Crunch channel is weak on JVM410H

[ChrisCYWG]

Sorry if this has been asked, Ive done a few searches and seems some people had similar issues, but never really seemed to read a fix..
OD1/OD2 on red/orange are great, crunch which is supposed to be a JVM800 is weak sauce... sounds more like the clean green with a tiny bit of tubescreamer engaged.. if I engage my tubescreamer or MXR Dis+ it brings it somewhat to life... Im assuming ive got a bad valve somewhere, or biasing is out?

I know there are mods, but don't really want to get into them.. just looking to get this crunch channel to life!

Thanks!!

 

[LPCustom28]

Have the 210, and am not crazy about the crunch tones (have heard similar sentiments about the crunch modes on the 410 as well). Not horrible, but leaves a lot to be desired (seems to respond a little better with greenback type speakers). May I ask what speakers you’re running it through?

 

[ChrisCYWG]

Have the 210, and am not crazy about the crunch tones (have heard similar sentiments about the crunch modes on the 410 as well). Not horrible, but leaves a lot to be desired (seems to respond a little better with greenback type speakers). May I ask what speakers you’re running it through?

Im running it through a 1960A cab .. they arent the greenbacks..

 

[spacerocker]

sounds more like the clean green with a tiny bit of tubescreamer engaged.. if I engage my tubescreamer or MXR Dis+ it brings it somewhat to life... Im assuming ive got a bad valve somewhere, or biasing is out?

I know there are mods, but don't really want to get into them.. just looking to get this crunch channel to life!

Thanks!!

I suspect you have a failed valve. Try replacing the first pre-amp valve (V6 -the one under the can) or V7.

The JVM Crunch isn't as bright as an 800, but Crunch Orange ought to have about the same as a 2203, whilst Crunch Red should have MORE gain than an 800. If this isn't the case, you have a faulty valve....

If you fix it and want it to sound brighter (and don' t want mods) try an EQ in the loop with a boost between 2-8Hz of between 3-5dB...

 

[ChrisCYWG]

I suspect you have a failed valve. Try replacing the first pre-amp valve (V6 -the one under the can) or V7.

The JVM Crunch isn't as bright as an 800, but Crunch Orange ought to have about the same as a 2203, whilst Crunch Red should have MORE gain than an 800. If this isn't the case, you have a faulty valve....

If you fix it and want it to sound brighter (and don' t want mods) try an EQ in the loop with a boost between 2-8Hz of between 3-5dB...

Thanks.. I got an entire new set of 12AX7s and EL34s the other day...its actually been a looooong time since theyve been replaced... I am interested to know though whos at fault!

 

[spacerocker]

Thanks.. I got an entire new set of 12AX7s and EL34s the other day...its actually been a looooong time since theyve been replaced...

That's OK - Valves last a looooong time! (up to 50,000 hours for pre-amp valves, up to 10,000 for power valves!) Replacing the lot sounds like overkill to me -but should certainly fix the problem! Let us know what you find....

 

[MickeyS]

I use crunch amber with a boss GE7 up front, and have been pretty happy.....until I started using OD2 Green, with no boost. I love my 410H, but the crunch channel is too dark and compressed for my tastes, and without a boost, or some help, lacks punch, and does not feel like an 800 or a 4 holer in any way. But I came from a 1959, so I'm used to bright, open, and punch lol. Just my opinion, but the descriptions of the channels are not really accurate, especially the crunch channel. I'm sure depending on the player itll work just fine, and like I said, I've figured out how to make it work for me, but the OD channels cover all that, and I'm digging OD2 Green currently That being said, you may have a bad tube, and if that is the case maybe itll work for you. Crunch red has a good amount of gain, but it's too dark, compressed and woolly without some eq shaping.

 

[ChrisCYWG]

I use crunch amber with a boss GE7 up front, and have been pretty happy.....until I started using OD2 Green, with no boost. I love my 410H, but the crunch channel is too dark and compressed for my tastes, and without a boost, or some help, lacks punch, and does not feel like an 800 or a 4 holer in any way. But I came from a 1959, so I'm used to bright, open, and punch lol. Just my opinion, but the descriptions of the channels are not really accurate, especially the crunch channel. I'm sure depending on the player itll work just fine, and like I said, I've figured out how to make it work for me, but the OD channels cover all that, and I'm digging OD2 Green currently That being said, you may have a bad tube, and if that is the case maybe itll work for you. Crunch red has a good amount of gain, but it's too dark, compressed and woolly without some eq shaping.

My crunch sounds more like a fart then anything... hopefully these valves wake it up...

 

[paul-e-mann]

My crunch sounds more like a fart then anything... hopefully these valves wake it up...

You didnt say if this amp used to sound better at one time or not, or has always sounded weak. If it used to sound better try swapping out one preamp tube at a time to see if theres a bad tube. Im thinking if its always sounded weak you need hotter pickups.

 

[ChrisCYWG]

You didnt say if this amp used to sound better at one time or not, or has always sounded weak. If it used to sound better try swapping out one preamp tube at a time to see if theres a bad tube. Im thinking if its always sounded weak you need hotter pickups.

It did sound good years back.. unfortunately all my gear sat for several (5) years just due to space limits etc... piclkuips I run Dimarzio Super Distortion/PAF combos in most.. EMG 81/85 in others.. Im going to be doing the tubes this weekend.. just had so much stuff going this week...

 

[ChrisCYWG]

So.. as a follow up.. all new tubes installed... although the crunch has improved..still kind of weak... sooooo for no reason at all, and I don't know why I decided to do this, but I rolled off the FX loop setting from 100% wet to about 65% and holy $hit... the distortion is through the roof.. initially I had turned the loop right off, then tweaked the setting on the back of the amp..

I understand the FX loop in the 410H is rather err touchy so to say, but it is night and day with 100% rolled off.. I am set at 10bd as well for pedals... ideas??

 

[spacerocker]

So.. as a follow up.. all new tubes installed... although the crunch has improved..still kind of weak... sooooo for no reason at all, and I don't know why I decided to do this, but I rolled off the FX loop setting from 100% wet to about 65% and holy $hit... the distortion is through the roof.. initially I had turned the loop right off, then tweaked the setting on the back of the amp..

I understand the FX loop in the 410H is rather err touchy so to say, but it is night and day with 100% rolled off.. I am set at 10bd as well for pedals... ideas??

First of all - the FX loop is AFTER the pre-amp, so should have no effect at all on the crunch channel (or any other channel) especially as the JVM gets almost all its overdrive from the pre-amp....

Which leads me to wonder - what effects have you got in the loop? and do you have the -10dB/+4dB switch on the correct setting for your effects? If your effects are designed for -10dB and you are running them in the loop set at +4dB, you will certainly get distortion - but it won't be pleasant!

Regarding the setting - the JVM serial/parallel loop selects between dry only (knob completely anti-clockwise) and Wet only (knob fully clockwise) in the middle position, you get both wet and dry signals added together, so the loop will certainly sound LOUDER in the middle position - but it shouldn't really affect distortion unless your loop settings are wrong (as explained above!)

 

[ChrisCYWG]

First of all - the FX loop is AFTER the pre-amp, so should have no effect at all on the crunch channel (or any other channel) especially as the JVM gets almost all its overdrive from the pre-amp....

Which leads me to wonder - what effects have you got in the loop? and do you have the -10dB/+4dB switch on the correct setting for your effects? If your effects are designed for -10dB and you are running them in the loop set at +4dB, you will certainly get distortion - but it won't be pleasant!

Regarding the setting - the JVM serial/parallel loop selects between dry only (knob completely anti-clockwise) and Wet only (knob fully clockwise) in the middle position, you get both wet and dry signals added together, so the loop will certainly sound LOUDER in the middle position - but it shouldn't really affect distortion unless your loop settings are wrong (as explained above!)

Hi,
-10bd is pressed in... in the FX loop (I have an NS-2 in the X pattern) I have MXR EVH Phaser, Boss Flanger, Boss Waza Chorus, Boss DD-3T and Boss reverb, and Boss RC-10R looper at the end)

Outside the loop are tuner, Xotic boost, Waza Blues Driver, tubescreamer, wah)

If have noticed alot if the FX loop is on there is a significant volume/tone drop Ive even tried a boost at the end of the chain to bring the volume back, but it still saps that crunchy tone...

 

[ChrisCYWG]

So here's another interesting new one that popped up.. with the FX loop setting backed off of anything but nearly full wet, it seems to actually engage my Boss Reverb pedal in the loop even though the pedal is not physically switched on... unplugging the power from the pedal, the reverb sound goes away.. going to full wet (or nearly) the reverb effect does not engage unless the pedal is turned on...

 

[spacerocker]

So here's another interesting new one that popped up.. with the FX loop setting backed off of anything but nearly full wet, it seems to actually engage my Boss Reverb pedal in the loop even though the pedal is not physically switched on... unplugging the power from the pedal, the reverb sound goes away.. going to full wet (or nearly) the reverb effect does not engage unless the pedal is turned on...

Here's what I think is happening - The Boss unit digitises the signal, processes it, adds reverb, then converts it back to analogue again. This process will (I believe) be happening whether the unit is on or off. The conversion process takes a small amount of time (called latency). Normally this would be to small to notice. When you have the "mix" knob on the amp up full, there is no problem, but when you set it lower than 100%, you are introducing some "dry" signal (that has not been through the effects loop) back into the mix. The difference between the "dry" signal and the signal that has been through the boss, and has been delayed by a tiny amount is giving you a sound a bit like reverb!...This situation can also give an unpleasant "phasing" sound for the same reason. Best to keep the mix knob up full, and control the reverb mix on the pedal!...

 

[scozz]

Here's what I think is happening - The Boss unit digitises the signal, processes it, adds reverb, then converts it back to analogue again. This process will (I believe) be happening whether the unit is on or off. The conversion process takes a small amount of time (called latency). Normally this would be to small to notice. When you have the "mix" knob on the amp up full, there is no problem, but when you set it lower than 100%, you are introducing some "dry" signal (that has not been through the effects loop) back into the mix. The difference between the "dry" signal and the signal that has been through the boss, and has been delayed by a tiny amount is giving you a sound a bit like reverb!...This situation can also give an unpleasant "phasing" sound for the same reason. Best to keep the mix knob up full, and control the reverb mix on the pedal!...

Excellent diagnosis!

 

[ChrisCYWG]

Here's what I think is happening - The Boss unit digitises the signal, processes it, adds reverb, then converts it back to analogue again. This process will (I believe) be happening whether the unit is on or off. The conversion process takes a small amount of time (called latency). Normally this would be to small to notice. When you have the "mix" knob on the amp up full, there is no problem, but when you set it lower than 100%, you are introducing some "dry" signal (that has not been through the effects loop) back into the mix. The difference between the "dry" signal and the signal that has been through the boss, and has been delayed by a tiny amount is giving you a sound a bit like reverb!...This situation can also give an unpleasant "phasing" sound for the same reason. Best to keep the mix knob up full, and control the reverb mix on the pedal!...

Perfect... I thought I had read something similar, but that explains it perfectly...
I saw a post you did a long time ago about the 410H losing volume/tone in the FX loop, and I saw you used a boost pedal and just upped it 4db I think you said.. did you run that at the beginning or end of the loop, or does/did it really matter?
Thanks for all the help

 

[spacerocker]

I saw a post you did a long time ago about the 410H losing volume/tone in the FX loop, and I saw you used a boost pedal and just upped it 4db I think you said.. did you run that at the beginning or end of the loop, or does/did it really matter?
Thanks for all the help

I don't use a boost pedal in the loop as such....but I use rack effects in the loop, including a "G-Major" unit where the input and output levels can be adjusted...I also have a dbX 131 Rack EQ where the levels can be adjusted. Basically I run my loop with the -10dB switch on (on the JVM) and then adjust the level on the G-Major until there is no difference between loop off and loop engaged...that fixes the volume loss. As for tone loss, I use my JVM with the loop engaged all the time (although most of the time the effects in the rack units are not being used), so I can't remember how much difference (if any) I am getting in the tone with the loop on vs loop off. When I get a chance, I will try a comparison between loop on/ Loop off, with just a patch lead between send and return (no effects units) and see how much difference there is tonally....