Impedance matching - what’s that?

[Deleted member 15865]

Guys, I want to understand this whole business of impedance matching, especially between preamp and amplifier. I am not an electrical/electronics engineer, and have forgotten the basics of impedance etc learnt in physics eons ago. So I need to revise the necessary concepts as well as understand what impedance means to audio equipment matching and how to evaluate the match. The what, why and how of it.

Can you refer me to any simple, but not simplistic reference material (article, blog etc) that I can read for the same? Thanks.

 

[Ashenden]

Hi Sachin, instead of me rambling about it, watch Paul here

 

[Hiten]

Here is another one.
https://www.soundonsound.com/techniques/understanding-impedance
Regards

 

[Deleted member 15865]

Hi Sachin, instead of me rambling about it, watch Paul here

Thanks, but sorry, he was all over the place. Didn’t help me a bit.

Here is another one.
https://www.soundonsound.com/techniques/understanding-impedance
Regards

Thanks. Tried reading. Developed some understanding of the ‘what’, but not much of the ‘why’. Not sufficient clarity at the moment to feel comfortable.

 

[Ashenden]

Thanks, but sorry, he was all over the place. Didn’t help me a bit.

Oh, sorry about that. The sound on sound link Hiten shared is excellent. It will give you all there is to know on this subject. After that Paul's video might make sense

 

[Deleted member 15865]

Ok. Let me request you to provide me some direct help. I drive my Audiolab 8200A’s power amp section with the Lyrita DHT Line Preamp. I want to check what’s the ratio between Lyrita’s output impedance and the Audiolab’s power amp’s (not the integrated mode) input impedance.

I am attaching below the spec sheets of both. Please go through and confirm if I am inferring the below correctly:
Lyrita’s output impedance: 1250 ohms
8200A’s power amp’s input impedance : 47 kOhms (need to particularly confirm that I’ve read this correctly from the spec sheet)

Therefore the impedance ratio = 47000/1250 which is 37.

Now is that enough? Like the questioner in Paul’s video says, some experts say the ratio should be min 10 some say 100. So how good is 37? If it is not enough, what effect should I expect - either in the performance or sound of the system?

 

[Ashenden]

Ok. Let me request you to provide me some direct help. I drive my Audiolab 8200A’s power amp section with the Lyrita DHT Line Preamp. I want to check what’s the ratio between Lyrita’s output impedance and the Audiolab’s power amp’s (not the integrated mode) input impedance.

I am attaching below the spec sheets of both. Please go through and confirm if I am inferring the below correctly:
Lyrita’s output impedance: 1250 ohms
8200A’s power amp’s input impedance : 47 kOhms (need to particularly confirm that I’ve read this correctly from the spec sheet)

Therefore the impedance ratio = 47000/1250 which is 37.

Now is that enough? Like the questioner in Paul’s video says, some experts say the ratio should be min 10 some say 100. So how good is 37? If it is not enough, what effect should I expect - either in the performance or sound of the system?

View attachment 37939View attachment 37940

Your inference about the impedance for pre and power amps are right.
If we consider a simple Voltage divider circuit, with R1 (Pre amp Z) and R2 (Power amp Z), Vin (input to R1) and Vout(voltage at input of power amp), the equation will be Vout = Vin x R2/(R1+R2).
So, by having a very high input impedance at power amp (47k here), there will be negligible attenuation/drop in the circuit and Vout = Vin (since R2 is almost equal to R1+R2).
Your pre and power are impedance matched.

 

[raghupb]

Very lucid explanation.
Cheers,
Raghu

 

[Deleted member 15865]

Your inference about the impedance for pre and power amps are right.
If we consider a simple Voltage divider circuit, with R1 (Pre amp Z) and R2 (Power amp Z), Vin (input to R1) and Vout(voltage at input of power amp), the equation will be Vout = Vin x R2/(R1+R2).
So, by having a very high input impedance at power amp (47k here), there will be negligible attenuation/drop in the circuit and Vout = Vin (since R2 is almost equal to R1+R2).
Your pre and power are impedance matched.

Thanks Sandeep!

 

[raghupb]

Ok. Let me request you to provide me some direct help. I drive my Audiolab 8200A’s power amp section with the Lyrita DHT Line Preamp. I want to check what’s the ratio between Lyrita’s output impedance and the Audiolab’s power amp’s (not the integrated mode) input impedance.

I am attaching below the spec sheets of both. Please go through and confirm if I am inferring the below correctly:
Lyrita’s output impedance: 1250 ohms
8200A’s power amp’s input impedance : 47 kOhms (need to particularly confirm that I’ve read this correctly from the spec sheet)

<snip>

I recently acquired the same preamp from a fellow FM. Also picked up a power amp with 47K Z-in.
Works well together.
Cheers,
Raghu

 

[sachinclemens]

Hello,
I’ve heard about damping factor on speakers and amplifiers could someone explain how we should select the speakers and amplifiers so that it’s a good match.

 

[sachinclemens]

Does damping factor play a role in selecting the equipment’s.

 

[ravikumar-rotel]

Guys, I want to understand this whole business of impedance matching, especially between preamp and amplifier. I am not an electrical/electronics engineer, and have forgotten the basics of impedance etc learnt in physics eons ago. So I need to revise the necessary concepts as well as understand what impedance means to audio equipment matching and how to evaluate the match. The what, why and how of it.

Can you refer me to any simple, but not simplistic reference material (article, blog etc) that I can read for the same? Thanks.

There is gain matching between the pre amp and the power amp. The specs of input gain on the power amp and the output gain on pre amp has to go as per the manufacturer specs