DSL40 CR scratching sound and uneven mA at EL


Hello. I bought Marshall DSL40 CR from the local dealer (BON STUDIO- Greece) in 2019. Since the first time that I turned it on, I noticed that the amp makes aweird scratching soun when I'm using High Output. I 've contacted the dealer and he told me that it is normal and the amp is doing a format. I accepted this information and I was using the amp like this. I still have the scratcing sound for 10 minutes, every time that I'm using High Output.

A week ago I desided to check the tubes and the BIAS and I found 11mA at the first EL34 and 17,5mA at the second. I'm trying to adjust them and increase them at 35mA but the trimmer stops when I reach at 20mA. I'm trying to understand what is the problem. Is it normal?

Thank you in advance

asked 31 Aug 2022 at 06:40 PM

Jim Vasalas
It sounds like cell phone or Wi-Fi interference to me from the little I heard. If your amp is not near a wireless router try moving your phone away from the amp.
- aayush km 03 Sep 2022 at 06:01 AM
Thank you in advance

- casamittal casamittal 09 Sep 2022 at 10:46 AM
Answers: 1


Did you ever find out why your bias mV values are so low?  I'm having the same issue. He highest I can go is around 30 mV.  I've just created a new question in the forum about this issue.

answered 04 Aug 2023 at 01:46 PM

Chris Lawson
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