Need to replace the valves from my JVM 410HJS?

Pete Farrington

Well-Known Member
Joined
Jan 18, 2021
Messages
1,318
Reaction score
1,413
Location
Staffordshire UK
The DI Out on the JVM is a simply R/C Filter

I agree that it’s nowhere near a decent IR. To be fair, bear in mind that the amp design predates the widespread roll out of that technology.
But it seems inaccurate to describe the emulation as simple RC filters, as IC3a drives a resonant filter gyrator circuit.
I’d take claims of the emulation modelling any particular speaker type with a grain of salt, it’s surely just marketing BS.
‘A very simplistic approximation of a generic guitar speaker’ seems a more reasonable description.
Whatever, the point is that it sounds massively less awful than a non emulated output, and provides an option if, eg, an absent minded guitarist forgets to bring their 4x12 :)
 
Last edited:

XTRXTR

Well-Known Member
Joined
Feb 14, 2021
Messages
897
Reaction score
1,015
Location
Some City, USA
What is going to happen, as it always does, is someday you're going to use that amp live with an actual cabinet and the settings you have it on, that you're used to using, will raise the noise floor so high you'll sound over compressed, and fighting feedback and hiss. All your presets will be wrong.

Please play the amp with the cabinet so you avoid this. Stage volumes should be employed.
Namaste
 

hosselausso

New Member
Joined
May 13, 2022
Messages
7
Reaction score
4
Nope, for a proper IR it would require a DSP Treatment with the correct Impulse Response. The DI Out on the JVM is a simply R/C Filter cutting down the Frequency to a range between 100Hz and 7kHz supposed to sound like a 4x12 with V30 (which is beside the 20/80 and T75 IMHO one of the worst speaker Celestion ever designed )
Ok, so before adding a IR, would it also require to correct those frequencies to bring up the high frequencies again?
 

Pete Farrington

Well-Known Member
Joined
Jan 18, 2021
Messages
1,318
Reaction score
1,413
Location
Staffordshire UK
I suppose a filter whose frequency / phase response was the inverse of the amp’s emulation is possible.
But it doesn’t seem feasible to me, as the effect of the emulation circuit seems somewhat more complex than the description you quoted.
Whereas the PA Send jack looks to be a non emulated version of the same signal.
 
Last edited:

hosselausso

New Member
Joined
May 13, 2022
Messages
7
Reaction score
4
I suppose a filter whose frequency / phase response was the inverse of the amp’s emulation is possible.
But it doesn’t seem feasible to me, as the effect of the emulation circuit seems somewhat more complex than the description you quoted.
Whereas the PA Send jack looks to be a non emulated version of the same signal.
You mean the pre-amp out directly to my DSP? I have plenty of IRs I could use from Bias FX 2.
 

Attachments

  • Screenshot 2022-05-22 at 18.10.48.png
    Screenshot 2022-05-22 at 18.10.48.png
    398.6 KB · Views: 3

RICHIE GRIMES

Member
Joined
Jul 31, 2010
Messages
49
Reaction score
5
I have one of these. I bought one of the first ones. I have only had 2 issues with mine in all these years. I had a 12ax7 fail, which left me with no sound and I had the noise gate fail, which left me with no sound. When I removed the original 12ax7 (ECC83) that went bad, it crumbled into pieces of glass as I was rocking it loose at the bottom! That never happened to me before. If you're only changing the 12ax7 tubes then it's always been my understanding that there is no need to have the bias reset. Confirmation anyone? I just swap them out and keep going. I get the head biased when I replace power tubes. At last check, about a year ago, my power tubes are holding up nicely.

I have also seen the video of the Satriani setup where he has the OD gain maxxed out. If I remember correctly, he acknowledged that this is an extreme setting, but he uses it because he is playing a lot of melodies and that works well for that. You can always keep the guitar volume on 8 or so and raise it to 10 for a full gain sound and I do that sometimes, even though I have the option to just switch channels with the other OD channel set differently. . I record with a 1960B cab. I haven't released anything in over a decade. I am working on some mix downs and a few final tunes for this project now. This will be the first stuff with the JVM410HJS rig. I was using a JMP1 and 9200 power amp previously.

When I have felt that the signal was weak, it turned out to be a cable or a weak connection between pedals. Sometimes patch cables or their connectivity with the pedal lose their integrity and I need to move or remove and replace the same cable to find a good connection. Sometimes it's best to just replace all of your cables. It is a really great amp though. A quality speaker cable makes a big difference for me too. The one that comes with the amp is fine, but all cables from all over the rig will definitely lose some character over years of being pulled and wrapped or stepped on. I use Les Pauls so I am not in pursuit of the Satriani sound (as cool as it may be), but I have dialed in similar sounds over the years. I took interest in this amp because of its versatility & its embrace of older Marshall and newer Marshall character.
 
Last edited:

hosselausso

New Member
Joined
May 13, 2022
Messages
7
Reaction score
4
I have one of these. I bought one of the first ones. I have only had 2 issues with mine in all these years. I had a 12ax7 fail, which left me with no sound and I had the noise gate fail, which left me with no sound. When I removed the original 12ax7 (ECC83) that went bad, it crumbled into pieces of glass as I was rocking it loose at the bottom! That never happened to me before. If you're only changing the 12ax7 tubes then it's always been my understanding that there is no need to have the bias reset. Confirmation anyone? I just swap them out and keep going. I get the head biased when I replace power tubes. At last check, about a year ago, my power tubes are holding up nicely.

I have also seen the video of the Satriani setup where he has the OD gain maxxed out. If I remember correctly, he acknowledged that this is an extreme setting, but he uses it because he is playing a lot of melodies and that works well for that. You can always keep the guitar volume on 8 or so and raise it to 10 for a full gain sound and I do that sometimes, even though I have the option to just switch channels with the other OD channel set differently. . I record with a 1960B cab. I haven't released anything in over a decade. I am working on some mix downs and a few final tunes for this project now. This will be the first stuff with the JVM410HJS rig. I was using a JMP1 and 9200 power amp previously.

When I have felt that the signal was weak, it turned out to be a cable or a weak connection between pedals. Sometimes patch cables or their connectivity with the pedal lose their integrity and I need to move or remove and replace the same cable to find a good connection. Sometimes it's best to just replace all of your cables. It is a really great amp though. A quality speaker cable makes a big difference for me too. The one that comes with the amp is fine, but all cables from all over the rig will definitely lose some character over years of being pulled and wrapped or stepped on. I use Les Pauls so I am not in pursuit of the Satriani sound (as cool as it may be), but I have dialed in similar sounds over the years. I took interest in this amp because of its versatility & its embrace of older Marshall and newer Marshall character.

Thanks for your experience! I actually have found out that having the gain at 6 or so for rhythm and then switching on the TS9 or similar creates that punch for the solos without that over-compressed sound. Yes, I remember that statement from him in the video, however, he also plays rhythms from time to time (maybe 5-10% only, but it's something).
 

texhex

Well-Known Member
Joined
Feb 1, 2016
Messages
305
Reaction score
473
You should look into getting a reactive load box and stop using the emulated out. Something like the Suhr Reactive Load is a must have if you are doing any type of recording where you aren’t micing the cabinet. I highly recommend the Suhr Reactive Load box and then using the IR of your choice in your DAW. Fractal Audio also makes a very good reactive load box but they are never in stock.

I also noticed that you are running the volumes at 10. Any reason for this? It seems totally overkill. With a reactive load and the right IR you will have a totally different experience.
 
Last edited:

Redguitar

Well-Known Member
Joined
Mar 16, 2013
Messages
212
Reaction score
261
You should look into getting a reactive load box and stop using the emulated out. Something like the Suhr Reactive Load is a must have if you are doing any type of recording where you aren’t micing the cabinet. I highly recommend the Suhr Reactive Load box and then using the IR of your choice in your DAW. Fractal Audio also makes a very good reactive load box but they are never in stock.

I also noticed that you are running the volumes at 10. Any reason for this? It seems totally overkill. With a reactive load and the right IR you will have a totally different experience.
Not really a reactive load, but I recently tried a H&K redbox. The amp signal passed through to the cabinet just fine. The XLR signal went to signifificantly overdrive the input of a AllenHeath board, with the trim set way down. Unusable mostly.

That device
 


Top