Help me with my JSX (overly bright sounding)

[madryan]

I'm thinking I need either different tubes or different speakers. My JSX sounds killer for some stuff but I have to keep the treble down or it gets all "hishy" and piercing.

I'm running Sovtek 12AX7LPS tubes which seem less brittle than the JJ's it came with, and I've got the original JJ EL-34's. All of this is running out into my Avatar Vintage 212 with Hellatone 60's.

Thanks
Ryan

[kmanick]

Sovteks are going to be more brittle than JJ's and EH 12Ax7's will be even brighter.
I've got JJ EL34's in mine with a tung sol in V1 and JJ's the rest of the way
thru V30's and I keep the treble right around 11:00 on both the crunch
and the Ultra
Presence goes between 11:00 and 1:00 depending on which guitar I'm
using and what I'm playing.
is it the cab maybe? I know with mine standing in different positions
around the room gives me a completely differnt tonality. If I stand directly
in front of my cab it sounds much brighter (hence the reson for beam blockers popularity)

[khabibissell]

I'm thinking I need either different tubes or different speakers. My JSX sounds killer for some stuff but I have to keep the treble down or it gets all "hishy" and piercing.

I'm running Sovtek 12AX7LPS tubes which seem less brittle than the JJ's it came with, and I've got the original JJ EL-34's. All of this is running out into my Avatar Vintage 212 with Hellatone 60's.

Thanks
Ryan

I don't have any fixes for ya because I can't find one myself... That is the exact complaint I have about the amp, and I've been trying to get rid of that on mine for the past eight months (cabs, tubes, settings, guitars, etc...). I guess some people like that kind of tone, but I don't. To me, it sounds like a wah is in front of the amp in a toe down position.

I think that is just the way it is voiced unfortunately. If you find a fix, let me know because I would love to hear it. IMO, it gets close to what I'd like to hear, but that "wah" thing ruins it.

[kmanick]

the Tung Sols in V1,V2 will help with that "wah" sound that you are talking about.
or switch to either KT77's or 6L6's, those tubes are a lot less "mid
pronounced" than the EL34's are. this amp sounds quite a bit different with 6L6's as compared to the El34's.

[Axewielder]

the Tung Sols in V1,V2 will help with that "wah" sound that you are talking about.
or switch to either KT77's or 6L6's, those tubes are a lot less "mid
pronounced" than the EL34's are. this amp sounds quite a bit different with 6L6's as compared to the El34's.

Interesting. My JCM2000 DSL100 has a pronounced wah sound to my ears. It's always driven me crazy, and I've never been able to fix it. I'm interested to see what other thoughts JCF'ers have about this issue.

[kmanick]

I put them in my 5150 a few months ago for this exact issue
with great results.
the tung sols are great tubes to put in V1,V2 slots

[madryan]

I'm going to switch to 6L6's and most likely get some different preamp tubes. I'm thinking about getting one of those mullard reissue 12AX7-M tubes and at least one Tung Sol. I'm thinking about the SED Winged-C 6L6's. I'm going to call Dougs Tubes today.

[khabibissell]

I'm going to switch to 6L6's and most likely get some different preamp tubes. I'm thinking about getting one of those mullard reissue 12AX7-M tubes and at least one Tung Sol. I'm thinking about the SED Winged-C 6L6's. I'm going to call Dougs Tubes today.

The things you mentioned will not get you what you want I'm afraid... I've tried: JJ, TungSol, Sovtek LPS, and Mullard reissue preamp tubes, and although it made a slight difference, it didn't totally cure the "toe down wah brightness thing". I've also tried a couple of different types of 6l6's (EH and Mesa). Save your money. Not to be negative... I'm just trying to save you from wasting money like I did . Like I said before, the amp is voiced a certain way and you'll either like it or not.

One thing you might like the tone of is running your cab with a mis matched output... Say setting your amp and four ohms and running it into an eight ohm cab, or setting it on eight and running it into a sixteen ohm (depending on what you have of course). A slight mis match will give a bit darker tone and is safe. I've been messing with the amp like this over the last couple of days and it helps more than anything else I've tried.

Of course don't have your amp output higher than the cab you are running into (amp switch on 8 ohms into a 4 ohm cab for instance)... that is bad news.

[madryan]

The things you mentioned will not get you what you want I'm afraid... I've tried: JJ, TungSol, Sovtek LPS, and Mullard reissue preamp tubes, and although it made a slight difference, it didn't totally cure the "toe down wah brightness thing". I've also tried a couple of different types of 6l6's (EH and Mesa). Save your money. Not to be negative... I'm just trying to save you from wasting money like I did . Like I said before, the amp is voiced a certain way and you'll either like it or not.

One thing you might like the tone of is running your cab with a mis matched output... Say setting your amp and four ohms and running it into an eight ohm cab, or setting it on eight and running it into a sixteen ohm (depending on what you have of course). A slight mis match will give a bit darker tone and is safe. I've been messing with the amp like this over the last couple of days and it helps more than anything else I've tried.

Of course don't have your amp output higher than the cab you are running into (amp switch on 8 ohms into a 4 ohm cab for instance)... that is bad news.

I see you tried both EH and Mesa tubes. In my experience both those branded tubes tend to be really brittle sounding. I'm going to get some TAD 6L6's and a Tung Sol for V1 per Doug's recommendations I'm also going to get another lower gain tube. Can't remember the number but it's not a 12AX7, but is hotter than a 12AT7. I'm going to try it in different spots in the preamp.

[khabibissell]

Generally speaking, high gain amps such as the JSX get most of their tone from the preamp. Changing power tubes will not completely revoice the amp. Things like changing pot taper on the EQ knobs, electronics internally (resistor values etc...), and preamp tubes to some extent will make the greatest impact. The amp just sounds the way it does. Power tubes especially in this case are not going to make that great a difference... but if you want to spend the $150+ retubing your amp, go for it. Good luck!

[toejam]

My JSX sounds killer for some stuff but I have to keep the treble down or it gets all "hishy" and piercing.

So what's the problem with just keeping the treble and presence backed down?

[khabibissell]

So what's the problem with just keeping the treble and presence backed down?

It doesn't work... The amp has an inherent treble boost thing going on. Personally, I think the amp is what it is and that is it. It is voiced a certain way and no amount of EQ tweaking changes it. The EQ knobs make a difference, but it still has that "wah" tone. I've had one for eight months and haven't sold it because it comes very close to being a great sounding amp and I'm hoping I'll stumble on to something that makes it sound good. All I've done so far is get more and more frustrated... unfortunately, that brittle treble thing is a deal breaker. I know exactly what the original poster is talking about.

I wonder if there is a batch of JSX's with sub part electronics floating around or the quality is hit or miss. So many people rave about them that I have to think that some sound better than others. I've heard great clips...

[kmanick]

could be, I've noticed people say the same thing about 5150's.
Mine sounds just amazingly good. I've had both the El34's and the 6l6's in there
and the 6L6's make this sound much more like dual recto
type of amp, (alot of the mids just flatten out) . I liked it but I like the El34's better
for what I do most of the time (fusiony shred). I kept my 5150 for the "Arch Enemy" type of stuff.
Have you tried an EQ in the loop? you could cut the upper mids and higher end treble that
way, I used to have to do that with my B-52.
I've also had a BBE sonic stomp in the loop of mine and it loved it.
Also I noticed that on the Ultra channel it sounds way better (to me anyway) if
I keep the gain at or below 1:00 and us a clean boost in front to push it into "Nevermore"
territory.
On the crunch channel I keep the gain at 3:00 or under and do the same thing, the amp
sounds more "open" to me that way.
Plus (sorry to be so long winded ,just trying to throw some stuff out I've noticed since I
bought mine), I noticed that the amp sounds better with both loop levels dimed full wide open
with the loop engaged on.
I'm hoping this weekend I'll actually get some time to record and if I do I'll post some clips up.

[Spivonious]

Heh, that trebly-ness is why I didn't like the amp. If you're dead set on keeping the amp, I would try different speakers in the cab or a different pickup on the guitar.

[Twisteramps]

I ran 6L6s, EH preamp tubes, GT75 loaded marshall cabs and had no issues with the things listed in this thread. Guess I got lucky. FYI, the EQ is active on the hotter two channels, I don't see how you guys are having this issue when you back the presence and treble down.

Pete