S&B TX102 and preamplier stages - diyAudio
Go Back   Home > Forums > Amplifiers > Tubes / Valves

Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum

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 26th October 2004, 02:06 PM   #1
KT is offline KT  United States
diyAudio Member
 
Join Date: Oct 2003
Location: USA
Default S&B TX102 and preamplier stages

Did you guys see the glowing review of the TX102 in Hi-Fi News and Record Review?

Given how great the TX102s sound just as a stand-alone attenuator, I'm wondering whether this renders the active preamplifier superfluous. Has anybody tried TX102 both as a stand-alone attenuator AND as the volume control for an active preamplifier? If so, which did you prefer?

I understand that one would need preamplification for vinyl and to drive amplifiers with very low sensitivity. But for sources such as CD and SACD, does the TX102 perform well enough that you wouldn't want to use a preamplification stage after it?

This is related to the resistive attenuator vs. active preamp question. I myself prefer using an active preamplifier over a stand-alone resistive attenuator because I find that it fleshes the sound out and provides a richness and body that the attenuator alone does not provide. This is with sources with sufficient gain.

Is the TX102 a different enough creature that this is not the case?

Love to hear some opinions.

Thanks,
KT
  Reply With Quote
Old 26th October 2004, 02:37 PM   #2
diyAudio Member
 
Join Date: Sep 2004
Location: A bloke from Stoke
I have an Alps blue pot connected to one input and output phono pair of connectors (no switching) in a small housing. The interconnects are DIY specially made for length, i.e just long enough.

I compared this directly, to the latest 800 Quad valve amp and a meridian pre amp and preferred the passive for clarity and transparency. No difference in the bass except possibly a tad more musicality in the passive but nothing exceptional.

Have you seen the WIKI for S&B TX102's, if you fancy a pair get your name down quick

Kev
  Reply With Quote
Old 26th October 2004, 04:55 PM   #3
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Default Re: S&B TX102 and preamplier stages

Konnichiwa,

Quote:
Originally posted by KT
Given how great the TX102s sound just as a stand-alone attenuator, I'm wondering whether this renders the active preamplifier superfluous. Has anybody tried TX102 both as a stand-alone attenuator AND as the volume control for an active preamplifier? If so, which did you prefer?
I prefer to avoid the added colorations from an unnecesary active stage, I have tried both options and various resistive passive preamps, buffered and unbuffered.

Quote:
Originally posted by KT
for sources such as CD and SACD, does the TX102 perform well enough that you wouldn't want to use a preamplification stage after it?
Absolutely.

Quote:
Originally posted by KT
This is related to the resistive attenuator vs. active preamp question. I myself prefer using an active preamplifier over a stand-alone resistive attenuator because I find that it fleshes the sound out and provides a richness and body that the attenuator alone does not provide. This is with sources with sufficient gain.
Same here.

Quote:
Originally posted by KT
Is the TX102 a different enough creature that this is not the case?
Yes.

Sayonara
  Reply With Quote
Old 26th October 2004, 05:14 PM   #4
Gregm is offline Gregm  Europe
diyAudio Member
 
Join Date: May 2003
Location: Wherever I leave my hat
Further on the subject I saw a pic of the belly (inside) of Kuei's TX102 volume control at Ardumann's site:

Kuei, you have a smal circuit connected at the output rca's but I can't figure out the "connection" from the photo.

Would you be willing to give a few hints?
Cheers
  Reply With Quote
Old 26th October 2004, 06:57 PM   #5
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Konnichiwa,

Quote:
Originally posted by Gregm
Kuei, you have a smal circuit connected at the output rca's
No, I have NOT. All I have is a switch that connects either RCA Ring or XLR Pin1 to the main Preamp ground, or floats both.

On the Input Connectors there are Series RC terminators (2n2 & 51R) for RF to preamp ground from the shield termination (Ring on RCA, Pin1 on XLR) the input is otherwise treated floating, with the exception of one RCA input (for TV sound) which has a 100 Ohm to preamp ground selected by a spare contact of the input relais as otherwise things hummed a little too much.

The thing that you should be asking about is the RC circuit on the switch. This was a (sucessfull) attempt to stop the MKI TX-102 from having as large an untrasonic peak at low volume settings as it showed. It was simply an RC Circuit across the top of the secondary (0db Tap) and the Wiper of the switch, which allowed the unconnected windings to be terminated corretcly.

From the MK II TX-102 these where not neccesary to stop ultrasonic peaks and even on the MK I I preferred the sound without them.

Sayonara
  Reply With Quote
Old 26th October 2004, 09:45 PM   #6
diyAudio Member
 
Join Date: Sep 2003
Location: London
Hi there, Thorsten - is this TVC unbalanced or can it be used balanced in and out? If it can be used balanced, is there a need for a coupling capacitor into it if the signal comes from, say, a diff pair? I'm not sure the answer I got from S&B is correct - they seemed to imply you needed a coupling cap in all cases. Is this true, and if so why exactly? Andy
  Reply With Quote
Old 26th October 2004, 10:44 PM   #7
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Konnichiwa,

Quote:
Originally posted by andyjevans
Hi there, Thorsten - is this TVC unbalanced or can it be used balanced in and out?
A TTVC (True Transformer Volume Control - as opposed to AVC's often called TVC's) is a transformer. A competently designed symmetrical audio line-level transformer is just that. The input and output is "differential floating". The concept of "balanced" or "unbalanced" does not exist.

It will pick up the signal between the two ends of the primary coil and output a signal between the two (selected) ends of the secondary coil. The one possible snag is a bifilar wound transformer (eg TX-102 MK II) which can cause in certain conditions problems with the balance at high frequencies.

Quote:
Originally posted by andyjevans
If it can be used balanced, is there a need for a coupling capacitor into it if the signal comes from, say, a diff pair?
The signal must be free of DC. You can ahieve this easiest and safest with a coupling capacitor. Using other methodes is of your perogative, but remember, NO (material) DC CURRENT in the primary or secondary.

Sayonara
  Reply With Quote
Old 27th October 2004, 06:41 AM   #8
Gregm is offline Gregm  Europe
diyAudio Member
 
Join Date: May 2003
Location: Wherever I leave my hat
Thanks, Kuei
  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
TVC Stevens & Billington TX102 Mickeman Swap Meet 5 22nd January 2009 12:30 PM
Wanted: S&B TX102 mk3 giulio Swap Meet 1 15th August 2006 04:54 AM
steven&billington TX102 MK2. etalon90 Swap Meet 0 29th May 2005 03:21 PM
Finally, I've tried S&B TX102 TVC with a GC amp Peter Daniel Chip Amps 105 5th November 2004 02:03 PM
FS: S&B Tx102 TVC transformers pooge Swap Meet 0 16th October 2004 12:59 PM


New To Site? Need Help?

All times are GMT. The time now is 05:57 AM.


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