You can't really have just a buffer. Some of the really expensive home amps are essentially what you want but they use brute force and a lot more components to get the signal through with very little distortion. Many use little or no global feedback.
It would be impractical to build car amps in this way. Car amps use the minimum number of components which means that they have to use a lot of global feedback to achieve low distortion. The input circuit for the power amplifier stage for most car amps is a differential pair. They are not designed for high input levels. That's why the output stage has significant gain.
How low do you NEED the noise to be? As stated before, you won't be listening to the amp with headphones. How close will you be to the speakers? How efficient ate the speakers? It's rare that you will hear the noise from the speakers when more than a few feet away with the amp at minimum gain.
Pass has all sorts of circuits but that's not the car amps that you're asking about here. If you ask about the individual circuits, ask about feedback and distortion when driving reactive loads.
It would be impractical to build car amps in this way. Car amps use the minimum number of components which means that they have to use a lot of global feedback to achieve low distortion. The input circuit for the power amplifier stage for most car amps is a differential pair. They are not designed for high input levels. That's why the output stage has significant gain.
How low do you NEED the noise to be? As stated before, you won't be listening to the amp with headphones. How close will you be to the speakers? How efficient ate the speakers? It's rare that you will hear the noise from the speakers when more than a few feet away with the amp at minimum gain.
Pass has all sorts of circuits but that's not the car amps that you're asking about here. If you ask about the individual circuits, ask about feedback and distortion when driving reactive loads.
I see. And in the end what sounds good is good. No problem with that.
this i do not understand ... the more active stages in series the more the open loop gain and so the more the need of global feedback.
The classic example are op-amps
I read
and
so the open loop gain should be very high and if you want to reduce it to low value you need a lot of feedback. But this is beyond my ability to understand it clearly ... it is very technical.
Someone says that low negative FB even zero feedback is the solution for real good sound ... others say instead that what counts is only low noise and distortion and high slew rate ... and if a high FB is useful to achieve this just let's do that
i do not know
For sure is a much debated topic in audio amp design
what i find interesting is that they have all that trimmer at the input while almost all home power amps avoid that completely
well ... ideal is zero noise and zero distortion.
I have noticed that when the noise is very low there is what i call a suck-in effect ... i feel like being transported in the real event and this sensation si phenomenal ... enthralling For instance if you take a great recording made in a church you feel like being transported in time and space in that very church
Wonderful ! like virtual reality with sound at least this is a very important thing and i would say as little as possible. I am smart working for the lockdown
well using the pc i have purchased some of those plastic desktop pc speakers Listening very close to them ... at about 3 feet i am amazed by the soundstage they can create ... and so i have become a believer in nearfield listening. And coaxial drivers as well ... nearfield and narrow dispersion also to avoid room reflections ... the sweet spot is very small ... but i am alone
my final speaker will have very high efficiency ... it will be some horn loaded speaker for sure. In this way it could go loud with few watts
I am thinking also to use some speakers for PA ... like EV, JBL or similar ...
if the car amps sound good for me they will be just perfect. I am open to all class ... actually i am against class A that puts to much stress on components and usually leads to failures in the long term. I like reliable things.
I have got already some very precious advice and suggestion of commercial products.
I am waiting for the 20A smps to be delivered and then i will be ready to start with some trials ...
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Virtually everything above is subjective. That's where I leave the discussion.
As far as more stages, more feedback...
A common power amplifier has 3 stages. Input, voltage amp, current amplifier stage.
Open loop gain?
Without feedback, an error of a tiny fraction of a volt would drive the output to the rails with virtually every power amp circuit in use in car amps (and most home amps).
A minimum number of components won't work without feedback without producing a lot of distortion and low damping factor. An expensive amp can have MANY components to boost the current drive to allow lower distortion with little or no feedback. Some may like the character of the sound from little or no feedback. That won't mean that it's more accurate but it may be more pleasing. As an example, I think sound produced through various transformers sounds better in some instances. This includes some tape decks (reel and cassette), phono and tube amps.
As far as more stages, more feedback...
A common power amplifier has 3 stages. Input, voltage amp, current amplifier stage.
Open loop gain?
Without feedback, an error of a tiny fraction of a volt would drive the output to the rails with virtually every power amp circuit in use in car amps (and most home amps).
A minimum number of components won't work without feedback without producing a lot of distortion and low damping factor. An expensive amp can have MANY components to boost the current drive to allow lower distortion with little or no feedback. Some may like the character of the sound from little or no feedback. That won't mean that it's more accurate but it may be more pleasing. As an example, I think sound produced through various transformers sounds better in some instances. This includes some tape decks (reel and cassette), phono and tube amps.
Hi i bought this one ...
LEDMO 12V 20A Alimentatore Interruttore AC 110/240V to DC Trasformatore di Alimentazione 240W: Amazon.it: Fai da te
but i am looking at this one ... much better i am sure
SP-240-12 MEAN WELL | Mouser Italia
i wonder if 20A will be enough ? seriously i have no clue
A Car battery is unpractical ... for now.
i am more than sure that i will end with MeanWell ... i have a great respect for that brand since i have seen one of their SMPS in my dac ... an Apogee ... a professional unit If they are good for them they are also good for me The price is extremely reasonable. Actually i am buying one now. The one i bought looks suspicious ... i see instead a declared MTBF for the Meanwell unit of 284K hrs min.
it's about 32 years of 24/7 use ... a good investment i would say
Thank you a lot again. Another fundamental advice and i was thinking the opposit
i was clearly on the wrong track ... again However a great reliability is a very nice thing to have ... expecially if the cost to get that is absolutely reasonable
OT _ Speaking of bad battery charger i am using a very bad one not regulated (just trasformer>diodes>cap) with a dc-dc converter to power a little system. The only noise i hear is from some transformer vibrations that make the metallic case to resonate.
I think to put the parts on a wood base with some plastic transparent cover n top.
To keep it in place i will use four screws
I will do that. Thank you so much again.
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Hi ! thank you very much indeed for the very useful advice.
I am not on Facebook
Anyway i will search for the products you mention right away.
Actually i have already found a guy selling an old Xbox psu ... the XBOX 360 - 1st Series - 175W (i can see 12V/14.2A on the bottom label)
I see the Xbox psu ... quite chunky Good !
I see it has a fan ... is it very noisy ? i see newer compatible ones much less noisy ?
And what about the amp in the attachments ? i should have said that i need little power ... i am using quite efficient speakers and the idea is to go with high efficiency ones So the sound can be low in power but quite clean because high efficiency speakers expose everything
They act like a magnifying glass for sonic details .... love them so much But this is another story
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Didn't you have another supply already?
Fans can be noisy for various reasons. Velocity alone can make a huge difference. Many fans are temperature controlled so that they're only noisy when they need to move a lot of air.
Many fans become noisy as the lubricant dries out (different from the noise produced by high-velocity wind noise). Many of these can be disassembled, cleaned and relubricated.
Fans can be noisy for various reasons. Velocity alone can make a huge difference. Many fans are temperature controlled so that they're only noisy when they need to move a lot of air.
Many fans become noisy as the lubricant dries out (different from the noise produced by high-velocity wind noise). Many of these can be disassembled, cleaned and relubricated.
Hi ! yes. But it is almost open frame and with high voltage inside ...
this one is sealed. Safer ?thank you very much for the very helpful advice. I already opened some smps for laptops cutting the plastic case gently with a little saw for metals.
I could try the same with the Xbox 360 psu and watch inside to check the fan. Considering the size it must be very small and so very fast.
From what i understand the top should be Meanwell ? i have seen one in pro audio equipment of high price. A great endorsement i think.
I read the to Mean Well means to try to be kind and helpful, even when problems arise.
So their smps must be very good
Yes ! so i stick with that for now. Thank you very much for your injection of sanity ...
I am negotiating for the amp. I like its connections so much ... that is how they should be made ... i think
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Hi ! thanks a lot for the very useful advice. I would check in the datasheet if i could find it. I have bought this one attached, currently waiting to receive it. Very cheap but working. As i said above i need very little power ... i am switching to high efficiency speakers
And about load tolerance i see written on top 2 ohm stable ... a comforting statement
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Congrats I hope and think its as good and probably even better than my GP4.
My Xbox supply did not have a fan. I dont have the model# Sold it cheap to a kid who wanted to do exactly what you want. I found tutorial to make it give power all the time. Maybe I could have used the amplifiers remote for this Im not sure.
Cheers!
My Xbox supply did not have a fan. I dont have the model# Sold it cheap to a kid who wanted to do exactly what you want. I found tutorial to make it give power all the time. Maybe I could have used the amplifiers remote for this Im not sure.
Cheers!
Hi ! thanks again for the suggestion. They guy says that is working Not big issue if i had to buy another one
I like JBL, Renegade ... the look i mean I know nothing about their actual quality and sound
Yes ! i will get one ... anyway i have already another one more powerful
I think i will end if the sound will be convincing with a MeanWell ... a brand i really admire
I have seen MTBF of 1069K hrs min
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