Jvm 410h Mods (variable Choke With Rotary Switch, Noise Reduction)

[traitorseyes]

I love my JVM 410H but I hate the noise! I haven't had a chance to play it band levels but I keep the gain at 9:30 for both OD channels using the red modes and it's still quite noisy compared to my Mesa TC-100 at the same volume. I'd rather avoid using a gate as I don't have any space left on my pedalboard.

Researching available mods (such a shame jvmforum is down), some have claimed that adding a choke has helped with the noise. I do like how the amp stock sounds, so rather than committing to a single choke, I purchased the Mercury Magnetics MultiChoke to mess around and see what setting I'll prefer.

I also purchased a noise reduction mod kit on ebay. I can't post links but you can search it by entering "Marshall JVM410 Mod Kit".

It offers the following:

-Full Noise Reduction, making every channel almost silent to the touch.
-Gain Reduction, Reducing the oversaturated gain and allowing the gain pot to be fully useable.
-Increased Headroom, Reducing the overly compressed tone through out all the High gain modes.
-Volume Rebalance, evening out the volume for the clean/crunch "Green/Orange" modes
-Increased Clarity, giving every channel a more... "HiFi Tone"
-Tight Bass Structure for all high gain Red-modes in the amp

I'll have this kit installed along with the choke. Knowing that I do like the stock sound, I'd like to add a rotary switch that will allow me to go between the various choke settings and even the stock R106 resistor. I am not familiar with rotary switches, especially for amp modifications. Looking for any recommendations/advice!

 

[ampmadscientist]

I love my JVM 410H but I hate the noise! I haven't had a chance to play it band levels but I keep the gain at 9:30 for both OD channels using the red modes and it's still quite noisy compared to my Mesa TC-100 at the same volume. I'd rather avoid using a gate as I don't have any space left on my pedalboard.

Researching available mods (such a shame jvmforum is down), some have claimed that adding a choke has helped with the noise. I do like how the amp stock sounds, so rather than committing to a single choke, I purchased the Mercury Magnetics MultiChoke to mess around and see what setting I'll prefer.

I also purchased a noise reduction mod kit on ebay. I can't post links but you can search it by entering "Marshall JVM410 Mod Kit".

It offers the following:

-Full Noise Reduction, making every channel almost silent to the touch.
-Gain Reduction, Reducing the oversaturated gain and allowing the gain pot to be fully useable.
-Increased Headroom, Reducing the overly compressed tone through out all the High gain modes.
-Volume Rebalance, evening out the volume for the clean/crunch "Green/Orange" modes
-Increased Clarity, giving every channel a more... "HiFi Tone"
-Tight Bass Structure for all high gain Red-modes in the amp

I'll have this kit installed along with the choke. Knowing that I do like the stock sound, I'd like to add a rotary switch that will allow me to go between the various choke settings and even the stock R106 resistor. I am not familiar with rotary switches, especially for amp modifications. Looking for any recommendations/advice!

Noise in what way?
Low frequency hum?
Buzzing from filament?
Hiss?

There is really only 1 choke value which gives maximum attenuation to power supply hum.
There is no need to make it "switchable," or adjustable.

Your frequency of noise attenuation is a combination of choke and capacitor, it's an LC circuit.
https://www.ampbooks.com/mobile/amplifier-calculators/LC-ripple-filter/


Adding the correct choke will definitely help the hum in the power supply (eliminates hum).
That's what a choke is for, power supply low frequency hum.

Another part of your hum/buzzing is filament noise.

However the choke does nothing for hiss, microphonics, oscillation, ringing, etc...it's just for low frequency noise (low frequency hum).
And the choke does make the output cleaner...but it does not increase headroom.

 

[RickyLee]

I love my JVM 410H but I hate the noise! I haven't had a chance to play it band levels but I keep the gain at 9:30 for both OD channels using the red modes and it's still quite noisy compared to my Mesa TC-100 at the same volume. I'd rather avoid using a gate as I don't have any space left on my pedalboard.

Researching available mods (such a shame jvmforum is down), some have claimed that adding a choke has helped with the noise. I do like how the amp stock sounds, so rather than committing to a single choke, I purchased the Mercury Magnetics MultiChoke to mess around and see what setting I'll prefer.

I also purchased a noise reduction mod kit on ebay. I can't post links but you can search it by entering "Marshall JVM410 Mod Kit".

It offers the following:

-Full Noise Reduction, making every channel almost silent to the touch.
-Gain Reduction, Reducing the oversaturated gain and allowing the gain pot to be fully useable.
-Increased Headroom, Reducing the overly compressed tone through out all the High gain modes.
-Volume Rebalance, evening out the volume for the clean/crunch "Green/Orange" modes
-Increased Clarity, giving every channel a more... "HiFi Tone"
-Tight Bass Structure for all high gain Red-modes in the amp

I'll have this kit installed along with the choke. Knowing that I do like the stock sound, I'd like to add a rotary switch that will allow me to go between the various choke settings and even the stock R106 resistor. I am not familiar with rotary switches, especially for amp modifications. Looking for any recommendations/advice!

Welcome to the Fabulous Marshall Forum!

I am fairly new to the JVM club myself. I found out just like yourself and so many others, that the original JVM 410H is quite gainy and sensitive. The hiss on the OD channels is normal, in relation to the design of this amp and its extreme sensitivity/high gain. I did a minor mod like so many to decrease it a bit as well. So I am very curious to hear how this works out for you.

I am somewhat confused on that companies claim that they will make every channel almost silent to the touch.

Keep us posted on your progress.

 

[traitorseyes]

Noise in what way?
Low frequency hum?
Buzzing from filament?
Hiss?

There is really only 1 choke value which gives maximum attenuation to power supply hum.
There is no need to make it "switchable," or adjustable.


Adding the correct choke will definitely help the hum in the power supply (eliminates hum).
That's what a choke is for, power supply low frequency hum.

Another part of your hum/buzzing is filament noise.

However the choke does nothing for hiss, microphonics, oscillation, ringing, etc...it's just for low frequency noise (low frequency hum).
And the choke does make the output cleaner...but it does not increase headroom.

Thanks for that info! I wanna say it's hiss. It'd be nice if it were just a tad less noisy. The real test is when I can crank it up to actual band performance levels.

I should've mentioned that I'm adding the rotary switch since I've been told by Mercury Magnetics that a higher choke rating gives you a more softer feel and response vs a lower rating for a tighter, faster response, so I'd like to play around with that as I do prefer a modern sound.

Welcome to the Fabulous Marshall Forum!

I am fairly new to the JVM club myself. I found out just like yourself and so many others, that the original JVM 410H is quite gainy and sensitive. The hiss on the OD channels is normal, in relation to the design of this amp and its extreme sensitivity/high gain. I did a minor mod like so many to decrease it a bit as well. So I am very curious to hear how this works out for you.

I am somewhat confused on that companies claim that they will make every channel almost silent to the touch.

Keep us posted on your progress.

Thanks for the welcome! It took a long time for me to realize I'm a Marshall kind of guy after going through so many different amps and modelers. I love how beastly this thing sounds and that it's operating smoothly as this particular head was made back in 2007.

Once I narrow down a switch, I'll move forward with these mods!

 

[ampmadscientist]

The

Thanks for that info! I wanna say it's hiss. It'd be nice if it were just a tad less noisy. The real test is when I can crank it up to actual band performance levels.

I should've mentioned that I'm adding the rotary switch since I've been told by Mercury Magnetics that a higher choke rating gives you a more softer feel and response vs a lower rating for a tighter, faster response, so I'd like to play around with that as I do prefer a modern sound.



Thanks for the welcome! It took a long time for me to realize I'm a Marshall kind of guy after going through so many different amps and modelers. I love how beastly this thing sounds and that it's operating smoothly as this particular head was made back in 2007.

Once I narrow down a switch, I'll move forward with these mods!

Choke won't do anything for the Hiss.
The choke is for power supply low frequency hum.
Switching between different chokes won't produce any noticeable change....so I think you are doing that for nothing.
People who sell chokes and transformers have been using a lot of hype to sell products...and people who install these products frequently say it makes no difference.

Yes I upgraded a choke...but for hum reduction. I didn't even believe that it would produce any kind of improvement otherwise.

 

[RickyLee]

AmpMad is not pulling your leg on the choke info. But then I do know many people who have said they liked and heard a noticeable increase in a few areas, like punch, clarity, low end response and less hum. We all hear things differently of course. Maybe there is a slight placebo affect as well?

Many years ago, I hooked up a switch on my SL-X and compared the stock resistor, 3H & 10H chokes. Honestly, I did not hear what others have claimed. I would say maybe a touch more low end clarity/focus when cranked extremely loud. I ended up leaving the 10H choke in it. On my TSL100, that same 10H choke did not impress me as much and I went with a 3H.

As for the JVM, I have read that the designer Santiago, designed this amp so that swapping in a choke would not not net as much audible change. I do not know what that would entail, as the only thing I see on the schem from the more traditional Marshall power supply specs is that the JVM has a high filtering value at the screens node. And then this amp also has an elevated center tap on the heaters and the first 12AX7 runs 12VDC. That right there is probably why this amp does not have much noise in hum. The hiss will not be improved by adding a choke as AmpMad mentioned.

 

[Australian]

I love my JVM 410H but I hate the noise! I haven't had a chance to play it band levels but I keep the gain at 9:30 for both OD channels using the red modes and it's still quite noisy compared to my Mesa TC-100 at the same volume. I'd rather avoid using a gate as I don't have any space left on my pedalboard.

Researching available mods (such a shame jvmforum is down), some have claimed that adding a choke has helped with the noise. I do like how the amp stock sounds, so rather than committing to a single choke, I purchased the Mercury Magnetics MultiChoke to mess around and see what setting I'll prefer.

I also purchased a noise reduction mod kit on ebay. I can't post links but you can search it by entering "Marshall JVM410 Mod Kit".

It offers the following:

-Full Noise Reduction, making every channel almost silent to the touch.
-Gain Reduction, Reducing the oversaturated gain and allowing the gain pot to be fully useable.
-Increased Headroom, Reducing the overly compressed tone through out all the High gain modes.
-Volume Rebalance, evening out the volume for the clean/crunch "Green/Orange" modes
-Increased Clarity, giving every channel a more... "HiFi Tone"
-Tight Bass Structure for all high gain Red-modes in the amp

I'll have this kit installed along with the choke. Knowing that I do like the stock sound, I'd like to add a rotary switch that will allow me to go between the various choke settings and even the stock R106 resistor. I am not familiar with rotary switches, especially for amp modifications. Looking for any recommendations/advice!

The JVM410 has been superseded. At one point I owned 3 JVM's sold all of them and now am planning on buying the JVMJS.
You're going to screw around with mods and still not eliminate those JVM bugbears that you lose sleep over. The best advice I can give you is to sell it and buy a JVMJS.

 

[RickyLee]

The JVM410 has been superseded. At one point I owned 3 JVM's sold all of them and now am planning on buying the JVMJS.
You're going to screw around with mods and still not eliminate those JVM bugbears that you lose sleep over. The best advice I can give you is to sell it and buy a JVMJS.

Yeah, I can see it too. I have already been bitten by the JVMJS curious bug. I only gave up $500 cash and well under $200 trade in on a small 1X10 combo I had no need for. So I am well on the cheap with my 2007 JVM410H. I did tune the gain down a bit on my OD channels, so I think I am fine with my amp. And then I found that rack gear jives with the FX loop as my Quadraverb Plus sounds fantastic in the JVM loop. And being I tamed the hiss quite a bit, I do not see needing the noise gate.

Later on I am going to explore some ideas I have with getting some other tones out of my JVM, similar to what the JS does. Except I do not want to have cloned OD1/OD2. I like having a slightly different voicing between the two. And I am now capable of making OD2 mimic OD1 now if need anyway.

But with all the being said, I am still curous about the JVMJS . . . .

 

[Australian]

Yeah, I can see it too. I have already been bitten by the JVMJS curious bug. I only gave up $500 cash and well under $200 trade in on a small 1X10 combo I had no need for. So I am well on the cheap with my 2007 JVM410H. I did tune the gain down a bit on my OD channels, so I think I am fine with my amp. And then I found that rack gear jives with the FX loop as my Quadraverb Plus sounds fantastic in the JVM loop. And being I tamed the hiss quite a bit, I do not see needing the noise gate.

Later on I am going to explore some ideas I have with getting some other tones out of my JVM, similar to what the JS does. Except I do not want to have cloned OD1/OD2. I like having a slightly different voicing between the two. And I am now capable of making OD2 mimic OD1 now if need anyway.

But with all the being said, I am still curous about the JVMJS . . . .

Yep I get cha. You're experienced handy with doing mods, but I don't know how far he wants to go or knows how to go with mods. But I know where he's coming from. When I had my 410 and Mark V side by side, the JVM had so much more 'background' hiss.

 

[RickyLee]

Yep I get cha. You're experienced handy with doing mods, but I don't know how far he wants to go or knows how to go with mods. But I know where he's coming from. When I had my 410 and Mark V side by side, the JVM had so much more 'background' hiss.

LOL. Yeah, that hiss is pretty bad. I had only had my amp for about a week. Played it a few times here at home somewhat low volume. Then decided to take it out to the jam at my buddys shop. It was actually a bit embarrassing when I first kicked on an OD channel. Actually shocked myself as I did not notice all the hiss at my house at the lower volume. And that was with the Gain set about 3 LOL.

 

[traitorseyes]

Man, you guys got me thinking I should just avoid the hassle of installing the choke altogether and just leave it as is. The hiss is quite noticeable by itself, but when I boost it with an OD for some tighter tones, it's crazy loud. And this is with just a volume boost with barely any drive. I can do this with the Mesa, no problem.

Before purchasing the JVM410 I did look into the JVMJS but I thought the identical OD channels was a negative feature. Maybe I'll have to do more research on that amp.

 

[RickyLee]

Man, you guys got me thinking I should just avoid the hassle of installing the choke altogether and just leave it as is. The hiss is quite noticeable by itself, but when I boost it with an OD for some tighter tones, it's crazy loud. And this is with just a volume boost with barely any drive. I can do this with the Mesa, no problem.

Before purchasing the JVM410 I did look into the JVMJS but I thought the identical OD channels was a negative feature. Maybe I'll have to do more research on that amp.

Are you still doing the mods you mentioned? Sounds like that will help out quite a bit, at least by that companies claims.

The stock JVM can be sorted out to be a quieter amp.

 

[traitorseyes]

I'm still gonna move forward with that noise reduction kit and see how that works out for now. I've come to realize that I prefer Marshall style voicing compared to Mesa. This amp would be perfect if it wasn't so dang noisy! Oh well, maybe I will sacrifice a pedal on my board and get a gate depending on how this mod works out.

 

[ampmadscientist]

I'm still gonna move forward with that noise reduction kit and see how that works out for now. I've come to realize that I prefer Marshall style voicing compared to Mesa. This amp would be perfect if it wasn't so dang noisy! Oh well, maybe I will sacrifice a pedal on my board and get a gate depending on how this mod works out.

The mesa has no expression: just one compressed sound all the time.
It removes the dynamic range and sounds flat.
Although this may be suitable for Metal...

There is TWO main methods of HISS suppression:
Conventional, and amorphous.

(a)Conventional focuses on attenuating noise after it is created. (used in most amps) Affects the tone and frequency response.
(b)amorphous focuses on preventing the noise from being created to start with. (newer high tech approach) does not affect the frequency response.

But here is what I found out so far: HISS - Amorphous Suppression

HISS comes from more than 1 source....then these sources mix together.

By suggestion from Dan Frank-
A. Part of the HISS is noise from the power supply. This is high frequency noise caused by diodes switching on and off as it turns AC into DC.
This type noise can be attenuated:
1. by using faster switching high speed diodes...(will help)
2. By using diode noise suppression called "spike killer."
3. Spike Killer: is manufactured by Hitachi / Toshiba. This is a small device which uses a cobalt alloy choke core. (it's tiny).

B. Part of HISS is created by resistors.
1. Between Carbon resistors and Bulk Metal resistors (like wire wound), there can be a difference of 42db in the noise floor. (this is a huge difference)
2. Added resistor noise includes thermal noise, and "shot noise."

https://toshiba.semicon-storage.com/us/product/amorphous/spike-killer-cores.html

"The amorphous noise suppression devices, AMOBEADS® and SPIKE KILLER®, suppress rapid changes in current which could otherwise lead to electrical noise in many circuits. Unlike other noise reduction methods which absorb noise after it is created, amorphous noise suppression devices suppress the source of the noise. Because of their square-shaped magnetic hysteresis behavior, amorphous noise suppression devices have a very large inductance when the current crosses zero (i.e. changes sign). This large inductance effectively blocks any further current changes. During normal current flow amorphous noise suppression devices have very low inductance. The reverse recovery phenomenon in semiconductor switching devices occurs when the current switches off. This phenomenon can lead to noise in the circuit. Amorphous noise suppression devices effectively and efficiently decrease the noise caused by the reverse recovery current."

 

[renips]

I sold my 410 and got the 410HJS because of hiss created by power supply and resistors. The 410 had way too much for my taste. The independent gates on each channel of 410HJS are very effective.

 

[Karl Brake]

I started with the standard H, loved it, was able to manage the feedback and noise with a gate and by using channel volumes for most of my gain, and using minimum amounts of notches on the gain knob. I finally did move over to the JS, mostly for the ability to cut through the band on higher gain settings...which the JS does much better than the stock model (much more classic Marshall mids) and the crunch channel really is to die for. The clean channel is a very different animal as well, all three modes really nice vintage tones, no sponginess as on the original. People mention not wanting two identical OD channels...well, the JS has a mid scoop switch for either OD, which makes it like the H OD2. I always used different gain settings on the two channels anyway, and the JS allows for that...and you can tweak the EQ. What Joe did was to allow the individual player to create two different OD channels per their own taste, which is clever, and totally practical at a gig. I use OD2 on my JS with gain at about 7, and the mid shift engaged. I can use it then for endlessly sustaining lead tones with feedback available to suit the song. So, while no amp is perfect, it's a misconception that the two OD's are just clones; they are just user-friendly.

 

[traitorseyes]

I just dun goofed. I've been putting this off as I've had other amps come in to play with and the amp tech that I was banking on to perform these mods has been giving me the run around in accepting my amps, so I decided to at least do the noise reduction mods which consists of replacing the resistors. On the very last resistor I needed to change, R96, the eyelet had come undone. Solder does not take to the PCB. I've looked up various eyelet repair kits which are ridiculously priced, so I came across a video that actually fed a bare wire through the eyelet and used solder to bond it to the track. My question is that can I just use any old wire that'll fit? Or should I be concerned of the voltage rating of the wire to be used? I uploaded the schematic with R96. It can be found by following the path towards the right and it is connected to tube V7b. Any tips would be greatly appreciated. Pretty bummed out that this has happened. I never understood the hate for "Oh it has PCBs inside!" until today.

 

[ampmadscientist]

I just dun goofed. I've been putting this off as I've had other amps come in to play with and the amp tech that I was banking on to perform these mods has been giving me the run around in accepting my amps, so I decided to at least do the noise reduction mods which consists of replacing the resistors. On the very last resistor I needed to change, R96, the eyelet had come undone. Solder does not take to the PCB. I've looked up various eyelet repair kits which are ridiculously priced, so I came across a video that actually fed a bare wire through the eyelet and used solder to bond it to the track. My question is that can I just use any old wire that'll fit? Or should I be concerned of the voltage rating of the wire to be used? I uploaded the schematic with R96. It can be found by following the path towards the right and it is connected to tube V7b. Any tips would be greatly appreciated. Pretty bummed out that this has happened. I never understood the hate for "Oh it has PCBs inside!" until today.

It's not an eyelet. It's a plated-thru hole.

1. Scrape the varnish off the end of the circuit track to expose the copper...I use an xacto knife.
2. Tin the end of the track where the copper is bare...
3. Put the lead thru the hole and solder it to the end of the track that is exposed.
4. You don't need any repair kit. Wick the excess solder out of the connection, clean the flux off the board with 92% isopropyl alcohol using a brush, paper towels, or a q tip dipped in alcohol. (not rubbing alcohol).

A. soldering PC boards takes special equipment, and lots of practice. (temperature controlled soldering station is the minimum)
B. The board is very easily damaged by inexperienced soldering (we have said this many many times).
C. Don't use your amp to learn on....
I hope if you are reading this: you learned something about soldering your own PC board: DON'T turn your amp into a paper weight.

Variable Choke with selector switch: it won't accomplish anything related to the audio. A choke is for HUM in the power supply! (remember this)
It won't do anything to reduce hiss (that's absolutely nothing).
It's NOT an audio device.

What you are doing: By changing the choke, you are making a resonant circuit. The frequency of resonance will change when the choke / cap is changed.
(the frequency will be pretty low because of the choke value and capacitor)
The actual idea : is to create an attenuation of 60 cycle hum by peaking this resonance at a certain low frequency. The "peak" will occur at one frequency, and the "dip" will occur at another frequency... (the "dip" will hopefully be centered at 60 cycles)....at least that's the theory...thereby reducing HUM.

Suppose your choke is Mercury Magnetics MultiChoke . Suppose your capacitor is 50uF.

10 Henry (100 ohms per Henry) with 50 uF capacitor: Ripple attenuation at 60 cycle= 49 db, voltage drop 27 volts.
15 Henry (125 ohms per Henry) with 50 uF capacitor: Ripple attenuation at 60 cycle= 52.6 db, voltage drop 50.625 volts.
20 Henry ( 148 ohms per Henry) with 50 uF capacitor: Ripple attenuation at 60 cycle= 55.1 db, voltage drop 79.920 volts.

NOW:
do you intend to re-bias your amp every time you change the choke with a switch? Because that's what you will NEED to do.
Every time you change the choke, your screen grid voltage will change, thereby requiring re-bias !

(Quote)
-Full Noise Reduction, making every channel almost silent to the touch.
-Gain Reduction, Reducing the oversaturated gain and allowing the gain pot to be fully useable.
-Increased Headroom, Reducing the overly compressed tone through out all the High gain modes.
-Volume Rebalance, evening out the volume for the clean/crunch "Green/Orange" modes
-Increased Clarity, giving every channel a more... "HiFi Tone"
-Tight Bass Structure for all high gain Red-modes in the amp

I hate to say this: but they baited you, and you swallowed the bait. ALL of these claims are a load of horse shit.

I hope you learned: that none of this stuff has a shred of truth to it.
The Purpose: was to get your money....and it worked.

 

[ampmadscientist]

This is what you got from the "variable choke mod..."

A. a damaged circuit board.
B. less hum...
C. No change in sound quality, as you were promised...
D. A useless switch. (now, there's a hole in the chassis...)
E. Less money in your pocket (they got your money).

-Full Noise Reduction, making every channel almost silent to the touch.
-Gain Reduction, Reducing the oversaturated gain and allowing the gain pot to be fully useable.
-Increased Headroom, Reducing the overly compressed tone through out all the High gain modes.
-Volume Rebalance, evening out the volume for the clean/crunch "Green/Orange" modes
-Increased Clarity, giving every channel a more... "HiFi Tone"
-Tight Bass Structure for all high gain Red-modes in the amp

(you never got any of that) But, you believed it.

BUT: this is what you can get: less hum in the power supply.

 

[RickyLee]

I just dun goofed. I've been putting this off as I've had other amps come in to play with and the amp tech that I was banking on to perform these mods has been giving me the run around in accepting my amps, so I decided to at least do the noise reduction mods which consists of replacing the resistors. On the very last resistor I needed to change, R96, the eyelet had come undone. Solder does not take to the PCB. I've looked up various eyelet repair kits which are ridiculously priced, so I came across a video that actually fed a bare wire through the eyelet and used solder to bond it to the track. My question is that can I just use any old wire that'll fit? Or should I be concerned of the voltage rating of the wire to be used? I uploaded the schematic with R96. It can be found by following the path towards the right and it is connected to tube V7b. Any tips would be greatly appreciated. Pretty bummed out that this has happened. I never understood the hate for "Oh it has PCBs inside!" until today.

I just noticed on the schematic that R96 is the 10K cathode on V7B. What are you changing that 10K to? And what other components are changed in this mod? If you are doing any mod to help with hiss on OD1/OD2, there are other places that need to be looked at.

Where did you get this mod from?