Quote from: phatt on June 08, 2009, 10:12:16 AM
Just adding Something to help you understand why this works so well.
Here is a snapshot of shootout between the *Tonemender and the PhAbbTone*.

Tonemender is average, at around 13dB cut in the mid.

The PhAbbTone big mid notch is clearly evident and my 30dB cut claim is really quite conservitive.
That deep mid notch does amazing things when used in front of even the most basic tube screamer OD pedal.

BTW all those frequency altering switches and add-ons only really shift the mid point up or down a bit and in reality are not much use (IMO)
I have built The famous Dumble tone stack and it's another one that shifts the mid around but nowhere near as powerfull as the HiWatt setup.
Cheers, Phil.

How did you plot that graphic out like that?  Is it some form of oscilloscope?  Do you hook up your guitar -> tonestack -> input on your scope or computer and strum the guitar?  You have me perplexed!

FPGA http://en.wikipedia.org/wiki/Field-programmable_gate_array is what I'm leaning towards in terms of switching.  Kind of funny if we could get this to work.  In the late 80's I was working with EPROMS at one point.  These are just the evolution of PROMs and EPROMs.  Lots of tools available to program them and they are cheap.  I've been away from electronics for so long that I'm unfamiliar with MOST of the current digital logic terminology.  I'm trying to find one (microcontroller)with BIG pins(ha, ha).  Just think you could really just pick which preamps/tone circuits you wanted and join them together with something like this.  The ability to control them from the footswitch using a device similar to this opens up a LOT of ground.

I'm sure a lot of people familiar with digital logic circuits would consider the use of FPGA overkill for utilizing them in a guitar preamp switching circuit but this is really intriguing to me.  I think it leaves the door open for the future and it gets me interested in what I like to call "low level programming" again.  For the time being I'll just breadboard it using typical logic gates.

Sideline info about programming microcontrollers http://www.sparkfun.com/commerce/tutorial_info.php?tutorials_id=93

Can you guys give me recommendations about breadboards.  I threw all that stuff out 20 years ago.  I need to buy two or three of them and I want them big and of good quality.  Thanks!

I really like the idea of what you are trying to do here with the different switchable preamps.  Maybe the way to approach this switching problem is to use a microcontroller in the footswitch that triggers another microcontroller on the main circuit board.  I'm sure  there are some controllable switches out there that would suit this task.  Programming micros is "no big deal" these days.  I've seen people using them in their own "home brew" stereo audio amps in some amazing ways.  The big deal here is that if you get it to work you're really unlimited on what you can do with it in terms of switching channels, mirroring tone stack controls, tone stack memory presets, etc...  Let me look into this a little bit more and I'll get back to you on this.

Anyone got any ideas about the multiple channel switching dilemma with respect to switch specifics?

I could be oversimplifying this in a great way but it sure sounds like fun.

I was trying to find an example of this in a modern solid state amp.  http://tech21nyc.com/support/index.html Check out the foot controller on the Trademark 120.  For my personal taste this footswitch design is awesome.  3 channel selectable with toggles on the effects loop, reverb, and boost elements.  Why are you grouping the different preamps in to 2 groups?  Is it because of a hardware issue with certain switches you are trying to utilize?

QuoteThat does sound cool. But I have no idea how it would work.

I'm not really sure how it would break down switch-wise but wouldn't it be simpler than breaking the preamps into 2 different sections with 2 channels like you were talking about above?

QuoteI came up with a way to switch between 4 preamp channels with led status indicators. There will be 2 sets of 2 channels. The 2 sets will be switched between with a DPDT toggle. That switch will go to another DPDT switch to choose one of the channels in the set. I have the diagram in the link below switched to the Dr. Boogie channel.

I think it would be really cool to have the footswitch setup like this :

5 buttons total.  All have LED indicators when active.  4 of the buttons to switch between the independent preamps and the 5th button the toggle on/off effects loop.

Just wondering how you decided on the 22 watt figure?  Are you going to utilize 2 LM386's for the stereo channel?  I'm anxious to hear about your progress.  Good luck!

Now, I've made it to this point.  Please critique this Eagle schematic.  I know I've got some things to clear up.  Specifically the implementation of :

IC: TL072D, capacitor polarity, battery source?

I can't find an exact match for 1N4001 or TL072 in the Eagle libraries that I have.  Any suggestions?

Any feedback greatly appreciated.

***Linked content removed due to malware***

I'm missing the power input stage, the input and output jacks and I need to change the symbols for some of the polarized capacitors.  I'm not sure where the ground symbols are in Eagle.  Also, are there input/output jacks in Eagle?  What heading are they under?  Where are the batteries?

I guess I screwed up on the TL072D.  I found something with similar name(TL072P) and appearance and just dragged it onto the circuit.  Please tell me what other errors you see.

Thanks!

Here's what I've got done in Eagle so far:
***Linked content removed due to malware***

Quote from: sergscar on May 27, 2009, 09:31:08 AM
Hi Phil,
Big help, of course !
I already had "throwed" all the components inside "Eagle", but some doubts always arise, and the picture clarified most of them.
I've installed Eagle a few days ago, just for doing the "Passive tone circuit" and takes some time to learn the "how to" (in particular, I'm feeling some difficulties for finding the right components in the libraries). Maybe there are easier softwares out there.

Just one more question: COM1, COM2 and COM3 are the Ground connectors for "IN", "LED/-Vcc" and "OUT", respectively ?

Thks again !

I've been doing the same thing.  What did you end up using for the variable resistors/POTS in the Eagle component library?  Also, are you sticking to a particular size/brand when it comes to capacitors and resistors?  I wish I knew more about this stuff but I'm taking a stab at it anyway.  Anxious to hear what Phil has to say about the above question of yours.  I found this link http://www.sparkfun.com/commerce/tutorial_info.php?tutorials_id=110 when learning about Eagle.  It may not apply to this project but it's interesting and informative.  I'm making an LM3886 right now just to get used to the Eagle component.library editor.

Quote from: phatt on May 21, 2009, 09:33:20 AM
Hello doug7410,
                     If your searching for a tweed circuit then try the Sansamp GT2 circuit
(I think it's still at "Tonepad") as it's one of the better ones.
It's just the first opamp part you need not hard to miss as it's much like the end of the professor tweed. Should give a big deep notch near 1khZ.
As your tonemender is already opamp powered then you can just tag that extra bit on the end.
But you may not get the edgey distortion of the fet circuit.

I can give you another circuit similar to the *tonemender* but IMO far better.
As you are at the bread board stage then why not experiment a little before you commit,
just a thought.
Cheers, Phil.

Hey Phil, can I get this circuit "similar to the tone mender" from you?

Thanks,
  Zappacat

Quote from: phatt on May 13, 2009, 03:59:03 AM
Hi zappacat,
Before you run off and get yourself lost in a maze of wire. Try to undersand the CONCEPT first it'll save a lot of wasted wire. If I say the Answer to great tone is EQ/Dist/EQ/Dist/EQ/Dist/EQ/Dist.

You might laugh but if you mess with guitar amplification for long enough you start to realise from the earliest of tube design to latest digital gizmo your just tweaking the tone shape. Sure in fine detail it's a lot more complex but why make it hard as all the good stuff won't happen unless you get the basics right first.

Line up a dist unit and note the sound.(or try the pod if you wish)
Next insert a Parametric EQ *IN Front* and apply a deep mid notch at around 400/500 hz. If you don't have Para EQ or you have trouble with how they work just use a graphic type but para works best at this point.
You want a deep narrow notch CUT for best results otherwise you'll pull out to much.

Stick a graphic EQ *After* the dist unit and pull down at around 1khz. I very much doubt there is much need for me to carry on as it should all become rather obvious just how many different sounds can be achieved via this simple exercise.

(I'm posting this because the site is unavailable so I can't find exact address for the whole page)

Lifted from,  [http://www.amptone.com/index.html]
--------
True "secret" of amp tone - eq>dist and power attenuators
Home (amp tone and effects placement)

You can almost certainly get satisfactory sound from your existing decent tube amp,
without mods, by using, or at least experimenting with, the following  chain:
guitar
eq pedal
Comp/OD/Dist pedals
eq pedal
amp's preamp
amp's tone stack
amp's tube power amp
good power attenuator
amp's guitar speakers

The above is truly the "secret" of great amp tone.  Most postings, books,
and amp tone videos dwell on amp brands and mods and swapping tube types
and swapping speakers or pickups, but such priorities are backwards.
The real first order of business is knowing how to make the most of *any*
decent tube guitar amp.  It's a shame that most guitarists try all sorts
of things other than the secret weapon that gets straight to the point:
the eq>dist>eq pedal chain, which you can put before any guitar amp,
in conjunction with -- just as important at the other end of the chain --
some way of getting power-tube saturation independently of speaker volume,
and this amounts to the (unfortunately) "secret" of power attenuators.
-----------
End quote

My rig just takes this one step further and instead of attenuation I *reamplify* the tube power amp with another SState poweramp. Even without power tubes you can still make inroads to great tone.

This is the basic layout I use;
First a very simple DIY tone stack based on an old HiWatt circuit, SS
B> into a highly modified OD SS device
C> then a very simple tube amp which drives a resistive load
(like an attenuator cept No Speaker, you tap off a line level instead)
D> feed into an old HiFi graphic EQ
E> ultimatly driving a 120watt SS power Amp.

The tube amp is an old rewired Gramaphone from the 50's and only outputs 7watts,
no need for expensive tube gear here as you actually want a bad/cheap basic amp.
Heck it only has 1 volume and 1 tone knobs. All the rest can be done via SState.
Cheers, have fun, Phil.

Thanks for taking the time to compose this.  I feel stupid after reading it.

Thanks for all your input Phil,
   I can't tell you how much I appreciate your time taken to shed light on this subject matter.  I'm still taking my time to digest your first response.   I can deal with the mixer idea.  I have a Mackie 1202 VLZ pro that would fit that bill quite well.  What do you use for a live guitar rig setup?

Sincerely,
  Tom

QuoteHello Zappacat,
                     Hey alot of Q's there!
I think you need to get some ideas nailed down first and kinda stick to one thing at a time,, kool?

I'll try to more precisely define what I'm looking for in the context of this message.

QuoteRe the LM 4780 chip Q.
You can simply look up the specs for that and it will be obvious if it is stereo or not.
----
Two of those proj 101 Amps will make your ears bleed my friend and you will need at least two quad boxes to make use of all that power. Anyway the cost of the PSU at 100VAC-CTap tranny will scare you!   oh and YOU have to carry it also.
I only mentioned it because even at 40/0/40 VDC it will still have ample power.

Well, I really don't need that much power.  I want the amp to drive two 12 inch speakers in stereo with enough wattage to play smaller venues.  I play keyboards as well.  It would be nice to use this setup for monitoring them onstage.  Right now I'm using a JBL Eon G2 15 that suits this purpose.  It would be nice to not HAVE to lug this thing around as well.

QuoteIf you want balanced outputs to send to a desk then I don't get it.
You wish to DI a 400watt Amp to a PA desk,,, like what For :duh

Well, I want to send stereo line level out to the board :duh  Maybe I'm stupid and I'm using the wrong terminology.  I'll have to say that I've played at venues when I wish I had the option to flick a switch and send 400 watts to Mr. genius house soundman at the board.  This thread doesn't need to turn into a "why do you want to send a stereo signal to the board" thread.  I want the option of doing this.  If anybody wants to debate that then start another thread.  I want to have the ability to send my stereo signal to the board.  Having 400 watts isn't important just as long as I can hear myself on stage and that I don't get drowned out by little half-stack boy.

QuoteIf you don't know *most* SState PwrAmps can handle 4 OHMS minimum load.
Less than that and you are pushing your luck.
Read project 101 more slowly and absorb it,,,the Answer for that is on that page anyway.

OK, I'll do that.  I still don't quite have this OHMs thing fully understood.

QuotePersonally I never got the stereo trip as a good guitar sound with a little time effect and good EQ will sound far more convincing than any stereo pod.

Really?  How much time have you actually spent using one?  A friend of mine has one of these http://tech21nyc.com/support/manuals/amps/Trademark120-OM.pdf connected to his POD XT Live.  Evey time he shows up at a practice or plays anywhere on stage it's not only the topic of conversations amongst the guitarists(in a good way) but he has to carry a stick with him to keep people away from trying to play it.  This combination of preamp(POD XT series) with the Tech21 Trademark 120 amp setup is amazing!  I'm not kidding you about this either.  I want to build something like this amp keeping the size/weight/cost to a minimum.  Maybe I should have been more clear about that before.  One of the best things is the ability to program your set lists using the Line6 software.  This way when you go to a gig it's an easy, quick setup.  The idea of building something like this is quite intriguing to me and I'm going to make it happen.

QuoteI can do more tricks with my simple gear than most of those cab sims.

You must be a LOT better at it than I am.

QuoteSadly these days the player is judged more by how up-to-date his pedal board is than his ability to play good music.

By who?  Maybe you look at it that way but I don't.  I like to hear them first.  I'm not really too concerned about what people think about the equipment I'm using either.

QuoteIf I'm getting this right you really need two things,,,
1/ a stereo preamp (with bal outs).
2/ a Stereo poweramp.

I already have a stereo preamp in the POD XT.  Stereo power amp = yes.  Also cost/weight/size are considerations.  It might be better for me to split the stereo signal before it hits the amp and send the POD signal direct to the board and the other signal to the amp.  I'm still debating this.  I think in a typical stage setup it would require less patching to run straight from the POD to the amp then amp to board.  This way I could toggle the amp input from guitar to keyboards without even more switching/cords.  Thanks for the input.

QuoteBTW there is some bal circuit ideas on ESP site
Cheers, Phil.

I'll check it out.  Thanks for the input Phil!

Quote from: J M Fahey on May 05, 2009, 05:06:16 AM
Hi Zappacat.
You seem to be posting practically the same questions on two different threads, at the same time.
It sure gets confusing, and difficult to follow.
Thanks.

Sorry, I didn't plan it that way.  I found the Tech 21 topic after posting this topic.  You'll notice when I first got involved with the other topic I stated that in the discourse of conversation.