Go Back   TalkBass Forums > Bass Guitar Forums > Bass Guitar Forums > Amps [BG]
Register Rules/FAQ/CUP Members List Search Today's Posts Mark Forums Read



Supporting Membership
Thank You

Latest Supporting Member
Donate to Upgrade Today

Reply
 
Thread Tools Search this Thread
  #1  
Old 12-04-2013, 05:32 AM
Registered User
 
Join Date: Dec 2013
Peavey Classic 400

I just bought a Peavey Classic 400 bass head I took it apart with my father everything seemed fine then after putting it back together we ran it out to a 4Ω Guitar cab (sadly its the only cab I own currently) after leaving it on standby for 30 seconds to let the tubes heat up some. we turned off standby I tried playing nothing would come out after that we kept trying different inputs nothing but when we would take it off standby the speaker would react as if it is drawing power. any ideas on how to fix this?
  #2  
Old 12-04-2013, 06:02 AM
CL400Peavey's Avatar
Registered User
 
Join Date: Nov 2011
Location: Grand Rapids Michigan
Supporting Member
Tech time.
__________________
Quote:
Originally Posted by JimmyM View Post
Who the heck wants to "cut" through a mix anyway? I want to punch the mix in the balls. Anyone can cut through the mix. Not everyone can beat the mix's ass.
Quote:
Originally Posted by Kawai-chang View Post
Yesterday my purple starfish was hurty.
  #3  
Old 12-04-2013, 06:11 AM
Registered User
 
Join Date: Aug 2009
Location: New Zealand
Definitely.
__________________
Team Trace Elliot #1, IWNBARMPB Prezident, Mediocre Bassist #399, Old Basstard #86, PBBBC #2
  #4  
Old 12-04-2013, 06:56 AM
Registered User
 
Join Date: Oct 2002
Location: Nashville TN
Quote:
Originally Posted by JustinC97 View Post
I just bought a Peavey Classic 400 bass head I took it apart with my father....
What exactly did you take apart-- and why?
  #5  
Old 12-04-2013, 07:50 AM
Registered User
 
Join Date: Dec 2013
The guy who owned it before me lost the fuse cap and said some of the internal fuses might be busted so we took it apart to look at the fuses and install a new fuse holder on the back. the fuses were fine none were busted

what do y'all think the tech might find?
  #6  
Old 12-04-2013, 07:52 AM
Registered User
 
Join Date: Dec 2013
Quote:
Originally Posted by nashvillebill View Post
What exactly did you take apart-- and why?
the took is out of the wood cab then took out the tubes while wearing latex gloves placed them on a towel, we opened it up to look at the board and the internal fuses
  #7  
Old 12-04-2013, 08:21 AM
Registered User
 
Join Date: Oct 2002
Location: Nashville TN
You don't need to wear latex gloves when working with tubes, your fingerprints won't hurt them.

Are you sure the cab and speaker cable works? Plug one end of your speaker cable into the cab, take a 9 volt battery and touch its terminals to the plug on the other end(one terminal on the plug's tip, one on the plug's shield). You should hear the cab make noise and the speaker cone itself should move. If nothing...the speaker cable or speaker is faulty, not the amp.

Confirm the cab and cable work properly before doing anything else.
  #8  
Old 12-04-2013, 10:17 AM
Registered User

MI Amp Engineer: Peavey Electronics
 
Join Date: Oct 2005
Location: Meridian, MS
Sorry, don't have much time. It's probably a blown IC on the preamp tube board.
__________________
Helping young rock stars annoy their parents for over a decade.
  #9  
Old 12-04-2013, 10:54 AM
Registered User
 
Join Date: Dec 2013
Quote:
Originally Posted by nashvillebill View Post
You don't need to wear latex gloves when working with tubes, your fingerprints won't hurt them.

Are you sure the cab and speaker cable works? Plug one end of your speaker cable into the cab, take a 9 volt battery and touch its terminals to the plug on the other end(one terminal on the plug's tip, one on the plug's shield). You should hear the cab make noise and the speaker cone itself should move. If nothing...the speaker cable or speaker is faulty, not the amp.

Confirm the cab and cable work properly before doing anything else.
I just did the 9v battery test cable and cab work fine i use this cab for my mixer all the time. so that proves its a intenal problem, I know it isn't any of my cables. any ideas of what could be going on on the inside?
  #10  
Old 12-04-2013, 12:15 PM
Steve Dallman's Avatar
Registered User
 
Join Date: Mar 2006
Location: East Central Wisconsin
Supporting Member
Rather than just shoot willy-nilly, you should take a systematic troubleshooting approach.

If this was on my bench, I'd put a signal into it with the amp plugged into a speaker. I would have a second, bench amp on. If no signal was passing to the speakers of the PV, I'd plug a cable into the preamp out/power amp in jacks. If sound passes to the speaker, then the power amp in jack switching is funky.

If no signal passed, I'd run a cable from the preamp out to the bench amp (I use a small guitar practice amp) Is there sound there?

If so, I'd patch my signal into the power amp in jack to see if the power amp is working.

I use a CD or MP3 player for my signal source.

This is the probe I made for tracing signals through an amp.

http://www.fenderforum.com/userphoto...ml?recid=69384

I'd repeat all with the effects jacks.

If there were still no signal, I'd take the amp apart and start by first confirming the correct voltages at the correct points.

Then I'd again put a signal into the amp, and using a probe connected to my bench amp, grounded to the PV chassis, I'd follow the signal through the amp, from input jack to the speaker jack. Where it stops is the problem.

Last edited by Steve Dallman : 12-04-2013 at 12:18 PM.
  #11  
Old 12-04-2013, 12:20 PM
Registered User
 
Join Date: Feb 2005
Location: Seweracuse, NY
Quote:
Originally Posted by BbbyBld View Post
Sorry, don't have much time. It's probably a blown IC on the preamp tube board.

^^^ I'd put some weight behind this guy's opinion...He seems like he probably knows a lot about stuff.
__________________
fEARful: for those who want something better: http://greenboy.us/fEARful/


For Sale : Bergantino HT115 with Cover: $500.00 + exact shipping cost.SOLD!
  #12  
Old 12-04-2013, 01:21 PM
Registered User
 
Join Date: Oct 2002
Location: Nashville TN
Quote:
Originally Posted by Steve Dallman View Post
Rather than just shoot willy-nilly, you should take a systematic troubleshooting approach.

If this was on my bench, I'd put a signal into it with the amp plugged into a speaker. I would have a second, bench amp on. If no signal was passing to the speakers of the PV, I'd plug a cable into the preamp out/power amp in jacks. If sound passes to the speaker, then the power amp in jack switching is funky.

If no signal passed, I'd run a cable from the preamp out to the bench amp (I use a small guitar practice amp) Is there sound there?

If so, I'd patch my signal into the power amp in jack to see if the power amp is working.

I use a CD or MP3 player for my signal source.

This is the probe I made for tracing signals through an amp.

http://www.fenderforum.com/userphoto...ml?recid=69384

I'd repeat all with the effects jacks.

If there were still no signal, I'd take the amp apart and start by first confirming the correct voltages at the correct points.

Then I'd again put a signal into the amp, and using a probe connected to my bench amp, grounded to the PV chassis, I'd follow the signal through the amp, from input jack to the speaker jack. Where it stops is the problem.
The first few tests (signal into preamp, signal out of effects loops) would be good for the OP to try.

After that, though, he needs to take it to a tech. B+ is 675 volts in this amp with enough current to be lethal. The OP doesn't need to be poking around inside the amp.
  #13  
Old 12-04-2013, 01:24 PM
Registered User
 
Join Date: Aug 2009
Location: New Zealand
^ He designs Peavey amps for a living, maybe even your one!

You do realise poking around inside a tube amp is exceedingly dangerous even when you know what you're doing? They store lethal voltages long after being switched off.
__________________
Team Trace Elliot #1, IWNBARMPB Prezident, Mediocre Bassist #399, Old Basstard #86, PBBBC #2
  #14  
Old 12-05-2013, 10:33 AM
Registered User
 
Join Date: Dec 2013
Quote:
Originally Posted by Downunderwonder View Post
^ He designs Peavey amps for a living, maybe even your one!

You do realise poking around inside a tube amp is exceedingly dangerous even when you know what you're doing? They store lethal voltages long after being switched off.
we weren't "poking" around. my dad use to work for alpine back in the late 70s to mid 80s and did car stereos for a good while. we were not going poking around inside the head like we're steve irwin
  #15  
Old 12-05-2013, 02:29 PM
Registered User
 
Join Date: Aug 2009
Location: New Zealand
Now you're really scaring me. Car audio has nothing in common with tube voltages. Did your Dad tuck one hand in his belt while probing? Gives you a fighting chance of surviving a 600v accident if the other hand isn't on the chassis.
__________________
Team Trace Elliot #1, IWNBARMPB Prezident, Mediocre Bassist #399, Old Basstard #86, PBBBC #2
  #16  
Old 12-05-2013, 02:53 PM
Registered User
 
Join Date: Oct 2002
Location: Nashville TN
This could be something as simple as a phase inverter tube that's not plugged in securely, but of course it could be something more serious. A qualified tech will use some basic troubleshooting logic to figure this out. Someone that's not familiar with tube amps can hurt themselves or the amp or both.

Where are you located? Perhaps someone on this forum is close to you and can help you out, either by looking at it themselves or recommending a good tech. If you were close to Nashville, for example, I could give it a quick look, I have all the schematics and am familiar with this amp since I have one.
  #17  
Old 12-05-2013, 03:04 PM
Registered User
 
Join Date: Sep 2011
Location: South Lake Tahoe, CA
Quote:
Originally Posted by Downunderwonder View Post
Now you're really scaring me. Car audio has nothing in common with tube voltages. Did your Dad tuck one hand in his belt while probing? Gives you a fighting chance of surviving a 600v accident if the other hand isn't on the chassis.
But big ass SS amps can have huge capacitors with big nasty amounts of current stored even after unplugging, so hopefully his dad did have some idea what he was dealing with.
__________________
Quote:
Originally Posted by IamJohn View Post
I heard my mom tell my dad she didn't want me listening to his Frank Zappa records... so I listened to his Frank Zappa records.
  #18  
Old 12-06-2013, 02:43 AM
Registered User

Uncompensated endorsing user: fEARful
 
Join Date: Sep 2011
Location: Groningen, The Netherlands
Quote:
Originally Posted by Major Softie View Post
But big ass SS amps can have huge capacitors with big nasty amounts of current stored even after unplugging, so hopefully his dad did have some idea what he was dealing with.
Let me make something clear: A capacitor does NOT store current! Storing current is impossible - it's like trying to store velocity.
A capacitor holds electric charge - you can say it stores energy. That'd be fine.
Furthermore (unlike stated before), Voltage is NEVER lethal! I have had 5million Volts in my hands and I still breathe quite regulary.

Please don't twist things, it gives electricians a migraine headache!

Still the bottom line is correct - do not poke around in a tube head without knowledge of what you are doing. It takes 12-24hours to be sure that all components are discharged.
__________________
FEARIUM IMPERIUM
https://soundcloud.com/feariumrock/dinner-1
  #19  
Old 12-06-2013, 02:22 PM
Registered User
 
Join Date: Dec 2013
Quote:
Originally Posted by Downunderwonder View Post
Now you're really scaring me. Car audio has nothing in common with tube voltages. Did your Dad tuck one hand in his belt while probing? Gives you a fighting chance of surviving a 600v accident if the other hand isn't on the chassis.
True car audio really doesn't but big stadium shows like Led Zeppelin he's wired up the speakers before. my dad understand voltages
  #20  
Old 12-06-2013, 02:26 PM
Registered User
 
Join Date: Dec 2013
Quote:
Originally Posted by vbchaos View Post
Let me make something clear: A capacitor does NOT store current! Storing current is impossible - it's like trying to store velocity.
A capacitor holds electric charge - you can say it stores energy. That'd be fine.
Furthermore (unlike stated before), Voltage is NEVER lethal! I have had 5million Volts in my hands and I still breathe quite regulary.

Please don't twist things, it gives electricians a migraine headache!

Still the bottom line is correct - do not poke around in a tube head without knowledge of what you are doing. It takes 12-24hours to be sure that all components are discharged.
well the only time we took apart it hadn't been plugged in, in well over a week
Reply


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

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

Visit TalkBass on Facebook   Download our iOS app   Download our Android app

All times are GMT -6. The time now is 11:13 PM.




2012 Talk Music Group Inc. All rights reserved.
Play guitar too? Visit TalkGuitar.com
Powered by vBulletin® Version 3.6.12
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.