NAD :: JSX

[Rex Rocker]

Curious: HHave you had the chance to compare the JJ 5881's to the Sovtek 5881's?

 

[MYLILSS]

Curious: HHave you had the chance to compare the JJ 5881's to the Sovtek 5881's?

I haven’t tried the sovtek 5881’s yet. The JJ 5881’s sounds very good, but I don’t have anything to directly compare them too.

 

[D-Rock]

Looking at the bias trim pot, seems like you're running the tubes pretty hot(?)

That pic of the chassis was while parts were still out. I was in the middle of the work, and hadn’t set the bias yet. These 5881’s are very similar to 6l6’s tone wise, they are just a slightly lower wattage. The tubes are biased at 37/38 Ma, so it isn’t too too bad

Funny thing is, I never use a meter on my JSX. Have always ran either matched quads or matched pairs and set the trim pot by ear. I can tell by sound and feel if it's too hot or too cold for my liking. Typically never an extreme setting. The pot usually ends up somewhere 10 & 2 o clock depending on the tubes.

 

[MYLILSS]

Looking at the bias trim pot, seems like you're running the tubes pretty hot(?)

That pic of the chassis was while parts were still out. I was in the middle of the work, and hadn’t set the bias yet. These 5881’s are very similar to 6l6’s tone wise, they are just a slightly lower wattage. The tubes are biased at 37/38 Ma, so it isn’t too too bad

Funny thing is, I never use a meter on my JSX. Have always ran either matched quads or matched pairs and set the trim pot by ear. I can tell by sound and feel if it's too hot or too cold for my liking. Typically never an extreme setting. The pot usually ends up somewhere 10 & 2 o clock depending on the tubes.

They sound good on the warmer side but the bias pot doesn’t have a shit ton of adjustment, so normally you are pretty safe. I know a lot of guys who set the tubes by ear, im just not that experienced with that aspect of things. The chassis was out and I have a bias rite probe so it was fairly easy to do. I won’t lie, on some of my older peavey amps I have been guilty of setting the trim pot at noon and calling it a day

 

[D-Rock]

Something else I do is run a higher master volume than channel volumes. I rarely break 1/10 on the channels while my master is always at 5/10 at the least. 8/10 with a band. It has always sounded bigger, wider and deeper that way.

 

[apophis]

how do you guys prefer to run the loops' send and return volumes for this amp? what's the consensus?

 

[napalmdeath]

how do you guys prefer to run the loops' send and return volumes for this amp? what's the consensus?

Both at noon. They have an excellent loop.

 

[napalmdeath]

Looking at the bias trim pot, seems like you're running the tubes pretty hot(?)

That pic of the chassis was while parts were still out. I was in the middle of the work, and hadn’t set the bias yet. These 5881’s are very similar to 6l6’s tone wise, they are just a slightly lower wattage. The tubes are biased at 37/38 Ma, so it isn’t too too bad

Funny thing is, I never use a meter on my JSX. Have always ran either matched quads or matched pairs and set the trim pot by ear. I can tell by sound and feel if it's too hot or too cold for my liking. Typically never an extreme setting. The pot usually ends up somewhere 10 & 2 o clock depending on the tubes.

They sound good on the warmer side but the bias pot doesn’t have a shit ton of adjustment, so normally you are pretty safe. I know a lot of guys who set the tubes by ear, im just not that experienced with that aspect of things. The chassis was out and I have a bias rite probe so it was fairly easy to do. I won’t lie, on some of my older peavey amps I have been guilty of setting the trim pot at noon and calling it a day

There's PLENTY of adjustment for EL34's, but has less of a sweep for 6L6's, I've found. I personally don't care for 6L6's in the XXX or JSX. KT77's are where it's at, IMO. 6CA7's sound monstrous as well!

 

[MYLILSS]

Looking at the bias trim pot, seems like you're running the tubes pretty hot(?)

That pic of the chassis was while parts were still out. I was in the middle of the work, and hadn’t set the bias yet. These 5881’s are very similar to 6l6’s tone wise, they are just a slightly lower wattage. The tubes are biased at 37/38 Ma, so it isn’t too too bad

Funny thing is, I never use a meter on my JSX. Have always ran either matched quads or matched pairs and set the trim pot by ear. I can tell by sound and feel if it's too hot or too cold for my liking. Typically never an extreme setting. The pot usually ends up somewhere 10 & 2 o clock depending on the tubes.

They sound good on the warmer side but the bias pot doesn’t have a shit ton of adjustment, so normally you are pretty safe. I know a lot of guys who set the tubes by ear, im just not that experienced with that aspect of things. The chassis was out and I have a bias rite probe so it was fairly easy to do. I won’t lie, on some of my older peavey amps I have been guilty of setting the trim pot at noon and calling it a day

There's PLENTY of adjustment for EL34's, but has less of a sweep for 6L6's, I've found. I personally don't care for 6L6's in the XXX or JSX. KT77's are where it's at, IMO. 6CA7's sound monstrous as well!

They sound massive with 6550’s which is what my other JSX has. It’s just more of everything, but in a good way. I have also ran a pair of kt88’s In the outside two sockets and they sound thick and beefy as well.

 

[D-Rock]

I like EL34s in my XXX and 6L6s in my JSX.

 

[MYLILSS]

I like EL34s in my XXX and 6L6s in my JSX.

Of those two tubes I definitely prefer the 6L6 power tubes for the stock JSX. If you go into the amp and clip the C35 cap out of the circuit though, it actually sounds pretty good with EL34’s. That cap value really boosts that cocked wah mid sound with el34’s in the JSX, so removing it helps to even things out.

 

[Kordoba]

how do you guys prefer to run the loops' send and return volumes for this amp? what's the consensus?

Both at noon. They have an excellent loop.

Same here, both at noon.

 

[Kordoba]

A little off topic, but I used to run a XXX Super 40 with 6L6s and the switch set to EL34. It was a happy accident, then later I read on the Eurotubes site where they talked about doing the same thing.

 

[napalmdeath]

I like EL34s in my XXX and 6L6s in my JSX.

Of those two tubes I definitely prefer the 6L6 power tubes for the stock JSX. If you go into the amp and clip the C35 cap out of the circuit though, it actually sounds pretty good with EL34’s. That cap value really boosts that cocked wah mid sound with el34’s in the JSX, so removing it helps to even things out.

I never really noticed a cocked wah thing, which I would attribute to being compressed, and really only accentuated with certain boosts. The mids are honky for sure, but it's designed to be. For me, it's what gives the XXX and JSX their unique character, which I totally dug.

If you listen to some of the Fortin flavors, they have that same honk. Especially the Thrasher/Satan, and even the hand built Fortin amps. Maybe it's me.

A perfect example is listening to Havok's Unnatural Selection, (which I believe was JSX, before David went to XXX II), and Exodus Shovel Headed Kill Machine. That's signature XXX all day long. I love both.

 

[napalmdeath]

A little off topic, but I used to run a XXX Super 40 with 6L6s and the switch set to EL34. It was a happy accident, then later I read on the Eurotubes site where they talked about doing the same thing.

Still digging the Triple XXX? That amp sounded fantastic with the 6CA7's!

 

[Econ]

Do you have a picture of those PRS’s?

Well it’s new to me anyways haha. I got this amp from napalmdeath and have to say this amp was clean as hell. I was very impressed with how well maintained the amp was. Needless to say, I got this amp to modify and after making sure everything was good with it I got to work on it. The bulk of the mods was some circuit changes I made from ideas Kyle Rhodes gave me years back. They tightened the amp up quite a bit and gave it a gnarly midrange grind while killing off some of that cocked wah midrange these amps inherently have. I also ended up changing the amp from el34, to a quad of JJ 5881 power tubes. Rounding the mods out was a mini toggle on the back to kick it into what me and Kyle called “ Mesa “ mode, and adding a choke. Looks wise, as much as I loved the carbon fiber, the amp seemed to be a bit hot inside the chassis so i took a spare rear grill I had with the big honeycomb design and modified it to fit the front. I also added my trademark white chicken head knobs

 

[MYLILSS]

Do you have a picture of those PRS’s?

Here are a couple pics of em. Both have been worked over by lee @ GMW with added Floyd’s and other stuff.

 

[Econ]

I remember the blue one. I’m still rockin the SAS Lee modded for me.

 

[Kordoba]

A little off topic, but I used to run a XXX Super 40 with 6L6s and the switch set to EL34. It was a happy accident, then later I read on the Eurotubes site where they talked about doing the same thing.

Still digging the Triple XXX? That amp sounded fantastic with the 6CA7's!

Yep, and it's the first amp I've had with 6CA7s and won't be the last.

 

[mav5150]

Awesome! I run mine at 60 watts with 2 x 6L6s. I've owned it since the year they were introduced in 2004. It's a very thick, aggressive and tight amp, and always has been. Your Ultra and Crunch channel settings are actually very close to mine.
How hard is it to swap out the knobs?

The knobs just pull off. Sometimes they will be a little stubborn, but it isn’t that bad at all to switch them.

Holy crap, I thought you had to loosen them from inside the chassis lol! Do you know the shaft diameter?

3/16” is the shaft diameter. I have part numbers from peavey for white and black chicken head knobs. For the best fit, I’d recommend going through them. They run 50-60 cents a piece

Hey do you have the part number for the white knobs ? I surely would appreciate that, I just got a JSX in pristine condition, and I love how your amp looks with those white knobs