Help! 5e3 Problems

Kuras

Hi

I have two problems with this amp.

1.I purchased this amp a few months ago and realised it goes crazy when I play a C# on the D or G string. It happens when I use the neck pickup on any guitar (I checked it with single coils and humbuckers and the result was the same). It almost sounds like a horn and it sustains endlessly (but not like Parisienne Walkways, unfortunately).

https://www.youtube.com/watch?v=nLLD3zWmK2w

Would anyone be able to tell me what the problem is? I have a Cellestion Blue fitted so could it have burned out? It sounds fine apart from that note.

2. The bright channel has some crackling and hissing going on. The noise happens with or without a guitar plugged into it.

https://www.youtube.com/watch?v=0ad3scBGgoA

 It does not seem to happen through the normal channel and does not happen when the bright channel volume is turned off. Am I safe in assuming it's the bright channel 12ax7? Is there a way one can tell valve is faulty without replacing them all?

Thanks

ICBM

1 is probably a microphonic power valve, although it’s possible but less likely it could be a preamp valve.

You can probably find out, if you get it to make the noise, then gently grip one of the power valves with a glove or cloth - if the noise stops, it’s that valve. If not, try the other one. If that identifies it, replace both power valves with a new pair and keep the non-microphonic one as a spare.

It is just possible it’s the speaker, if the voice coil has a loose winding, but not as likely as a valve problem.

2 is probably the first preamp valve (directly under the input jacks), which is the gain stage for both channels, but each channel only uses half the valve so only one half has gone bad. You can easily test this if you swap the preamp valves round - if the problem goes away, or is now (but probably quieter - the second valve is for both channels, but later in the gain path) on both channels, it’s that.

It could also be a non-valve fault - probably the plate resistor for that channel - in which case you will need a tech, but try the valves first.

Does that help?

Kuras

Thanks so much @ICBM. I will give this a go

fretfinder

Is this the TAD one you recently did a glowing NAD post about? That’s a shame if it’s now gone tits up. Is there no warranty from the shop you bought it from?

Kuras

Unfortunately so. I bought it from a small independent guitar shop in Frome so I hope to replace valves rather than go back there

Kuras

An update
Gently grabbing the power valves didn't change the noise in video 1 but I will have a go at swapping them with my Deluxe Reverb's next week. Fingers crossed it isn't that expensive speaker Celestion Blue voice coil!

 Changing the first pre amp valve got rid of the crackling and hissing demonstrated in video 2 so thank you @ICBM ;

57Deluxe

Tweed Deluxes traditionally have issues with buzzing baffles...

john_r

If none of the other things proves to be the problem could be the upper back panel rattling against the chassis. Take the panel off, if the problem goes away you should be able to loosen the chassis bolts and edge it forward slightly to prevent it.

Kuras

Alas, it was the speaker after all.

I'm taking it to a tech see what the problem could be, fingers crossed I can get it working again without spending a tonne of money cause I really enjoyed the Blue/5e3 combo.

I now have a Weber 12f150 in the 5e3, sounds nice, especially with a Les Paul but I reckon the Blue is more of what I am looking for tone wise. I have a 74 Deluxe Reverb so the Blue in the 5e3 moved it away from the DR sonic space are gives it some Britishness!

I do have a spare Blue but it is 16 ohms, I am assuming I am not able to use that cause of the homage mismatch?

ICBM

Kuras said:

I do have a spare Blue but it is 16 ohms, I am assuming I am not able to use that cause of the homage mismatch?

It’s not ideal, although it will reduce the power which may make it less likely to get blown again. Or you could connect a load resistor in parallel with it to make the amp see 8 ohms, and further reduce the power going to the speaker.

Personally I would probably fit a higher-rated speaker.