JVM410H and JVM410HJS FX Loop Differences

SunTzuBean

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Hi all,

I am toying around comparing the JVM410H and the JVM410HJS, and one of the differences I noticed was that the FX loop adds more noise to the same group of pedals in the HJS. In the H, the volume drops considerably, but that's to be expected, since there is no boost on the return. Even when adjusting the FX loop return level down to that of the volume drop of the JVM410H, there is considerably more noise from the HJS when idle. I know it's the FX loop because when I disengage the FX loop from the amp, the hissing white noise practically disappears. This is most annoying when the master volume is cranked up all the way, since you don't hear much hiss when the MV is cranked up all the way without the FX loop engaged, and then suddenly more noise is added when you engage the FX loop. This is most noticeable when on the clean channels of both amps.

I have noticed that the levels from the FX loop are different. One of my pedals has a little red light that indicates when the pedal is overloaded with signal at the input. The HJS has a lower FX loop volume compared to the regular H.

Could someone who is an expert chime in here? Why is the noise floor higher with the same set of pedals on the HJS compared to the regular H? Could it simply be because of the lower level at the FX loop, there is more amplification to return to unity at the return, thus the noise level is also amplified? Or maybe it's because there is added noise due to the solid state buffer at the send (which is necessary for the noise gate)? Is there anything I can do to reduce the noise of the HJS FX loop? Tube swapping perhaps?

Thanks for reading :)
 
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marshallmellowed

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Hi all,

I am toying around comparing the JVM410H and the JVM410HJS, and one of the differences I noticed was that the FX loop adds more noise to the same group of pedals in the HJS. In the H, the volume drops considerably, but that's to be expected, since there is no boost on the return. Even when adjusting the FX loop return level down to that of the volume drop of the JVM410H, there is considerably more noise from the HJS when idle. I know it's the FX loop because when I disengage the FX loop from the amp, the hissing white noise practically disappears. This is most annoying when the master volume is cranked up all the way, since you don't hear much hiss when the MV is cranked up all the way without the FX loop engaged, and then suddenly more noise is added when you engage the FX loop. This is most noticeable when on the clean channels of both amps.

I have noticed that the levels from the FX loop are different. One of my pedals has a little red light that indicates when the pedal is overloaded with signal at the input. The HJS has a lower FX loop volume compared to the regular H.

Could someone who is an expert chime in here? Why is the noise floor higher with the same set of pedals on the HJS compared to the regular H? Could it simply be because of the lower level at the FX loop, there is more amplification to return to unity at the return, thus the noise level is also amplified? Or maybe it's because there is added noise due to the solid state buffer at the send (which is necessary for the noise gate)? Is there anything I can do to reduce the noise of the HJS FX loop? Tube swapping perhaps?

Thanks for reading :)
Can't tell you why, but I can confirm that my HJS loop was also more prone to noise than my standard 410H. Don't have either amp any longer, as there were things about both that I did not like. For what I wanted from an amp, I'm much happier with the 2203x.
 

SunTzuBean

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Does it have both serial and parallel like the OG JVM?
It does! But this FX loop is passive AND line level, and I'm putting the FX loop through pedals. So it'll be clipping those poor little op-amps, which is never a pretty sound (except if it's called a Big Muff)
 

SunTzuBean

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Can't tell you why, but I can confirm that my HJS loop was also more prone to noise than my standard 410H. Don't have either amp any longer, as there were things about both that I did not like. For what I wanted from an amp, I'm much happier with the 2203x.
I plan on getting a 2203 one day... But the JVM gets close enough to the one time I tried out an 80's combo JCM in a guitar store in Nashville. The biggest thing for me compared to the original JVM crunch channel is that the 410HJS has a very similar amount of gain to the OG JCM800.

But it's actually kind of relieving to hear that your HJS also had a fairly noisy FX loop. That way it's more likely there is nothing wrong with the amp, that's just how it is.

What didn't you like about either amp?
 

El Dunco

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It does! But this FX loop is passive AND line level, and I'm putting the FX loop through pedals. So it'll be clipping those poor little op-amps, which is never a pretty sound (except if it's called a Big Muff)
Mine as an active/bypass switch on one FX loop and an adjustable pad on the other to prevent clipping. Maybe I’m just lucky but properly gain-staging between the channel volume and master, it’s really not very noisy at all plugging my guitar directly into the amp.

Have you also tried running a patch cable between the FX loop in/out when you’re not using effects? I hear that solves a lot of noise issues.
 

marshallmellowed

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I plan on getting a 2203 one day... But the JVM gets close enough to the one time I tried out an 80's combo JCM in a guitar store in Nashville. The biggest thing for me compared to the original JVM crunch channel is that the 410HJS has a very similar amount of gain to the OG JCM800.

But it's actually kind of relieving to hear that your HJS also had a fairly noisy FX loop. That way it's more likely there is nothing wrong with the amp, that's just how it is.

What didn't you like about either amp?
Standard JVM -
The Good (IMO) - Loved the clean channel of the standard JVM, Loop was quiet, and worked great for my purposes.

The Bad (IMO) - Too compressed, too much gain, required too much modding to get "close" to what I was after, but never quite there. The crunch channel sucked, useless to me.

HJS -
The good (IMO) - Loved the crunch channel, best feature of the amp (IMO). HJS had a more "quality" look and feel than the standard JVM. Independent channel noise gates were nice.

The Bad (IMO) - Lacked the pick attack of the standard JVM, Clean channel was dry and a bit lifeless, preferred the clean channel of the standard JVM. FX loop seemed noisy, compared to the standard JVM.
 
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SunTzuBean

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Standard JVM -
The Good (IMO) - Loved the clean channel of the standard JVM, Loop was quiet, and worked great for my purposes.

The Bad (IMO) - Too compressed, too much gain, required too much modding to get "close" to what I was after, but never quite there. The crunch channel sucked, useless to me.

HJS -
The good (IMO) - Loved the crunch channel, best feature of the amp (IMO). HJS had a more "quality" look and feel than the standard JVM. Independent channel noise gates were nice.

The Bad (IMO) - Lacked the pick attack of the standard JVM, Clean channel was dry and a bit lifeless, preferred the clean channel of the standard JVM. FX loop seemed noisy, compared to the standard JVM.
I practically share the same sentiments about both amps. I will say the crunch on the H is not terrible. It’s not bad at all, really! I just much prefer the HJS crunch.

The clean of the 410H is indeed sooo wonderful. It definitely pains me to be rid of it because it was such a nice pedal platform but the yellow clean on the HJS is pretty comparable to my modded SF Bassman. And overall, the clean modes are all more usable on the HJS over the other modes on the H.
 

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