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Old 2nd September 2008, 11:39 AM   #1
Professor smith is offline Professor smith  United Kingdom
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Default passive attenuator

I would simply like to know why passive pots lack dynamics and bass?

This has been my own experience with them and I'd like to know what kind of distortion could cause such effects?
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Old 2nd September 2008, 12:27 PM   #2
juma is offline juma  Germany
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The eternal question, torturing mankind since the dawn of time

Impedance matching, dear professor, impedance matching !
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Old 2nd September 2008, 05:34 PM   #3
Professor smith is offline Professor smith  United Kingdom
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ok well could someone explain the details of this to me?

what is impedance mismatch and how does it make the sound lacking in dynamics?
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Old 2nd September 2008, 05:55 PM   #4
hifimaker is offline hifimaker  United States
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Quote:
Originally posted by Professor smith
ok well could someone explain the details of this to me?

what is impedance mismatch and how does it make the sound lacking in dynamics?

Please consider getting "The Art of Linear Electronics" by John Linsley Hood. It covers all the essentials about audio electronics, like filters, impedances, circuit theory, etc.

The book is now in reprint from Audioxpress: http://www.audioxpress.com/bksprods/BKSELEDES.htm

Also consider reading Nelson's prior articles on the ZEN line of preamps and amps. They are available on www.passdiy.com.

Both of these resources are a gold mine for learning!

-David
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Old 2nd September 2008, 05:58 PM   #5
juma is offline juma  Germany
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SEARCH button is your friend
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Old 2nd September 2008, 09:42 PM   #6
Stefanoo is offline Stefanoo  Italy
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Quote:
Originally posted by Professor smith
ok well could someone explain the details of this to me?

what is impedance mismatch and how does it make the sound lacking in dynamics?

well impedance mismatching is the theory that stands behind the maximum transferred power.
Now the theory says that a real generator with its internal resistance connected to a load transfers the maximum power to the load when the load has the same impedance of the internal resistance of the generator.
The power figure is, if i don't recall wrong, an upside down parabolic behavior (the maximum is Pgen/2).
As you can understand by varying the load connected to generator the ability of the system to transfer power varies accordingly.

How do we summarize this?
A passive attenuator's system obviously varies the impedance seen by the stage behind it as the volume position varies.
This leads to the problem of different adaptive conditions at different volume level positions and not all them will be the ideal one, of course.
As the dynamic might be defined as the ability of an amplifier to output power", you easily understand how this, of course, affects the above parameter.


Stated this, i like them both : active and passive volume control system.
I would personally try to make them both and see what i like the most.


Hope this helps.
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Old 2nd September 2008, 10:08 PM   #7
Nelson Pass is offline Nelson Pass  United States
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passive attenuator
Default Re: passive attenuator

Quote:
Originally posted by Professor smith
I would simply like to know why passive pots lack dynamics and bass?

This has been my own experience with them and I'd like to know what kind of distortion could cause such effects?
I don't know. There is no theory which adequately explains this, but there
is a common perception that this is so. Having the wiper see a high impedance
load seems to improve it.

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Old 3rd September 2008, 02:06 PM   #8
Professor smith is offline Professor smith  United Kingdom
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What does reducing the current of the signal source do to the sound?

I have heard that this is what causes the lack of bass drive and dynamics, is this a myth?
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Old 3rd September 2008, 06:15 PM   #9
Nelson Pass is offline Nelson Pass  United States
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passive attenuator
Probably. It's a conclusion lacking context. I can probably come up
with counter examples pretty easily.
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Old 1st July 2017, 02:41 PM   #10
tiefbassuebertr is offline tiefbassuebertr  Germany
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Default Passive Pre-amp/Volume Control/Attenuator Line-Up with Resistors and Auto-Transformer

All mentioned models are equipped with input selector switches.
There are also plug-and-play devices resp. boxes with input selectors but without volume control - this I have listed on post # 22 under
Rotary source selector for audio

Passive Pre-amp/Volume Control/Attenuator with Resistors and Auto-Transformers


Basic descriptions
SoundStage! Pete's Place - Aggressively Passive: Everybody Needs a Philosophy (12/1998)
Passive Vorstufe mit High-End Leitplastikpoti
Passiver Vorverstrker

Commercial available Attenuation Devices with Resistors/Potentiometers

Sonic Frontiers model "First Reference"
(on the web I don't find any descriptions and images - thank you very much for upload this).
Luminous Audio's Axiom II (Passive Pre with Walker Mod)
https://luminousaudio.com/collection...passive-preamp
Luminous Audio's Axiom II Passive Pre with Walker Mod
YAMAHA MVS-1
YAMAHA MVS-1 ????????????????? : ?????????blog
B&K Pro 10MC (line path provided both for active and pasive mode)
B&K PRO-10MC Pre-Amp & B&K ST-202 Amplifier ? Polk Audio
B&K Pro-10MC Sonata Series | Steve Hoffman Music Forums
B&K Components Pro10MC Preamplifiers reviews - Audioreview.com
Dodocus Model "Vorstufe N" (German language)
Dodocus – Vorverstrker im Retro-Design
https://www.hifitest.de/test/stereov...rstufe-n_11664
Creek OBH22
http://www.creekaudio.com/instructions/obh22.pdf
Creek OBH-22 passive 'pre-amp' | Rock Grotto
Rotel RC-870BX
https://www.fein-hifi.de/Vorverstaer...ufe::1045.html
Rotel RHC-10 (MICHI-series)
Rotel MICHI Serie
ROTEL RHC-10 High End Passiv Control Amplifier "TAKUMI" "MICHI" mit OVP (M714) | eBay
Sonus-Qualitas PVV-Series
http://www.hifi-forum.de/viewthread-172-7119.html
Sonus Qualitas passiv Control Center-Preamp Typ PVV Series I; Vorverstä (B00076) | eBay
Sonus Qualitas
https://www.htforum.com/forum/thread...-alemao.99211/
Walter H120/Z034 (very cheap)
Walter Elektronik ? Fachgeschäft für Elektronik und Hifi in Mannheim
Walter Elektronik ? Fachgeschäft für Elektronik und Hifi in Mannheim
Monacor ILA-100RCA (very cheap)
https://www.monacor.com/de-de/monaco...ng/ila-100rca/
Technolink Enterprise TC-754/TC-760LC (incl. audiophile MC & MM Phono Preamp)
http://www.tnt-audio.com/ampli/t-preamp_e.html (TCC TC-754)
Technolink (TEC) TC-760LC RIAA Moving Magnet / Moving Coil (MM/MC) Phono Preamp (Preamplifier)
TECHNOLINK ENTERPRISE CO. ???????? - Audio amplifiers, phono preamp, Audio Mixer, A/V switcher, Phono accessories, Integrated Stereo Amplifier, Controllers, Audio controller, Speaker controller, Audio control, vedio control, Speaker v
Spring Air passive Preamp
Passiver Vorverstärker | audioScout.eu | HighEnd für alle
ebay XLR/RCA passive Preamp
Fully Balanced Passive Preamp Volume Controller XLR/RCA Passiver Vorverstärker | eBay
Khozmo Acoustic Dual Mono
High Quality Audio & Industrial Attenuators and Passive Preamplifiers
Thel passive Vorstufe (only German language)
Passive Vorstufe mit High-End Leitplastikpoti
Lightspeed Attenuator
Optus Member Website - georgehifi
https://www.whathifi.com/forum/compu...eed-attenuator
Nano Patch
Nano Patch Plus
Little Nelly
Agent Audio
Palmer MONICON
PMONICON Palmer PRO MONICON - Passiver Monitor Controller
SM-PROaudio Nanopatch/M-Patch2
SM Pro Audio Nano Patch+: Passiver Lautstärkeregler vorgestellt ⋆ delamar.de
SM Pro Audio ? M-Patch 2 ?
WLM PRE
AUDIOsuite WLM PRE-/PASSIVE CONTROL (PPC) - die puristische Vorstufe und Klangmodulator
EMT Selector DU-111
Selector DU 111
Icon Audio Passive Line Pre Amplifier
Passive and Passive R Pre Amp | Icon Audio
Icon Audio Passive Line Pre Amplifier for £399.95 at Audio Affair
Hattor Ultimate Passive preamplifier
HATTOR - HighEnd Audio Manufacture
Hattor Audio Passive Preamplifier | eBay

Passive Preamp/Volume Control/Attenuators with Auto-Transformer (TVC):

Basic descriptions TVC:
Grundlagen passive Vorverstärker | silvercore.de
J&K Audio Design: Transformer Volume Control TVC
TVC erfahrungen ( transformer volume control) - Phono - Restaurierung und Selbstbau - Analogue Audio Association
TNT Audio Django preamp Review [English]
Django TVC Passive Vorstufe - Seite 2 - Verstärker, Lautsprecher, Zubehör - Analogue Audio Association (also mentioned "Lightspeed attenuator" at last posting)

Transformer parts and commercial available TVC devices for plug-and-play

Sonic Euphoria PLC
https://www.stereophile.com/solidpre...ic/index4.html
https://www.audiogon.com/listings/so...plifiers-01543
Promitheus Audio - Transformer Volume Control Preamp (various models)
Promitheus Audio Frontpage
???&????????from USA?:Promitheus TVC?????2? - livedoor Blog?????
Django TVC Preamp
http://www.store.diyhifisupply.com/C...p?q=catalog/74
Stevens Billington - Line input and output transformers
Stevens & Billington/Music First Audio | The Ear (factory visiting)
http://www.stevens-billington.co.uk/
https://lhlabs.com/force/media/kunen...y20Classic.jpg (Preamp on Spikes)
Intact Audio PCB-units including auto transformer, rotary switch input selector and ELMA-04 for attenuation
intact audio
SAC Supermalloy Transformer Attenuator, model STA-522A
SAC Thailand
Teramoto-FINEMET
Premium Finemet Transformers
Teramoto FINEMET Premium Transformer Volume Control, TVC Custom Seiden Switch | eBay
Jandkaudiodesign
J&K Audio Design: Transformer Volume Control
Audio-Consulting - Silver-Rock
Silver Rock TVC - Silver Rock TVC
https://www.blackdahlia.com/tipindex/Tip_39/tip_39.html

Last edited by tiefbassuebertr; 1st July 2017 at 03:01 PM.
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