Why Is High Feedback Considered Bad In Audio? In Simple Terms

I don't get that. A simple CRCR network can have an impulse response that swings negative, but it doesn't ring.

John

Only if you want inferior results. For proper measurement you must Platinum RTDs.

Highpass filters ring by definition. The step response goes up and then down.

Vladimir Vassilevsky DSP and Mixed Signal Design Consultant

Oh, different definition.

So a simple C-R differentiator "rings"?

John

This older thread gives an interesting explanation that I've not seen anyone post here yet:

Warmth is measured by the number of 12AX7's in the signal path.

The goldenearies seem to love the 6SN7. I always hated 6SN7s when I was a kid. Rotten transconductance, lots of plate capacitance, a klunker in general.

I really liked the frame-grid tubes, 6DJ8 sorts of things, with screaming gain-bandwidth. Nuvistors were fun, too.

John

Example? There are laws regarding what they can say.

I thought the warmth came from the 6L6s.

For playing worn 78s they do have an advantage: a soft stylus contacts most of the groove cross-section, thereby averaging out the roughness. The S/N ratio can be considerably better than if you played the same record with a hard polished stylus which only made contact at two points.

If the flexible stylus is connected to a pickup with massive moving parts, it will additionally form a low-pass filter, which may remove the frequency band where the S/N ratio is poorest or may resonate and make the scratch sound worse. A soft stylus should be in a pickup with low moving mass to give a better frequency response - any filtering that may be required can be applied electronically further down the chain.

Has the L.F. noise figure of a Nuvistor ever been bettered by a semiconductor? For a long time they gave the lowest flicker amplitude in F.M. oscillators and E.M.G. amplifiers.

Has the L.F. noise figure of a Nuvistor ever been bettered by a semiconductor? For a long time they gave the lowest flicker amplitude in F.M. oscillators and E.E.G. amplifiers.

That is not ringing.

Ringing implies some sort of cyclic action.

ge

ar

he

he

ack

to

n."

or

me

ear

=A0If

her

"In particular, high order filters are to be avoided at all costs because they ring like bells and sound like s*it."

There is no reason a higher order filter should ring, unless you design it that way. I can believe that they may sound different, depending on where the corner frequency is.

George

"Highpass filters ring by definition. The step response goes up and then down."

What? I don't get this. Do we have a different definition of ringing?

George

Definition: ringing = step response is not monotonous.

VLV

I suspect so. I don't know what's your criterion for "lf", but in a properly tuned amplifier, some of the PHEMTs can get down to noise figures of 0.4 dB, which is a noise temperature ballpark 30 kelvins.

I think there were some big ugly tubes that would get around 1 nv/root Hz in the audio range, which only the best jfets and opamps can do now.

John

Some steps are certainly more boring than others.

John

That's what they taught us. If a thing rings, it rings forever.

A simple CR doesn't ring, it thuds.

John