Fender Deluxe Reverb 65 Reissue Crackling Distortion

[guitarspirit]

Hi folks,

i hope you are doing fine during these crazy pandemic times.

I need your help, concerning a bad crackling/distortion problem with my Fender 65 DRRI.
I added a sound file where you can hear some crackling when a chord is strummed, especially at the sustain part of the chord.

Settings are:

- Humbucker Guitar directly in Vibrato Channel 1
- Vol = 3
- Treble = 7
- Bass = 6
- Reverb/Vibrato off

The crackling/distortion occurs on all channels and with or without reverb/vibrato and also with another singlecoil pickup guitar.
There is no crackling when nothing is played. It's only the bad distortion when the strummed volume is high enough. So when strummed very gently the amp stays clean.
I recorded with an ox box, but it should not be the problem, my other amp is working just fine with it. I also hear the crackling straight thru the speaker without an ox.

So i suspect some tube(es) are making trouble, but i just recently (some months ago) had my power tubes professionally replaced and biased. I had the amp serviced and checked also.
So do you think this crackling/distortion can come from a failing preamp-tube or could it be something major?

My main problem is, i don't have much experience in trouble shooting these things and my amp-tech is unavailable during the lockdown.
So can you give me some advices how to trouble-shoot this and if it could be a major problem?
I need my amp to stay mentally healthy

Thanks a lot, stay save!

Cheers,
Sebastian

[Stevem]

I could not open your attachment to play it, but here is one thing to try out to start to narrow down on what the issue maybe.

I am thinking that one of your output tubes may have gone micophonic on you. To test this out tap on each output tube pretty hard with a finger nail, there should be no grumbling or cracking noises hear like what you posted if both tubes and there sockets they sit in are good.

[guitarspirit]

Thanks for your answer!

Here is a new link to the sound-file:
https://www.dropbox.com/s/1d23haln23apu ... n.mp3?dl=0

I made the taping test on all tubes, and there seems to be no issue.

[Stevem]

How many hours of play time do you have on this amp and where on the volume control does the amp have to be turned up to to get what I heard on your recording to take place?

[guitarspirit]

Hi thanks for your answer,

i bought the amp 4 years ago use, gigged and played regularly on it. The pre-owner played the amp also for some years. So difficult to say how many hours of play time. I would guess, plenty
But it always used to be in very good shape and worked fine, i had the amp serviced, checked and the power tubes replaced and biased professionally some months ago. Everything fine till recently.

Settings on the recording are:
- Humbucker Guitar directly in Vibrato Channel 1
- Vol = 3
- Treble = 7
- Bass = 6
- Reverb/Vibrato off

I tried rolling treble and/or bass off and the problem still exists. Below volume 2-3 the amp stays clean with no crackling.
So when the amp starts breaking up it makes these weird crackling distortion sounds.

Thanks for your help!

[pdf64]

Valves are a consumable, they can develop problems at any time, may provide anywhere from 5 seconds to 5 decades of good service.
Hence them being socket mounted, to make it easy for the user to check / replace them as necessary.
From that, the owner / user of a valve amp should have a spare of each valve type that their amp uses that they know to be good. Then when issues like yours's arise, swap in the appropriate spare to each socket in turn; if no improvement with the spare, take it out, put the one just taken out back in, and move on to the next socket.
As the issue is affecting both channels equally, you could probably save time by starting at V6 socket, as the issue is likely to be regarding the power amp / power supply, which is covered by V6-V9.
A useful tip is to buy your 6V6 in matched quads, then you'll have another pair that will work just the same as the first pair did at that bias setting.

Note that any other part may fail at any time too. The difference with the valves is that we know they will, the only unknown is when

[Stevem]

I would say that a good starting point since you have no real idea of how many hours are on the tubes would be to atleast get a new matched set of output tubes, and a new rectifier tube .

Your new rectifier tube should be a JJ electronics brand.

Having a volume control open to only 3 and having your issue would lead me to think that your preamp tubes may not be that bad.

[guitarspirit]

Thanks for your answers!

I ordered some new pair of matched power tubes, exactly the same ones that are already installed. So i don't have to re-bias the new tubes when installed, did i get that right?
I also ordered a spare for all the other tubes, so i will do the trial and error.

Thanks so far, i'll be back with my results...

Stay save!

[EVMode]

To me this is how these amps sounds when they breakup. I notice the same thing when playing alone and it drove me to adding a bright cap switch and new tubes. I found when playing with a band I don't even notice the crackle.

You should try another DRRI if possible just to make sure you're not fighting the natural sound of the amp breakup. It could be there is nothing wrong with your amp.

[pdf64]

...I ordered some new pair of matched power tubes, exactly the same ones that are already installed. So i don't have to re-bias the new tubes when installed, did i get that right?...

Did you check with the supplier that the new pair would bias the same as your existing pair? The pair you’ve just bought may be matched to each other, but unless the supplier has confirmed the above, the new pair are unlikely to be exactly matched to, perhaps not even be reasonably close to, the current pair. If so, it would be best fof their operation in the amp to be checked; may require adjustment to get the best results out of them.

[Stevem]

Please note that on any amp, let me say that again, on ANY amp that has enough low end / bass response to have a nice fat sound on the neck pickup at low volume ( below 3 or so on the volume pot) that once the amp is played loud enough to distort the output stage the bass pot needs to go way down even If using just the bridge pickup to maintain good sounding distortion and not just farting out taking place on the low notes!

[guitarspirit]

Hey folks I'm back with the news on the topic!

First, thanks for your answers, you helped me a lot! After trying out a lot of things I finally landed at something I like. And I learned a lot!

1. Yes the Amp fuzzez and crackles out a bit, thats the way it distorts. Which I don't particularly like, but when playing along to a backing track or a band, it doesn't seem to bother too much. Depends on my mood also.. sometimes I get very annoyed, sometimes I don't really recognize it. But I love this amp Thanks EVMode!
2. I changed the output tubes and the rectifier tube and got myself a biasing tool to measure the current flow. I noticed that one of the older tubes was lower than the other one. After swapping both it's fine now. I set the bias to about 22 (low). I think the crackling thing improved a bit due to that. Thanks pdf64!
3. The bass amount is a big thing, so when overdriving the amp, the bass makes everything ugly and seems to affect the crackling problem towards more crackle. I'm getting accustomed to a treble-boost in front of the amp at the moment, which improves the tone a lot in the direction of my taste. Furthermore I get a lot bigger range for using my tone-knobs on the guitar. So thats a great new discovery for me. Thanks Stevem!
4. I switched the V2 Tube to a low gain tube (12AY7). So the vibrato channel is louder and cleaner now, which I like. The crackling thing is also improved. Not quite shure if I keep it like that, but it's a very interesting finding. Do you have any more tricks and tipps like that for me to try out? I looked into the bright cap mod but I don't want to open the amp and die probably

So thanks and keep save and healthy in these crazy times!

Greetings,

Sebastian

PS: Sorry for some goofy english

[Stevem]

Good to hear!
You have made a lot of sonic progress in a short time.