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Parameter Mods - SS-ified Jazz Bass models

Postretro

Inspired
This is my favorite hack for reducing interference and note-to-note IM in a Bass Amp.

(Amp block; Speaker page)

1) Choose your favorite Impedance Curve -- any curve at all. (The Jazz 120 is nice for Jazz sounds.)

2) Set "High Freq" to 40000 -- the max.

3) Set "HF Reso" to 0.0 -- the min

This will completely flatten the the HF Resonant Peak -- even more than an SS amp.
If you feel like you are missing something in your HF sound, then add some HF lift back in by increasing "HF Reso,"
This will give the Impedance Curve a bit of a lift in the HF's.
Flat will give you a clearer sound with less wavering between multiple notes.
A lift will bring some of that wavering back.
But, it will also be closer to a SS amp which is flatter than a high impedance tube amp, but not completely flat.

4) Set "Xformer HF" by ear. I end up at around 16K for bass sounds. Whatever sounds good to you.
My thoughts are to decrease it until I feel like something is missing or wrong (100% subjective.)

5) Adjust "Cab Resonance" to taste; down = cleaner but less organic, up = more organic, more complex, less clear


While, the same thing can be done for the LF Resonant Peak, it is less satisfying.
The LFRP provides a lot of the bass amp's characteristics and qualities.
A flat LFRP is cleaner, some people will like it.
To me, it just sounds boring with less interesting characteristic tone.
 

Postretro

Inspired
@jzucker, are you out there? Don't bother with a video of the modded Jazz 120. I have a bass amp that is much, much better. Your Bass will sound as clean as a baritone guitar.
 
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jzucker

Experienced
@jzucker, are you out there? Don't bother with a video of the modded Jazz 120. I have a bass amp that is much, much better. Your Bass will sound as clean as a baritone guitar.
hi, @Postretro I was locked out for a while. I'm back now. where's the new link? I spent a couple hours with the jc120 trial and I feel like it's nasally. I've gone back to the original bass mods 1
 

jzucker

Experienced
@jzucker, how did the presence and depth work for you?
presence worked good. Did not play around with depth. I flipped back and forth between the trial preset and the bass mods 1 and it struck me that the newer version had a nasally quality to it. I tried tweaking the tone controls and amp's output graphic eq but couldn't get rid of it...
 

jzucker

Experienced
if you toggle back and forth between bass mods 1 and the jc120 trial, the trial amp has sort of a semi-cocked wah quality to it. Not sure what's causing that...
 

Postretro

Inspired
I sent you a friend request on facebook. Some of this can move quicker with a conversation.

While I get the next patch ready. Try playing with the "tonestack frequency" on the preamp page. Try raising it, if the 5th string sounds weak. I don't know if that is what you might mean by nasally.

Also try swapping "tonestack types". This just to get you comfortable with some of these mods. Once you get comfortable it is easier to fix things to your liking. Try the "Skyline" tonestack and the "Shiver Cln" tonestack. The one that is in there now is the "skyline deep" tonestack. Also, "default" is the original Jazz 120 tonestack.

These experiments might give you some new observations and insights. And it might give me some clues that will help.

All these parameters are in the lower right hand corner of the preamp page.

Also, try out each of the six options for "tonestack location." They will each change the character of the tone. See which one you like. It will be good for me to know.

I have a sense of "nasally" and I get the "cocked wah" sound. I will watch for that

This is not an effort to fix anything right now. Although, it might. Since this patch is disposable, this is just a way to get some quick experience with no consequences. I know you are sensitive to details in sound. I am too -- but, in different ways. often after sitting with a sound for a while the parts of the sound I don't like become more obvious. Getting a sense of how to tune it in for yourself is really the only way to go, eventually.

But, that is only if you feel like it. Just to say, having a few of the tricks can empower you to get the sound you want.

Incidentally, I suspect I may have been put into some trick-bag forum-jail. It is as if no one sees any of my posts. I hope not, I actually love this product and FAS for making it happen. I had hoped to come up with a solution that would open the door for more Jazz bassists and more non-rocker types. But, it is easy to rub people the wrong way these days. It is just the Spirit of the Times. I actually wonder what I look like to some people.

Anyway, try some of these things. Don't get to serious about it. Just get a sense of what can be done.

Don't let me condescend. If you know about this and have done it already, let me know. I have no problem with being corrected with useful information.
 
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jzucker

Experienced
Here's one of of the @Postretro bass presets. Originally, I was unable to get a sound on the fractal that was "as good" as my mark bass amp but now the fractal sounds better. More clear and less colored. This is bass mod 1 based on the JC120.

 

Postretro

Inspired
@jzucker, here are a few Jazz 120 Amp block parameters for you to adjust to your own taste. I made some guesses about your tone. But really, it is about you, and other Jazz bassists, being able to dial these things in to your exact hearing.

I do wonder if the "nasally" quality might be connected to one of these parameters.
Things like that are easier to determine as you dial them in and out for yourself.

"293. If I say of myself that it is only from my own case that I know what the word "pain" means -- must I not say the same of other people too? And how can I generalize the one case so irresponsibly?
Now someone tells me that he knows what pain is only from his own case! Suppose everyone had a box with something in it: we call it a "beetle". No one can look into anyone else's box, and everyone says he knows what a beetle is only by looking at his beetle. -- Here it would be quite possible for everyone to have something different in his box. One might even imagine such a thing constantly changing. -- But suppose the word "beetle" had a use in these people's language? -- If so it would not be used as the name of a thing."

-- Wittgenstein, 'Philosophical Investigations‘ (1953)


For me, nasal means a sound thinner in the higher frequencies. Perhaps a thinness in the sound of the highest (5th) bass string. And "cocked wah" indicates a formant value of some sort -- typically in the 350-1400 Hz range

But, I am not using a bass. I am using a 6 string guitar with a Whammy octave-down pitch block. Now that the amp sound has become much clearer, it is getting harder to hear the tone details that I need to hear with the guitar/whammy setup..

I will pickup a 6 string bass to pursue this. It does interest me. And it will be useful for me in general. It has to be a 6 string bass. Even with the whammy setup, I have noticed how some bass amps are weak on the frequencies found in the higher, additional strings. Probably, because they didn't hear them while developing the amp's sound.

All of this is to say, it will be easier for you to discover the tone defect that bothers you. This will be more and more true as the tone defects become smaller and less prominent. And, "nasal/cocked wah" could also be something caused the chosen "tonestack" and "tonestack frequency" or even "tonestack location."


Anyway, try adjusting these parameters. And let me know what you find.


Power Type - set to DC (default is AC)

(Amp block; Power Supply page)

A DC "Power type" will be quieter, cleaner, no ghost notes and less distorted than AC. But, DC will also be less lively, less organic and less dynamically complex.

Try both AC and DC listen for the one you like best.
Also, sweep the Variac voltage for while using DC -- and again while using AC.

Trust the sounds you are drawn to instinctively.
Trust the sounds that make you feel like playing for a while.

Theory is good. And theory always gets the ball rolling.

But, whatever it is that makes something instinctively beautiful, and instinctively attractive, is not os easy for theories to explain.



______


Variac - set to 135%

(Amp block; Power Supply page)

You can try any value from 70% - 150%.
Listen to the tone as you change the value. Listen for what you like.
You can always set it back to 135% - or even to the original 100%.

In General:
higher = cleaner, faster, more accurate, fewer overtones, less IM
lower = dirtier, slower, more distorted, more overtones, more IM

In Practice:
With some models, raising or lowering the voltage might cause some circuit instability.
Especially when the difference is more extreme.
For most of the best tones of many genres, avoid any change that increases:
warbling, chorusing, muddiness or IM distortion.

Ideally, 150% power would be better for punch and transient response.
In actuality, raising the voltage on an amp may introduce oscillations that,
while not very obvious, cause unwanted IM, ghosting and chorusing in the tone.

I settled on 135% for the Jazz 120. Mostly, due to caution. And, because you use very clean tones. But, you should listen and adjust for yourself.

The stock value is 100%.

Important to note:
These instabilities do not arise from errors in the modeling. But rather, they arise from the accuracy of the model. A lot of old guitar amps were not particularly safe from parasitic and PSU oscillations. And those oscillations can become even more of a problem when pushing the amp beyond it's design limits. Even when these oscillations are outside the range of human hearing, they can have deleterious effects on the audible notes - specially in a Bass note.
 
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jzucker

Experienced
@Postretro I played around with all those parameters, wasn't able to dial out the middy character of the preset. One thing i'd recommend is going back to your v1 jc120 and a/b'ing it with the newer versions. Due to psychoacoustics, our ears normalize out certain sounds and sometimes if you go back and forth between the two, you may hear some differences that aren't apparent just listening to one over and over. Of course, the pitch block with a guitar is also not the ideal way. I know you're aware of both of these things. :)
 

Postretro

Inspired
@stub, this patch is for you, and anyone else who might be interested, let me know what you think. This is the Citrus tube bass amp model. I modified a number of parameters for a cleaner sound with more note-to-note separation. There is also a text file that details the changes that I made. You can reverse some of the changes -- to add some color back in, if you want.. Or, you can start with a fresh Citrus bass amp block and add each change in from the text to see which ones you like. You could try them on any amp model to change it into a clean bass amp. But, the results will be different with different amps. The tone controls are all still on 5. Set them as you wish. The text is a short list of only the parameters I changed. I think the big trick here is in the Speaker Impedance Curve. Feel free to ask any and all questions and to be critical. You, at least, allowed for the possibility of a cleaner bass amp model. I would appreciate your thoughts. If nothing else, this will give you some understanding of the parameters and how they can be used to change a models sound and behavior. edit: I added a similarly modded Jazz 120 patch to compare.
 

Attachments

  • Bass Citrus 3.8 -2.syx
    24.1 KB · Views: 2
  • Bass Jazz 120 -2.syx
    24.1 KB · Views: 3
  • Bass Amp Parameter Mods.txt
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stub

Member
Disclaimer: I'm taking my first baby steps with the FM3, much less with FM3 for bass, so I appreciate your patience as I may just say a bunch of noob nonsense.

When I load either Citrus or Jazz 120, I get lots of clipping. Perhaps my basses' have hot pickups. When I drop my bass volume to half, it is clean. I modded my bass with a balanced/low-z transformer/built-in-DI, engaging that it also drops the level enough to clean it up the signal.

The output of the 120 amp block was low, so I boosted it up from -12 dB to 0 dB.

With the chosen IR's and the others I tried, they all are variations of high-passing at around may 80 Hz, and a hump at around 140 Hz. It almost makes me want to just not use an IR and try just using parametric EQ, so I can get the vibe and shape I want.

They were both a tad dark (rolled off in the upper spectrum). I want some clarity, which is both a bit of overtone and finger-skin at around 3K-- not a lot, but enough.

Anything that can be done to eliminate compression is all I'd ask for in either of these models.

Once I played an Orange gtr amp and I wasn't able to get a clean sound without loads of compression. It made me think it was called "orange" because you squeeze them for juice. I worried the citric bass amp might also be similarly squishy. Neither the 120 or Citrus seemed overly compressed, but I did feel like it was squishing some.

I was hoping I'd be able to offer something more useful in my first little batch of feedback, but I'm in over my head a little.
 

Postretro

Inspired
Disclaimer: I'm taking my first baby steps with the FM3, much less with FM3 for bass, so I appreciate your patience as I may just say a bunch of noob nonsense.

When I load either Citrus or Jazz 120, I get lots of clipping. Perhaps my basses' have hot pickups. When I drop my bass volume to half, it is clean. I modded my bass with a balanced/low-z transformer/built-in-DI, engaging that it also drops the level enough to clean it up the signal.

The output of the 120 amp block was low, so I boosted it up from -12 dB to 0 dB.

With the chosen IR's and the others I tried, they all are variations of high-passing at around may 80 Hz, and a hump at around 140 Hz. It almost makes me want to just not use an IR and try just using parametric EQ, so I can get the vibe and shape I want.

They were both a tad dark (rolled off in the upper spectrum). I want some clarity, which is both a bit of overtone and finger-skin at around 3K-- not a lot, but enough.

Anything that can be done to eliminate compression is all I'd ask for in either of these models.

Once I played an Orange gtr amp and I wasn't able to get a clean sound without loads of compression. It made me think it was called "orange" because you squeeze them for juice. I worried the citric bass amp might also be similarly squishy. Neither the 120 or Citrus seemed overly compressed, but I did feel like it was squishing some.

I was hoping I'd be able to offer something more useful in my first little batch of feedback, but I'm in over my head a little.
I appreciate that, @stub. Your comments are very useful to me, thank you. I know you gave me your honest opinion. And, I appreciate you doing that when this still new to you. ”Not being able to get a clean sound without compression” was a very helpful comment. I eliminated a lot distortion from the tubes and transformers. And, I reduced a lot of IM with the flatter Speaker Impedance Curve. But, compression is an issue I did not notice or consider. And, that may be a tube thing. It might be coming from the power amp. And it might be solved by lowering the MV or the input drive. Or, it may be a response to the flatter SIC. You might want to try several of the different Speaker Impedance Curves that are available and compare them to the Resistive SIC - which is close to the one I set up — see if one of the other SIC’s work better for you. Try the Jazz 120 SIC. And see if that makes the amp feel less compressed.

As far as IR’s go, that was a big eye-opener for me. Multiple speakers in a cab, using 2 different IR’s — even when aligned— and some speakers more than others will add IM, interference and a lack of string-to-string clarity. I chose the 1x15 SV M88 because it had the least of that. But, it is also dark and not so flat. I have been using a 3rd party IR that was suggested to me by jzucker. It is about $7 for two wave files. But, it is a 1x12 that is very flat and clean with a wide frequency range — up to 15k. It is a copy of his Aguilar 1x12 cab Otherwise, you may want to look for a 3rd party IR of a speaker cab that you know well and prefer.

I got the aguilar SL112 IR here. https://www.tylerspicermusic.com/shop/p/a-slight-112-ir

Jzucker said, "it's the best IR i've found for doing the jazz stuff that I'm doing. I tried the bergantino from celestion but really didn't think it was flat enough. It seemed very bright and midrangey."


The patch is set up to send output1, through the IR, to the FOH. He uses output2 to to go into the return of his Markbass and cab on stage. The IR he uses is the same as his Aguilera 1x12 on stage. You may want to find a 3rd party IR to match the cab you use. If, you are happy with it. If not, look for a 3rd party IR of the cab you wish you had. But, if you want clarity. I think, the modern one-speaker, coaxial/tweeter cabs are generally going to be the best for that.

I will make an effort to set up the patch up to be less "compressed." But, I will be guessing at identifying the exact cause.

Many people are not interested in the amp parameters. And, if you would rather not adjust them yourself, that is fine, I understand they can seem imposing. But, you might find some value in making each parameter change in the text file one-by-one with a clean Bass Amp block. That way, you could determine for yourself which changes sounded best to you. I would be happy to answer any questions about what each parameter does and what to expect. I highly recommend the Amp Block Wiki. But, I would be interested in what you heard when adjusting each parameter. My original thought was not that I would patch together the ultimate Bass amp. But, rather that the adjustments toward a cleaner more jazz oriented bass amp would be laid out. I had really hoped for more hands-on community discussion and exploration of the possibilities. My experience is that even if one falls short of the ideal goal. The things that are learned in the process have a much wider range of uses and possibilities.

If you have any more ideas or discoveries about any of this, @stub, Please feel free to expand on what you find.
 
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Postretro

Inspired
@stub, this is the new patch and explanations of the changes.

FIX #1 -- This will make a big difference!

(AMP block; Speaker page)

This may solve the "compression" that was bothering you. And maybe, the poor performance of the IR's.
Try these settings for a stiffer, punchier, tighter Bass Speaker Response

"Speaker Compliance" - 100.00%
"Speaker Compression" - 0.00
"Speaker Drive" - 0.00

For bass, I found these extreme settings to work quite well.
(I would hate these settings on guitar. But, on bass they sound great!)

Adjust as desired.

______

FIX #2

(AMP block; Speaker page)

I also changed the "Speaker Impedance Curve" in 4 scenes

Scene 1, A - SIC low rise at 200 Hz
Scene 2, B - SIC flat extended frequency
Scene 3, C - SIC sharp peak at 58 Hz
Scene 4, D - SIC sharp peak at 250 Hz

For bass, in the lower frequencies, a rise in the SIC produces a "growl."
(distortion due to load mismatch)

For bass, in the higher frequencies, a rise in the SIC produces IM distortion.
And, poor string-to-string clarity.

I will discuss these more in another post.

I think learning to customize the SIC is key to getting the exact bass sound you want.

______


FIX #3

CAB block

I found some other things in that CAB block to change.
This may solve the uneven bass response. And again, maybe, the poor performance of the IR's.

(CAB block; Cab page)

Set "Proximity" = 0.0
Set "Low Cut" = 20.0 Hz
Set "High Cut" = 20,000.0 Hz

(CAB block; Preamp page)

Set "Low Cut" = 20.0 Hz
Set "High Cut" = 20,000.0 Hz


The "High Cut" settings are higher than necessary.
But, I will let you decide how much to lower them - if at all.

"Low Cut" should have been at 20.0 Hz -- they weren't.
"Proximity" should've been at 0.00 -- they weren't


______

General information on the proximity parameters:

"Proximity" (CAB block; Preamp page) controls how much proximity effect the cab mic has.

"Proximity Frequency" (CAB block; Room/Air page) sets the frequency of the proximity effect.

"Proximity Frequency" has no effect when "Proximity" = 0.00

Adjust as desired.

______


General Information On The Speaker Parameters:

Fairly Common Default Values:

"Speaker Compliance" - 50.00%
"Speaker Compression" - 1.00
"Speaker Drive" - 0.00
"Speaker Time Constant" - 2000 ms



1) "Speaker Compliance" - models speaker stiffness/newness

To my ears, increasing "Speaker Compliance
will make the speakers sound tighter and more accurate.
But, it will also make them sound less smooth, less complex and less musical.
A good subjective description is that 50% Speaker Compliance sounds "broken in."
Higher values move closer to a stiffer, newer speaker sound.

100% = tightest, punchiest, cleanest, clearest, most accurate


2) "Speaker Compression" - models a speaker being driven hard to compression

More "Speaker Compression" adds some softness and tonal complexity to the sound

0.00 = tightest, punchiest, cleanest, clearest, most accurate


3) "Speaker Drive" - "This simulates distortion and gentle compression
caused by pushing a speaker too far."
"Don’t overlook this when striving for “vintage” tones as it helps
make edge-of-breakup tones sound like an old, well-played amp."

-- "old well-played," "vintage tones" =/= not! typical for jazz bass sound.

0.0 = tightest, punchiest, cleanest, clearest, most accurate


4) "Speaker Time Constant" - Important! This Is Not A Faster Transient Response!

- this is a thermal time constant, that determines
slow, small, but dynamic changes in the DCR of a speaker due to heat.

I have been unable to settle on a personal preference here.
I generally leave it at the default (2000 ms or so)

also:

"If Speaker Comp is zero the time constant does nothing.
Any perceived difference is perceptual bias."
 

Attachments

  • Bass Citrus 4.0.syx
    24.1 KB · Views: 1
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Postretro

Inspired
I would also suggest experimenting with the "Tonestack Freq" (AMP block; Preamp page.)
Ignore the frequency displayed. It won't be accurate for a different tonestack (besides "Default" - if untouched.)
Simply sweep the control while playing. Listen for the setting that works best for you.
It helps to do this while playing in your normal musical context
-- with your band, with a track or a song of the music you usually play.
Sometimes, different music means a different setting.
 
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Postretro

Inspired
One more step forward. Criticism is appreciated. There are numerous small, more subtle, changes. I will list them later.
 

Attachments

  • Bass Citrus 4.1.syx
    24.1 KB · Views: 4
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