Rattling from Marshal Origin 20C valves or valve holders at certain frequencies
1

vote

Hello,

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!

Kind regards,

Ed

 

edited 09 Sep 2018 at 11:28 AM

Edward Arnold (1)

asked 09 Sep 2018 at 11:27 AM

Edward Arnold (1)
Hey Edward, I’ve just bought one & experience this to! From what I’ve seen on line a lot of people put rattles down to a faulty tube, but could be other issues, this video was insight full, check it out: https://m.youtube.com/watch?v=fWJJonZr4Ro

Also this video maybe the answer on tube rattle, seems to be a common problem that can be fixed with tube rings: https://m.youtube.com/watch?v=OQ_rdYbvfAo

Would be interested to know your out come, did you change the valves? Or taken it back? Or what you pinned it down to? Will probably try the rings myself. Other wise gorgeous sounding amp! Luvin it except for that one thing.
- Fonk Zilla 29 Sep 2018 at 03:41 PM
Hey, I sent the amp in for repair and return as it was under factory warranty. Haven't had it back yet, but it was almost certainly the EL34 tube - perhaps both. That video link you sent was interesting and I think confirms the diagnosis. However, he mentions that he swapped it out for a different tube, so I hope this isn't just a thing with most EL34s. To give further description of what I had, it was like you'd strum a chord in the right frequency range and the tube would oscillate as the chord died away, sounding a bit like a tambourine shaking. Glassy/metallic is a good description. Looking forward to getting the amp back, as it really does otherwise sound terrific. I've done a number of gigs with it now. It's always been miked up so I've not had it full tilt (mid wattage setting). Loving the Tilt control, and it just seems to 'bark' really nicely for mid-rocky stuff, with the Master being driven not just the front end. That said, I tip the front end over with a TubeScreamer a lot of the time, and it's great. I play a Pro series Strat through it as well as a Tele, and couldn't be happier. I think they got the boost just right as well - it's not an outrageous leap between off and on, more like a singlecoil-tap-back-to-humbucker-mode change I find. I'm currently back to gigging my (rather modified) Fender Blues Junior - I think they had their fair share of rattles in early models but nailed it down with sprung tube retainers for the series III. Fingers crossed there was just a bad batch of valves that worked their way into some early Origin examples and it's just a case of swapping them out. I'll let you know what happens when I get mine back.
Cheers, Ed
- Edward Arnold 29 Sep 2018 at 04:48 PM
Hey Ed, I haven’t gigged mine yet, just jamming with friends & enjoying the sound on my own, I just love the basic sound ...sounds great natural nice & even & the tilt control is helpful, I feel like it has refreshed my love for playing again...I just love what I’m hearing back & that’s direct without pedals, add a spark boost & im in cranked heaven! Haha. Hope you get yours back soon rattle free! Also came across this for rattle solution which I’m considering check it out it’s quite an interesting one: Guitar amp ultra sonic 35: https://herbiesaudiolab.com/collections/tube-dampers/products/guitar-amp-ultrasonic?variant=12645127913527

- Fonk Zilla 02 Oct 2018 at 02:24 PM
Hi Ed, I am having the same issue you described with my new Origin 20c (rattle) and I've tried 2 sets of brand new tubes for both pre-amp and power and basically went through the same troubleshooting process you described in your first post and the rattle is still unchanged. It does seem that the cabinet vibration is causing some kind of mechanical rattle. Did you ever get your issue resolved? Cheers, Fabio - Fabio Gelsomini 27 May 2021 at 06:38 PM
Answers: 1
0

votes

Hello Edward,

From your description it sounds as though you may have a noisy valve as this can manifest itself it the way you have described, so you may need to have the valve replaced. We have not had any issues or complaints from customers with the any rattling issues so it is not a known issue. 

 

Kind Regards

Marshall Support

answered 10 Sep 2018 at 01:02 PM

Marshall
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