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Topic: How much does an amps tonestack effect the overall sound? |
Tim Toberer
From:
Nebraska, USA
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Posted 24 Apr 2024 6:22 am |
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I am curious what people think. How much of an amps sound comes from the tonestack, compared to the power amp (tubes, power chip etc.) and speaker? From my experience the character of the amp is almost completely defined by the tonestack. The feel of the amp is more effected by the power amp in terms of sag vs. tight, generally a very subtle thing. The speaker seems to effect everything, but not enough to completely change the character of the amp.
Here is an interesting amp which has inspired my view on the subject. The Quilter amps are based on a similar concept from what I know.
https://www.award-session.com/5E3-EXTRA_combo.php
He makes many claims about the design of his amp. From reading reviews people seem to like them. For people who love the sound of vintage steel guitar, the old simple circuits really can't be beat. There is something magic here and most people think it is the tubes, but there is an argument to be made that it is really mostly the tonestack. Here are some popular tone stacks. https://monster.partyhat.co/article/amplifier-tone-stacks/
In this day of high technology, I am not sure how much interest for this sort of thing there is, but guitar amps are one thing where people seem to cling to the past. While I love my little amp modeling multi FX pedal, nothing will ever beat playing through a "real" amp. My definition of "real" may different than some peoples it seems.
Here is my first project based on this idea. It is sort of a solid state Eh-185. https://bb.steelguitarforum.com/viewtopic.php?t=393110&highlight= I am still completely blown away by how simple this amp is and how good it sounds and am really dedicated to this concept. I am collecting parts to build an amp around a Tweed Princeton tonestack using another cheap class D power amp. |
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Stephen Cowell
From:
Round Rock, Texas, USA
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Tim Toberer
From:
Nebraska, USA
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Posted 25 Apr 2024 5:38 am
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Thanks for that, looks very useful. |
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Jack Hanson
From:
San Luis Valley, USA
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Posted 25 Apr 2024 7:16 am
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| An old pal of mine who was into building amps once made a Marshall 18-Watt clone with a switch that bypassed its tone stack entirely. Possibly the best-sounding amp I've ever played through with its tone stack switched out. Super-responsive, and tone to die for. A one-trick pony amp, but man, it was a good trick. A very good trick. |
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Ken Morgan
From:
Midland, Texas, USA
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Posted 25 Apr 2024 7:48 am
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https://robrobinette.com/How_The_TMB_Tone_Stack_Works.htm
This explains it all pretty well I think. Almost all amps have passive tone networks, meaning the knobs only cut frequencies instead of boosting them.
On old designs like Fender, one can get real close to bypassing it by turning all tone knobs up to 10 (11 on Marshall 😉)
Lots of variations of course.
_________________
67 Shobud Blue Darling III, scads of pedals and such, more 6 strings than I got room for
Ken Morgan
Midland, TX |
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Tim Toberer
From:
Nebraska, USA
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Posted 26 Apr 2024 5:50 am
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| Ken Morgan wrote: |
https://robrobinette.com/How_The_TMB_Tone_Stack_Works.htm
This explains it all pretty well I think. Almost all amps have passive tone networks, meaning the knobs only cut frequencies instead of boosting them.
On old designs like Fender, one can get real close to bypassing it by turning all tone knobs up to 10 (11 on Marshall 😉)
Lots of variations of course. |
That site was my bible as I was building my first 2 amps! It just goes on and on and on. Absolutely amazing resource. I think I forgot most of what learned doing that. 
It seems the more complicated these tone stacks get, the harder it is to dial in a good sound. I added a tone control cut to my "real" Princeton giving me a Champ basically, but I generally like the tone control. I also added a potentiometer to the negative feedback circuit to give a range of distortion. These are nice additions, but it really doesn't need anything else. I added the RobRob 3 position negative feedback switch mod to my Fender Deluxe which makes it way more versatile, and I recently built an attenuator, which is an absolute necessity! It took at least 1 1/2 years to work the bugs out of this amp. The last fix was was a bad speaker which Eminence replaced free of charge. It will be nice to have a Princeton and a Deluxe clone to compare my transistor based clones to. These amps to me are still the holy grail. Wish I had a real Eh-150 but those just look like a nightmare in a box.
I am not anti tube by any means, the tube sound is definitely part of the equation, but as far as building amps no more tubes for me. I really didn't like working with them. The high voltage especially and the hard to source, expensive, fragile, heavy parts just caused me tons of stress. Building my third amp proved to me that you can get pretty close with transistors by using preamp pedal designs and matching them with these tiny power amp boards. This is more of a cheap fun hobby now and I can experiment to my hearts content, and my wife won't be asking why I needed to order $300 more from TubeDepot. She will be saying what's this $100 order from Small Bear Electronics?  I am also thinking about a small FFFR cabinet to match my modeling amp pedal. This way I can have my cake and eat it too.
For anyone interested in this stuff I also made a tutorial for a Tweed cover or recover. I am happy to see the pictures are still there. This was my favorite part of building this amp!
https://bb.steelguitarforum.com/viewtopic.php?t=382557&highlight=tweed+tutorial |
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Dave Grafe
From:
Hudson River Valley NY
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Posted 26 Apr 2024 6:02 am
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| Jack Hanson wrote: |
| An old pal of mine who was into building amps once made a Marshall 18-Watt clone with a switch that bypassed its tone stack entirely. Possibly the best-sounding amp I've ever played through with its tone stack switched out. Super-responsive, and tone to die for. A one-trick pony amp, but man, it was a good trick. A very good trick. |
It is important to understand that ALL audio filters introduce some phase distortion to the signal, whether active or passive, analog or digital. This includes the common low-pass tone controls on musical instruments and high-pass switches on some microphones, and why premium mixers, hifi stereo preamps, and studio gear generally offer an EQ bypass option to remove the filter components from the signal chain completely so as to preserve phase integrity of the original program audio. This is also why knowledgeable recording engineers track without EQ, applying necessary corrections only during mixdown. The task for users is to find gear that is most pleasing to our ears, i.e. Fender's classic midrange "scoop" that more-or-less reflects the Fletcher-Munson curve of human hearing sensitivity. Note that turning all tone knobs to "10" on a cut-only filter set does not necessarily restore the full range or phase integrity of the instrument or microphone being amplified. A well-designed active circuit can minimize this interference when all controls are at the mid 0dB position, but the presence of filter elements can still affect the signal. For this reason it is considered best practice to cut undesirable frequencies rather than boosting those we wish to enhance, as the phase issues that are part of the affected spectrum tend to thus be reduced rather than increased. |
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Donny Hinson
From:
Glen Burnie, Md. U.S.A.
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Posted 26 Apr 2024 2:46 pm
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| Quote: |
| How much does an amps tonestack effect the overall sound? |
I think that probably 85%-90% of the sound or tone that we hear from an amp comes from the tone control network (or "tone stack", if the amp has that type of tone network). The rest, that last 10%-15%, comes from amp design, the speaker, and the cabinet. (With all other things being equal). The Fender tone stack, by the way, is essentially flat with bass and treble at 0, and the mids at 10. "Flat" means no boost or cut in the amps frequency response, and that is reasonably close to the sound with no tone network added at all. Although, as Dave says, any tone change institutes some phase change, I tend not to worry about that, and urge others to do the same. The reason is that, as stage musicians, we're seeking a certain sound, a certain tone, not a scientifically accurate or "phase change free" sound, per se. One must understand that with the severely limited equipment we're inclined to use, worrying about minor phase changes can be unproductive. As one engineer explained to me, when you're pushing high levels of power through one speaker (or two identical speakers) in an open-back cabinet, you're really out of audiophile* territory, far from ideal or accurate reproduction. There's enough to worry about with overmodulation, intermodulation distortion, standing waves, and other situational variables like room acoustics, without thinking about minor phase differences. True audiophiles (and some recording engineers) have separate speakers for different audio ranges, in custom sized, designed, ported, and placed speaker enclosures, stuff that often costs tens of thousands of dollars. (The stuff we're forced to use is crude tinker-toys, in comparison.) And because audiophiles tend to obsess over minutiae, and are used to the best of everything, their phenomenally large and expensive gear probably wouldn't suit us, and our simplistic gear would seem like junk to them. And while it's true that engineers like to record with no graphic or parametric EQ added, they also like to leave out all other EFX as well, because it's far easier to add something down the line than it is to take it away once it's there.
As long as your gear gives you the sound you want, nothing is bad, including any type of tone controls. Since we're essentially playing a solid-bodied guitar with only a bridge pickup and usually no tone control network on our guitars, we usually need all the tonal help we can get.
But if you don't like tone controls, tone stacks, graphic and parametric EQ's, that's fine too. Whatever floats your boat!  |
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Dave Grafe
From:
Hudson River Valley NY
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Posted 26 Apr 2024 3:10 pm
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| As always, Donny is spot on, I was primarily addressing Jack's comment about how great his friend's custom build amp sounded with the tone stack switched out and explaining why it's so. I love my Vibroverb and Webb amps, and agree that tonal response of our steel guitar pickups, speaker cabs etc. are pre-loaded with all manner of phase interactions, thus the dramatic differences in how various rigs sound, especially in the higher frequencies. |
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Bob Carlucci
From:
Candor, New York, USA
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Posted 27 Apr 2024 4:07 am
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I don't have the knowledge and can't explain why like you guys can, but from experience I can say that tone stack configuration makes a huge difference in the tone of an amp... over the years I have had several 100 watt Fender amps,,, Showman, Twin Reverb,Quad Reverb, and a couple of PA 100 heads which are twin Reverb amps with more channels and a different tone stack setup... The PA 100 amps through the same speaker do sound like a Fender amp.. The heritage is there. However, try as I might I could never get them to sound like a showman or twin. The PA 100 amps sound good, but not really like the Twin or Showman... I would imagine if someone took one of those amps, rewired the pots to whatever specs a showman or twin uses, they would sound exactly the same. It was never worth it to me personally as I would have had to have it done by a tech, and simply always went back to a proper Showman head....
_________________
I'm over the hill and hittin'rocks on the way down!
no gear list for me.. you don't have the time...... |
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Tim Toberer
From:
Nebraska, USA
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Posted 27 Apr 2024 5:13 am
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| Donny Hinson wrote: |
| Quote: |
| How much does an amps tonestack effect the overall sound? |
But if you don't like tone controls, tone stacks, graphic and parametric EQ's, that's fine too. Whatever floats your boat! |
That was a very good explanation. I think the problem for me and probably others is that having more complicated controls allows a much wider variety of sounds, but it also means you have to know how to use them. For me fewer tone adjustments means I spend more time playing and less time fiddling with knobs. Of course these older amps are a sound mostly associated with older styles of music. That just happens to be the sound I love. It seems you can almost find this sound in more modern amps, but it just isn't quite there. |
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