clarification re line out from source, vs pre-out from AVR, vs source + preamp = ?double preamp

[Jinster]

Hi guys. I have always used AVRs for all my listening needs but have recently started dabbling in 2-channel and want to get into valves, too.

My current setup include:
Yamaha RXV2081 AVR - driving all surround and atmos speakers
Emotiva XPA-2 power amp - driving front speakers

The Yamaha AVR allows "scene" switching to instantly call up a source and an output configuration. So I have two scenes set up. One with the FLAC source within the AVR network function outputting to Emotiva in pure-direct 2-channel mode. Second scene with Nvidia Shield source and outputting to Emotiva plus surround speakers in multi-channel configurations.

The problem is the music doesn't sound very "warm" through the Emotiva... less warm than with just the AVR directly amping itself... so I want to add a valve pre-amp or "buffer" in my 2-channel pathway...

I just need some clarifications please mainly because I keep hearing double pre-amp is not advisable and yet it seems to me that any source + pre-amp + power amp = effectively double pre-amp'ed, logic being:
1. A pre-amp goes in between source and amp, right?
2.. Now: pre-amp + active speakers would work, right?
3. But: source + active speakers also work, per my experience...
4. So this means effectively any source would have a pre-amp built-in.... or at least the output from source line-out is a similar voltage to pre-out from a pre-amp....
5. So then: source + pre-amp + active speakers = double pre-amp effectively? Since there is "pre-amp like" function inside the source?
6. So then why do I read double pre-amp is usually "frowned upon"? Other than the practicalities of having two volume controls?

Ultimately, I want to see if it is advisable for my home theatre setup and 2-channel setup to share a source (my AVR is also a network player), a power amp and speakers. The only different item in the path of the 2-channel configuration is that I want to add a valve pre-amp. So, this would mean I go from source AVR pre-out to valve pre-amp (therefore effectively have two pre-amps in the path now) to power amp to speakers.....

 

[WaynePflughaupt]

What’s typically referred to as a pre-amp is the component that will accept and switch between multiple sources, regulate the output level, and provide some signal processing (such as basic tone controls, or these days, room correction and bass management).

The output stage of a source component or the input stage of an active speaker doesn’t do all that (although it’s not inconceivable that a pre-amp could be built into an active speaker).

Look, you don’t need to justify your experiment to anyone. Give it a try if you think it will get you something you’re after. There’s also plenty of talk about how bad equalizers are for the main speakers, but that never stopped me from using them.

Regards,
Wayne A. Pflughaupt

 

[PENG]

I just need some clarifications please mainly because I keep hearing double pre-amp is not advisable and yet it seems to me that any source + pre-amp + power amp = effectively double pre-amp'ed, logic being:
1. A pre-amp goes in between source and amp, right?
Right
2.. Now: pre-amp + active speakers would work, right?
Right
3. But: source + active speakers also work, per my experience...
It depends, if the "source" is something like an external DAC, BDP (such as some Oppos), streamer etc., that has volume control. If it has the typical "fixed" level output, then it will still work with active speakers that have their own volume control.
4. So this means effectively any source would have a pre-amp built-in.... or at least the output from source line-out is a similar voltage to pre-out from a pre-amp....
Yes and No, pre-amp typically means it is an "electronic amplifier that converts a weak electrical signal into an output signal strong enough to be noise-tolerant and strong enough for further processing, or for sending to a power amplifier and a loudspeaker." See wifi: https://en.wikipedia.org/wiki/Preamplifier. So that's why you are confused, because it depends on how you would want to define "pre-amp.."
5. So then: source + pre-amp + active speakers = double pre-amp effectively? Since there is "pre-amp like" function inside the source?
Yes and No per 4. above.
6. So then why do I read double pre-amp is usually "frowned upon"? Other than the practicalities of having two volume controls?

I would assume it gets "frowned upon" if the "double pre-amp" you referred to means the two pre-amps both have volume controlled output and no "fixed" output. In that case, there may not be any issue if you know what you are doing (a different topic..), and are willing to accept the added distortions and noise because of the extra volume control circuitry (could be discrete, and an IC).

Ultimately, I want to see if it is advisable for my home theatre setup and 2-channel setup to share a source (my AVR is also a network player), a power amp and speakers. The only different item in the path of the 2-channel configuration is that I want to add a valve pre-amp. So, this would mean I go from source AVR pre-out to valve pre-amp (therefore effectively have two pre-amps in the path now) to power amp to speakers.....

If you have the time and money, and know how to do it, then have fun. If your goal is more than having fun, but also the best possible "sound quality" in terms of transparency and/or accuracy, then you are going to be wasting your time and money. I am sure many of us on this forum may say, been there, done that...