Peavey 5150 failed me :(

Colo Springs E · December 3rd, 2005, 12:37 PM

Had a gig last night, and something happened with the 5150 head I picked up a couple months ago. Basically, the volume died on it. I was playing and the sound just died. I shut it on and off couple times, it came back on for a few songs, then did it again. Had to go the whole 3rd set direct and I sounded like @ss. When I was able to get sound out of the amp on a set break, I had the gain and vol nearly max'd and you could hear it, but it wasn't loud, ie my face was right in front of the amp and it was not that loud.

I put in new power tubes about a month ago and played a weekend with it then just fine (Halloween weekend). I've never swapped the preamp tubes. All tubes were glowing the same color (sort of orange), and when standby was flipped they had sort of a blueish hue to them.

Any thoughts? Power supply?

At this point really wish I'd kept my solid state Peavey XL which sounded just fine and never failed me. :(

Ringo · December 3rd, 2005, 01:28 PM

Sounds like you have some bad power tubes.
I did that with a vintage Deluxe Reverb, changed the tubes without biasing them, played around the house and had no problems, went to a gig and had similar problems, in my case it was also a bad "new" preamp tube.
I put back in my old tubes and had a tech check it, no issues.
FWIW Bob at Eurotubes has some interesting info on the 5150 amp, you might want to check it out.
Don't give up on it just yet.

Caper · December 3rd, 2005, 01:40 PM

Eric, I also had the same problem with a HRD, preamp tubes.

Colo Springs E · December 3rd, 2005, 02:36 PM

....I've gone ahead and put in new JJs in the preamp stage, and I'll have a backup head tonight in case the problem still isn't solved.

Thanks to both of you for input, wish me luck!

-E

RussBert · December 3rd, 2005, 04:42 PM

try plugging a jumper cord in the effects loop when it acts up...

make sure the impedance switch is not "in between" settings

Madmaestro · December 3rd, 2005, 05:16 PM

I had the same thing happen with my Classsic 30 just after I bought it and put in some new J.J.'s. The tubes blew during a high profile gig. That was the start of my classic 30 mods begining with a bias circuit. Had no problems since.

Colo Springs E · December 5th, 2005, 09:15 AM

...it was one/some of the preamp tubes--I changed them all out and it worked fine the second night.

Question: Ok, I can keep spare preamp tubes at a gig, but if something like this happened again, how would I know WHICH preamp tube was bad? They were all glowing the same at the gig?

e-merlin · December 5th, 2005, 07:04 PM

The best thing to do in that situation is to change 'em all and sort it out later.

Ringo · December 5th, 2005, 08:27 PM

Why not take all the preamp tubes you have to an amp tech who has a good tube tester and have them checked out, then you will know which ones are bad or weak, (throw them away so they don't get mixed in with the good ones)
And you get a schematic from Peavey for your amp - I think you can download one for free, a tech can tell you what tube does what.

RussBert · December 5th, 2005, 08:35 PM

Thanks to Roger Crimm of Peavey for this info...

Quote:

The 5150 actually uses the same tubes for both channels, and just throttles back the gain for clean/crunch.

If you look at the rear of the amp, the preamp tubes are on the right side. Looking from right to left, the tubes are arranged as follows:

#1 Input gain/2nd gain stage-shared by rhythm and lead
#2 is shared by the rhythm and lead channel
#3 & 4 additional gain, mostly for the lead channel
#4 effects loop
#5 phase splitter

Roger Crimm

telel6s · December 5th, 2005, 09:29 PM

Quote:

Ok, I can keep spare preamp tubes at a gig, but if something like this happened again, how would I know WHICH preamp tube was bad? They were all glowing the same at the gig?

That's when you hope you wore your best fitting jeans as you lean over the top of the amp with your good side to the audience while switching tubes in and out. Take my word for it.

But to try and help with your question, knowing what the tubes are doing can be helpful (see list from Peavy in previous post). For example, on my Super Reverb, when I plugged into the normal channel and got the same low volume ugly distortion as on the Vibrato channel, I could guess that the problem was not V1 or V2. There will always be a little hunt and peck if the tubes "look" OK, but you can probably narrow down the bad egg a little bit with some simple troubleshooting.

Caper · December 5th, 2005, 10:02 PM

Eric, usually you just swap one at a time until you find the culprit. Once you swap the 1st one if that hasn't solved your problem, take the new tube back out, replace the old one and move on to the next socket, and so on.

refin · December 5th, 2005, 10:11 PM

I had a BF Vibrolux Reverb that would fade in and out when I played it---traced it to a bad 12AT7 driver tube.

December 3rd, 2005, 12:37 PM	#1 (permalink)
Colo Springs E Poster Extraordinaire Join Date: Mar 2003 Location: Colorado Springs Posts: 5,279 5 Photos	Peavey 5150 failed me :( Had a gig last night, and something happened with the 5150 head I picked up a couple months ago. Basically, the volume died on it. I was playing and the sound just died. I shut it on and off couple times, it came back on for a few songs, then did it again. Had to go the whole 3rd set direct and I sounded like @ss. When I was able to get sound out of the amp on a set break, I had the gain and vol nearly max'd and you could hear it, but it wasn't loud, ie my face was right in front of the amp and it was not that loud. I put in new power tubes about a month ago and played a weekend with it then just fine (Halloween weekend). I've never swapped the preamp tubes. All tubes were glowing the same color (sort of orange), and when standby was flipped they had sort of a blueish hue to them. Any thoughts? Power supply? At this point really wish I'd kept my solid state Peavey XL which sounded just fine and never failed me. :( __________________ Think I'll pack it in and Buy a pickup Take it down to LA...

December 3rd, 2005, 01:28 PM	#2 (permalink)
Ringo Tele-Afflicted Join Date: Mar 2003 Location: Memphis TN Posts: 1,925	power tubes Sounds like you have some bad power tubes. I did that with a vintage Deluxe Reverb, changed the tubes without biasing them, played around the house and had no problems, went to a gig and had similar problems, in my case it was also a bad "new" preamp tube. I put back in my old tubes and had a tech check it, no issues. FWIW Bob at Eurotubes has some interesting info on the 5150 amp, you might want to check it out. Don't give up on it just yet.

December 3rd, 2005, 02:36 PM	#4 (permalink)
Colo Springs E Poster Extraordinaire Join Date: Mar 2003 Location: Colorado Springs Posts: 5,279 5 Photos	Thanks for input.... ....I've gone ahead and put in new JJs in the preamp stage, and I'll have a backup head tonight in case the problem still isn't solved. Thanks to both of you for input, wish me luck! -E __________________ Think I'll pack it in and Buy a pickup Take it down to LA...

December 3rd, 2005, 05:16 PM	#6 (permalink)
Madmaestro Tele-Meister Join Date: Mar 2003 Location: Lethbridge, AB, Canada Posts: 182	I had the same thing happen with my Classsic 30 just after I bought it and put in some new J.J.'s. The tubes blew during a high profile gig. That was the start of my classic 30 mods begining with a bias circuit. Had no problems since. __________________ The smoker you drink the player you get~Joe Walsh

December 5th, 2005, 09:15 AM	#7 (permalink)
Colo Springs E Poster Extraordinaire Join Date: Mar 2003 Location: Colorado Springs Posts: 5,279 5 Photos	Apparently..... ...it was one/some of the preamp tubes--I changed them all out and it worked fine the second night. Question: Ok, I can keep spare preamp tubes at a gig, but if something like this happened again, how would I know WHICH preamp tube was bad? They were all glowing the same at the gig? __________________ Think I'll pack it in and Buy a pickup Take it down to LA...

December 3rd, 2005, 01:40 PM	#3 (permalink)
Caper Friend of Leo's Join Date: Mar 2003 Posts: 2,169 7 Photos	Eric, I also had the same problem with a HRD, preamp tubes.

December 3rd, 2005, 04:42 PM	#5 (permalink)
RussBert Tele-Meister Join Date: May 2005 Location: Connecticut Posts: 321	try plugging a jumper cord in the effects loop when it acts up... make sure the impedance switch is not "in between" settings

December 5th, 2005, 08:27 PM	#9 (permalink)
Ringo Tele-Afflicted Join Date: Mar 2003 Location: Memphis TN Posts: 1,925	get your tubes tested? Why not take all the preamp tubes you have to an amp tech who has a good tube tester and have them checked out, then you will know which ones are bad or weak, (throw them away so they don't get mixed in with the good ones) And you get a schematic from Peavey for your amp - I think you can download one for free, a tech can tell you what tube does what.

December 5th, 2005, 10:02 PM	#12 (permalink)
Caper Friend of Leo's Join Date: Mar 2003 Posts: 2,169 7 Photos	Eric, usually you just swap one at a time until you find the culprit. Once you swap the 1st one if that hasn't solved your problem, take the new tube back out, replace the old one and move on to the next socket, and so on.

December 5th, 2005, 10:11 PM	#13 (permalink)
refin Friend of Leo's Join Date: Feb 2005 Location: Florida Panhandle Age: 52 Posts: 2,033	I had a BF Vibrolux Reverb that would fade in and out when I played it---traced it to a bad 12AT7 driver tube. __________________ "For You,Lord,are good,and ready to forgive,and abundant in mercy to all those who call upon You." Ps. 86:5 http://www.soundclick.com/bands/0/refin_music.htm MASTER VOLUME? WHAT'S A MASTER VOLUME?