Serious problem with my Windsor

[abaga129]

I'm hoping some of the experts on amps can help me out. I was at practice today and I noticed in the middle of a song that my volume had dropped considerable. When I checked after the song it was even lower. I singled it out as my amp. Does anyone know what could cause this? I can't use the amp like this.

 

[lanky noob]

sudden volume drop sounds like valves

 

[Sweetnothing]

Power tubes yes

 

[JeffTD]

95% of all problems with tube amps are related to the tubes. The other 5% is usually related to the user.

 

[abaga129]

Okay thanks guys. I'll check the power tubes then. I'm almost positive its the amp. I tried the guitar directly into the amp and still bad low volume even turned up to 13. I don't think it would be the cab.

 

[JeffTD]

Is there an FX loop? Plug your guitar straight into the FX return (be careful of volume, it there's no master volume it'll be incredibly loud) and see what happens. If the volume is still low and giving you the same type of issues albeit with a 'clean' tone, then you know it's the power amp.

You can (for all intents and purposes) think of the FX send as a "preamp out" and the FX return as a "poweramp in."

 

[abaga129]

Ah I wish I would have thought to do that before I brought the head home without a cab. I suppose I could do the reverse and check if the preamp isfunctioning okay and rule that out. I've changed preamp tubes before but never messed with power tubes. Is there a visible way to determine if one has gone bad? Or possibly a way to check with a volt meter? Thanks so much for the help guys

 

[bryan_kilco]

In my experience, tube failure won't create that much volume drop.

I've had this issue once at a gig. Mark IV just kept getting quiet then loud again then quiet. Tubes were good. Someone told me it could be master volume pot. But then the issue never occurred again.

 

[JeffTD]

^^Power tube failure can DEFINITELY create this kind of an effect.

 

[bryan_kilco]

Hmm. I'll take your word on it. When I had power tubes going bad for sure, I would get a lose in volume but it wasn't a huge amount.

OP: Hook your amp up, power it on and tap on the tubes with the eraser-end of a pencil. Usually if you have a bad tube, you'll hear a crackling sound.

 

[abaga129]

Alright i'll try that when i get a chance to plug it in. I did get a couple hours to tinker with it today and here is what I found. This tube seemed to look a little off. The metal plate at the top looked almost like it was oxidized or something. Here's a picture

I ended up breaking one of the tubes so I went ahead and ordered a new pair. Another thing that I noticed, which I will feel really stupid if this was the cause of the problem is that several weeks ago I tried doing a mod to the amp that I saw sloan had posted on another forum a few years back. I added a toggle switch between the old resistor and new resistor + capacitor. It worked fine and sounded good. After I had everything apart in the amp today, I noticed that the wire had detached from the resistor on one channel. Bad wiring on my part. Im not entirely sure that it was like that before i took everything apart though. So i guess i'll fix that tomorrow and wait for the tubes to come in and see if it's fixed.
On the bright side someone came up with a great idea to drill a new hole in the chassis so i could put the toggle switch in instead of it just hanging out the back of the amp haha.

 

[Sloan]

haha, omg my attempt to add a clean mode to the windsor. i never finished that junk. lol

 

[abaga129]

It works for me since I don't need to switch channels on the fly. I just have a little toggle switch in the back and then I can back off the pre amp gain. I'm glad I found your thread it was also a great learning experience for me.

 

[Sloan]

Very cool, I'm glad someone got something out of it. I would like to get a Windsor again in the future and continue messing with it. I think they are totally underrated...

 

[abaga129]

I completely agree. The price tag is nowhere near what this amp is worth. If it had another channel or two it would be amazing.