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Post subject: Noise in Deluxe reverb reissue
Posted: Sun Feb 02, 2014 11:04 am
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Hello,

I have a Fender DRRI which I bought new 9 months ago. I will bring it back to the store, but I would appreciate if someone with the right experience could tell me what kind of technical issue are typical for this kind of noise.

I have just replaced the tubes. the normal channel is OK, it is only on the vibrato channel with the volume above 5-6. It is a kind of wobbling, echoing, chopping sound :?

If you would bother, please download a small sound file with this link;
[*]http://rapidshare.com/share/5BACDB635F03A6F5F669BA902F9FB77C[*]





Your help is appreciated

Regards
Sigmund㒧


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Post subject: Re: Noise in Deluxe reverb reissue
Posted: Sun Feb 02, 2014 11:47 am
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Rock Star
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sigmunds,

Welcome to the Forum! :D

Your link to a sound bite didn't work for me. But, by the description this sounds like a motorboating issue. This can be caused by many things. Coupling between the gain stage filter caps being number one issue. Did you buy the DRRI used? Any idea how old are the original filter caps?

Edit: I see you bought the amp new. Still, you may have defective new filter caps.

Lead dressing around the vibrato portion of the circuit and the 12AX7 that drives the vibrato can also be the problem.

Here are a few general solutions to a tremolo/vibrato induced noise problem:

This is from the great electronics guru R. G. Keen. For an astonishing amount of information about tube amps and guitar effects check out his website, geofex.com.

• Fiberboard contamination: Dust, dirt, and junk can let the LFO signal leak into the audio path. Vacuum the dust and dirt away, and if it still persists, remelt the wax top and bottom with a hair dryer.

• Solder blobs from eyelets touching insulating board: Sometimes excess solder drips out the bottom of an eyelet and can intermittently contact the insulating board, can cause ticking. Remelt the eyelets and examine the board underneath for any blobs dripped down.

• Funny ground on some SF Fenders; On one of the signal tubes, the cathode cap was placed on the tube socket, and wired to a ground lug on the vibrato cancel jack instead of across the resistor on the fiberboard. The vibrato shares this ground line, and can the vibrato current can cause audible ticking in the audio path. Rewire the cap to another ground or relocate it to the board.

• Poor Signal wire layout: signal wires run too close to vibrato leads can pick up the LFO signal. Move them around and see if the ticking goes away.

• Bad repair/replacement foot switch cable: the Fender foot switch cable is not two conductor; it's single conductor shielded, plus single conductor. The reverb wire is shielded, vibrato wire is not. This keeps vibrato out of reverb. If you retrofit with two conductor shielded, you get vibrato ticking onto reverb audio.

• Sharp tick in vibrato oscillator: On neon/LDR Fenders, on the neon bulb side of the module there is a 10M to one side of bulb, 100K to the bulb; from the 10M straight across the board is the gnd point of the LDR. Put a 0.02 cap from 10M/bulb to the ground point; this works by filtering the output of the oscillator.


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Post subject: Re: Noise in Deluxe reverb reissue
Posted: Sun Feb 02, 2014 11:59 am
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Location: Natural Bridge, Virginia
Before the OP rips apart and modifies his amp, he should make sure it is not simply trem tick that he is hearing (I can't get his link to work either). If it is, I doubt the fixes you referenced will work since I believe the latest DRRIs have some sort of integrated circuit that does the tremolo and not an LDR or trem roach. Arjay knows more about this than I do. In any case, the amp is brand new and should just be taken back to the dealer for warranty repair/replacement.

_________________
Bill

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Post subject: Re: Noise in Deluxe reverb reissue
Posted: Sun Feb 02, 2014 6:34 pm
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Bill,

Yeah, you are correct. Wish there was a simple fix for this issue. Whether a well-isolated board for the tremolo-vibrato circuit. Or a better layout-dressing of the offending portion of the main circuit.

Maybe, in these amps, it's better to forgo the onboard tremolo, for a stomp pedal. And just remove the offending portions by pulling the appropriate tube? :?: :?: :?:


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Post subject: Re: Noise in Deluxe reverb reissue
Posted: Sun Feb 02, 2014 7:40 pm
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this works, https://rapidshare.com/share/5BACDB635F ... 902F9FB77C


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Post subject: Re: Noise in Deluxe reverb reissue
Posted: Sun Feb 02, 2014 10:47 pm
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Link doesn't work without adding a bunch of software I really don't wish to have. Like 24/7 help and some oddball search engine.

Sorry.


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Post subject: Re: Noise in Deluxe reverb reissue
Posted: Sun Feb 02, 2014 11:11 pm
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Aspiring Musician
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BMW2002Ti wrote:
Link doesn't work without adding a bunch of software I really don't wish to have. Like 24/7 help and some oddball search engine.

Sorry.

I just clicked "to download" then "DRRI mp3" no software download, just an mp3 file onto the desktop


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Post subject: Re: Noise in Deluxe reverb reissue
Posted: Mon Feb 03, 2014 1:09 am
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Thanks for your replies,

Sorry for the downloading trouble through rapidshare. Any other suggestions for sharing files easy?

Reagarding the noise it doesn't seem to be related to the vibrato, it is still there when the vibrato is off..


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Post subject: Re: Noise in Deluxe reverb reissue
Posted: Tue Feb 04, 2014 1:18 am
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In lack of reply from the store (not surprised) I did open the amp to se if there were any visible defects, loose wires etc.. I carefully moved the wires connected to the tube sockets. I could not see any bad connections.

When I assembled the amp again and tried it the noise was gone..
Of course, when it disappears so easily it sure can appear again, but so far everything is fine.

Thoughts anyone?


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Post subject: Re: Noise in Deluxe reverb reissue
Posted: Tue Feb 04, 2014 4:21 am
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Nothing special to note. Maybe the gnomes fixed it overnight? :D

Let sleeping dogs lie and play the thing. Hope for the best.

Good luck! :mrgreen:


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