Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

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

marshall valvestate 8080 hiss raw/growl
marshall valvestate 8080 hiss raw/growl
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 16th May 2009, 07:08 AM   #1
meta11icafreak is offline meta11icafreak  New Zealand
diyAudio Member
Join Date: May 2009
Angry marshall valvestate 8080 hiss raw/growl

i have a marshall valvestate 8080 that just started growling when i turn on boost channel sounds like heavy rain.

it is only present when lead is pluged in (guitar or no guitar)
intensifys with more distortion
equlizer changes the sound from wind to heavy rain
i can still hear guitar but growl is 40% louder
volume controls growls volume
i can use clean channel with stompboxes etc.

what do i do. how do i test
  Reply With Quote
Old 16th May 2009, 02:08 PM   #2
Enzo is offline Enzo  United States
diyAudio Member
Join Date: Sep 2004
Location: Lansing, Michigan
Probably an op amp went noisy.

The input jack has an extra contact used to mute the circuit when the jack is empty. That is why you can't hear it when nothing is plugged in.

You have discovered that certain controls affect the sound of this noise. That means those controls are after the source of the noise in the circuit.
  Reply With Quote
Old 16th May 2009, 08:14 PM   #3
Nigel Goodwin is offline Nigel Goodwin  England
diyAudio Member
Join Date: Jul 2005
Location: North Derbyshire
There's really not a great deal that could cause it - for a start try removing the valve and see if it still growls without that. I'm assuming it won't, as it's probably either the valve duff (if you have one in something else, try it in and see if it cures it), or one of the three 'opamps' before it. One of those is a double, and more than an opamp (IC3) - but there's a second one (IC5) which you could try swapping over and see if the fault changes.

For the circuit see:

Nigel Goodwin
  Reply With Quote
Old 18th May 2009, 02:54 AM   #4
meta11icafreak is offline meta11icafreak  New Zealand
diyAudio Member
Join Date: May 2009
its just started doing it on the clean channel. but obviously not as loud and distorted. when i unplug lead it sort of pulses but out of time for a few seconds. doesn't do it every time

also does it with distortion pedal
  Reply With Quote
Old 23rd February 2010, 04:23 PM   #5
01redcobra is offline 01redcobra  United States
diyAudio Member
Join Date: Feb 2010
Wondered if you ever got to the source of this problem? Have a similar issue myself. Thanks
  Reply With Quote
Old 30th March 2010, 12:25 PM   #6
hhh is offline hhh
diyAudio Member
Join Date: Mar 2010
1. check the send and return plugs from the FXloop, sometimes the switched contacts in these jack give bad contact
2. check the solder connections on the big power resistors next to the tube and also check the power resistors in the power supply section (somwhere behind the on/off button
  Reply With Quote
Old 5th April 2010, 03:52 PM   #7
01redcobra is offline 01redcobra  United States
diyAudio Member
Join Date: Feb 2010
Enzo was right again, at least on the one I had in here. IC1 was the culprit!
  Reply With Quote
Old 7th April 2010, 02:26 PM   #8
wahab is offline wahab  Algeria
diyAudio Member
Join Date: Nov 2009
Location: algeria/france
A friend of mine has one with the same problem..
It was a power resistor that is so hot that it made
the soldering having a random electric contacting..
  Reply With Quote
Old 10th July 2013, 02:20 PM   #9
Beauxdean is offline Beauxdean
diyAudio Member
Join Date: Jul 2013
Default Dog peed...

I have the same issue. My Valvestate 8080 was found in a trailer remodel and had been dog peed all over it and around it....some people. To treat this jewel like that.... Anyway, all the pots were sealed tight. I got all the pots and put them in. They work now and I've finally gotten the nerve to put power to it and test it. It works without blowing the fuse. Yah! Both channels have a small ground noise or something when powered up but not bad. The Normal channel works and sounds great but the boost channel is very cruddy sounding and acts like it's got a noise gate on it turned up WAY too high. I got a new 12AX7/ECC83S tube but that just does the same and makes it rougher. I changed out the R112 and R113 resistors even though they test ok because they get real hot and I wanted new ones with a bump more wattage. No change. I read here (where someone has an almost identical problem) that it could be IC1. In fact, 01redcobra that had this issue changed IC1 and that solved the issue. After reading this, I fired her up and touched the top of all the Ic chips with my finger. IC1 made the ground noise get louder when I touched it but none of the others did. You think that's it? I'm tired of this amp on my counter top! Any help would be appreciated!
  Reply With Quote


marshall valvestate 8080 hiss raw/growlHide 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Marshall Valvestate 8080 kdawg Instruments and Amps 10 1st May 2012 12:08 AM
marshall valvestate 8100 trai1824 Instruments and Amps 4 27th March 2012 01:36 PM
Guitar amp problem (marshall 8080 valvestate) Palmu85 Instruments and Amps 3 26th September 2011 09:33 PM
Marshall Valvestate 8080 low gain on Boost Channel mgjimbo Instruments and Amps 0 28th May 2008 02:04 AM
marshall valvestate 8080 repair tips needed skid Instruments and Amps 4 25th April 2006 01:01 PM

New To Site? Need Help?

All times are GMT. The time now is 11:27 AM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 16.67%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio