Fender Hot Rod Deluxe Issue!

[Muskratt]

I want to point out I am researching this for a friend that don't have the means to Internet.

The problem is when the amp is playing it is quiet and fairly clean but upon engaging the Channel One it gets the weird oscillating high frequency like a capacitor bleeding noise. I did a tap test of the tubes and non were microphonic and they were all lit normally. Nothing looked like it was burning hotter.
I was On my AMP and i was getting all this noise bleeding through the houses wall outlets.
I thought it was my new amp but it turned out it was his causing it. I tried different receptacles to try and isolate the noise first but it didn't matter, it was still there.

So when the channel One is engaged it gets this noise, when the OD channel is engaged it ramps up the noise worst. Turning up louder it is still there other then at higher volume tend to drown out the noise some.

Any Ideas..
Thx.

[Enzo]

Don't plug ANYTHING into the amp. Does teh amp make this noise all by itself? Or only when something is plugged into it?

And when making the noise, do ANY of the controls have ANY affect on the sound of it? DO volume/gain controls affect its volume? DO tone controls affect its tone?

[Muskratt]

No I don't recall it making noise.

Thx for getting back so soon Enzo,
The amp plays but I had my amp (Bugera) plugged up on a different wall with surge protectors I was getting a huge amount of noise like a His with a cycle humming of sort.

On the Fender amp it plays on clean pretty good but when the Channel One is engaged this loudish weird cycle hum with a highish pitch sound happens and if the OD channel is engaged with the Channel One it is even worst..
its a bit different sound though.
Sort of like this in this youtub vid..

[Jazz P Bass]

It could be:
Bad filter capacitors.
A bad output tube.
A broken connection "somewhere"

[Muskratt]

My friend don't know anything about the amps other then plug it is turn it on and go.. He did buy it used from a local dealer sometime back.
So anyways thats all I know to do without me taking it apart the next time I can get him over.
I know tubes can be lit but still be bad to.

THx..

[Chuck H]

You need to answer Enzo's post the next time you have the amp. Does the amp have these problems with nothing plugged into it? Do any of the controls (volume, tone controls, etc.) affect the problem? How? The information we have so far is not enough to begin a diagnosis. Even the video you linked only serves to confuse the matter since it is not the actual amp and these kinds of problems can be very different but sound similar.

Are you saying that your amp works fine, but when your friends amp is used at your house your amp also has noise problems?

[Muskratt]

Never mind.
I answered but not gonna be my issue..

Thx.

[Pedro Vecino]

Some HR Deluxe / Deville have problems of oscillation in the first tube. Even the manufacturer has changed its construction over time including some separated shielded lines on the grids.
The problem was enhanced by using certain tube models as the Chinese 12AX7. It is best to use a reference 12AX7WA Sovtek and rearrange those shielded cables looking for the best placement and fixing his final position. Even this may also need disconnect the shielded screens of the PCB and take them directly to the chassis ground (the screw next to the input jacks).
NOTE: Can not remember exactly if I disconnected completely or if just added up a new connection from the shield to the screw. If so, start with this last formula.
Regards

> I found a photo of these cables in a unit without problems:

[Muskratt]

Hey Awesome on the photo.

Sorry i didn't know you updated the post but now I know it is there. It is great that you guys are able to help others in this realm.

I will post as soon as i can try to get hold of the amp again.

Thx Thx..

[Muskratt]

Hey Guy's I just got the amp for a bit and i tried this. I grounded one side of the Grid Screen to the Chassis ground but it still does it.
I listened to my amp on the other wall outlet and it is a oscillating hum of sort. it was after 1:50 am here and can't really run a good test or i wake the wife. I tried to record the sound but the web cam refused to pick it up at all.
I have this Video and a snapshot of what i grounded below.

http://s754.photobucket.com/albums/x...ent=Video6.mp4



I am way tired and had allot on my plate today that I totally forgot he was coming by tonight with the amp. So I set up two guitars and got to look inside. He did switch the power tubes around but it still makes the noise.

Cheers!

[soundguruman]

I want to point out I am researching this for a friend that don't have the means to Internet.

The problem is when the amp is playing it is quiet and fairly clean but upon engaging the Channel One it gets the weird oscillating high frequency like a capacitor bleeding noise. I did a tap test of the tubes and non were microphonic and they were all lit normally. Nothing looked like it was burning hotter.
I was On my AMP and i was getting all this noise bleeding through the houses wall outlets.
I thought it was my new amp but it turned out it was his causing it. I tried different receptacles to try and isolate the noise first but it didn't matter, it was still there.

So when the channel One is engaged it gets this noise, when the OD channel is engaged it ramps up the noise worst. Turning up louder it is still there other then at higher volume tend to drown out the noise some.

Any Ideas..
Thx.

Generally, it's the resistors. Replace all the resistors in the signal path. The mechanical relay does not help either.
The FET transistors also go bad.
The carbon resistors used were kind of cheap and noisy. However it takes a lot of skill to rework the circuit board, and it's not a job for an inexperienced person.
Kind of silly just to guess, you need an O scope to troubleshoot it.

[Muskratt]

Well for the time being we swapped the preamp tubes and that cleared up the problem for now.

Will Post if there is any more issues.

Thank you everyone for you ideas and tech help.
Muskratt