Marshall Valvestate I preamp drop out problem? - diyAudio
Go Back   Home > Forums > Live Sound > Instruments and Amps

Instruments and Amps Everything that makes music, Especially including instrument amps.

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 28th April 2012, 05:09 PM   #1
diyAudio Member
 
Join Date: Apr 2012
Default Marshall Valvestate I preamp drop out problem?

Hi. I have 3 old Valvestates and my friends have 3 more and we all have the same fault on them. The preamp drops out ... Sometimes in a second and sometimes after 5 minutes and then the sound come back later.

They ALL work if you run them straight in the loop as amplifier and bypass the preamp part which mean it must be in the preamp .... I have tried to clean it, replaced pots, checking all soldering and so on ... Nothing helps =/

One friend sent his on repair and got it back. He asked what was wrong but they refuse to answer and then on his invoice it was stated mosfet and that was all .... They also charge him around $500 ... totally nuts... But his works fine now.

So any good old marshall tech that know what I could do more ?
All inputs are more then welcome.
Thanks in advance.
  Reply With Quote
Old 30th April 2012, 11:45 PM   #2
Wotnotz is offline Wotnotz  Wales
diyAudio Member
 
Join Date: Apr 2012
Hi. I've also just come across the same problem in my Marshall 8080 Vavlestate amp. Nothing works on the preamp but I get a respose when I bypass it via the effects return loop.

I've given it a thorough once over and nothing stands out at broken.

Anyone got any ideas? Have you had any luck Evilution?

Thanks
  Reply With Quote
Old 1st May 2012, 12:54 AM   #3
kevinkr is offline kevinkr  United States
diyAudio Moderator
 
kevinkr's Avatar
 
Join Date: Sep 2004
Location: Boston, Massachusetts
Blog Entries: 6
Guitar amplifier discussions belong in I & A where I am moving it now. Hopefully someone there will have some helpful tips for fixing this pre-amp.
__________________
"Extraordinary claims require extraordinary evidence." - Carl Sagan
  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
Marshall Valvestate mods Nelec Instruments and Amps 22 10th June 2013 01:01 AM
Marshall Valvestate 8080 kdawg Instruments and Amps 10 1st May 2012 12:08 AM
Guitar amp problem (marshall 8080 valvestate) Palmu85 Instruments and Amps 3 26th September 2011 09:33 PM
Marshall 8100 valvestate tube problem help megagtiguy Solid State 3 17th September 2011 02:59 AM
Marshall AVT150H Valvestate 2000 Power Amp Problem fenster94 Solid State 10 22nd May 2011 02:56 PM


New To Site? Need Help?

All times are GMT. The time now is 10:33 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