This article explains a lot about the input/output impedance thing in plain English https://www.lifewire.com/output-impedance-3134904
This article explains a lot about the input/output impedance thing in plain English https://www.lifewire.com/output-impedance-3134904
Chris
Common sense isn't anymore!
That was indeed a very helpful article ... and easier to follow than many.
I found this paragraph very interesting but am curious what exactly the 'substantial effect on the frequency response' would be (i.e. how it would sound) Don't know if any tube amp designers would care to clarify/comment.
"to simulate the sound of a tube amp in his Sunfire solid-state (transistor) amplifiers, famed designer Bob Carver added a “current mode” switch that placed a 1-ohm resistor in series with the output devices. Of course, this violated the 1-to-10 minimum ratio of output impedance to expected input impedance that we discussed above, and thus had a substantial effect on the frequency response of the connected speaker, but that’s what you get with many tube amps and it’s exactly what Carver wanted to simulate."
"Today scientists have substituted mathematics for experiments, and they wander off through equation after equation, and eventually build a structure which has no relation to reality"
Nikola Tesla
Its now a conspiracy theory to believe that the Immune system is capable of doing the job it was designed to do.
A fish is only as healthy as the water its swimming in ! [Dr Robert Young]
www.tubedistinctions.co.uk
Matthew 5:10
Therefore; by varying the pot, you're varying the resistance, or impedance that the source has to drive, and thus at low volumes, where the wiper of the pot is nearest to ground, your're literally making the front end of the amplifier harder to drive! I hope that makes sense.
"Today scientists have substituted mathematics for experiments, and they wander off through equation after equation, and eventually build a structure which has no relation to reality"
Nikola Tesla
Its now a conspiracy theory to believe that the Immune system is capable of doing the job it was designed to do.
A fish is only as healthy as the water its swimming in ! [Dr Robert Young]
www.tubedistinctions.co.uk
Matthew 5:10
With an AVC does the impedance seen by the source increase as the higher turns are used? I recall they differ from pots.
TT 1 Trans-Fi Salvation with magnetic bearing + Trans-Fi Terminator T3Pro + London Reference
TT 2 Garrard 301 with NWA main bearing + Audiomods Series Six 10.5" + Ortofon 2M Mono SE
Digital Lindemann Bridge + Gustard R26 with LB external clock
Pre and Power Amp EWA M40P + M40A
Bass Amp & DSP Behringer iNuke NU3000DSP x 2
Speakers 1 Bastanis Sagarmatha Duo with twin baffleless 15" bass drivers per side
Speakers 2 MarkaudioSota Viotti Tower
First of all; the speaker load is a constant variant, due to the varying signal frequency it has to deal with in musical content,, so both types of amplifiers will put out diffrent amounts of power into the load throughout the frequency bandwidth, due to this ever changing load impedance of the speaker, ofcourse, the affect will vary depending on how good the speaker is, but dont be fooled into thinking one topolgy is perfect at driving a speaker over the other, I have gone into this in some detail in various other posts over the years here.Yes, you can introduce some form of crude impedance, by inserting a resistor in the output of a solid state amp in an effort to similate what a valve amp's output does when connected to a speaker, but its not an accurate way of describing the diffrences between how a solid state amp deals with a speaker versus a valve amp, I just see it as an attempt to bias non technical folk into thinking that solid state amps are automaticaly better than valve amps, which is far from the case in many situations.
"Today scientists have substituted mathematics for experiments, and they wander off through equation after equation, and eventually build a structure which has no relation to reality"
Nikola Tesla
Its now a conspiracy theory to believe that the Immune system is capable of doing the job it was designed to do.
A fish is only as healthy as the water its swimming in ! [Dr Robert Young]
www.tubedistinctions.co.uk
Matthew 5:10
"Today scientists have substituted mathematics for experiments, and they wander off through equation after equation, and eventually build a structure which has no relation to reality"
Nikola Tesla
Its now a conspiracy theory to believe that the Immune system is capable of doing the job it was designed to do.
A fish is only as healthy as the water its swimming in ! [Dr Robert Young]
www.tubedistinctions.co.uk
Matthew 5:10
In the Carver challenge he used null testing to tweak his SS amp so it sounded like the valve amp. He succeeded but I don't think the resulting SS amp was unconditionally stable as a result.
Current Lash Up:
TEAC VRDS 701T > Sony TAE1000ESD > Krell KSA50S > JM Labs Focal Electra 926.
The input resistance/impedance of the pot, ie; the part that the source see's [usualy the full resistance of the pot] as you and I both seem to agree on" is not the problem, where the issue some describe as some passives sounding lifeless, IMHO, its all to do with the lowering of the amplifiers input resistance, or impedance, by the wiper of the Attenuator being nearer to ground at low, to medium volumes!
"Today scientists have substituted mathematics for experiments, and they wander off through equation after equation, and eventually build a structure which has no relation to reality"
Nikola Tesla
Its now a conspiracy theory to believe that the Immune system is capable of doing the job it was designed to do.
A fish is only as healthy as the water its swimming in ! [Dr Robert Young]
www.tubedistinctions.co.uk
Matthew 5:10