*FIXED* My Peavey 6505 is raising and dropping in volume

[Deleted member 10619]

At first this was subtle and only happened during extended playing sessions.

I thought it was just the lead post gain being too sensitive and it being caught in between volume settings, but after multiple tests I've concluded that this is a real problem and I'm very worried...

The amp is now dropping volume and raising volume every 3 to 5 mins and it's getting progressively worse. The raise in volume is so sudden at times that it sounds like a very loud deafening *POP*

It's been impossible to track with my amp at this point...

I've read about this problem online but there isn't a real clear-cut answer.

Before I take it to a tech, what are some DIY things you might suggest I do prior?

Not sure if this might be related or not but the amp has a "choke" installed.

Things I've done already:

- swapped guitars and cables
- tried different speakers
- tried other amps at my place
- tried the 6505 at another place
- tried cleaning the FX loops contacts
- connected a cable in the fx loop

(And yes, for those wondering, this is the infamous "mint" 6505 I made some fuzz about on my other thread)

 

[Zachman]

At first this was subtle and only happened during extended playing sessions.

I thought it was just the lead post gain being too sensitive and it being caught in between volume settings, but after multiple tests I've concluded that this is a real problem and I'm very worried...

The amp is now dropping volume and raising volume every 3 to 5 mins and it's getting progressively worse. The raise in volume is so sudden at times that it sounds like a very loud deafening *POP*

It's been impossible to track with my amp at this point...

I've read about this problem online but there isn't a real clear-cut answer.

Before I take it to a tech, what are some DIY things you might suggest I do prior?

Not sure if this might be related or not but the amp has a "choke" installed.

Things I've done already:

- swapped guitars and cables
- tried different speakers
- tried other amps at my place
- tried the 6505 at another place
- tried cleaning the FX loops contacts
- connected a cable in the fx loop

(And yes, for those wondering, this is the infamous "mint" 6505 I made some fuzz about on my other thread)

Clean the molex connectors on the board

 

[Deleted member 10619]

At first this was subtle and only happened during extended playing sessions.

I thought it was just the lead post gain being too sensitive and it being caught in between volume settings, but after multiple tests I've concluded that this is a real problem and I'm very worried...

The amp is now dropping volume and raising volume every 3 to 5 mins and it's getting progressively worse. The raise in volume is so sudden at times that it sounds like a very loud deafening *POP*

It's been impossible to track with my amp at this point...

I've read about this problem online but there isn't a real clear-cut answer.

Before I take it to a tech, what are some DIY things you might suggest I do prior?

Not sure if this might be related or not but the amp has a "choke" installed.

Things I've done already:

- swapped guitars and cables
- tried different speakers
- tried other amps at my place
- tried the 6505 at another place
- tried cleaning the FX loops contacts
- connected a cable in the fx loop

(And yes, for those wondering, this is the infamous "mint" 6505 I made some fuzz about on my other thread)

Clean the molex connectors on the board

Like this guy?

https://youtu.be/Ke1Whqzw13Q

 

[strungout82]

Hello. I would suggest to clean the preamp and poweramp sockets and tighten the clamps in sockets to make sure that the tubes are seated properly with good connections. If this does not solve the problem, then replace the preamp tubes one by one. Or switch the powertubes (6L6) between your other amps and this amp. Or you can plug your guitar directly into FX loop return and play a little to find if the problem is isolated within the poweramp.

 

[Deleted member 10619]

Thank you guys.

I went ahead and cracked the head open and cleaned every contact, including the molex connectors on the board. I also cleaned the pre and power tube sockets. All of this done using CRC 5103 Electronic Cleaner (quick dry).

I'm still experiencing the same issue... But hey, at least my amp is super clean inside out!

I connected the guitar directly to its FX loop return and it did give me a different perspective of what might be going on.

I have the impression that "dirty" power might be at play or that one of the preamp tubes is faulty.

I'll run some tests tomorrow and report back.

If anybody else has different DIY solutions please let me know.

Thanks everybody!

 

[strungout82]

You can connect the preamp out or FX send to your DAW or slave it to another amp FX return to isolate the problem to the preamp section. And when you plug your guitar straight into the fx return, then what happens? Do you get the volume drops? When I had bad power tube in my engl poweramp I have experienced volume drops too.

 

[skullfxr]

I would replace the PI and power tubes and see if it changes. I have had failing power tubes do dumb stuff. Have you cleaned the pots?

This has already been covered, but every time I get a new to me amp, I...

Clean the tube soxkets
Clean the jacks
Clean the pots
Tighten the socket pins
Clean the AC plugin
Check and clean all internal connections (especially molex)
And generally replace the PI tube.


I am a little bit of an odd type with (legit) OCD, so I do more than the average person, but I do this on every new to me amp, regardless of condition.

I have recently been replacing the PI with NOS/VOS GE or JAN tubes and have found that the amp buzz/hiss is quieter than new production atuff. It works so good for me, I have not been using my decimators as much.

I also run power conditioners on every amp that I have,despite having generally clean power.

 

[maddnotez]

You have a bad preamp tube.

 

[XSSIVE]

I had that same problem with a Peavey Ultra Plus many years ago. It was the tubes. Popped in a fresh set and it was all good again.

 

[DragonCrestPC]

I would figure that's a pre-amp tube issue.

 

[Wizard of Ozz]

Preamp tubes. Replace them. IIRC from the pics you posted, the compartment that holds the preamp tubes took a hit in shipping and likely damaged one or more of the preamp tubes and or sockets.

If that doesn’t help, swap out the power tubes next.

 

[Kordoba]

I've been playing PVs since the mid 1980s and have had this problem numerous times. Each time it's been one or a combination of the folowing:

Dirty/corroded FX loop jacks (I know you checked that out).

Cracked solder joints, but as the amp warms up the volume fluctuations may go away then return when the amp cools off and is fired up again.

Bad power and/or preamp tubes.

 

[Deleted member 10619]

Thanks everybody.

After all the troubleshooting it's all pointing to the preamp tubes.

I'll be receiving a new set by tomorrow and I'll report back.

 

[maddnotez]

Thanks everybody.

After all the troubleshooting it's all pointing to the preamp tubes.

I'll be receiving a new set by tomorrow and I'll report back.

Careful, even a brand new set can have a bad tube it can be a serious hassle. unless you have a few tubes that you know 100% are good.

 

[napalmdeath]

You have a bad preamp tube.

Yep, yep, yep..

 

[Deleted member 10619]

Update

I bought a full kit of fresh power and preamp tubes.

Good news is that my old tubes are OK.

Bad news is... well yeah... it doesn't work.

I'll have to call a tech.

Not going to shy away this time to call out Mark for what he truly is. It's laughable at this point that I got truly suckered into buying a lemon.

For anybody that missed my initial recap:

The amp was working fine when I got it and ran some short tests on it (5 to 8 min jams). I did notice a minor "volume issue" first hand but thought it could've been just anything at that moment. I didn't nitpick or call out Mark on it because I liked the sound I was getting when I tested the amp. I got too distracted with all the "mint drama" conversation surrounding the amp. When the dust settled and it came time to truly track with the amp (while having a paying client tracking guitar parts) it was just too noticeable for me not to worry. Now it is so bad that my ear got tinnitus from the loud *POP* it just made a couple of minutes ago (still ringing as I write this). And for the record I run a fairly expensive home studio setup that offers power conditioning and has zero ground issues. My other tube amps and speakers DO NOT behave this way at all.

To make things worse, now I have reason to believe that Mark might've packed in a "free" footswitch because the footswitching is faulty and delayed on the original Peavey footswitch. I'm not even going to bother trying the "free" one he added as a bonus.

But yeah Mark is an "outstanding" guy, so go figure.

Real problems so far:

- Got a "mint" amp with a sunken chassis and bent preamp tube cover. Not damaged in shipping.
- Footswitching doesn't work properly. Faulty, delayed, scratchy.
- Amp has a horrible volume oscillation defect that does not come from tubes. I cleaned the amp in its entirety (all contact points and molex connections). Bypassed the fx loop. Bypassed the entire preamp section. Nothing inside looked burnt or incorrectly soldered.

Money I've spent so far restoring the amp:

- Amp came with no front grill. I know this is a non-issue (my fault), but I bought the amp thinking this would be included, so extra money I wasn't intending on spending. So far I've spent $25 on the wooden grill (thanks to a Rig-Talk member). $18 on the 6505 badge (new from eBay) and $10 on the Peavey badge (thanks to the 5150/6505 Facebook group). Just missing the "made in USA" badge.
- Bought new tubes for $115. It is always good to have extra tubes, but still an unforeseen immediate expense.
- Had to buy contact cleaning supplies (again, not bad to have, but still, never had to really use them on any of my other amps). Add another $20.

I've spent close to $190 dollars on an amp that was supposedly "mint". So now let's add a tech bill on top of this. Having spent so much time and resources with all this nonsense and not tracking with the amp I was supposed to be tracking with 2 weeks ago is excruciatingly tedious.

Will Mark pay my amp tech bill? I don't think so. Not after I read his ridiculous accusation of me grabbing a mallet and busting my "mint" amp.

This sucks big time...

Here is a video I just did a couple of minutes ago showcasing the problem:

I'll report back after the tech hands me a bill.

 

[311splawndude]

Sucks all the way around. Not sure and I'm certainly not qualified to diagnose anything - especially over the internet. So again, not taking sides here. So there is volume swells and popping? Like at 1:45? And this happened before the new tubes? And your video has the new tubes in it? And you sprayed the tube pins and worked the tube in and out and not sprayed contact cleaner in the sockets? And we are sure non of this damage happened during shipping? Also, TBH, the cost of new tubes, contact cleaner, faceplate parts, is not really a thing.

If I had to guess, I'd say there is a loose connection/cold solder joint somewhere - possibly in the power section. If you are comfy with being inside a live amp (dangerous) you could tap around with a chop stick but safe thing to do is send it to a tech - which it appears you are doing.

 

[skullfxr]

Sucks all the way around. Not sure and I'm certainly not qualified to diagnose anything - especially over the internet. So again, not taking sides here. So there is volume swells and popping? Like at 1:45? And this happened before the new tubes? And your video has the new tubes in it? And you sprayed the tube pins and worked the tube in and out and not sprayed contact cleaner in the sockets? And we are sure non of this damage happened during shipping? Also, TBH, the cost of new tubes, contact cleaner, faceplate parts, is not really a thing.

If I had to guess, I'd say there is a loose connection/cold solder joint somewhere - possibly in the power section. If you are comfy with being inside a live amp (dangerous) you could tap around with a chop stick but safe thing to do is send it to a tech - which it appears you are doing.

I gotta agree on that. Not taking sides either. Personally whatever I buy a new to me amp, I plan on new tubes.

I'm this case if it happened with the old tubes am still happens with the new tubes, they weren't faulty. They weren't a problem. Save them for down the road.

Personally when I get a new amp prior to affirming the deal and/or leaving feedback, I go through it thoroughly. You have had the amp for a while. You should have identified the problem sooner.

 

[panhead]

At first this was subtle and only happened during extended playing sessions.

I thought it was just the lead post gain being too sensitive and it being caught in between volume settings, but after multiple tests I've concluded that this is a real problem and I'm very worried...

The amp is now dropping volume and raising volume every 3 to 5 mins and it's getting progressively worse. The raise in volume is so sudden at times that it sounds like a very loud deafening *POP*

It's been impossible to track with my amp at this point...

I've read about this problem online but there isn't a real clear-cut answer.

Before I take it to a tech, what are some DIY things you might suggest I do prior?

Not sure if this might be related or not but the amp has a "choke" installed.

Things I've done already:

- swapped guitars and cables
- tried different speakers
- tried other amps at my place
- tried the 6505 at another place
- tried cleaning the FX loops contacts
- connected a cable in the fx loop

(And yes, for those wondering, this is the infamous "mint" 6505 I made some fuzz about on my other thread)

Who installed the choke would be my first thought. Stock those amps are pretty indestructible. Years ago I had a 5150 fall about 5 feet on to concrete and the thing still worked fine.

 

[skullfxr]

Start a thread in the tech subforum.