails to match.
All transformers sag under load.
No load figure is irrelevant in my opinion, it has to work on load only.
Ask an electrical engineer about it.
And don't obsess over it, unless it is over 5% or more difference in rails under load.
No load figure is irrelevant in my opinion, it has to work on load only.
Ask an electrical engineer about it.
And don't obsess over it, unless it is over 5% or more difference in rails under load.
No.
The more you read, the more crap you find.
What sounds bad about it? Why isn't it your preamp, your sources, your speakers?
Before somebody asks where I read this.
Its here
http://www.videorockola.com/proyect...amplificadores-con-control-de-tonos-y-fuente/
Look for the words the pre-amp is noisy.
I built both circuits one with 78xx and 79xx and one with zener diodes. I could not get the output to match under load or no load.
And this guys says it has to match to 0.2 volts.
If you look at the data sheets for the 78 series regulator the output rating does factor in a % of error. If Im not mistaken.
Its here
http://www.videorockola.com/proyect...amplificadores-con-control-de-tonos-y-fuente/
Look for the words the pre-amp is noisy.
I built both circuits one with 78xx and 79xx and one with zener diodes. I could not get the output to match under load or no load.
And this guys says it has to match to 0.2 volts.
If you look at the data sheets for the 78 series regulator the output rating does factor in a % of error. If Im not mistaken.
no its not but my preamp is. And that is what I am trouble shooting.
Im also trying to get my TDA7294 amp to sound better.
This is what I read on this forum.
"A full bandwidth amplifier with TDA7294 can benefit from a regulated power supply. This can let you use smaller, 100uF or smaller, local power caps (while the large power parts remain located at a separate power supply board). With TDA7294's sensitivity to power supply differences, a regulated power source can be quite noticeable"
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