2. amps-preamps
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Impedance Matching in the Modern Audio System

Hey everyone, I'm still learning a lot about audio and audio equipment. I know that I am supposed to impedance match my components, but my question is this:

If I will have 1 source (In my case a Bluesound Node 2i streaming DAC) that will have an analog out to an integrated amp, do I need to worry about matching the impedance of the analog out on the DAC to the input on the integrated amp? I can't seem to find the impedance for the analog output on the Bluesound Node 2i, but if I were to find it, how would I know if the input is properly matched on the integrated amp? 
subsonic1050
13 responses Add your response
erik_squires
15,948 posts
 
Hey subsonic,

In general this isn't something we worry about with solid state gear.


The issue has more to do with tube output stages. They need fairly high impedance targets. A typical situation is a tube pre trying to work with a low impedance amp, or with 2 of them at the same time.
Here's a very typical situation:

https://www.stereophile.com/content/primaluna-evo-400-preamplifier-measurements

Look at how much the output changes from a high to a low impedance output.  Compare that to a typical solid state preamp:

https://www.stereophile.com/content/pass-laboratories-xp-22-line-preamplifier-measurements

So you should be fine. :)

Best,

E
subsonic1050 OP
8 posts
 
Thank you for the reply erik_squires, but the integrated amps I am looking at are tube setups. Specifically looking at the Raven Audio Nighthawk, PrimaLuna Prologue, and the Line Magnetic LM-518A. I was hoping that the main impedance matching needed to occur between the pre-amp and the amp - and in the case of an integrated amp that the matching would all have been worked out by the manufacturer within the unit. Do I need to worry about matching the analog out on the Bluesound node 2i to the analog input on the tube amp?
georgehifi's avatar
georgehifi
10,312 posts
 
In general this isn't something we worry about with solid state gear.
👍
kalali's avatar
kalali
1,977 posts
 
"Do I need to worry about matching the analog out on the Bluesound node 2i to the analog input on the tube amp?"

No.
mapman's avatar
mapman
21,928 posts
 
Yes not a concern typically with all ss gear.
erik_squires
15,948 posts
 
Hi OP:
The issue is generally that Tube OUTPUT stages can't drive a low impedance input.
Your streamer is solid state, therefore it has a solid state OUTPUT stage that feeds the integrated. That the pre/integrated is tube doesn't matter for the sake of the advice I posted.

Best,
E
subsonic1050 OP
8 posts
 
Why do people keep referring to SS gear? My source is digital to analog, but the preamp and amp are both tube?
erik_squires
15,948 posts
 
Subsonic :


Because solid state gear, like your source, can handle a broad range of targets, therefore, you won't have any issues.


The problem is when you have a tube source ---> low impedance target.
You don't have that. You have a solid state source ----> tube target.
That will be fine. 

If you had a CD player with a tube output stage, then you'd care.

Erik
erik_squires
15,948 posts
 
I'm using the term "source" here as the opposite of "target" , not as a type of equipment.

If you think of this chain:

CD Player ---> Preamp ---> Amplifier


The CD Player is the source of the preamp.  The preamp is the source of the amplifier.


The Preamp is the target, or destination of the CD player.  The amplifier is the target or destination of the pre.


So, yes, you have a solid state source. That means it has an output stage which will handle almost any target impedance.




erik_squires
15,948 posts
 
To continue, say you have this:
SS Streamer ---> Tube Pre --> SS Amp
The concern would be whether the impedance of the SS Amp is high enough for the preamp. 


The streamer on the other hand is not concerned with the nature of the preamp.


subsonic1050 OP
8 posts
 
Ok, fantastic! Thanks again for the help!
itsjustme
681 posts
 
The solid state streamer should have a sufficient low output impedance as to not really care. plus tube have high input impedance, which means they are easy to drive. Its the output side of tubes that can get tricky.
worry not
good to ask!
brucenitroxpro
23 posts
 
Ask any competent amateur radio operator about impedance matching.

de KQ2E
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