Nashville 400 Mid-Shift control

Mark Herrick · From: Bakersfield, CA

I was monkeying with my Nashville 400 the other day trying to dial in a better sound for my Mullen. I was playing with the Mid control and the Mid-Shift control. I got a really loud popping sound that I have never heard before and afterwards it seemed that the Mid-Shift control seemed to have more of a pronounced effect than before; then I got the pop again and the Mid-Shift control seemed to have less of an effect - even when going from minimun to maximum.

My question is this: should the Mid-Shift control have a really pronounced effect in its range of adjustment, or is it a very subtle effect? Sometimes it seems that there is almost no, or only a very slight, noticeable change when adjusting the Mid-Shift control. I'm wondering if my amp needs to be checked out. By the way, it does have the Miracle Audio mod.

Lee Baucum · From: McAllen, Texas (Extreme South) The Final Frontier

Good question, Mark. My old 1983 Nashville does the same thing. When it pops, it is so loud it makes me jump off my pack-a-seat.

By the way. As you know, I also play a Mullen. I recently had the Lemay mod installed in my Nashville and I now set the Shift control straight up, instead of at 800, where I have always set it. (Even with the old Emmons.)

Mr. Brown, any suggestions?

Lee, from South Texas

C Dixon · From: Duluth, GA USA

'tis best if one understands the real purpose of the "mid-shift" controls to figure how to set them.

In the early days of amplifier design, it was discovered that an amp which reproduced a guitar's natural sound, ie, flat amplifier frequency response (HI-fidelity), that players did not like the sound. Further no amount of adjusting the bass and/or treble controls could over come the objection.

Extensive research by many engineers, discovered that if the "flat" response was altered in the area around 800 HZ, it made a decided difference in players feeling about the amplified sound.

So most amps had "built-in" attenuation around 800 Hz. But it was fixed. That is, non adjustable.

Peavey went a step further. They did not build it in. They put a mid and a shift control on the face. Now players could have it, not have it or anywhere in between.

So here is what happens. IF, the mid control is in the 12 oclock position, the shift control should have no affect. Flat response (assuming the bass and treble and presence is also at 12 oclock).

However, if the mid control is moved to the left or right of 12 oclock, then the frequency tones determined by the setting of the shift control will be attenuated or boosted respectively.

Here is an example: IF the shift control is set at 800Hz, and the mid control is at 12 oclock nothing happens. But if he mid control is turned to say the 10 oclock position, then 800 hz frequency tones will be attenuated a small amount.

If on the other hand, the mid control is set at the 2 oclock position, then the 800Hz frequency tones will be boosted by a small amount.

Moving the mid control further in either direction increases the amount of attenuation or boost of the 800Hz frequency tones.

So here is the way to start. Put all controls; bass, treble, and presence included at the 12 oclock position. Now start with the shift control at around 800Hz. then set the mid control at the 10 oclock position. If it sounds real bad, put the mid control at the 2 oclock position. IF it sounds better then you need boost and not attenuation. From here tweak the mid and shift until you find the correct timber for your steel.

Now, alter the treble, bass and presence to taste.

The popping is probably a dirty control. Buy contact cleaner from an electronics supplier to spray in them to clean them.

hope this helps,

God bless,

carl

[This message was edited by C Dixon on 30 April 2000 at 09:32 PM.]

Earnest Bovine · From: Los Angeles CA USA

And don't worry about that loud noise when you turn the Mid and Shift controls. When those pots get old and scratchy, the noise they make gets amplified really loud. All the Peavey amps do it.

Jack Stoner · From: Kansas City, MO

Ernest apparently doesn't like Peavey. But, ALL amps have pots that can become noisy and scratchy, just like volume control pedals. No matter what application the very thin resistance strip in the pot can wear away and or the slider that contacts the resistance element can become dirty and make poor contact.

I've cleaned or replaced pots in all brands of amps.

Earnest Bovine · From: Los Angeles CA USA

I like Peavey amps. Why wouldn't I?

You can quiet down the scratchy pots by turning them a few times, or a few dozen times. It's a lot easier on the ears if you do it before you turn the amp on.

Bill Terry · From: Bastrop, TX

For some reason I've seen a lot of Nash 400's that have that loud pop when you move the mid shift. It's much louder than the noise you'd normally hear from a dirty pot. Mine does it too....

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bterry.home.netcom.com

Mike Brown · From: Meridian, Mississippi USA

My first impression was defective pots. "Any" pot on "any" amp can become scratchy after being used for several years.

I know what Jack and Carl are technicians and have been using Peavey products for a long time and there is a reason for this...........good amps for a reasonable amount of money. I don't really understand why some people want to make negative comments about a amplifier company's products that have been in the field for awhile under normal use, when that company supports the steel industry moreso than any other amplifier company.

Peavey is "always" researching new ways and methods of designing and manufacturing products. A mechanical pot can become defective just like one of four tires on a car.

Carl pretty much described how the "mid" and "shift" controls work. When the mid control is set at 12 o'clock, the shift control has no effect. Any mid control setting to the plus or minus side(to the right or left of '0') will allow you to cut or boost that frequency setting.

Thanks for Jack and Carl's help in this and thanks for using Peavey products. As always, I can be reached toll free inside the U.S. at 1-877-732-8391.

Bill Terry · From: Bastrop, TX

Mike,
Sorry, no slam on Peavey intended here, just noting that a dirty shift control pot seems to exhibit itself a little more exuberantly on the Nashville for some reason....
BT

Mark Herrick · From: Bakersfield, CA

Thanks for the explanation of the Mid-Shift control, Carl. (Copied that one to the PSG folder!)

The popping noise does not sound like a dirty pot. It is much too loud. But it seems to be OK now; must be just an “intermittent” thing.

Lee Baucum · From: McAllen, Texas (Extreme South) The Final Frontier

Mark - My amp rarely makes that loud popping noise, but when it does, it takes a while to get the old ticker started again. I hardly ever adjust those two controls, so I'll just live with it. Maybe that's the problem. Maybe some corrosion has built up from not using the controls.

Lee, from South Texas

Mark Herrick · From: Bakersfield, CA

Hi Lee,

Yeah, I know, I jumped like a scared cat when it first happened. (Worse than a reverb crash!) You are probably right, I hadn’t used the amp in at least a month (switched to the Mesa Boogie for a while).

I did “zero out” everything as Carl suggested and started adjusting from scratch. It sounds better now!

Ernie Renn · From: Brainerd, Minnesota USA

As Mike said, any pot on any amp can be defective and it sounds like the problem is that the pot was in the same position for an extended period of time and developed a glitch. If you have a tendency to leave the pot in the same position for a long time, take a few minutes every so often to run them back and forth, from 1-10, a few times. This may solve some of the pot problems.
Good luck finding your problem! Mike's the guy to help.
BTW: Mike - I've been using Peavey amps exclusively since 1977, when I bought my first Session 400. I've used the Session 400, the LTD 400, the Vegas, the Nashville, the Renown, and the Session 400 LTD. You guys make great amps. Now if you'd just re-issue a vintage Session 400, with those big silver knobs. That would be killer! Just a thought.

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My best,
Ernie

The Official Buddy Emmons Website
www.buddyemmons.com

Mike Brown · From: Meridian, Mississippi USA

I don't take offense to musicians having their own views on music and the type of gear that they use. I "do" appreciate your comments and realize that not "everyone" likes a Peavey amp. I have owned several different amplifiers in the past and still do, but presently I use a Nashville 400(1985) and a Delta Blues for my live playing.

But, comments that are unjustified without an explanation kind of rub me wrong. I think that it would for anyone. I consider myself very fortunate to be allowed to convey information about Peavey products to customers on this forum, but I have to "set the record straight" sometimes. Thanks for allowing me to participate.

rickw · From: nc

Hi Carl Dixon,I first meet you in Saluta,S.C.WE are Rick and Teresa Worley.Would you know of any hand book that would explain the terms like "mid-shift,presence,lows"and all that kind of stuff. Im lost.Thanks----Rick W

Lee Baucum · From: McAllen, Texas (Extreme South) The Final Frontier

Mike - We are the ones who are fortunate. It's great to have you participate on this forum. Peavey has done so much over the years for us steel players. Having you here gives us a direct connection to the source.

Thanks again.

Lee, from South Texas

Buck Grantham R.I.P. · From: Denham Springs, LA. USA

Mark, My two older Nashville amps both started doing the popping so loud that I was afraid it would ruin a speaker. I took them both to Peavey and they cleaned the pots and also blew the dust out of the speakers. They came back sounding better than I remembered they ever had before. The pots are dirty!!

C Dixon · From: Duluth, GA USA

HI Rick,

Nice to hear from you.

I know of no book explaining how to set tone controls on an amplifier. If you read the Peavey owner's manual, you may get confused. It is a difficult subject and very difficult to put into words.

Let me give you a little layman's instruction that may help you.

For the moment forget about the prescence control. Just set it at 12 oclock position so in affect it has no affect on the tone.

Now take two straight sticks say 6 inches long. Join them so they form a straigt line. Lay them on a table so they form a horizontal line from where you are viewing them. Label the one on the right treble and the one on the left bass.

Now on a peavey Nashville 400, when the treble and bass controls are straight up (12 oclock position), the sticks are straight across. In other words your amp is amplifying all tones flat. No alteration to the tone from the pu.

Now move the treble control clockwise from 12 oclock position. This is the same as taking the right hand stick and pivoting it up slightly at the point where it is connected to the bass stick.

If on the other hand you moved the treble control counterclockwise, it is the same as pivoting the right hand stick downward a bit.

The same thing happens with the bass control with respect to the left hand stick.

So in affect you are boosting the highs (or lows) or attentuating them (often erroneoulsy called "cutting") depending on whether you go to the right or left of center position of the control. And the sticks give you a visual picture of this action as to the flatness of the amplifier. Notice, using the sticks, that the highest of the highs or the lowest of the lows move much greater than tones towards the middle.

And this is THE problem with a Bass and treble control. Say you wanted to boost or attenuate something other than the highest of the highs or lowest of the lows. And leave the rest set flat? HUH?

That is where the mid and shift come in to play. They allow you to raise the middle portion of the left stick or lower it without necessarily raising the end of the stick. Clever huh?

The mid control determines how high or low the middle of the left stick goes and the shift control determines where it happens on the left stick within a narrow range. By the way this range is very sensitive to most people's ears when it comes to a guitar's sound.

The prescence control is a spacial thing and tends to affect what the listener in the audience hears more than what you hear close to your amp. And as such is best set using a listener to help you.

Hope this little simple analogy helps you.

Say hello to your wife for me.

God bless you both,

carl

Curt Langston · Posted 7 May 2000 8:42 am

Guys, I have had Peavey amps for several years. New and used. Of course they are very reliable. But not eternal! Those scatchy pots are no problem. #1 unplug the power cord. #2 unscrew and pull the chassis out. #3 turn chassis upside down, place on a card board pedestal. #4 spray ELECTRONIC Control and Switch cleaner into the very small hole on the back (inside) of the pot.#5 rotate knob several times completely.#6 allow to dry completely.#7 replace chassis and enjoy "pop free" entertainment!..NEVER USE WD-40!!!!! This can ruin Nylon components and will leave oily residue that will create the same problem..WD-40 is fine for household, NON ELECTRONIC stuff...I have done this numerous times and so far have not had to replace pots.(I can't speak for each individual circumstance, but I would definately do this first)...Hope this helps!

rickw · From: nc

Thank You Carl Dixon---Now I understand more about the amp. Just a few more question if you dont mind.I have a delay;is this nessasary? I have a matchbox;what does this do? How would you set a 400 amp to come close with a sound somewhat like everbody elses.Last SAT.,I notice a player with 2 cables from the padel to the patch infront of the amp-I only have.Why? Thank you-Rick--Am I a pest?

rickw · From: nc

Lelf out the word "one" SORRY

C Dixon · From: Duluth, GA USA

Rick, you are NO pest. "Inquiring minds want to know!"

Ok, delay? match box? number of cables?

1. Delay----what is delay. To most technicians it is a way of "fattening a note". Now how in the blue-blazes do you fatten a note?

OK, IF, one can create the IDENTICAL note that one has just played while the original note is still sustaining, it tends to feel like the original note is wider (in time) or "fatter" sounding. Now this time is critical. TOO much delay and it will appear as though you picked the same note twice in rapid succession.

So, if you can adjust the delay AND the level of the second note ("delay") just right, you can achieve a fatter note. In essence it is like holding a key down on an electric piano. rather than just hitting it fast. This "time" delay sounds like the note is fatter.

The earliest way it was done was with the old Fender Echoplex, where they used an audio tape unit with a playback head only micro inches from the record head. So what happend was, immediately after a note was recorded, it was played back again. Albeit, with a slight delay. The playback head was adjustable in distance from the record head to be able to adjust the amount of delay.

Buddy Emmons's is the world's master PSG player using delay IMHO. Wrote and entire song using it to its extreme limits, ie, "Witches Brew".

Some, (I included) believe a good delay unit, can almost do away with reverb, since reverb is nothing more than the note coming back at you a few milliseconds later.

One caveat on delay. The tempo of the tune you are playing has a decided affect on how fast or slow the delay should be. Some delay units have a button that can be hit 2 or more times in time with the tempo, to automatically set the delay time. A boss DD-5 is one of these units.

2. Match box? What is it? What does it do? OK, digress for a moment. Whenever you have a source of music connected to another piece of musical gear, maximum transfer of this music and tone is ONLY possible when the source "impedance" and the receiving impedance are indentical.

Most PU's "impedance" is quite low. Most amplifier impedances is quite high. So when we plug our guitar into an amp, whamo!! we immediatetly have a missmatch. So some level and tone "coloration" (change) will happen, more or less.

So a "match box" tries to match the PU's impedance to the amp's impedance. And many do a good job of it.

Now there is a little problem here. The above does not take into account the volume pedal. And since it is a changing resistance constantly, it can change the tone according to some players. I personally and categorically refute this (at audio frequencies). But that is for another time.

So that leads us to number 3.

Peavey decided to build the matchbox into the amp. Now what does this do and how did they do this. Well, the first amp I recall that did it was a Session 500. Most steel amps since have it.

It allows you to connect your guitar into the amp without the volume control in the circuit. Then the signal gets amplified and THEN it is send to the volume pedal under "matched" conditions and THEN back to the amp under supposedly matched conditions. Thus more than one cable form volume pedal to amp. I have always seen 3. You say two. Not sure about that.

A great advantage of connecting your guitar straight into the amp bypassing the volume pedal at this time, is you get the benefit of amplification of the very tiny signal that PU's put out. This then minimizes noise and other unwanted things BEFORE it goes to the volume pedal.

Hope this didn't end up being "Clear as mud"

Walk with HIM

carl

Lee Baucum · From: McAllen, Texas (Extreme South) The Final Frontier

Well put, Carl. (As Usual!

)

Lee, from South Texas

rickw · From: nc

Carl Dixon, thank you very much. You have helped me alot.Yes' I have three jacks on the padel. Does one of the cables go to the gain on the amp? I have bought many amps but never used the whole thing.I think learning a little steel is easier than learning the equitment. Its nice to hear someone mention God. Thanks------Rick W

C Dixon · From: Duluth, GA USA

Rick,

To use the 3 cable system utilizing Peavey's built in "matchbox", do this:

1. Connect a cable from the guitar straight into the top left input on the Peavey amp.

2. Connect a second cable from the amp's "Pre EQ Patch" OUT jack to the volume pedal's "in" jack.

3. Connect a third cable from the volume pedal's "out" jack to the amp's "Pre EQ Match" IN jack.

Note: the second "out" jack on the volume pedal is not used in this case. Some players connect their tuner to this jack. Others connect a delay unit in series with this second "out" jack into a 2nd amp. Most do not use this jack at all.

Feel free to call me anytime if you wish--770-448-8455

take care,

carl

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