"...the best preamplifier ever made" says Mr. David Price, Hi-Fi- World - Page 8 - diyAudio
Go Back   Home > Forums > Source & Line > Analog Line Level

Analog Line Level Preamplifiers , Passive Pre-amps, Crossovers, etc.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 13th January 2010, 02:42 PM   #71
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Hi,

Quote:
Originally Posted by hornperfect View Post
Thorsten, what are your thoughts re autoformers vs transformers issue?
Well, strictly as a pure volume control there is little to choose, I am sure different devices from different manufacturers sound different and may be preferable to one or the other for a range of reasons.

What I find attractive with a true transformer as VC is that it can be employed in a wide range of "unorthodox" applications and that it can break earth/ground loops and so on.

An Autoformer simply can never do that and the performance gained with the unorthodox applications certainly convinces me.

Ciao T
  Reply With Quote
Old 13th January 2010, 02:46 PM   #72
diyAudio Member
 
Join Date: Jan 2007
oh definitely, that's a great feature of a transformer. though dave slagle used to say that it's not a way to sort the ground loop out but to fight it at its very source. can't agree more.
  Reply With Quote
Old 10th April 2013, 08:50 PM   #73
gander is offline gander  United States
diyAudio Member
 
Join Date: Jun 2008
Location: Denville, NJ USA
Send a message via Yahoo to gander
Quote:
Originally Posted by Peter Daniel View Post
Well, the comparison is not that simple. The TVC can actually work as stand alone preamp, offering 6dB gain, high input impedance and low output impedance, it can be wired for phase reversing and unbalanced to balanced (and opposite) conversion, all without any additional active circuitry.

Can your Lightspeed do all that?
Well said. And this isn't even the best quality of a TVC. With every signal there is power (watts), which is voltage times current. With a resistor type attenuator, the voltage drops, but the current does not proportionally increase, resulting in a loss of power. With a TVC, as the voltage drops, the current increases, maintaining the original power (less a small amount for the transformer windings).

ALSO, as the voltage drops, the impedance drops by a factor of squared. So, LOTS of punch and detail at low volumes.
More info about TVCs here:
FAQ for transformer volume contr

I have a Promitheus TVC, made in Malaysia (standard version, not reference).
Transformer Volume Control

I plugged it in at the home of the head of my audio club, who has a Jadis 4-chassis tube preamp, a truly high end machine (one of the channel power supplies was not working, so he didn't have a preamp at that time). My little Promitheus TVC was at least the equal of that incredibly expensive tube collection, according to the owner. And the Promitheus (basic) is only about $500US. Of course the better the core and the transformer, the better it will sound. And Promitheus offers their reference c-core transformers with the TVC, for a bit higher price of course.

And this is just one company. Check out Sowter:
SOWTER ATTENUATOR TRANSFORMERS TVC VOLUME CONTROL
They offer transformers with taps that you can use to build your own TVC.

Companies are coming out with TVC preamps claiming theirs is the best, but you can pay 1/20 of the price and get a damn fine preamp.

Gary
__________________
Cheers!
Gary
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Looking for Transistor based Gyrator info. Any "Wireless World" collectors out there? Hearinspace Everything Else 24 19th February 2011 08:58 PM
"The power of hearing" - Physics World May 2002 x-pro Everything Else 6 11th March 2004 09:55 PM


New To Site? Need Help?

All times are GMT. The time now is 07:37 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2