Santiago Alvarez (electronics engineer, JVM, YJM, AFD...)

[lofe]

Hi @santiall , I recently bought a used JVM 410HJS in excellent condition. I love the quality of this amp. One question I have is about the clean channel in green mode. My understanding is the channel volume pot for that channel does not apply for the green mode. When the gain is set around 12 o'clock, master volume at 3 o'clock, I noticed a light but still noticeable static noise in the green mode (changes in level with the gain setting), but as soon as I switch to orange mode (channel volume at 3), that base noise is gone at the same gain setting. If the channel volume is at 12 o'clock, their noise levels are similar. Not sure if this is normal/expected. The amp is connected to an 4x12 1960A.

 

[santiall]

Hi @santiall , I recently bought a used JVM 410HJS in excellent condition. I love the quality of this amp. One question I have is about the clean channel in green mode. My understanding is the channel volume pot for that channel does not apply for the green mode. When the gain is set around 12 o'clock, master volume at 3 o'clock, I noticed a light but still noticeable static noise in the green mode (changes in level with the gain setting), but as soon as I switch to orange mode (channel volume at 3), that base noise is gone at the same gain setting. If the channel volume is at 12 o'clock, their noise levels are similar. Not sure if this is normal/expected. The amp is connected to an 4x12 1960A.

Hi, I wouldn't worry too much. Since that mode doesn't have the volume active all th enoise that might be generated in the preamp will pass through withough being attenuated by the channel volume. Master at 3 is VERY loud too.
You may want to try a different input tube to see if that improves, if it bothers you of course.

 

[lofe]

Hi, I wouldn't worry too much. Since that mode doesn't have the volume active all th enoise that might be generated in the preamp will pass through withough being attenuated by the channel volume. Master at 3 is VERY loud too.
You may want to try a different input tube to see if that improves, if it bothers you of course.

Thank you so much for confirming. It doesn't bother me, just wanted to understand the different behavior between the modes. It's an amazing amp, really love it. I feel so fortunate to own one.

 

[santiall]

Thank you so much for confirming. It doesn't bother me, just wanted to understand the different behavior between the modes. It's an amazing amp, really love it. I feel so fortunate to own one.

all good then .
There are not so many HJS available out there,have fun!

 

[Flman]

Hi, first thing to suspect in any tube amp is the tubes.
Do you know if the noise depends on the volume/tone controls of one of the channels only?

It doesn’t. It only has static when a guitar cable is plugged into a jack. It doesn’t matter which of the 4 (2 clean & 2 reverb jacks). I’ve changed guitar cables and guitars. I’ve run straight from my guitar to the amp bypassing my pedal board. I’ve zeroed out tone and volume controls. I checked speaker connections and the jack from the speaker to the cabinet back. I’m not sure how to check the tubes to be sure they’re seated correctly. None seem loose to me. Still the same.

 

[santiall]

It doesn’t. It only has static when a guitar cable is plugged into a jack. It doesn’t matter which of the 4 (2 clean & 2 reverb jacks). I’ve changed guitar cables and guitars. I’ve run straight from my guitar to the amp bypassing my pedal board. I’ve zeroed out tone and volume controls. I checked speaker connections and the jack from the speaker to the cabinet back. I’m not sure how to check the tubes to be sure they’re seated correctly. None seem loose to me. Still the same.

hmm, now that's interesting. Everything would point to a faulty cable... having the cable connected to a guitar with the volume at zero should be the same as not having the cable connected to the input at all. It should be a shorcircuit from signal to ground.
If you want you can record a short video with your setup and send me the link. I'm curious to see what's actually happening