I've noticed that there is rattling/jangling coming from the amp (not the speaker) when playing notes between low A and C and their respective octaves above. It sounds like it is coming from the EL34 valves - is this due to the way that they are mounted without spring dampers? They have not gone microphonic as far as I can tell, and are otherwise performing as expected, so I feel this is more a mechanical issue with the chassis/mounting, or it's just an undesirable characteristic of the valves themselves. What I'd ideally like to know is, do all Origin 20Cs do this or is this the first anyone has heard about this?
I've removed every external variable there could be, moving the amp to another location and isolating it from floor vibrations in the studio. I've taken the 'amp' out of the cabinet so that I could lightly tap the valves, and check the screws around the supports are not loose. You can generate the rattle (or very similar) just by tapping lightly with the handle of a screwdriver, on both valves. This is what I was expecting if it was just physical vibrations from the speaker causing them to rattle in sypmathy. The rattling sound does not get amplified, so it's not in the audio path.
It's enough to be offputting when tracking/practicing in the studio unless pushing out really high volume so that you can only hear the guitar. I play fairly clean a lot of the time so it is more obvious under those conditions.
Would really appreciate some advice. If the answer is, "It's the same for all and there's not much that can be done..." then ok, I just need to know. That said, I spotted there was some sort of similar issue perhaps on Class 5 amps that a kit was developed for to resolve? I may have misunderstood though.
If there is any further mechanical troubleshooting to be done then please let me know. I wouldn't want to void the warranty status if possible. For what it's worth, I'm a systems and support engineer for a large format mixing console company, so I'm competent enough to poke around as required... just figured someone may have alreday solved this one before I carry on!
I recently bought a Marshall DSL20HR head and a Marshall 1936 Lead 2x12 cab.
The head has a cab emulator out, so I hooked it up to my audio interface and was playing through my pc monitors. I turned up the volume and gain on the ultra gain channel and a strange buzz/noise came from the head when I would strum a chord or pick a note.
I only noticed this because I had the level on my interface low as I was just testing the cab emulator out. I have alos tested this with the head not plugged into either my interface or the cab and still get a strange noise/buzz.
As this is my first valve head I'm not sure if this is just something that happens when you turn up the volume and gain - as the amp is being pushed harder, or if there is a fault with the head and I need to take it back to the shop I purchased it from.
I will link below some video of the problem. The first video sounds worse than it is as I put my phone directly on top of the head as I play. It's not the signal noise from the amp that I am worried about, it's the rattle when I strum chords or hit notes...
Any help would be greatly appreciated, I'm probably just over reacting, but it would be good to get some reassurance.