Peavey mod kit VS. the Ken Fox mod

Curt Langston · Post by **Curt Langston** » 7 Apr 2008 9:50 am

Is the Peavey mod for the Nashville 400 easily installed? (no soldering)

How does it improve the sound?

Is it relatively inexpensive?

I hear so many good things about the Ken Fox mod, and I would like to hear the pros and cons of the Peavey mod. Sort of a comparison.

Thanks for the input!

Glenn Suchan · Post by **Glenn Suchan** » 7 Apr 2008 11:12 am

Curt, I did the Peavey mod on my N'400 about 5 years ago. At that time, the cost for the Peavey mod was approx. $55. After the mod, the amp has more resonant lows and more balanced mids (less boxy sounding). The job took about an hour and a half, with my amateur skills. A pro could probably do it in far less time. It was well worth the effort and the cost.

The Peavey mod comes with a electronic schematic diagram as well as a pictoral diagram of the components on the circuit board. All components are referenced by standard indications (ie) C41 for "capacitor 41", etc. If I remember correctly, the mod included several capacitor changes, several resistor changes (I think) and 6 Op Amp changes. (Mike Brown: Correct any mistakes, as my memory ain't what it usta' was.

)

You will need a basic knowledge of how to work on a printed circuit board which includes desoldering original components and soldering their replacements. Tools needed are: philips screwdriver and nut drivers (or crecent/box wrenches) for chassis hardware; a soldering iron suitable for printed circuit boards (gun-type soldering irons tend to be too hot and too clunky for this type of work); a desoldering tool is handy but not necessary; a small pair of wire cutters and a small pair of needle-nose pliers.

If I've forgotten some info, maybe Mike Brown will add to it. Incidently, Mike Brown and the rest of the staff at Peavey were very helpful with everything I needed for the mod.

Best wishes for a successful mod. and...

Keep on pickin'!
Glenn

A. J. Schobert · Post by **A. J. Schobert** » 7 Apr 2008 11:21 am

Curt if you don't want to solder send your amp chasis to peavey and they will put the mod kit in for you, you can call them to get an exact quote, or you can get a hold of ken fox, either way there is soldering involved.

I have a peavey mod kit I will put on myself and later I think I will have Dr Fox check it out.

Jerry Erickson · Post by **Jerry Erickson** » 7 Apr 2008 1:47 pm

I think that Ken has also incorporated some modifications to the reverb circuit as well as the mods that are in the Peavey kit. John LeMay is the guy that first sold mod kits for the NV400/ProfexII. You can read about it here:

http://bb.steelguitarforum.com/viewtopic.php?t=95861

Steve Norman · Post by **Steve Norman** » 8 Apr 2008 9:21 pm

If your soldering skills are low, solder IC sockets in the board and clip the ics into them. That way the heat from soldering iron will not destroy the chip if you take to long. (makes chip removal easier if you want to switch back to the og chips)

LARRY COLE · Post by **LARRY COLE** » 8 Apr 2008 9:50 pm

The IC's are plug in but there are quite a few other parts that have to be soldered.
Ken Fox does the reverb mod too.
I done the Peavey mod and the reverb mod and it made my Nashville 400 sound like a giant Fender Twin. Ken has improved the Peavey mod. It even sounds great with my 3 P/U Carvin Tele.

John Fabian · Post by **John Fabian** » 9 Apr 2008 1:28 am

Your UNsoldering skills need to be good or you will be repairing broken traces on the circuit board.

Ken Fox · Post by **Ken Fox** » 9 Apr 2008 3:56 am

The mod has 38 parts that I change out. I use Orange drop caps in the reverb and tone mods. All audio coupling caps are changed from the cheaper and poor sounding electrolytic caps to higher grade tantalum caps. The tantalum caps are known to have a tube like tone and it is huge improvement in tone for the amp.

All filter caps are changed out in the power section.

The audio chips are all changed out to Burr Brown chips, same chip Peavey used in their mod kit.

However, every Peavey amp I have modded that had the factory mod installed did not have Burr Brown chips installed from the factory! The only change was the resistors and caps that are in their factory kit they sell. The factory kit does have the Burr Brown chips in it.

I have modded a lot of amps that had the Peavey factory mod, after market Peavey mod and the Lemay mod. So far everyone seems pleased wit the tonal change of the amp.

Thanks again!!!

Mike Brown · Post by **Mike Brown** » 9 Apr 2008 5:33 am

Curt, the Peavey Tone Mod Kit part number is 90500048 and carries a U.S. MSRP of $39.99. Our techs can install the kit for you and repair any additional symptoms that your amp might have while it is here at the factory. Additional time may be required if other problems exist.

It takes our techs about 1 hour to install a kit. If you need further assistance, please don't hesitate to contact me here at Peavey by calling toll free at 1-877-732-8391, ext. 1180 and I will be glad to assist. In the meantime, here is a link from the Peavey website about our mod kits;
http://www.peavey.com/support/steelguitaristinfo/

Mike Brown
Peavey USA

Tom Gorr · Post by **Tom Gorr** » 9 Apr 2008 10:00 am

Ken's prior post may explain my experience.

I bought a used Vegas that was advertised as having the latest mod, but when I cracked it open and looked at the circuit board, it didn't have the (absolutely amazing sounding) Burr Brown chips. Peavey sent me the "kit", which did have the Burr Brown chips, so I plugged them into the right sockets, and was done in about 20 minutes. Those chips gave silky highs and removed the harshness from the amp.

I have been happy with the tone ever since.

BTW - I substitute Burr Brown chips into every amp with a solid state front end. They are that good.

Curt Langston · Post by **Curt Langston** » 9 Apr 2008 11:35 am

Your UNsoldering skills need to be good or you will be repairing broken traces on the circuit board.

Indeed!

That's exactly what I am concerned about. I have done soldering through out the years, just not on a circuit board.

Steve Norman · Post by **Steve Norman** » 9 Apr 2008 9:28 pm

If you have an old vcr or a dvd player they make good de-soldering practice....lots of printed circuit boards in them to de-solder and resolder on. People around here throw them out all the time. Another good way to learn is get a build your own clone kit and build a real cool pedal as you learn.

http://www.buildyourownclone.com/index1.html

using de-soldering braid is hard to learn but works great once you get the hang of it, it does a real good job of wicking the solder out of the PCB holes, and its cheap

this way you dont ruin the amp learning

Steven Welborn · Post by **Steven Welborn** » 18 Feb 2019 11:05 am

Ken Fox wrote:The mod has 38 parts that I change out. I use Orange drop caps in the reverb and tone mods. All audio coupling caps are changed from the cheaper and poor sounding electrolytic caps to higher grade tantalum caps. The tantalum caps are known to have a tube like tone and it is huge improvement in tone for the amp.

All filter caps are changed out in the power section.

The audio chips are all changed out to Burr Brown chips, same chip Peavey used in their mod kit.

However, every Peavey amp I have modded that had the factory mod installed did not have Burr Brown chips installed from the factory! The only change was the resistors and caps that are in their factory kit they sell. The factory kit does have the Burr Brown chips in it.

I have modded a lot of amps that had the Peavey factory mod, after market Peavey mod and the Lemay mod. So far everyone seems pleased wit the tonal change of the amp.

Thanks again!!!

I'm doing repair and maintanance on my N400 which has the original LeMay mod and thinking about doing the Fox mod described above. I'm wondering if the two mods have anything in common in terms of parts or is everything different going from the LeMay to Fox? Thanks

Erv Niehaus · Post by **Erv Niehaus** » 18 Feb 2019 11:37 am

To anyone considering the mod for their Nashville 400, you need to check the serial number on your amp.
After a certain serial number, the mod is already incorporated in the amp from Peavey.
Erv

Ken Fox · Post by **Ken Fox** » 18 Feb 2019 1:22 pm

After seeing close to 400 or more N400 amps thru the shop I can say the so called factory mod was not the same on all the amps. There were different versions as it evolved. It never used Burr Brown chips either. However the factory mod kit sold to users did have the Burr Brown OPA2604 chips

The chips in the Lemay mod were painted red, no idea what was used there

James Flaherty · Post by **James Flaherty** » 18 Feb 2019 6:38 pm

Do the mods really make a difference in sound? I ask because I have a couple of Nashville 400's I bought around 1983/84. What kind of difference will it make? Thanks.

Bill Moran · Post by **Bill Moran** » 18 Feb 2019 8:46 pm

James Flaherty wrote:Do the mods really make a difference in sound? I ask because I have a couple of Nashville 400's I bought around 1983/84. What kind of difference will it make? Thanks.

Don't screw up those amps. If they have the 1502-4 speakers that came in them it is as good as Peavey gets. I have tried them all looking for the magic . The stock 83 and 84 are the best you will ever hear out of a Peavey ?

Donny Hinson · Post by **Donny Hinson** » 19 Feb 2019 7:31 am

John Fabian wrote:Your UNsoldering skills need to be good or you will be repairing broken traces on the circuit board.

One easy trick for unsoldering is to first use small cutters and just cut the leads from the component to be removed. (Cut off the leads close to the component.) When you do this, the component itself won't act as a heat sink, pulling the heat away from the point you're trying to unsolder. Use a pair of needle-point tweezers to hold the lead while you're unsoldering it.

Richard Sinkler · Post by **Richard Sinkler** » 19 Feb 2019 7:47 am

Bill Moran wrote:
James Flaherty wrote:Do the mods really make a difference in sound? I ask because I have a couple of Nashville 400's I bought around 1983/84. What kind of difference will it make? Thanks.
Don't screw up those amps. If they have the 1502-4 speakers that came in them it is as good as Peavey gets. I have tried them all looking for the magic . The stock 83 and 84 are the best you will ever hear out of a Peavey ?

I have a 1984 NV400 with a 1502, and had Ken do his mod to it. I definitely noticed a difference in the tone. Bass seemed warmer, mids not as honky, highs not as brittle. I also had as later black corner NV400 with a 1501,no mod, no comparison to my '84 amp.

James Flaherty · Post by **James Flaherty** » 24 Feb 2019 5:21 pm

How can I tell if my speakers are the 1502-4? Thanks.

Steven Welborn · Post by **Steven Welborn** » 24 Feb 2019 5:23 pm

James Flaherty wrote:How can I tell if my speakers are the 1502-4? Thanks.

The cone is ribbed.
1501's have a smooth cone.

The # should be indicated somewhere as well

James Flaherty · Post by **James Flaherty** » 24 Feb 2019 5:36 pm

Thanks. Yes, my speaker cone does have ribbing.

James Flaherty · Post by **James Flaherty** » 24 Feb 2019 5:38 pm

I haven't checked my other NV 400 (it's in a rally cluttered room) but I bought them both at the same time from the same dealer. I'll have to dig it out to confirm if it is the 1502-4.

Derrick Unger · Post by **Derrick Unger** » 26 Feb 2019 11:14 am

Ken..I have a vegas 400 and a Nashville 400 that you modded ..not for me but previous owners and the paperwork..but I also have a Nashville 112 that I was told had your mod..Is there a quick down and dirty way to make sure you have modded it??

Ken Fox · Post by **Ken Fox** » 27 Feb 2019 6:53 am

The Nashville 112 would have the user installed OPA2134PA chips on the preamp board.

The user mods for the Nashville 400 and Vegas could be OPA2134P chps or the older OPA2604AP chips.

The Intense mod would have many parts replaced and was only done in my shop. I never sold kits for the mods. However some users may have done the full mod themselves as I did share the info on that mod with Forum members a while back.

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Peavey mod kit VS. the Ken Fox mod

Peavey mod kit VS. the Ken Fox mod

Peavey Nashville 400 Mod Kit

Ken Fox