Hammond growl reduction

[bluesdisciple]

Hello all,

 

I have a 1956 Hammond C3. This past week, I had the tube sockets on the preamp cleaned out and tightened to reduce pin drag and had the whole preamp wiring cleaned up as well. This solved the initial problem of reduced volume rather well, in fact almost too well.

 

Now I have volume and volume to spare, along with that sweet Hammond growl when I boost the volume on the pedal. The only problem is that at higher volumes (on the Leslie) it is now hard to get a clear, clean sound especially in the middle octaves. It seems I now have too much growl and distortion for some songs. If I go up to the higher octaves, it is clear and cutting (as expected), but it takes away from some songs if play on the higher octave all the time.

 

This whole thing may just by my imagination or the result of playing for too long with reduced volume which did not create the growl/distortion I have now. Is there anything mechanical I can do to the Hammond to address this situation, or is it best addressed through drawbar manipulation and using one or two finger chording and finding "the right space" on the manuals? Or is it now a Leslie Preamp problem? Or is something that will need to be addressed at a gig through the PA?

 

This is not a bad problem to have by no means as there is truly nothing like a Hammond growl. As the C3 is my "main" instrument for most of our songs, I guess I am now in quest of a perfect, all-around, multi-use Hammond sound.

 

Any suggestions would be greatly appreciated.

 

BD

[DanL]

You may need to back off on the Leslie master volume a bit.

[Dan Savage]

I would love to have this problem.. one man's ceiling, another man's growl.. my C2 / 45 is just too clean.

 

My guess - and that's all it is - you've got more bass than high end being emphasized. There's a trim pot on the preamp that adjusts tone. I'd try adjusting it to get a brighter sound overall, de-emphasizing the bass that might be breaking up your Leslie. That could also change your drawbar settings.

[kwgm]

Originally posted by bluesdisciple:

Hello all,

 

I have a 1956 Hammond C3. This past week, I had the tube sockets on the preamp cleaned out and tightened to reduce pin drag and had the whole preamp wiring cleaned up as well. This solved the initial problem of reduced volume rather well, in fact almost too well.

 

Now I have volume and volume to spare, along with that sweet Hammond growl when I boost the volume on the pedal. The only problem is that at higher volumes (on the Leslie) it is now hard to get a clear, clean sound especially in the middle octaves. It seems I now have too much growl and distortion for some songs. If I go up to the higher octaves, it is clear and cutting (as expected), but it takes away from some songs if play on the higher octave all the time.

 

This whole thing may just by my imagination or the result of playing for too long with reduced volume which did not create the growl/distortion I have now. Is there anything mechanical I can do to the Hammond to address this situation, or is it best addressed through drawbar manipulation and using one or two finger chording and finding "the right space" on the manuals? Or is it now a Leslie Preamp problem? Or is something that will need to be addressed at a gig through the PA?

 

This is not a bad problem to have by no means as there is truly nothing like a Hammond growl. As the C3 is my "main" instrument for most of our songs, I guess I am now in quest of a perfect, all-around, multi-use Hammond sound.

 

Any suggestions would be greatly appreciated.

 

BD

I've seen this happen with other kinds of analog electrical equipment, which is why we have a saying in engineering "if ain't broke, don't fix it."

 

You have probably changed the impedance looking into the preamp with all that "cleaning" and you now have an impedance mismatch that's pushing the Leslie over into distortion too quickly.

 

Is there a dial on the Leslie amp to "tune" the circuit, or a pot in it's input stage? If so, you may be able to change the amps' input circuit Q to better match your new preamp's output characteristics.

 

Otherwise since you have "volume to spare", either reduce the gain of the preamp or Leslie (or both) and you'll be pushing less current and therefore playing more in the normal range with less distortion within the expression pedal ranges your right foot is accustomed to.

 

Or, sell that C's preamp to a heavy rocker type--maybe the guy from Deep Purple--they love that growl.

 

And remember, I have a masters degree, in science.

[bluesdisciple]

Thanks guys,

 

I will have to check the trim pot on the Hammond pre-amp as this seems to make the most sense and may do the trick. (I take it that this is the small knob in the outside right corner of the preamp?)If so, it may have been mistakenly turned as part of removing, fixing, carrying, and reinstalling the preamp

 

I did lower the master volume on the Leslie and that works for the more quieter songs we play, but doesn't cut it on the louder stuff (combination of a ex-heavy metal drummer and two LOUD guitarists).

 

If adjusting the trim pot doesn't work, we will go in and check the impedance too.

 

This is what I love about owning a Hammond--everytime you play it is a new adventure and on top of that, there is always more to learn about it.

 

Thanks again,

 

BD

PS147---Rockin Christian Rock

[Hammodel AV]

The Hammond FAQ (search the net for this) has the adjustment proceedure to set (or reduce) the preamp output level, which causes the 'growl'. The Leslie volume control will not generally affect this, as it is the overdrive of the input stage of the 12AU7 that creates this (plus maybe a little dirty output from the A0-28 preamp too).

[Steve Nathan]

I may have to disagree with the above post. I've always found the Leslie volume control to have a definite affect on the "Growl" factor. I'll bet if you turn the volume pot down on the leslie, it will sound more like it used to. If you have it set in the old ballpark, you're getting to the "Growl" sooner perhaps because you're hitting the tubes harder now. You could also try some alternate 6550s. I'm sure someone around here can tell you which ones are cleaner at higher volumes. I've always been heading in the other direction (Svetlanas).

[paully]

Originally posted by Hammodel AV:

The Hammond FAQ (search the net for this) has the adjustment proceedure to set (or reduce) the preamp output level, which causes the 'growl'.

>>>>>>>>>>>>>>>>>

http://theatreorgans.com/hammond/faq/hammond-faq.html#SEC16

 

Paul

[Jim Alfredson]

What Leslie are you using? Try some modern tubes with better gain stages. I find the Electro-Harmonix preamp and power tubes to offer a lot of gain before breaking up in my 122.