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Hoffman Amps Forum image Author Topic: Tube Amp Distortion Qualities  (Read 5346 times)

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Offline TurboGuitarMelton

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Tube Amp Distortion Qualities
« on: May 23, 2013, 02:10:38 pm »
Hi everyone, after being away from distorted guitars for a while(learning Jazz guitar at college) and going back to it I am hearing lots of stuff that ive never heard before.

Its seems that on my tube amps when i distort them the distortion is really shaky and doesnt settle. almost like there is the fundamental  of the note and then another pitch on top of it that goes in and out of tune ever so slightly while i play them :dontknow: This is only when i play single notes though on the G string to the E string (high one). I really do not like how this sounds. It sounds unsettled and takes the beautiful qualities of the notes and basically throws it out the window.

On my solid state amps in the past ive never had this problem. The distortion usually sounds smooth and there is no restless/jumpy quality to it.

I guess the main thing is I am wondering is if this is just a trait of overdriven/distorted tube amps or is there something wrong with my amps that may need to be fixed or tweaked? BOTH of my amps are like this. Although one is more noticable than the other one. I have a laney cub12R that has 2 el84's and 3 12ax7's and the other amp is a laney TT100H with 4 el34's and 6 12ax7's. Messing with the EQ doesnt help on either and ive tried 3 different guitars each amp to see if i notice a difference. There isnt much of difference. My the tubes in both amps havent been changed. I have used the cub maxed out alot and the TT is an older amp that has never had its tubes changed.

Should i look into buying new tubes, another brand of tube amp, a solid state amp, or what?

Thanks in advance!

Offline HotBluePlates

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Re: Tube Amp Distortion Qualities
« Reply #1 on: May 23, 2013, 03:04:43 pm »
Its seems that on my tube amps when i distort them the distortion is really shaky and doesnt settle. almost like there is the fundamental  of the note and then another pitch on top of it that goes in and out of tune ever so slightly while i play them :dontknow: This is only when i play single notes though on the G string to the E string (high one). ...

When the noise is only on a single string, and only over a span of a few frets, it makes me tend to question the guitar.

But let's assume the amp/distortion is the problem...

You may want to try less distortion. Every pitch that's note a pure sine wave has overtones. That equates to a fundamental and one or more (usually many) multiples of the fundamental frequency. The lower harmonics are musically related, but the upper harmonics are not. Further, some of the natural harmonics produce a pitch which is out of tune with the same note in the equal temperament system.

I'm mainly thinking of the 5th harmonic, which is a major third but is 14 cents flat of equal temperament.

Further, more than one tone (and this is true of a fundamental and its harmonics, even for a single note) applied to a non-linear device/amplifier outputs the original tones plus the sum and difference of every two of the tones present in the original signal. This is intermodulation distortion, and creates notes both above and below the original pitches.

Intermod distortion is part of why distorted notes/chords sound like they have more "beef" but can result in a lot of new tones which are discordant with the original note. A good way to hear the effect of intermod distortion is to play/release an oblique bend (say, play/hold 12th fret high E, bend 12th fret B string up a whole step) up around the 12th fret. Under heavy distoriton, you'll hear intermodulation as a low subharmonic that seems to go up in pitch as you release the bend. This is a difference frequency you're hearing.

There's other possible causes, like power supply ripple being amplified by a stage that's distorting heavily. But rather than try to second-guess the quality of the amp you have, there's 2 general solutions:
1. Reduce the distortion.
2. Try a different amp.

If it's not the guitar, you'll probably find amps that make the weird sound less than others, if at all. I can't say I've ever had an amp make the sound you describe, though my ears have gotten more acute and I'm starting to get very frustrated with the out-of-tuneness of equal temperament and the guitar.

It almost makes me want to tune to an open chord and play slide instead. I did once know a jazz guitarist who built himself a fretless guitar, largely for soloing and (I assume) to be able to finger every note in tune.

Offline tubenit

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Re: Tube Amp Distortion Qualities
« Reply #2 on: May 23, 2013, 03:14:24 pm »
Just a thought that may or may not be useful .................

Do a search on the "enhance cap".  It tends to smooth out those higher frequencies on tube amps with an LTPI. I have wondered if it is actually eliminating some subtle oscillation issues (which you may or may not be having)?

What you're describing sounds sort of like what Geezer and I sometimes referred to as high end "hash".  Smoothing caps and the "enhance cap" can help with that.

With respect, Tubenit

Offline TurboGuitarMelton

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Re: Tube Amp Distortion Qualities
« Reply #3 on: May 24, 2013, 12:05:23 pm »
I really dont use much gain which is the problem. If i turn it down to the point that i get no sustain it is fine but at the sweet spot it gets harsh. i usually have the gain on like 7 or 8.

Anyone think that buying new preamp tubes would help? I have a couple of JJ's and TAD's in it now. Which from what i have read are typically high gain and sometimes harsh. What if i added tubes that were darker and lower gain?

Offline TurboGuitarMelton

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Re: Tube Amp Distortion Qualities
« Reply #4 on: May 24, 2013, 12:41:05 pm »
I guess the kind of sound that i am going for is a kind of sax like smooth overdrive that gives me just plain sine waves when i play a note with no vibrato that can give me some sustain and also crunch in the lower range.
Sorta like this (sax example) https://www.youtube.com/watch?v=KIxEGnzxnxs

And a guitar player i think comes close tone wise (Mattias Eklundh)- Mattias IA Eklundh - White Trash Hyper Blues

The lead sound is overdriven but it is still clean and warm.

But he uses laney amps and TAD tubes. I cant get the tone though.  :BangHead: Although, they may have put all kinds of filters on the sound in the studio....

Offline Ed_Chambley

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Re: Tube Amp Distortion Qualities
« Reply #5 on: May 24, 2013, 12:54:37 pm »
Sounds to me like you ear has changed.  Happens to all of us as we begin to enjoy different styles.  I looked at you blog and you are in my area of Atlanta.  What to do?  Take a trip to Atlanta Discount Music and play some different amps.  Dr Z, Tophat and a couple of old fenders and marshalls.  Take you guitar and see if the problem disappears.  I would think not since you are not liking 2 different amps.

Playing a 7 string and shredding is a lot different than Jazz forms and a Gibson Archtop.  I have never been a huge fan of Laney Amps, but many are.  The cub12R I have played and did not notice anything unusual.  That is with a Les Paul, Fender Tele and Gibson 335.  It lacks a little warmth and punch when clean, but Laney and clean usually do not go together.  Lots of preamp distortion in Laney amps.

Sure you can roll tubes to see if you like the change, but different circuits create different tones.  High output Humbuckers can cause a shrill in upper mids.  Try lowering you PUPs from the strings.

I can here some dissonant harmonics in this clip from the same dude playing a Laney.
Mattias Eklundh - Disco Diabolique
« Last Edit: May 24, 2013, 01:07:26 pm by Ed_Chambley »

Offline TurboGuitarMelton

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Re: Tube Amp Distortion Qualities
« Reply #6 on: May 24, 2013, 01:24:51 pm »
Ed,

thanks a bunch for the reply, i definitely agree with you when you say my ear has changed. Music college will do that to ya. I listen to tons of jazz and orchestral music these days. Which has changed my composition habits and my desire for the tone my guitar is giving me. Ill check out the music store this weekend for sure!

Would you say that Marshalls are a lot smoother sounding than laneys? Ive always thought theyd be similar since they are both British made? Satriani has been using marshalls lately and ive always thought his tone was very warm and clean overdriven.

Offline Ed_Chambley

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Re: Tube Amp Distortion Qualities
« Reply #7 on: May 24, 2013, 02:01:08 pm »
Marshalls vary a lot.  For instance, I have a original JTM 45 which is warm and heavy.  Easy to get a woman tone, but hard to get a good clean at much volume.  Plexi's are great Rock amps with a wonderful upper mid content and JCM 800 made the 80's shredders.  They can get harsh, but they will scream as well.  I like the Plexi best, but it is more affordable to build one.  Not a fan of new marshall much.

Suhr amps and Soldano are quite nice and harmonically rich high gain amps.  If you can, play a Cornford MK50HII.  Great in high gain.  This British/American sound kills me.  In reality I cannot get it.  If British means Marshall then the first Marshall was a Fender Bassman.  Pete Townsend and Jimi both used Marshalls, but so did Ritchie Blackmore before he became an ENGL Rep.  They pushed for more wattage as in those days stage volume was really loud.

Think about it.  Does David Gilmore sound like Pete Townsend?  Both British using British amps.  Does Jimmy Page sound like either of them?  The Beatles came and the Beach Boys were here.  When the Who arrived, things changed.  There are many good sounding amps and a lot of builders here who build great amps.  There is no replacing moving of air. 

Everything sounds synthetic compared to a 100 watt Marshall Plexi with every knob dimed running through 2, 4 12 cabs with Vintage 30.  Even better, 6 of them side by side.

Now that's Rock.  Have fun at the Purple Building which is Atlanta Discount Music.  Tell George, Ed Chambley said hello.  Tell him you want my discount.

Offline SILVERGUN

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Re: Tube Amp Distortion Qualities
« Reply #8 on: May 24, 2013, 02:55:00 pm »
Hey TGM,
I enjoyed your website and also enjoy the video clip of Mattias

That "sax" sound you hear is not obtainable with just a guitar and amp.......to get the drive you need for that style you may want to start with a great straight forward low gain sound on the Laney and dial a distortion pedal to get you close to that gainy solo sound
At first, the lead sound effect came off as a synth type....(but most synth style setups would probably have tracking issues trying to keep up with that kind of speed)....however, if you'd really like to get a sax-type sound you might want to consider a midi pickup:
Roland GR-20 sax and more

There's definitely some type of pitch shifting (Whammy pedal style) on the Mattias track, and he may have been able to conjure up the total effect from one unit....
So I would say minimally you need: your Laney, a distortion pedal, and a pitch shifting, filter type pedal

For the distortion pedal, I read somewhere where he may have used one of these:
http://amtelectronicsusa.com/productpagefataltube.html

The best example of the synth setup that I've ever seen live is Steve Morse, who uses a straightforward amp setup, and then blends his synth sound in with a separate volume pedal that drives a totally separate "wet (effected)" amp

For the record,,,,Ed C has probably forgotten more about good sound than we will ever know :icon_biggrin:

Offline Ed_Chambley

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Re: Tube Amp Distortion Qualities
« Reply #9 on: May 25, 2013, 08:22:30 am »
For the record,,,,Ed C has probably forgotten more about good sound than we will ever know :icon_biggrin:
[/quote]
See how they talk when you are getting old? :l2:

 


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