Simulate any circuit before breadboarding...
If you have a lot of options you should simulate all those circuits first, there's a little (about 5 megs) but very powerful totally full featured free software (no student versions no shareware) called LTSpice I use it (and lots of DIYers too) to fine tune all my projects before actually building them.
Also you can plug your guitar to your computer, record it (using windows sound recorder for example) preferably without any distortion or effect added and run the circuit using the sound sample as your input, if your computer is powerful enough you can record a large clip! and hear an aproximation of how the circuit actually sounds!
Here is a good website with lots of models (valve and speaker models too) compatible with LTSpice (theres also a special section explaining how to add models in LTSpice)
www.duncanamps.com
and here you can download the software:
http://www.linear.com/company/software.jsp
This can save you a lot of money and frustration!
If you have a lot of options you should simulate all those circuits first, there's a little (about 5 megs) but very powerful totally full featured free software (no student versions no shareware) called LTSpice I use it (and lots of DIYers too) to fine tune all my projects before actually building them.
Also you can plug your guitar to your computer, record it (using windows sound recorder for example) preferably without any distortion or effect added and run the circuit using the sound sample as your input, if your computer is powerful enough you can record a large clip! and hear an aproximation of how the circuit actually sounds!
Here is a good website with lots of models (valve and speaker models too) compatible with LTSpice (theres also a special section explaining how to add models in LTSpice)
www.duncanamps.com
and here you can download the software:
http://www.linear.com/company/software.jsp
This can save you a lot of money and frustration!
I consider LTspice as one of the best softwares I have ever used. Even without the awesome function of being able to feed the circuit with .wav files and record a node voltage/current to a one the software would be one of the best ones: It is easy to use, versatile and implementing your own models and subcircuits is easy once you get the hang of it. I recommend everyone who designs audio circuits to at least try this software. In my opinion it beats any tonestack simulator out there 10 - 0, although not being as interactive as most of them. Why: Because you can put together any circuit you like and it forces you to consider the effect of input and output impedances - far too often left unconsidered when using, say, Tone Stack Calculator. Can teach you a great deal of circuit theory as well.
To add a little detail and go bit off-topic here, the LTspice's ".wave" function can not accurately "record" voltages that exceed 1V and currents that exceed 1A (if I remeber right). This can cause a lot of "unexpected" results since the function will just clip off all signal content that exceeds 1 V (or 1A when plotting current). If one wants to use the .wave function of LTspice it's best to learn to use the "e"-model in conjugation and scale all "recorded" voltages down to maximum of 1V.
To add a little detail and go bit off-topic here, the LTspice's ".wave" function can not accurately "record" voltages that exceed 1V and currents that exceed 1A (if I remeber right). This can cause a lot of "unexpected" results since the function will just clip off all signal content that exceeds 1 V (or 1A when plotting current). If one wants to use the .wave function of LTspice it's best to learn to use the "e"-model in conjugation and scale all "recorded" voltages down to maximum of 1V.
Nice Girl Hard Driver preamp improved!
In case you are interested in building it, I added an active Q-type 8 band graphic equalizer (using ultra quiet TL2272 opamps) to the input of the NHGD and an active T-type notch filter to virtually eliminate mains freq hum (that works ok if you can get 1% resistors and caps), this thing is really capable of serious metal tone!!
The addition of an active eq at the input gives you a practically unlimited pallette of tones (an extra band makes it friendly with 7 or 8 string guitars) and the marsh"#!$ type eq after the preamp shapes distortion...
In case you are interested in building it, I added an active Q-type 8 band graphic equalizer (using ultra quiet TL2272 opamps) to the input of the NHGD and an active T-type notch filter to virtually eliminate mains freq hum (that works ok if you can get 1% resistors and caps), this thing is really capable of serious metal tone!!
The addition of an active eq at the input gives you a practically unlimited pallette of tones (an extra band makes it friendly with 7 or 8 string guitars) and the marsh"#!$ type eq after the preamp shapes distortion...
That sounds like a versatile solution. I share the same opinion that the plain Fender/Marshall/Vox-style tone control circuit is not enough for amps if you want to have some good distortion tones. In case anyone wants to try out tonestack that has controls, which are less interactive with each other here is one. I tweaked the Bench/Acoustic Control amps style stacks and came up with a circuit that is worth trying. haven't had time to test it out yet - other than in pspice. Don't get scared by the inductors: I particularly modded the circuit so that it can be used with with ordinary gyrator circuits.
By the way frickecello, pardon my ignorance but what do you mean by active Q? Does that mean like using gyrator circuitry or adding some control to turn the constant-Q filter into a parametric EQ? I have never heard this term?
By the way frickecello, pardon my ignorance but what do you mean by active Q? Does that mean like using gyrator circuitry or adding some control to turn the constant-Q filter into a parametric EQ? I have never heard this term?
Attachments
Q's and inductors
It is the way of bandwidth calculation (some people refer to this eq config as an active Q eq), a bandpass filter is used instead of classic stacked low pass filter stage graphic equalizers, where Q determines the bandwidth of a bandpass filter, for example if you want an octave eq, (like in the Nice Girl Hard Driver preamp) and you want your lowest resonant freq to be 82 Hz, you can calculate this stage bandwith like this:
Q=1.7 (for an octave eq)
82*(1/1.7)=48
so this bandpass filter has cutoff freqs of:
82 - 48 = 34 Hz (imagine those palm mutes!) and 82 + 48 = 130 Hz
Inductors are no problem since you can simulate them in real life with opamps. I personally dont like inductors, they are easy to find in Europe but since Im a Netherlands exchange student in Mexico I have to simulate them =P (Im not talking about computer simulation but real opamp simulation)
Regards.
Louise Goedhoop
teemuk said:
It is the way of bandwidth calculation (some people refer to this eq config as an active Q eq), a bandpass filter is used instead of classic stacked low pass filter stage graphic equalizers, where Q determines the bandwidth of a bandpass filter, for example if you want an octave eq, (like in the Nice Girl Hard Driver preamp) and you want your lowest resonant freq to be 82 Hz, you can calculate this stage bandwith like this:
Q=1.7 (for an octave eq)
82*(1/1.7)=48
so this bandpass filter has cutoff freqs of:
82 - 48 = 34 Hz (imagine those palm mutes!) and 82 + 48 = 130 Hz
Inductors are no problem since you can simulate them in real life with opamps. I personally dont like inductors, they are easy to find in Europe but since Im a Netherlands exchange student in Mexico I have to simulate them =P (Im not talking about computer simulation but real opamp simulation)
Regards.
Louise Goedhoop
Oh I see, so it's just a general term for filter circuits utilizing series resonance of L, C and R. Similar circuit to one in the "middle" control of the circuit I posted. Few of them in parallel, each set up for different resonant frequncy, would create a "graphic equalizer". Very easy to modify it to be parametric as well.
I knew what yo meant by simulated inductor. They are also called "gyrators", thus I mentioned them. There is a brief description about them in http://en.wikipedia.org/wiki/Gyrator - they work with ordinary transistors too. Pretty nice invention; in some cases circuits with gyrators can operate even better than circuits utilizing less-ideal real-life inductors.
This link is a must read for everyone who's interested about the equalizer/tone control topic: http://www.geofex.com/Article_Folders/EQs/paramet.htm
I knew what yo meant by simulated inductor. They are also called "gyrators", thus I mentioned them. There is a brief description about them in http://en.wikipedia.org/wiki/Gyrator - they work with ordinary transistors too. Pretty nice invention; in some cases circuits with gyrators can operate even better than circuits utilizing less-ideal real-life inductors.
This link is a must read for everyone who's interested about the equalizer/tone control topic: http://www.geofex.com/Article_Folders/EQs/paramet.htm
Yes simulated inductors can made really nice low-Q active band pass filters, my eq uses opamps, it has a buffer stage needed to drive the 7 stages, this are my resonant freqs:
82
164
328
656
1312
2624
5248
(I like full bodied sound and not found an 10496 Hz stage useful)
I think they are more musically correct (they are actual musical octaves, mess-a booger amps feature a similar approach) than most graphic eq res. freqs.
(standard 100, 200, 400, 800, 1200 Hz, etc etc)
I compared it with a boss GE-7, and found it more harmonically correct, and better sounding (in my personal opinion).
82
164
328
656
1312
2624
5248
(I like full bodied sound and not found an 10496 Hz stage useful)
I think they are more musically correct (they are actual musical octaves, mess-a booger amps feature a similar approach) than most graphic eq res. freqs.
(standard 100, 200, 400, 800, 1200 Hz, etc etc)
I compared it with a boss GE-7, and found it more harmonically correct, and better sounding (in my personal opinion).
well the 100w boogie amp idea fell through
my bud had just finished the pcb for the run off groove uno and the poweramp im using blew up when i plugged it in
i dont just mean stopped working
there was smoke and everything
it had been left in the shed for a week or two and something short-circuited
so now im working on a pedal im designing from 'electric's dual rec jfet emulator but with a modified tonestack and stuff.
i posted another thread which is stupid as i could have just posted it here but oh well
if you feel like helping out that would be appreciated.
my bud had just finished the pcb for the run off groove uno and the poweramp im using blew up when i plugged it in
i dont just mean stopped working
there was smoke and everything
it had been left in the shed for a week or two and something short-circuited
so now im working on a pedal im designing from 'electric's dual rec jfet emulator but with a modified tonestack and stuff.
i posted another thread which is stupid as i could have just posted it here but oh well
if you feel like helping out that would be appreciated.
fingerwizards7 said:
Let's skip all the mumbo jumbo and sworn testimony and get straight to what you want. You want the tone of all these maestro guitarists you hear and everyone will tell you ya need tube or you need this type of distortion circuit if it's going to be solid state..yadda yadda yadda yadda....
Here's the simple truth, whatever you build you're going to want at least a 6 band EQ. That's where all the legends true tone comes from. They have either a shelving EQ or a parametric EQ on their effects loop to suck out and boost some very specific frequencies. You'll see all these fancy, expensive tube amps on stage but what you usually don't see is the fancy case of literally a dozen rack mount processors they use to actually get their tone. Tube...solid state, it's all sounds exactly the same once you start fussing with the frequencies, don't get sucked into all the mumbo jumbo because it's balogna even though the most experienced techs will swear otherwise.
I've been fortunate enough to see the rack set ups of some of the most respected solo guitarists and metal guitarists, once they get the gain and frequency wave form they desire from their amp, their true tone comes from a multi band EQ. This is why you hear a solo guitarist like Steve Vai and think, "why does it sound like he has all his midrange scooped out but then he hits some bass notes and you hear that vocal, groany honk of midrange??". Everyone will fight you to the death insisting it's because he's using tube but that's nonsense, it's the way he's cut and boost specific frequencies. I figured this out as a kid when I was piecing together equipment and ended up playing through my PA with a 9 band EQ and the death metal pedal. The pedal is a wall of noise but there's a trick to it. It's by far the dirtiest and most harmonic saturated distortion out there. More so than any tube amp or pedal or solid state amp or pedal.
A lot of gurus refer to this stage of signal processing as the sculpting because with the multi band EQ you can do .so much more than just with the 3 and 4 band tone stack EQ on your amp.
Parametric EQ's are definitely favored but shelvings work just as well. This is truly the holy grail to nailing everybody's tone once you have the gain sound and response you're looking for. I'm sure this seems off topic but it's really not, you've probably already gotten swept away by the myths of tech talk posted on your thread.
It's all foowy, once you find the distortion you're looking for, you'll need a good multi band EQ to nail all those tones you're after.
You couldn't have said it better; playing around with graphic EQs in front of - and after a signal clipping unit was a quite educative experience for me too. Excited about the thing, I once tried to build a distortion pedal that would replicate the "sweet spot" of EQ curves but soon realized that an analog circuit would become too complex and gave up. Both were pretty eye-opening experiences for the sake of understanding sound processing and it's relation to analog circuit design.
Fitting this kind of system inside one unit is plausible allright but I'd rather put it together from individual devices than try to build it as one. (That is why I suggested building a clean preamp, implementing FX loop and using external effects in my first post to this thread). Either way one does it, it is often either too expensive or too complex and scares away people who are usually after easy solutions.
Did the guy who started the thread follow my advice? No. He picked up an easy solution that someone had already designed. ...Anyway, that's just human nature I guess.
A friend of mine once built a DSP unit that worked on one of those microprocessor "training" platforms. A computer interface allowed drawing the EQ and transfer function curves. It was pretty impressive and if I knew more about digital stuff I would build it right away on a different and more compact platform. For me something like this would be the way to go as far as only distortion is concerned. The idea of using DSP to replace complex analog circuits is really cunning although it gets a lot of critique.
A basic FMV tone control (Fender-Marshall-Vox) is pretty poor, the simplicity being the only real merit of it. All controls are too interactive with each other and it cannot do midrange boost. The midrange scoop is a nice feature but sometimes one would like to get rid of it in other means than diming the mid and turning treble and bass to zero. This circuit is just too overrated! To make matters worse, most of them are passive and have horrible insertion losses.
Most graphic EQ circuits are based on resonance so the controls are less interactive with each other. A typical graphic EQ can boost and cut frequencies, usually on a much narrower band than FMV. Most of these circuits are active so they improve SNR. There were pretty good examples about these circuits presented in this thread. As far as I see it, the added complexity is the only reason why these circuits haven't become that popular in guitar amplifiers. Bass players have enjoyed of them for years.
If I'd had to build a preamp I would likely scrape it together from:
1. High input impedance gain stage with clean sound and variable gain control
2. Active 5 to 8 band graphic EQ
3. two switchable and bypassable FX loops with line level selection
5. Spring reverb
6. Another active graphic EQ (5 or six bands)
7. Bypassable active FMV tonestack
8. Limiter/compressor
9. Line out send with switchable cabinet simulator and line level selection
10. Same circuit feeding a headphone amplifier stage
11. Volume control and buffer for PA send.
Not listed are well-regulated power supply circuit, foot pedal remote and solid-state switching circuitry.
I have also been planning on a concept of using switchable FX loops categorized for different effect types: i.e. separate FX loops for delay and echo effects, FX loop for distortion effects etc. This would allow better control and more importantly would allow using individual tone controls for each type of effect category. i.e. graphic EQs for distortion effects, simple hi/low pass controls for reverbs, delays chorus, etc. type effects. Something like that should be pretty versatile.
Fitting this kind of system inside one unit is plausible allright but I'd rather put it together from individual devices than try to build it as one. (That is why I suggested building a clean preamp, implementing FX loop and using external effects in my first post to this thread). Either way one does it, it is often either too expensive or too complex and scares away people who are usually after easy solutions.
Did the guy who started the thread follow my advice? No. He picked up an easy solution that someone had already designed. ...Anyway, that's just human nature I guess.
A friend of mine once built a DSP unit that worked on one of those microprocessor "training" platforms. A computer interface allowed drawing the EQ and transfer function curves. It was pretty impressive and if I knew more about digital stuff I would build it right away on a different and more compact platform. For me something like this would be the way to go as far as only distortion is concerned. The idea of using DSP to replace complex analog circuits is really cunning although it gets a lot of critique.
A basic FMV tone control (Fender-Marshall-Vox) is pretty poor, the simplicity being the only real merit of it. All controls are too interactive with each other and it cannot do midrange boost. The midrange scoop is a nice feature but sometimes one would like to get rid of it in other means than diming the mid and turning treble and bass to zero. This circuit is just too overrated! To make matters worse, most of them are passive and have horrible insertion losses.
Most graphic EQ circuits are based on resonance so the controls are less interactive with each other. A typical graphic EQ can boost and cut frequencies, usually on a much narrower band than FMV. Most of these circuits are active so they improve SNR. There were pretty good examples about these circuits presented in this thread. As far as I see it, the added complexity is the only reason why these circuits haven't become that popular in guitar amplifiers. Bass players have enjoyed of them for years.
If I'd had to build a preamp I would likely scrape it together from:
1. High input impedance gain stage with clean sound and variable gain control
2. Active 5 to 8 band graphic EQ
3. two switchable and bypassable FX loops with line level selection
5. Spring reverb
6. Another active graphic EQ (5 or six bands)
7. Bypassable active FMV tonestack
8. Limiter/compressor
9. Line out send with switchable cabinet simulator and line level selection
10. Same circuit feeding a headphone amplifier stage
11. Volume control and buffer for PA send.
Not listed are well-regulated power supply circuit, foot pedal remote and solid-state switching circuitry.
I have also been planning on a concept of using switchable FX loops categorized for different effect types: i.e. separate FX loops for delay and echo effects, FX loop for distortion effects etc. This would allow better control and more importantly would allow using individual tone controls for each type of effect category. i.e. graphic EQs for distortion effects, simple hi/low pass controls for reverbs, delays chorus, etc. type effects. Something like that should be pretty versatile.
Sounds like a good layout, similar to the route I'm currently taking though I'm not sure what I'll do for an EQ stage. I am contemplating buying a reasonably priced passive EQ for automotive audio which will be compact in size and easy to wire to my transformer. Older Mesas, some Randall's and few other amp makers out there have shelving EQ's built in, meanwhile any pro that knows the score adds one on their loop if their amp doesn't have it. Tone stacks are good for getting a good starting frequency wave form but for a sound that truly performs, you need to sculpt and polish your overall tone with a multi band EQ.
My layout is as follows.
1. Distortion/clean stages
2. Tone stacks stage
3. Effects loop
4. Multi band EQ
5. possibly a reverb
6. cabinet voiced line out
7. headphone out
8. amp stage..possibly stereo
I'm not concerned with compression or limiting in any of the stages since my preamp design gives a nice yet mild level of compression and all my guitars are really finely tuned as it is. With high input impedance, compression really isn't necessary anyway which is the same route I'm going.
I'll work in a bypass for channel switching and probably use an op amp based preamp to drive my signal through my tone stack for the clean stage. Not positive if I'll bother with a reverb tank but I've formulated a plan that only requires a single pot to blend it into the mix which eliminates adding yet another active circuit when my goal is to have as small of a part count as possible. I have some schematics for multi band shelving and parametric EQ's but don't have the time, patience, money and probably not the skill required in building one.
I'll likely just ditch the multi band EQ and build a master 3 or 4 band active filter which I can tailor to the specific and crucial frequencies I know give that ultimate lead tone everyone believes is the result of using all tube, if only they knew.
Mesa's been smart enough to incorporate a shelving EQ on some of their more popular models once again, I partially credit this as one of the reasons the myth continues.
I'll be doing everything on perf board and if I'm happy with the final project I'll etch some boards or possibly have some printed up commercially.
I notice that more and more amp manufacturers are adding all sorts of bell and whistle switches that are nothing more than fixed EQ's or specific frequency boosts which are taking the place of a mutli band EQ. They are gradually increasing the number of tone controls too though.
The more guys like us build our own rigs and inspire others to get active in the DIY audio hobby and community, the more I suspect the myths of tube superiority will fade away over the next 10 years and why shouldn't it, I personally feel solid state is better with the greater detail, clarity and super efficient building costs.
Would be nice if someone would just produce a more thorough unit at a reasonable price though, a lot of s.s. with all the tone shaping goodies are now in the same price range as all tube units and everyone that's an advanced player ends up adding all sorts of rack gear anyway. I'm really put off by amps not having everything built in minus digital effects. The lack of stacking effects with most amps that have them built in is a huge disappointment. I want more than compression, flange and delay for my effects stacking options. 7 to 10 stackable effects at once, now you're talkin. I don't know enough about digital to build my own from scratch either so if I want the ultimate rig, I'll be adding at least one piece of outboard gear.
.
My layout is as follows.
1. Distortion/clean stages
2. Tone stacks stage
3. Effects loop
4. Multi band EQ
5. possibly a reverb
6. cabinet voiced line out
7. headphone out
8. amp stage..possibly stereo
I'm not concerned with compression or limiting in any of the stages since my preamp design gives a nice yet mild level of compression and all my guitars are really finely tuned as it is. With high input impedance, compression really isn't necessary anyway which is the same route I'm going.
I'll work in a bypass for channel switching and probably use an op amp based preamp to drive my signal through my tone stack for the clean stage. Not positive if I'll bother with a reverb tank but I've formulated a plan that only requires a single pot to blend it into the mix which eliminates adding yet another active circuit when my goal is to have as small of a part count as possible. I have some schematics for multi band shelving and parametric EQ's but don't have the time, patience, money and probably not the skill required in building one.
I'll likely just ditch the multi band EQ and build a master 3 or 4 band active filter which I can tailor to the specific and crucial frequencies I know give that ultimate lead tone everyone believes is the result of using all tube, if only they knew.
Mesa's been smart enough to incorporate a shelving EQ on some of their more popular models once again, I partially credit this as one of the reasons the myth continues.
I'll be doing everything on perf board and if I'm happy with the final project I'll etch some boards or possibly have some printed up commercially.
I notice that more and more amp manufacturers are adding all sorts of bell and whistle switches that are nothing more than fixed EQ's or specific frequency boosts which are taking the place of a mutli band EQ. They are gradually increasing the number of tone controls too though.
The more guys like us build our own rigs and inspire others to get active in the DIY audio hobby and community, the more I suspect the myths of tube superiority will fade away over the next 10 years and why shouldn't it, I personally feel solid state is better with the greater detail, clarity and super efficient building costs.
Would be nice if someone would just produce a more thorough unit at a reasonable price though, a lot of s.s. with all the tone shaping goodies are now in the same price range as all tube units and everyone that's an advanced player ends up adding all sorts of rack gear anyway. I'm really put off by amps not having everything built in minus digital effects. The lack of stacking effects with most amps that have them built in is a huge disappointment. I want more than compression, flange and delay for my effects stacking options. 7 to 10 stackable effects at once, now you're talkin. I don't know enough about digital to build my own from scratch either so if I want the ultimate rig, I'll be adding at least one piece of outboard gear.
.
just a few points i'd like to make:
1 - im not looking for the tone of a maestro i want a simple(ish) high gain circuit with minimal controls and a compact design. i feel trying to emulate other peoples sounds instead of finding your own is the pussy way to go.
2 - i never ruled out multi band eq's in fact i have the boss ge7 and already use it to tweak the tone. however a preamp without at least a simple tonestack would narrow the range of sounds i can get and i find the ge7 doesnt define the sound as much as id like.
3 - the reason i didnt opt for the clean preamp with an effects loop is because my bassist is making me a 2x12 cab in which to mount the amp and its much easier to carry around a combo to gigs than have a box of extraneous leads and pedals and a seperate amp and cab.
4 - yes, using a graphic eq is the way forward but not two and a tonestack. that seems a bit excessive.
peace
1 - im not looking for the tone of a maestro i want a simple(ish) high gain circuit with minimal controls and a compact design. i feel trying to emulate other peoples sounds instead of finding your own is the pussy way to go.
2 - i never ruled out multi band eq's in fact i have the boss ge7 and already use it to tweak the tone. however a preamp without at least a simple tonestack would narrow the range of sounds i can get and i find the ge7 doesnt define the sound as much as id like.
3 - the reason i didnt opt for the clean preamp with an effects loop is because my bassist is making me a 2x12 cab in which to mount the amp and its much easier to carry around a combo to gigs than have a box of extraneous leads and pedals and a seperate amp and cab.
4 - yes, using a graphic eq is the way forward but not two and a tonestack. that seems a bit excessive.
peace
I want It!!!!!!!!!!
Yeah I want it please please you would blog this pedal with a complete layout and PCB; please my friend!!!!!!!!!!!!!!
Yeah I want it please please you would blog this pedal with a complete layout and PCB; please my friend!!!!!!!!!!!!!!
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