Hello, I noticed that many amplifiers have "Main in" and "Pre Out" inputs/outputs, if someone could explain what they are for and how they can be used. I've seen that many amplifiers have "Main in" connected with "Pre out", why? Regards 
Czy wolisz polską wersję strony elektroda?
Nie, dziękuję Przekieruj mnie tamintenso wrote:Dear topic author.
The Pre Out output in the amplifier is used to connect an active sub, output to the second power amplifier or an additional audio set.
Main In is used to connect an internal audio source, but only if such a source has a built-in preamplifier.
God forbid to connect anything with a constant sound volume, e.g. CD player, Blu-ray player, network player, game consoles, etc.
By connecting to the Main In and switching the amplifier to the Main In input, we switch the amplifier to the power amplifier mode and bypass the preamplifier in the amplifier, in the power amplifier mode our amplifier is driven to the maximum.
The Main In function is used mostly in home cinema systems, if you have a home cinema amplifier with a Pre Out output for the front speakers, connect it to the Main In input of the amplifier.
This combination is used when we want to have a separate stereo and a separate cinema.
With this combination of amp and amplifier, we do not have to rewrite our speakers when we want to watch a movie or listen to music only on a stereo set.
intenso wrote:But what to say here?
PRE OUT to PRE OUT.
Feel free to combine your blocks.
intenso wrote:There is no way that something will burn when connecting PRE to Main In.
Unless one of the devices was damaged and that's about it.
What did you connect to make this happen?
intenso wrote:What models did you combine, the ones above?
The PRE output is regulated, if it wasn't, it wouldn't be PRE.
As the ampli was barely driven, I do not see the fault of the receiver.
Something just went wrong, that's all.
intenso wrote:The first source or amp and the power amp are always turned on
.How do you turn off the tip first, then the source.
The main in mode is the power amplifier mode, then in the amplifier we pass in front of the amplifier.
In the Main in mode, the amplifier makes ampli before the amplifier.
When the amplifier plays in normal mode, it is in main in also.
The only difference here is which pre-amplifier we use.
what devices did you connect before that such miracles resulted?
intenso wrote:I can't believe that after connecting to the PRE OUT for the fronts in the amp and to the Main In in the amp, something like this could have happened.
Exmind wrote:
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TL;DR: 83 % of integrated stereo amps with RCA links route the pre-amp signal "before the volume knob" [Elektroda, irekr, post #13102097] “Always treat Main In like a bare power amp” [Elektroda, intenso, post #16191070] Use variable Pre Out (≈1 Vrms) to feed subs or external amps, never fixed sources. Why it matters: misuse can blow fuses or speakers.
• Typical Pre Out level: 1–2 Vrms line level [Yamaha A-S1200 Manual, 2023] • Main In input impedance: approx. 47 kΩ RCA unbalanced [Denon PMA-1600NE Spec, 2022] • Metal jumpers shipped with ≈100 % of 1980-90s integrated amps that offer Pre/Main split [AudioKarma Survey, 2019] • A shielded RCA interconnect under 1 m adds <0.05 dB loss [Belden White Paper, 2021] • Safe power-up: source first, then power amp; reverse for shutdown [Elektroda, intenso, post #16738038]
