Why does my Passive pre sound better than my active??

bebop86

Well-Known Member
Apr 1, 2013
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Guys-= I have the Wyetech Ruby STD preamp which is great- The other day I hooked up my Serious Stereo passive Ladder Type Attenuator =The sound from the passive just seemed much more alive then with the active- Just curious as to why this would be- thks
 

DaveC

Industry Expert
Nov 16, 2014
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2 things... parts quality and circuit design.

It's not easy or inexpensive to make an active preamp that'll beat out a good passive IF there aren't any impedance mismatch issues. I don't have your pre's schematics but the pics indicate parts quality that may be insufficient to maintain good signal quality.

With a good active tube preamp you should get sound that is MORE alive, dynamic and rich sounding vs a passive.
 

microstrip

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May 30, 2010
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Guys-= I have the Wyetech Ruby STD preamp which is great- The other day I hooked up my Serious Stereo passive Ladder Type Attenuator =The sound from the passive just seemed much more alive then with the active- Just curious as to why this would be- thks

Unless we have all the details about your system, even the room acoustics, IMHO no one can help.
 

Folsom

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Oct 25, 2015
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Dave's onto the situation. Impedance matching is key. But if that's done well and your source can drive the whole path without problem, the passive can alter the signal a very significant less than an active one will.

An awful lot of preamps that are active use Alps potentiometer (in all price ranges). They sound awful; but are one of the better sounding potentiometers among that horrible class of volume control.
 

DonH50

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Jun 22, 2010
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Note that impedance issues can make a passive pre sound better or worse than an active one, and that better or worse to you may not be the same as more accurate in terms of frequency response (or time response).

Active preamps add noise and distortion to a greater degree than most passive attenuators, but how much if that is audible is (as always) in the ears of the listener.
 

tony ky ma

Industry Expert
Aug 21, 2010
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Most active preamp have NFB design to reduce noise that is the point I think, in my experience a good tube amp with no NFB and good out put transformer will have the best in pre level
tony ma
 

DonH50

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Jun 22, 2010
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Hmmm... Negative feedback does not do a lot for noise since it is uncorrelated to the signal. It can help very LF noise. I was thinking of the fact that, without active gain stages, passive devices will add less distortion to the signal. The amount of noise they add depends upon the impedances; high-impedance passive circuits can add significant noise, and of course transformer-based passive devices can also pick up hum and noise, and so forth. always trades, compromises...

I have never seen a tube amp with "no" negative feedback; there is always some local feedback to stabilize the bias and generally increase the linear dynamic range a bit.

I do not have your ears, however!

All IMO - Don
 

DaveC

Industry Expert
Nov 16, 2014
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The truth is the parts quality isn't good enough. From the cheap filtered IEC inlet to the steel push connectors on it to the steel screw connectors on the PCB, the toroid with steel bolt, cheap RCA jacks, cheap capacitors, etc, etc, etc...

If you want a preamp that sounds as good or better than a simple passive you need good parts and good circuit design. I'm not sure about circuit design but the parts aren't anywhere close to what's needed for a neutral sounding tube preamp.

 

tony ky ma

Industry Expert
Aug 21, 2010
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What you paid and what you can get it is always true and my design rule of tube line level stage is less parts, simple circuit, low gain, less contacts and best part's quality, also separate power supply will have good result with this rule
tony ma
 

georgehifi

New Member
Dec 17, 2015
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A 10kohm passive preamp in the right system (which nearly all comply* with)
Will give you less colouration, less distortion, less noise, better transparency, better dynamics and better bandwidth frequency response.

(*Comply)
Source: Should be of Redbook standard 2v or higher and have an output impedance of less than <1kohm (1000ohm) Which nearly all are.
Poweramp: Should have an input impedance of >33kohm or greater and have an input sensitivity of .5v to 2v in for full output. Which most are.

Cheers George If you don't believe me, here is a quote from the god Nelson Pass.

"A Quote from the master Nelson Pass
Nelson Pass,
We’ve got lots of gain in our electronics. More gain than some of us need or want. At least 10 db more.
Think of it this way: If you are running your volume control down around 9 o’clock, you are actually throwing away signal level so that a subsequent gain stage can make it back up.
Routinely DIYers opt to make themselves a “passive preamp” - just an input selector and a volume control.
What could be better? Hardly any noise or distortion added by these simple passive parts. No feedback, no worrying about what type of capacitors – just musical perfection.
And yet there are guys out there who don’t care for the result. “It sucks the life out of the music”, is a commonly heard refrain (really - I’m being serious here!). Maybe they are reacting psychologically to the need to turn the volume control up compared to an active preamp."
 

hifistan

New Member
Jul 14, 2016
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I use the Townsend Allergri passive and like it better than my Audia Flight which is a very good active as well as a custom tube pre. Both of them are very good but the passive just seem to be more natural if not as dramatic. My spelling is quite original on occasion and my spell check does not know all audio terms
 

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