Also, on a related topic, what is the best way to handle the two different volume settings to keep the tone clean and strong at higher volumes.

The MID and SHIFT controls are designed to work together, meaning that you can select a frequency between 150Hz. and 1.5(1500Hz.) using the SHIFT control. That selected frequency can then be "cut"(to the left of "0") or "boosted"(to the right of "0") at the selected frequency. NOTE: From my experiences and from input by other steel guitarists, the mid range of a Nashville 1000 sounds best by "cutting" the MID to negative 9 and selecting the frequency of approximately 800Hz. on the SHIFT control. This means that you have cut the decibel level by 9dB at approximately 800Hz..

The LOW, HIGH and PRESENCE controls operate differently in that they are all "centered" at one frequency. The LOW is centered at 45Hz., the HIGH is centered at 6kHz. and the PRESENCE is centered at 10kHz.

On the SPECIFICATIONS sheet in the operating guide, there is a DESIGNED INPUT LEVEL rating of 1 volt RMS. This means that to drive the power amp section of the 1000 to full power, the signal would have to be at least 1 volt.

So, with this being stated, it is recommended that the MASTER GAIN be adjusted to a considerably higher level than the PRE GAIN. Even as high as 10, but in this example you probably wouldn't be able to turn the PRE GAIN up very much. A lot of this concept is related to the signal after the PRE GAIN setting, which in turn is related to how strong the input signal is, etc.,etc.. The previous example is one way to keep the signal strong and clean.

If you have further questions, I can be reached toll free at the factory by calling 1-877-732-8391.

Mike Brown
Peavey Electronics

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[This message was edited by Mike Brown on 24 June 2003 at 01:11 PM.]

The Mid knob controls the frequency range from the lowest open string to the middle strings barred about halfway up the neck. The High knob controls the frequencies from there up to the highest string at around the 24th fret. So really the upper half of the notes you can play are controlled by the High knob, and the lower half by the Mid knob. And as Mike said, you can shift the center (but not the range) of the Mid knob, and cut or boost the frequencies around that center.

At least that is the way the published specs on my Nashville 400 fall out. A modified NV 400 is a little different, as is the NV 1000, but I think this is still approximately true for them also. Mike can tell us.

These two knobs are very well engineered to match the range of the pedal steel guitar. Regular guitar amps do not have controls that so well match the instrument (can't speak for other amps designed for steel). You might then wonder what the Low and Presence controls do if they control frequencies beyond the notes the instrument can play. The Low knob controls ultra low frequencies corresponding to pick impact, and the Presence controls high frequencies of the high overtones that determine the timbre of the instrument's tone. You can confirm all this by turning all the controls off and then turning them up alone, one at a time.

To my mind the knobs are slightly mislabelled. The Mid knob controls both what we think of as middle tones as well as the lowest tones we play. A more accurate labelling system might call the knobs Sub-low, Low/Mid, High, Ultra-high. The Shift knob then moves the center of the Low/Mid knob between the Low and Mid tones.

Your lowest note B is 61.7Hz
(the G# with the boo-wah is 51.9)
Your highest open string G# is 415.3
That string at the 24th fret (Hughey-land) is 1661.2

Remember that there are overtones that may be several-fold higher than those values, but the fundamental frequencies are all between the low and midrange. The high and presence only emphasize overtones.

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Larry Bell - email: larry@larrybell.org - gigs - Home Page
2003 Fessenden S/D-12 8x8, 1969 Emmons S-12 6x6, 1971 Dobro, Standel and Peavey Amps

[This message was edited by Larry Bell on 24 June 2003 at 02:51 PM.]

But there is another concept of presence in amplifiers. I am referring to Fender amplifiers specifically. The prescence control in most Fender tube amps is not a filter that boosts frequencies in the range of 4-10kHz in the amplifier chain. It actually changes the feedback loop of the power amp. To reduce distortion, a typical power amplifier will invert a sample of the output and feed it back into the input of the power amp (or feed it back into an input section that is out of phase with the output). This reduces gain but also greatly reduces distortion. It also decreases the output impedance of the amp. The presence control in the Fender circuits is a low pass filter in the feedback path, limiting the amplitude of highs fed back. This increases the high frequency gain, sounding like a presence control. However, this also increases distortion at high frequencies. The combination of frequency dependent distortion and high output impedance makes for a unique sound. The high output impedance reduces the amount of damping on the counter EMF generated in the speaker coil. This "loose" control of the coil at high frequencies results in a characteristic sound of its own.

I don't know how or why the Fender amp engineers came up with this, but it is a cheap simple way to achieve the high end boost. I suspect they didn't know the added sound benefits from the high frequency distortion and output impedance increase would be regarded to this day as a vintage sound feature. If any of you have any insight on this, let me know.

Regards,
Terry Downs

[This message was edited by Terry Downs on 24 June 2003 at 06:06 PM.]

Here is some history on musical intrument evolution.

In the very early days, it was assumed that an amp with flat frequency response would be the ideal amplifier for musical instruments. Nothing could have been further from the truth.

This can easily be proven by feeding your guitar into a high end quality stereo. NOTHING a person does with the controls will satisfy MOST players!

Why is this?

Before I answer it, let me muddy the waters even further. A recording using a PSG can sound beautiful when played thru a stereo player that has flat response.

So why does that same PSG sound horrible when played through the same stereo unit?

Well the answer is NOT conclusive, but audio engineers found out that when any stringed instrument is amplified the frequencies at or near 800HZ are extremely sensitive to most players. There is NO consensus as to exactly why!!

Also, it is NOT consistent. And this jives with what Mike said. On some amps, the engineers had to cut those frequencies to satisfy players. While on other amps, they had to boost those frequencies.

So prior to Peavey, this cutting or boosting was built into the amp, and the player lived with what the consensus was when that amp was designed.

Peavey gives the player a choice. That is again as Mike says, we can boost; OR cut a given frequency centered more or less around 800HZ. And we have control of how much cut or boost; as well as the specific frequency to cut or boost.

So how do you set them? Very easily. Start with the mid at 12 o'clock. This means the shift control has NO affect. That is, there is NO cutting OR boosting. It is as though you did NOT have the controls at all in that position.

Now start with the shift at 800. Why 800? Because this has proven to be THE most sensitive frequency in exhaustive tests by audio engineers down thru the evolution of amplifiers.

Now, first try cutting (counterclockwise) a little bit. IF it sounds better to your ears, then try cutting a little more. You will reach a point where it starts to sound worse; since too much cut is not good either.

IF it sounds worse when you cut just a little, try to boost (clockwise) instead and follow the steps above. Again if it sounds better, there will reach a point where it starts to sound bad again, because too much boost is not good either.

Finally ONCE you have found the necessary "cut OR boost" that sounds good to YOUR ears, then tweak the shift to the left or right of the initial 800HZ position to find THAT spot that gives you the best sound.

Once you find this, you should rarely have to readjust it; unless invironmental conditions cause a drastic change in the reflected sound perceived back to your ears. Then try moving the shift just a tad to the right or left.

Finally, the distortion Terry Downs was talking about on early Fender amps using a "Presence" control is called "crossover" distortion. It is a built in distortion that is caused by Push Pull ampifiers.

In simple terms, it is when one tube is shutting down as the other one is starting to operate. This is a very critical point in designing Push pull output stages, and if not done carefully, the distortion can be intolerable.

However, Fender found out that there was a very narrow range that if made adjustable, could give the amp a warmer tone. Leo Fender coined it "presence". The Presence control on Peavey amps is an entirely different animal, so follow Mike's suggestion on these amps.

May Jesus richly bless you all,

The Shift control is part of the midrange control section. The midrange knob either boosts or cuts the midrange frequency. The "shift" control chooses what frequency will be boosted or cut. It seems that most people keep the shift knob around 800Hz (1 o'clock) and cut just a few dB with the midrange knob.

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Brad Sarno
Blue Jade Audio Mastering
St. Louis

In response to Carl's comment about how 800Hz is a common place to want to control steel guitar midrange;

Bill Lawrence once explained to me in what seemed like pretty heavy calculus why 800Hz is an issue. He said that based on the size of a 10 or 12 string pickup, the typical strength of magnets used, eddy currents, wire guage, number of turns, etc. that when it's all said and done, no matter whether the pickup is wound at 14kOhm DC or 30kOhm DC, a steel pickup will almost always have it's greatest power or loudness around 710-850 Hz. By having a midrange control in that frequency range and cutting that band, you can actually help flatten out the response of the pickup opening up a wider range of harmonics. It's not about controlling the guitar notes in that range, it's about smoothing out the harmonic aspect of the pickup in that range. I rarely see people boosting this band since it's already quite hot coming out of the pickup.

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Brad Sarno
Blue Jade Audio Mastering
St. Louis