Fortin Modded Marshall JVM - Help Needed

  • Thread starter Thread starter Walnuts
  • Start date Start date
W

Walnuts

Member
Hi All,

I recently puchased a Fortin Modded Marshall JVM from a forum member about a month ago. The transaction went super smoothly and everything arrived at my place as promised and in great condition. After A/Bing the JVM with a number of other amps (Friedman Naked, Bogner Ecstacy, Bogner Uberschall), I can't help but notice that although it has an ungodly amount of gain, it doesn't have much low end and can sould a bit shrill. While, I haven't played any other Fortin modded amps, it is my understanding that they generally have quite a bit of thump to them. Is it possible that something could have gotten jostled during shipment or there is a bad tube? I have e-mailed Mike Fortin for advice but wanted to open it up to you all as this forum is generally a great resource for trouble-shooting issues like these.

Thanks!

Paul
 
Walnuts":2u43gej7 said:
Hi All,

I recently puchased a Fortin Modded Marshall JVM from a forum member about a month ago. The transaction went super smoothly and everything arrived at my place as promised and in great condition. After A/Bing the JVM with a number of other amps (Friedman Naked, Bogner Ecstacy, Bogner Uberschall), I can't help but notice that although it has an ungodly amount of gain, it doesn't have much low end and can sould a bit shrill. While, I haven't played any other Fortin modded amps, it is my understanding that they generally have quite a bit of thump to them. Is it possible that something could have gotten jostled during shipment or there is a bad tube? I have e-mailed Mike Fortin for advice but wanted to open it up to you all as this forum is generally a great resource for trouble-shooting issues like these.

Thanks!

Paul
Click to expand...

What speakers are you using and Where do you have the resonance set?
 
Hi Ralph,

I am using a Bogner 4x12 Cabinet with Vintage 30's in it. Overall, I can't recall where the resonence was set but we played with a large number of settings (currently in the studio with Zeuss producing some new tunes).

Regardless, we did the pencil test and it appears that the tubes may be the issue. That being said, what do you suggest I order for replacements?

I really appreciate your help!

Paul
 
Walnuts":1hartqek said:
Hi Ralph,

I am using a Bogner 4x12 Cabinet with Vintage 30's in it. Overall, I can't recall where the resonence was set but we played with a large number of settings (currently in the studio with Zeuss producing some new tunes).

Regardless, we did the pencil test and it appears that the tubes may be the issue. That being said, what do you suggest I order for replacements?

I really appreciate your help!

Paul
Click to expand...

Paul!


Yup, You might have a tube problem!


I'm pretty sure that Im running Winged c el-34's in Mine and Im still using the Stock 12ax7's that the amp came with and it kills.
I'm not even sure what Preamp tubes are in mine but I can look in the amp if you want! With that said, if you want to tame the highs a bit,
you might want to try a darker preamp tube (ive Used JJ's in some of my amps to tame the highs and it worked Great.. I know some people rag on JJ"s but they do work well in some amps and not so great in others lol!)


The resonance in the amp should add the bass that you are looking for. I noticed that if you run it Low then you will get more of a vintage Marshall type sound (lack of bass, more mids)

The Midrange is pretty humped up on that mod (I actually love that) but you can get away with scooping the mids on that amp because of that and you wont get washed out.
I use weird settings with mine when I use v30s. I run the treble and the mids very low (like 3) and it crushes though a PA.

hope this helps!!

Let me know how you make out!

~R~
 
This is great information. Thank you for the quick response.

The amp currently has Gold Lion Kt66s and various 12ax7s.

I may reach out to Eurotubesto see what they reccommend but the idea of Winged Cs is very intriguing.

Thanks again!!
 
Check and make sure you have messed with all the push pull pots, can't remember off hand but I think pulling the master volume resulted in way more bottom end. Also I would check elsewhere for tubes instead of eurotubes, nothing wrong with eurotubes...good company and I've done business with them but by dealing with them you limit yourself to ony one brand of tube, JJ's is all they sell.
 
I have a Fortin modded amp as well. One thing that I have notice about this amp is that it likes the power amp section. So also try, if the tube thing doesn't solve it, cranking the power amp. The amp sounds insane when you crank it, and mine thunders quite a bit. Enough to rattle my chest, and make my pants legs flap in the wind.

I use this company for tubes if it helps, http://www.amplifiedparts.com/. But I bet Ralph knows better places.
 
You can also contact Laura at http://www.valvequeen.com/

KT66? Unless the bias supply was modified there are most likely running way too hot and reason for lack of bass:-)

Laura has some properly burned in and matched EL34s. Winged C or Tung Sol reissue EL 34s if your on a budget.

Cheers
Mike
 
Walnuts":2kg4uz80 said:
This is great information. Thank you for the quick response.

The amp currently has Gold Lion Kt66s and various 12ax7s.

I may reach out to Eurotubesto see what they reccommend but the idea of Winged Cs is very intriguing.

Thanks again!!
Click to expand...
Are you sure it's a Modded JVM? The JVM uses El34's and all the Modded JVM's that Ive sold used el34's in th epower section. If your amp has KT66's then someone else has been in the amp and as Mike said, that is most definitely the reason for lack of bass ;)

All the best!!
~R~
 
You guys are the best.

I am 100% positive that it is a modded JVM. I purchased it from sjk who commented above. I am going to reach out to Laura now and get this all sorted out.
 
Gainfreak":21ohis22 said:
Walnuts":21ohis22 said:
This is great information. Thank you for the quick response.

The amp currently has Gold Lion Kt66s and various 12ax7s.

I may reach out to Eurotubesto see what they reccommend but the idea of Winged Cs is very intriguing.

Thanks again!!
Click to expand...
Are you sure it's a Modded JVM? The JVM uses El34's and all the Modded JVM's that Ive sold used el34's in th epower section. If your amp has KT66's then someone else has been in the amp and as Mike said, that is most definitely the reason for lack of bass ;)

All the best!!
~R~
Click to expand...

I owned this amp for a month after buying it from a respected member here, Squank and the amp came to me with KT66's and I sold it to walnuts with those same tubes. Mike Fortins signature is on the chassis of the amp and it has a Fortin Badge on the front, so it seems a legit mod?
[img]http://img560.imageshack.us/im...le.imageshack.us/user/steveinsene]steveinsene at 2012-06-11[/url]
[img]http://img804.imageshack.us/im...le.imageshack.us/user/steveinsene]steveinsene at 2012-06-11[/url]
 
That is a Vintage Modern, not JVM:-)

I did some with and some without depth controls.

Cheers
Mike
 
Ok Gents, Now I know what the confusion is. That is NOT a modded JVM hahahahaha! It's a Modded Vintage Modern!! (VM)
 
To the original OP, yours does not have the depth control hence the lack of sub-bass.

Cheers,

Mike
 
Oh Man....Very sorry for the confusion!

That being said, what should I be using for replacement tubes?
 
You must log in or register to reply here.
Back
Top