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rocktron piranha vs marshal jmp1


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i have the piranha at the moment. i just changed both valves recently but i still find it a bit rubbish in terms of the sounds i can get out of it. maybe it's the rest of my rack but i think that it should sound better than it does. has anyone here done an A/B test with these two pre-amps? how do they compare? I find the piranha treble control particularly useless. I have to have it set on minus 15 on all the distortion voices otherwise it just adds this horrid layer of 'fizz' which takes all of the 'grrrr' out of the sound. there's also an annoying midrange frequency which cuts through a lot and i can't seem to get rid of it.

 

ps - the rest of my rack when i switch the fx out is: marshall 9200 -> marshall 4x12 A cab.

 

maybe my power-amp is much too powerful?

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Keep working with the Rocktron... IMO it smokes the JMP1. The tubes in both pres are lightbulbs so pay them no attention. They are both solid state pres. The Rocktron has the sweepable mid range and that is where the tone lies... you must find it Grasshopper....:D

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They BOTH have tubes in the circut path but, they do not really effect the tone... they are lightbulbs. Some "tube" items just have tubes in them so the so called "tube-guys" won't dismiss the product entirely. Its pretty much a marketing device. I am surprised they have not made a tube tuner or a tube metronome or a tube guitar strap!

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So you are saying that if you swapped out the tubes, there'd be absolutly no change in tone?

 

If that was true I'd then think they were a waste, but I've heard people talk about swapping tubes and getting great results.

 

That leads me to believe they are not just lights ;)

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I would say that depends on how much you play and how hard you push them when you do play. The power amp tubes to effect the overall tone of your rig, some people will tell you different. Swap them out and you will quickly see a difference, especially at gig volume.

 

The biggest difference that I noticed when I swapped out the JMP-1 tubes with JJ's was that the tone smoothed out and that sterile harshness was gone.

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ok, look. this is in the user reviews. another JMP-1 fan who wanted to talk find out once and for all the truth.

 

this is what he said:

 

 

after reading some other posts regarding this unit. and the fact that it supposably uses diodes to get its distorted tones. i contacted marshall and asked them about wether the jmp-1 is a tube preamp or a solid state preamp that uses tubes to just warm up the sound a bit. here is the respones i got from them.

 

 

The JMP-1 preamp is built around 2 ECC83 tubes (4 tube gain stages) and the sound is largely based on the tubes themselves. There are a lot of programmable parameters built into the JMP-1 which require control circuits comprised of IC's as well as some IC's used as buffers or as a part of those controlled stages. There is one solid-state clipping circuit comprised of BR3 which is a diode bridge, but that only kicks in if the signal level is over 1.2 Volts and it's found just before the first tube which is quite early in the signal path. You can have it removed by a qualified tech but you'll see that it contributes to a somewhat overall "roundness" of the tone for lack of a better term. It levels off some harmonic spikes and generally doesn't affect the fundamentals unless the input is extremely hot or has been insanely boosted by another pedal or preamp. As far as the so-called 'experts' are concerned, yes, if you bypass the tubes and max out all the gain you will still get some clipping. However, the overall QUALITY of the tone in the JMP-1 does come from the tubes alone. I hope this answers your question.

 

 

so there ya go.

 

I don't fully understand every word, but it seems pretty reasonable to me.

 

And at least, it's completely wrong to say that they have NO effect whatsoever, because different tubes make huge deifferences.

 

so:p :p :p

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http://acapella.harmony-central.com/forums/showthread.php?s=&postid=6518352#post6518352

go here.

 

I posted my settings.

See if anything intrigues you.

 

Also, the tubes and toroid transformer are ment to add warmth, high headroom, and dynamics.

you overall distortion is probably going to come from the diodes.

The tubes help to give it a more natural sounding,less fabricated

tone.

 

Kent

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  • 5 years later...
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Many argue that despite the presence of the tubes in the preamp, they say the tone is all from the Solid-State parts.


I don't know I've never looked at the schematics of the JMP-1 or the Piranha

 

 

Well I have, and I can only agree on the JMP-1. It is builded with a lot of very cheap op-amps.

 

(don't know much about the Rocktron).

 

http://www.schematicheaven.com/marshallamps/jmp_1.pdf

 

Pay attention to all the TL072/74 opamps.

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The key to making a pre's tubes "work" the tone, is the amount of plate volts hitting the tubes. The more votage hitting them, the more sensitive they become. They are "marketing tubes" if there's low voltage put to the tubes. A Fender Twin has about 240 to 280 hitting the pre tubes. More depending....

 

I've been told that the Pirhana has less than 50. dunno tho....

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I thought the big marketing push for the piranha was that it wasn't starved plate.

Now, I only remember that as a marketing push so take that for what it is...some guys MEMORY of a MARKETING campaign

 

and I'll cop to it - I tend to distrust marketing guys (not personally - just the engineering v marketing thing I suppose, Dilbert would be funny if it weren't so realistic :) ) -- I'm pretty biased that wy

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I thought the big marketing push for the piranha was that it wasn't starved plate.

Now, I only remember that as a
marketing
push so take that for what it is...some guys MEMORY of a MARKETING campaign


and I'll cop to it - I tend to distrust marketing guys (not personally - just the engineering v marketing thing I suppose, Dilbert would be funny if it weren't so realistic
:)
) -- I'm pretty biased that wy

 

Seem to remember R-tron having a "high voltage tube preamp" somewhere in their line. My info was from a friend who had one who "wasn't happy" with the plate voltage. He said he checked it and it read only 50 pv. But it was a bunch of dudes talkin smack in a music store....go figure....

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  • 2 weeks later...
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I'm still using my Piranha.

I don't find is fizzy or fuzzy sounding at all.

Granted I don't use the amount of gain a lot of

players use these days.

Guess you could say I have a very "Old School" sound.

 

http://www.myspace.com/heddatheband

 

The 4 songs on our Myspace page were recorded with the Piranha.

The tone I got on "Never Yield" is probably my favorite of the bunch.

Basically my rig is,

Piranha

/ /

BBE Maximizer

/ /

Rocktron Intellifex

/ /

Peavey Classic 50/50

/ /

4x12 w/Celestion G12m70's, 4x12 w/Carvin GT12-16's

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Somehow I don't think he posts here anymore. This topic is 5 years old man

 

 

haha true... until now!

 

I've not been in a band for a few years until recently I started one up again. I never got to the bottom of this problem at all.

 

Last night the other guitarist in my band brought his JCM 800 over and we had a good A/Bing session. There was a huge difference in sound between the two. His 800 has what I'd call a ballsy, gritty sound. My piranha sounds muddy and fizzy and just generally cheap and nasty, verging on offensive. There was absolutely nothing I could do to get it sounding anywhere near nice, let alone anything like the 800. Even with the bass setting on the piranha at maximum, it had nowhere near the bass output of the 800.

 

We tried routing the output of the piranha into the fx return of his 800 to hear what it sounded like using the power stage in the 800. It didn't sound as good as it did with my rack power amp - one side of a marshall 9200. this leads me to believe that my power amp sounds better than the 800's power stage. if I had a decent sounding preamp, my rig would sound awesome!

 

There are so many reviews on this website which say that the piranha sounds great and can sound like a JCM 800, which is why I bought the thing in the first place. Either all of these people are wrong or there's something drastically wrong with mine. I replaced both tubes in it a while ago for new marshall 12AX7s which changed the sound slightly but nothing major.

 

I have emailed Rocktron to see what they suggest. I'm thinking maybe the odd capacitor here and there might need replacing or something like that. If I get the time next week I'll try and record both amps and post them up here so that you can hear what I'm on about.

 

If it turns out that my piranha isn't broken and they actually do sound like mine then I'm seriously unimpressed.

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  • 3 months later...
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The other guitar player in my band had a Piranha through a Carvin 50/50 Tube power amp and we tried everything, tube swaps, different power amps, different guitars, different pickups, etc and neither one of us could ever get comfortable with any of the sounds out of that thing. We would swap it out for my Chameleon and got better tones than with the Piranha. We both wanted to like it but just couldn't get anything decent out of it.

 

He then got a Mesa Quad/Mesa 395 and it wasn't even funny how much better that sounded than the Piranha.

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