[Harp-L] amp sweet spot

["John F. Potts" <hvyj@xxxxxxx>]

Bruce K Ritter asks:

I've read several mentions of an amps sweet spot-what do I listen for  
the
find it, is there a process of dialing in settings and testing?

Bruce,

A good tube amp is almost like a living, breathing creature.  The  
response to tone and volume settings is not necessarily linear, and  
will also be different depending on how hot the tubes get during  
performance. Most tube amps sound and respond best when pushed--you  
get the volume at a certain point (with appropriate tone control  
settings) and the degree and quality of the resulting overdrive, tube  
compression and distortion gives you the particular sound and  
response you are after. The real challenge is to get that level of  
tone and response without feeding back.  This is why many of us swap  
tubes for lower gain preamp tubes and unbalanced phase inverter  
tubes, keeping in mind that tubing down too much may rob the amp of  
tone,  Also, if the amp has tilt back legs, like many Fender amps do,  
using them may open up, and therefore change, the tonal  
characteristics, sometimes dramatically.

Now, the "sweet spot" is an entirely subjective determination and has  
a lot to do with playing style.  You use your ears and different amp  
and mic settings to find it. The "sweet spot" may be different for  
different mics into the same amp, and will be different for different  
players using the same mic into the same amp.  Personally, i like a  
somewhat cleaner sound, so what i consider the sweet spot on, for  
example, my Super Reverb Reissue, will be different than what some  
other player may prefer who is after more "crunch."  But depending on  
the amp settings and the particular mic used, the amp will respond to  
playing technique somewhat differently.  Personally, I think too much  
"crunch" deprives me of articulation and i don't use a bullet mic.   
Other players may prefer a bunch of low end distortion to fatten tone  
and will play through a bullet and use mic handling and breath  
technique to vary the resulting crunchy sound--each of us will find a  
different "sweet spot" on the same amp for what we are trying to do,  
or may prefer to play through amps with different gain  
characteristics and speaker configurations.

Personally, I'm not fond of amps with a master volume control. but  
such amps are supposed to allow one to set the sweet spot using the  
volume knob and then set performance volume using the master, which  
may work for guitars, but which I think works better in theory than  
in practice for playing harp. But YMMV.  Anyway, don't be afraid of  
extreme tone control settings. like, for example, turning the treble  
all the way off.  On my SRRI, I find I need just a touch of treble  
(between 1 and 2, and closer to 1 than 2) for cut.  Be careful about  
the conventional wisdom that you should always turn the bass all the  
way up--bass frequencies can feed back, too, and may muddy your  
sound.  Personally I find a mid range control very useful .  Others  
may like to use an outboard equalizer to boost the freqs around 240,  
or use an EQ or an outboard preamp or compressor to attenuate (or  
boost) input gain. There are no set rules--if it gives you the sound  
you are after, it's the right thing to do.  But, in general, the more  
gear you have, the more problems you have, so, all things being  
equal, the simpler the set up, the better.

Also, --(and this is extremely important)-- keep in mind that what  
sounds good in your living room may not sound right on stage at the  
venue.

Lately, i've just been using the volume control on my 545 Ultimate to  
attenuate input gain, allowing me to set the volume on my Supper  
Reverb Reissue at 7 or 8 (or on my Princeton Reverb Reissue, which is  
my smaller  tube amp, at 6 or 7 ) which is  a level where I think the  
tube response sounds best (the "sweet spot").  The reduced input gain  
from the mic allows me to turn the amps up that far without feeding  
back and then I will adjust the VC on the mic a little to control  
overall performance volume, and I  don't use any pedals or outboard  
devices. I find that attenuating the input from the mic is pretty  
reliable way to control feedback. But there are other ways to do it,  
and the tonal qualities of some mics will degrade if they are turned  
down, so it's a trial and error thing.  Some players will use a super  
clean mic, like an Audix Fireball V (which also has a very high  
feedback threshold), into a high gain amp, using the clean mic signal  
to balance what might otherwise be unmanageable heavy distortion from  
the amp, which can also be pretty effective.  But I like the sonic  
character and proximity response of my 545 Ultimate.

On my PRRI there is no midrange control and i set the  treble at 0,   
bass at 10.  This makes the amp sound a little "boxy" but i put a set  
of 14" Fender tilt back legs on it, and if i tilt it back, the tone  
opens up nicely and it sounds perfect. But, I've heard other players  
who use a bullet mic into a PRRI say they like to keep the amp on the  
floor at all times  for better low end response. One man's sweet spot  
can be another man's sweathog, to borrow a metaphor from the world of  
romance.

Actually, i usually play through a pedal board into an SWR Baby Baby  
Blue bass amp which has a solid state power stage, a tube preamp and  
on board semi parametric EQ for tone shaping, so  I'm not a regular  
full time tube amp user myself. But, depending on the gig, I use what  
i consider to be the right tool for the job which may be my PRRI or  
my SRRI if I'm not using my SWR.  There are a lot  players on here  
that have much more extensive experience finding the "sweet spot" on  
tube amps than i do.  But. since i recently used that term in a post,  
I thought I would give you my take on it, FWIW.

Best regards,

JP