VTL Compact 100 Monoblock x 2. - diyAudio
Go Back   Home > Forums > Amplifiers > Tubes / Valves
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

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
Thread Tools Search this Thread
Old 15th October 2004, 08:19 PM   #1
sstong is offline sstong  Hong Kong
diyAudio Member
Join Date: Aug 2004
Location: HONG KONG
Default VTL Compact 100 Monoblock x 2.

Hello everybody!
I own a pair of VTL Compact 100 Monoblocks that use 2 x 12AT7 & 4 x EL34 tubes. I'm quite satisfied with the sound they produce
but few years ago one of their volume became very small that I
have to move myself pretty close to the speaker to hear the sound. At the same time a hi-fi shop is on sale and I bougt a pair
of Audio Resource power amp so that I can still listen to my CDs. I've been using the Audio Resource model Amp One since then (
that was 1997 or 1998) and they are still working normally. Since
I have some basic knowledge of electronics, I intend to fix the VTL myself. The biggest drawback is my lack of experience (also lack of time) that keep me from starting the project for so many years.
I should be grateful if you would please:
1. share that kind of experiences,
2. show the test report or review, if there's any,
3. suggestions of modifications to make it sound even better,
4. the way you think of its sound quality.

All best wishes!

The other audios that I have:
Sansui CD Alpha 717-Extra cd player,
Marantz CD-63 II KI,
Dynaco PAS3,
Spendor Prelude,
Linn LP-12 Export,
SME-3009 III,
DIY 12AU7 preamp,
DIY 6AN8 + EL84 power amp.
  Reply With Quote
Old 16th October 2004, 12:30 AM   #2
diyAudio Member
Join Date: Aug 2003
Location: Indiana USA
Hi there,
How old are the tubes??
Try to retube yet??
If so, are all working voltage correct?
  Reply With Quote
Old 16th October 2004, 04:30 PM   #3
sstong is offline sstong  Hong Kong
diyAudio Member
Join Date: Aug 2004
Location: HONG KONG
Hello Contaxchen,
I've tried another set of tubes and also checked the B+ voltages
on both amps, the measured values are quite the same (~430V),
and the tubes look ok too.
Thanks anyway!
  Reply With Quote
Old 17th October 2004, 12:04 AM   #4
diyAudio Member
Join Date: Aug 2003
Location: Indiana USA
Check out this link. It was written in simplied Chinese.
Well, if all working voltage is correct, then the problem is big.
I have a pair of VTL M100, too. Like 18 years old.
  Reply With Quote
Old 17th October 2004, 03:49 AM   #5
diyAudio Member
cogsncogs's Avatar
Join Date: Jul 2003
Location: Wayne, West Virginia
Here's a stab at it: possible bad cathode bias resistor bypass capacitor on the 12AT7 AF amp (1st stage) or a bad grid bypass cap on the 12AT7 LTP phase splitter. Also check the coupling caps to the EL34's. And IIRC since the VTL's use PCB's, look for cold/bad soldier joints.

  Reply With Quote


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
New Compact TL Project MJL21193 Multi-Way 80 15th June 2009 11:25 PM
WTB: aleph-x compact PCB ashaw Swap Meet 0 23rd March 2008 08:24 AM
Compact Sub Suggestions lgchristianson Car Audio 4 19th May 2007 11:05 PM
Compact sub DocLorren Subwoofers 11 8th January 2005 12:34 AM
Compact subwoofer Vatos Subwoofers 0 20th March 2003 08:17 AM

New To Site? Need Help?

All times are GMT. The time now is 03:53 AM.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2