Using a Tube Screamer with a vintage Hammond B3 and Leslie 122.

[lowvolt]

It's not hard to tap a signal from a Hammond's preamp to get down to guitar-pedal-type levels (the preamp puts out around THREE FLIPPIN VOLTS, but a simple voltage divider takes care of that with relative ease).  So *that part* is covered.  And modding the TS-type circuit to get back up about 35db isn't too awful (at least I think so).  But I need to run a few things by the Jedis around here to make sure my head is at least attached to my shoulders on this one.

MAIN GOAL:  Basically the Hammond/Leslie relationship is the same as a guitar amp in that you have a preamp (The Hammond) and a power amp (the Leslie).  The idea is to "break in" to the Hammond/Leslie signal chain, and insert the TS so that the Leslie is receiving the "unity" level signals that it is used to seeing.  The idea being to NOT overdrive the Leslie's vintage power amp and to use the TS to make all of the desired distortion.  The bypass switch will disengage the attenuator (voltage divider), the distortion circuit, as well as any unbalanced-to-balanced conversion transformer.  The bypass switch needs to make the whole works just disappear, and give the Hammond's original hot-assed signal straight to the Leslie again (this part of the idea shouldn't be difficult at all, I would think).  Physical size of the works isn't an issue either ... a chassis suited for this is plenty large enough for circuitry and such, probably two-times over!

SOME OF THE ISSUES:  Well, for one, the Leslie 122 needs a balanced input signal.  So there's that.  I suppose I could just *gut* a passive DI's trxfrmr and install it in the chassis with the TS-gerts, post-TS.  It will most likely be run with a ground lift to prevent loops/hum anyhow.  The other being getting the signal level back up to the levels to properly push the Leslie.  I'm a bit concerned about noise floor issues here.  The signal coming from the Hammond is cut about 30 to 35db to get it to where it doesn't just blast the hell out of the input stage of the TS.  So after it's been distorted I need to get that gain restored to push the Leslie.

CURRENT DEVELOPMENT PROGRESS:  I've been using JD's (General Guitar Gadgets) ITS8 for this and have been fairly happy with some of the results so far.  At least I like the sounds I'm getting .. that said if we can stay within the boundaries of that circuit I'll be more likely to understand any replies.  I've been able to tweak the ITS8 sufficiently to obtain some pretty wicked-high output levels, MAYBE even onough to offset the 30-35db of "cut" that is put on the input signal coming from the Hammond's preamp after it's been attenuated with the voltage divider.  I'm sticking with the vererable JRC4558D IC, it has the mid-humpiness that seems to suit the Hammond for my purposes better than the Burr Brown and the TL072 (those are the only other two I've tried so far).  I'm using some fairly high voltage LEDs for clippers, I've tried TONS of diodes and the LED ~family~ seems best for my needs.  And I figure 18vdc main input power would also suit this setup best as well, for all of the known-good reasons (headroom, etc ..).  So 50-volt caps are in order I would think.

I am NOT one of the Screamer Yodas that knows the circuit up and down.  I actually just have a basic working knowledge of all of this stuff to be honest.  I may not sound like it, but I'm essentialy an  electronics idiot.

BACKGROUND:  I am new here, so I'll offer this ... My mechanical skills are fine (I can drill straight holes in a box) and my solder skills are up as well, just to get that said.  However sometimes the simplest of concepts seem to elude me!

There, big posting but I think that covers it all.

Any input would be mucho-apreciated-o ... heheh.

Thanks a lot for listening ... lowvolt. 

PS:  I see that this forum has that dreaded "jittering edit screen thing" going on ....  once I get to typing below the visible level the screen won't auto-scroll down and the danged thing jumps all over the place.  It makes writing something that is longer than the 3-inches of exposed edit screeen REALLY DIFFICULT TO DO!  I'm using Internet Explorer as a broswer... and jsyk byoc has this same issue going on.  I know that several of the members there at byoc have verified this same complaint over there.  Dunno if it ever got resolved there or not.  You basically have to type "blind" and scroll down to look at what you've typed every few dozen keystrokes .. then edit .. edit .. edit to fix the typing mistakes made from "blind typing".  Just sayin' ..

[bwanasonic]

You might want to get in touch with these guys: http://bossorgan.com/. Tyler knows his way around both stompboxes and B3s.

[lowvolt]

You might want to get in touch with these guys: http://bossorgan.com/. Tyler knows his way around both stompboxes and B3s.

Thanks!  I'll give it a shot!  Sounds like a nice place to try, thank you for the reference ..   

Is this something that is a bit "OT" around here or am I still "inbounds" .. just trying to learn the what and whys of this forum!   

[Cliff Schecht]

I don't have an answer but I saw Ian Mclagan at SXSW in Austin and got to inspect his old Hammond and Leslie up close. Not a lot of pedals that I saw but I think he was using an Ernie Ball volume pedal as the Leslie controller. Either way he played the hell out of that Hammond/Leslie... THAT was a FUN show!

[ashcat_lt]

I think you're trying too hard.  Seems like decreasing the gain (by decreasing the size of the drive pot and the 51K resistor in series with it) and/or increasing the forward voltage of the diodes (use LEDs, or several diodes in series), along (maybe) with a power supply bigger than 9V (watch your cap ratings here) pretty much handles the level issue, no?

You can probably "pseudo-balance" the output, or even just tie the - to the neutral without much problem.

[lowvolt]

I think you're trying too hard.  Seems like decreasing the gain (by decreasing the size of the drive pot and the 51K resistor in series with it) and/or increasing the forward voltage of the diodes (use LEDs, or several diodes in series), along (maybe) with a power supply bigger than 9V (watch your cap ratings here) pretty much handles the level issue, no?

I already did all of that.. every bit of it .. (see my opening post).  You may have missed it. 

I was just seeing if anyone had any other ideas ... looks like so far I've exhausted the options ... so I'll just go with it then!   

Thanks ..

[lowvolt]

You can probably "pseudo-balance" the output, or even just tie the - to the neutral without much problem.

Jsyk, gotta be uber careful with this idea ... the ouput transformer on the preamp is center tapped ... tying the wrong legs together will overload one side of the trxfrmr.

Thanks for the suggestions! 

[PRR]

Why not put the TS before the Hammond preamp, like the usual way it connects to guitar amp?

[Cliff Schecht]

Well, for one, the Leslie 122 needs a balanced input signal.

[lowvolt]

Why not put the TS before the Hammond preamp, like the usual way it connects to guitar amp?

Totally do-able!  Problem is that requires modding the Hammond.  An FX loop at what is called the "matching transformer" in a Hammond would need to be installed, and that is no easy feat.  It requires tearing into the Hammond and doing soldering, drilling holes, mounting jacks, rewiring, bla bla .. all of which I am avoiding like a disease in this particular setup.  

The main idea with what I'm cooking up is a "no mods required to the Hammond or Leslie" deal.  This gizmo is actually to be placed on the floor, ~in between~ the organ and the Leslie.  In a normal B3/Leslie setup you simply plug the Leslie into the Hammond using a 6 conductor cord.  The "umbilical" cord is usually at least 25 feet long to allow distant placement of the Leslie from the organ so the Leslie can "breathe" a bit.  I'm making a box that plugs into the the Hammond where the Leslie normally plugs into, then the Leslie will plug into that box.  Just exactly the same way that an FX pedal "goes in between" your guitar and your amp without doing any mods to either the guitar or the amp.

Badda BING ... no mods to precious vintage Leslie or precious vintage Hammond while gaining access to those insanely cool Jon Lord (Deep Purple) and Keith Emerson type Hammond sounds.

[lowvolt]

The more I talk this out with you folks, the more I think I'm as ready as I'm gonna be with it!  I'm still concerend about some noise-floor issues (cutting the signal 35db - distorting it - then jacking it back up 35db .. yikes!).  But I guess just digging in and givin' it a shot is the only way to find out!

Where I'm totally weak is how to source the passive "DI transformer".  The one in that passive DI I've used (and like) seems to be great.  It's the "Live Wire Solutions SPDI".  It's ~only~ about $30 bux shipped, but I don't like the idea of a gutted DI hanging around, and besides I'm not learning much if I go that way, now am I?

I've done a good deal of searching/reading here among the forum about building DIs, but I've yet to locate anything about determining how to spec the proper trxfrmr for one's needs.  I suppose the Jenson Audio site is as good a place as any to start.  Any help on this angle of the project would be appreciated!

Thanks fellow solder jockies !!

[slacker]

Apart from the balanced bit, this is pretty much what you're after http://www.cgs.synth.net/modules/cgs60_sba.html no mods needed to Hammond, Leslie or the TS. He has it running on a dual +-15 volt supply but, you could rework it to run off a single 18 volt supply, that would probably still give enough headroom so that the adaptor wouldn't distort, or as you're building the whole thing from scratch go with +- 15 and run the TS off just the positive supply.

A reasonable non DIY way to do it would just be to buy a little mixer, one with an FX loop or some sort of AUX channel where you can stick the TS, that would take care of everything.

[lowvolt]

A reasonable non DIY way to do it would just be to buy a little mixer, one with an FX loop or some sort of AUX channel where you can stick the TS, that would take care of everything.

Actually it wouldn't take care of ANYthing.  

** There's no provision to come out of the Hammond into the small mixer (no "jacks" or other outlets).  So that would require DIY solutions.

** And you'd still need to attenuate the Hammond's THREE VOLT audio signal, wouldn't you?  (Or would a small mixer handle that much input signal? I don't know about that part at all really).

**And you'd still need a way to go from the mixer back in to the rig to go to the Leslie (again, no "input jacks" or other way in to the Leslie).  Yet more DIY solutions.

I really don't see how a small mixer would offer a thing to this setup other than un-needed complication.  So if I still have to make a breakout box, and the attenuator .. all that is left is to insert the TS circuit (which is all DIY anyhow).

[lowvolt]

I THINK I FIGURED IT OUT FELLAS!!!!!

Mic pre!!  So here's the proposed chain ...

** Hammond preamp output .. into ..
** DIY Attenuator (to cut the 3 volt preamp signal down to a level the TS can use) .. into ..
** DIY Modded TS .. into ..
** OTC Mic Preamp!  One that accepts "instrument levels" (such as one of the Presonus Tube Pres and has a BALANCED OUTPUT with up to 48db of output gain!!!  Remember I need about 35db of gain to push the Leslie) .. into ..
** Leslie power amp input!!!

Hot Dayum boys .. I think I've got it! 

Now then .. the trick is gonna be ~wedging~ all of that stuff into an enclosure of some type, as well as getting the power supplies for the TS and the mic pre handled.

Oh man  .. my brain is on fire!  I just LOVE it when something all comes together!  Now I need to work out the details, the mechanicals (boxing it all up), the I/Os, etc .. kidz stuff really.

THANK YOU THANK YOU THANK YOU for allowing me to kick this around ~verbally~ here ... just discussing it and such really helped me arrive at this epiphany.  Still have a lot of details to work out, but I think the concept is solid.  I have a Leslie power amp, and of course my own 1962 Hammond A102 console to use to test out things and build a "proof of concept" unit before I construct an actual prototype.  After the proto is up and flying, then the actual completed unit can be built.

Oh happy day!

  Lowvolt ... 

[lowvolt]

WOA!  WTF happened to the forum's format?  Everything just went "pink and flowery" on me!  Little girly hearts and crap all over the place too!  Zis some kinda April Fool's gag?

[slacker]

I really don't see how a small mixer would offer a thing to this setup other than un-needed complication.  So if I still have to make a breakout box, and the attenuator .. all that is left is to insert the TS circuit (which is all DIY anyhow).

Sorry, I was taking the breaking the signals out of the umbilical cord as read, you already seemed to have that bit worked out, should have been clearer. I was thinking the mixer would replace the whole conversion from balanced to unbalanced, assuming that's required, attenuate, feed the signal to the TS, boost it back up and send the balanced signal back on its way to the Leslie.

The DIY way is more fun though 

[lowvolt]

I really don't see how a small mixer would offer a thing to this setup other than un-needed complication.  So if I still have to make a breakout box, and the attenuator .. all that is left is to insert the TS circuit (which is all DIY anyhow).

Sorry, I was taking the breaking the signals out of the umbilical cord as read, you already seemed to have that bit worked out, should have been clearer. I was thinking the mixer would replace the whole conversion from balanced to unbalanced, assuming that's required, attenuate, feed the signal to the TS, boost it back up and send the balanced signal back on its way to the Leslie.

The DIY way is more fun though  

AH!  Yes, gotchya now!  Well, I think I've got this dragon whipped with the "mic preamp" idea though.  Perhaps one of those "ART" units .. them things are only $30 bux!  Hammonds are WAY "lo-fi" so having a lot of excellent freq response isn't necessary ... hopefully some little mic-pre is gonna save the day here for getting the "unbalanced/balanced" conversion done, as well as pumping the signal back up to "Leslie levels".  I just need to go the total opposite direction with the TS that I was gonna do .. meaning I'll need to reduce it's output down to roughly instrument levels rather than getting as much output gain as I could squeaze out of it.  Shouldn't be too hard to do that!  Pad the output er sunthin sunthin ..  There's probably six ways to get that done!

Thanks for the help!  

Lowvolt headsparkage.  ('at's a-me!)

[PRR]

Are you using the Hammond preamp for guitar or not?

Seems to me you aren't; and that makes it all very messy.

The hammond or Leslie _speaker_cab_ needs BIG balance signal, so it can run 400 feet over and around the church.

Hacking the Hammond preamp for guitar is a very common thing.

If you won't play organ and guitar at the same time, rig a SPDT switch before V4B grid, to switch to a guitar jack. You can even use a switched-jack, no finger-switch. Nobody will be horribly upset about a 1/4" jack on an AO-28; lots of church organs got modded in odd ways.

Then your TS goes between guitar and that jack.

[lowvolt]

Are you using the Hammond preamp for guitar or not?

Seems to me you aren't; and that makes it all very messy.

The hammond or Leslie _speaker_cab_ needs BIG balance signal, so it can run 400 feet over and around the church.

Hacking the Hammond preamp for guitar is a very common thing.

If you won't play organ and guitar at the same time, rig a SPDT switch before V4B grid, to switch to a guitar jack. You can even use a switched-jack, no finger-switch. Nobody will be horribly upset about a 1/4" jack on an AO-28; lots of church organs got modded in odd ways.

Then your TS goes between guitar and that jack.

Uh .. no.  Please read my OP better.  This is a mod being done to an organ/leslie that does not belong to me and is thousands and thousands of miles away from me .. so doing any "hole drilling and mods" to the preamp is completely not an option.  The design order is very specific.  (Where did you get the idea I was using a guitar in this at all?).

And it isn't messy at all, sir.    It's becoming quite simple, to be honest! 
Tap the AO-28 (preamp)  ... then out to attenuator .. then to TS .. then to Mic preamp .. then back out to Leslie.  Install the works in a metal chassis that sits below the organ (I may even use an amp-chassis for this).  Done!    Set it up with ~true bypass~ (as in Hardware Bypass) before the entire pile to provide "clean tone".

So to be perfectly clear here ... this is a setup to place between the B3 and the 122 to utilize the standard "Leslie Connectors" as the insert point.  It is designed to be used as a distortion rig that will provide Jon Lord - Keith Emerson TYPE overdriven sounds without having to modify either the organ or the leslie one teensy tiny little bit.  The entire unit simply plugs in to the available connectors that connect the Leslie to the B3.  B3, as in organ.  No guitars are involved.    No mods to organ or leslie involved.  100% plug-n-play.

The reason I came "here" to ask about this was to see if there was a better way to mod the standard garden variety TS circuit to better suit this application.  When I started this thread I .. at first .. was going to use the TS to provide the distortion AND "reamplify" the attenuated signal back up to the Leslie's requirements (to be able to push the signal "four hundred feet" as you said.  Something I am already very conscious of having to do).  I also had the "balanced output" issue to tackle as well.

Wellllll .... Since I now know that I can use a simple attenuator (that I've already designed and used a number of times over the years) to pipe the audio signal into the TS and a mic pre to re-amplify the TS's output to the needed 35+db AND convert it's output to a balanced output, I think the potential mods to the TS I was seeking from you folks are no longer needed.  Hence my big huge thanks for allowing me to vocalize the whole thing here in forum and get it all worked out. 

I've verified my ideas on my own A102 yesterday ... 100% success.  (Jsyk .. the A100 series .. as in A100, A101, A102, A103 etc .. are IDENTICAL in every way to the B3 and the C3 Hammonds ... every single nut, bolt, and wire is the same .. the only differences that matter *in this case* are the A1xx, B3, C3 have different furniture.  That is to say their "cabs" are different.  The B3 has four legs, the A1xx and the C3 do not.  There are some other differences but they are moot in this instance.  So my own 1962 A102 is a fine test-bed for this particular setup I'm designing.  Just to get it said.

I am HIGHLY familiar with Hammond/Leslie systems ... so I am VERY aware of how high the signal must be to drive a Leslie "four hunderd feet" or whatever as it were.

However ... I am NOT as familiar with distortion pedals .. specifically the mighty mighty Tube Screamer ... I know there is an enormous knowledge base on that particular pedal, which is exactly why I came to you good folks for help on this situation.

CURRENT SITUATION:  The only thing I'm not totally certain about at this point is what the "best way" is to get the TS's OUTPUT down to (unbalanced) "instrument levels" to better work in conjunction with a tube-type mic preamp.  One of the lesser expensive ones like (let's just say) one of the $30 bux ART units (their specs seem to say that they can provide up-to/over +45db of output gain which is more than I actually need in this case).  I'm sure it's as simple as adjusting the output stage of the TS in some manner .. different resistors at the proper point or sunthin sunthin .. er whatever.  That way the VOLUME control will be more usable and not all super touchy.

PRR .. I want to thank you for taking the time you have set aside to assist me with this so far.  I totally appreciate your input on the issue, and I wish to genuinely thank you for your opinions and research. 

Lowvolt ...

[lowvolt]

Also ... jsyk ... what I do NOT want to do the TS to reduce the output to instrument levels is use more "choked" clippers.  I've done a BUTTLOAD of research with my own A102 and a GGG-TS and I've already worked out which IC and which clippers will work out the best for the sounds I'm wanting to get, as well as the "midrange cap" (listed as "C3" on the GGG TS).

So .. the clippers, the IC, and the "C3" cap (as it is listed on the GGG ITS8) are off limits.  I've got those worked out to provide the actual tone and distortion sounds I want for the Hammond.

So, that said ... any help on ideas of how to reduce the TS's output to a nice "instrument level" woud be great.

I know the clippers I've selected (from the LED family) and the C3 cap I'm using have kinda taken me the wrong direction and actually INCREASED the output levels, but they just make it sound so frelling great with this combo I've got going on!  The distortion is coming a bit from the IC this way, with a combined distortion of the clippers.  "Diode lift" is too chaotic and disorganized sounding .. too "fuzz-like" for my needs.  Too many LEDs (series connections) allow the IC to actually break before the diodes as well.  Might as well go with "lift" at that point.  So the combo I've got worked out is pretty much "the thang"!

Btw ... I've tried some other distortion circuits for this Hammond thing and the ones I've tried make everything too "scooped" .. Hammonds LIVE in the midrange and low end .. "scoop" it, and it's entire voice disappears.  Starts making it sound like a VOX or Farfisa organ.  I've tried "Bluesbreaker" type ods, GuvNor type ods, and I've tried single opamp circuits too.  Nope, they're just not right.

Thanks!