Tone stack for bas guitar amp

[tpaairman]

I'm building an amp geared for a bass guitar, including a three position tone stack. I'm thinking 4 string, but could be for a 5 string while I'm at it, so knowing that the frequency range would be about 30-400Hz range, what would be a good cutoff frequency for each of the three? Or more specifically the high and the low, knowing the mid would overlap. Would I want the high and low to cut off right at the third of the way mark so to speak or maybe a bit closer to the middle? Or even one closer to the middle than the other?

[loudthud]

What are you talking about ?

If you are running a windows PC, download this and see if you can find what you want: http://www.duncanamps.com/tsc/index.html

Can you name any amp that does what you want ?

[tpaairman]

I can't download it. I use a Mac.

I'm not really sure what amps would do what I'm wanting, but I guess to put it another way, I'm wanting to adjust the tone stack for the range of frequencies of a bass guitar rather than a 6 string.

[J M Fahey]

Then you can´t go wrong with the classic Ampeg tone stack.
Old style was tubed, had Bass and Treble controls and a separate selectable midrange one using a multitapped inductor.
Check Ampeg SVT preamp.

Modern (transistor) ones use Op Amp gyrators to replace inductors.

Or check SWR Bass amplifier tone controls, as in the Workingman ones.

Or classic Gallien Krueger tone controls, 4 bands , although in general they are considered somewhat "mild" compared to others.

[SoulFetish]

I can't download it. I use a Mac.

I'm not really sure what amps would do what I'm wanting, but I guess to put it another way, I'm wanting to adjust the tone stack for the range of frequencies of a bass guitar rather than a 6 string.

I use this program on a mac, as well as Duncan's power supply simulator.
In fact, I run several windows programs(particularly older sofware not available on mac os) with no problem at all.
This is made possible by one of the most useful and clever developments in software I've ever come across, and it's called WINE.
In my opinion, wine is a must have for Linux/Mac OS user.
I can walk you through what you need to do to set this up, if you want. But, in the meantime, do a little internet reading on the two things which should make this a painless experience:
1. Wine
2. Homebrew

Check those out and report back

[tpaairman]

Juan - Thank you for the info. I will research those.

SoulFish - Thank You for the suggestions. I have tried WINE before and it seemed hit or miss. I think What I'm going to do is buy a cheapie Windows laptop on Black Friday for shop use. There's a few items of software that I'd love to use that are Windows only, and I won't be as concerned with it getting a bit dirty on the bench or the like.

[Lauri]

Someone has created a tone stack calculator that runs on web browsers http://www.guitarscience.net/tsc/info.htm

[the fatch]

I can't download it. I use a Mac.

I'm not really sure what amps would do what I'm wanting, but I guess to put it another way, I'm wanting to adjust the tone stack for the range of frequencies of a bass guitar rather than a 6 string.

Increasing the capacitor values by a factor of two will shift the response of a tone stack down one octave.

[tpaairman]

I appreciate the info, however that's not my question. I know how to adjust the values to get to a certain frequency. What I need to know is what frequencies should I be aiming for?

[Malcolm Irving]

The strings on a 4 string bass are tuned an octave down from the low strings on a 6 string guitar, so I think the advice from the fatch is a good place to start. For a 5 string bass, perhaps increase the value of the capacitors by a factor of 3. A similar increase would apply to coupling capacitors in the amp.

[J M Fahey]

Plans B, C, and D

* Use a relatively simple Ampeg Bass and Treble control, as-is, which has been time tested and a favorite for almost 60 years now, and add a 9/10/12 band Graphic Equalizer, adjust to taste.
Even better a 31 band one, with 1/3 octave bands, can´t get closer than that.

* same but with a 3 or 4 band Parametric Equalizer ... infinite range of adjustment

* or add to the tried and true Commerciañ designs to explore, the Sunn Coliseum 300W equakizer.
Id I don´t remember wrong, it was 3 or 4 band, and at least 2 of them had switch selectable center frequencies, use your ears to decide which ones you like best.

That said, IF you make a killer wide range Bass Cabinet (which is neither easy nor inexpensive), you´ll find playing it flat is already very good, and needs little or not tweaking.
Check the EV 2 way Bass Cabinet used by Stanley Clarke, *anything* you plug there will sound very good.

Since fashion changes with the wind, you might find one of those, used of course, for relatively peanuts; virtuoso Bass Players have been out of fashion for quite a few years now

[darkbluemurder]

One more vote for the James tone stack as used in various Ampeg amps. I used this in one amp I mostly use for bass but I combined it with the Framus mid control.

[Chuck H]

I'm in Juan's camp for the very simple reason that, whatever frequencies and knee points you think you need to target to get good bass tone HAS ALREADY BEEN WORKED OUT~!!! Litterally decades of development of instruments, amps and speakers have been designed to work together to give all the good tones that you hear. So it follows that to get a good tone and target the appropriate frequencies you only need to look to those circuits that are already doing it. No need to reinvent it and no need to concentrate on the specific frequencies created by the strings either. Because of deficiencies in the cabinets and speakers and overtones and harmonics in the actual amplified wave form you can't take the literal spectrum at face value to formulate good tone. Ergo, do what others have done that works with what others have done. It's technology that reached it's pinnacle with the SVT amps. Still revered by most players. Use THAT tone stack and you'll KNOW that you are targeting appropriate frequencies.

There. I've used up all my logic for the morning.

[catalin gramada]

From my limited experience found a good bass tone comes (over all frequency shaping discussed) from the manner you load the stage in front of. Is nothing but impedance match matter exactly as an acoustic top oppose to the vibe of the string over the bridge which act like a transfer filter element like your tone control does. That.s by You if prefer a dry sound or to ring like a bell full harmonic contents. Don.t be afraid to load the stage as much and feel the difference then shape by trial and error. In short can get tonal character by impedance matching over you poles in filter network.

[bea]

One more vote for the James tone stack as used in various Ampeg amps. I used this in one amp I mostly use for bass but I combined it with the Framus mid control.

Which makes a lot of sense to me, except that You could easily go for an AMZ tone control instead of the James (IMHO). Or use a None Ray control.
Or just a simple Gibsonette-like semiactive treble control + Double-T-filter based mid control and maybe switchable coupling caps as a bass control (Orange-like)

The idea behind this: bass and treble adjust to the room, mid control adjusts the voicing of the amp. So the mid control might be even switchable between "fenderish" and "hiwattish" center frequency.