Question about Factory Tone Enhancement Mod

[George Erdman]

Not to be confused with the relatively simple swap of the OpAmps this Peavy factory "Tone Enhancement" modification was discussed in a recent post https://bb.steelguitarforum.com//viewto ... highlight= with participating forum members Pat Chong and Richard Sinkler. The modification apparently makes the bass and treble controls more effective in achieving a true "steel tone" in earlier models* according to Pat. The procedure and parts for this kit and mod are listed on the Peavey Website https://peavey.com/PDFs/nsh400mo.pdf.

My question is: Can this tone modification which appears to be specific to the 400 also be applied to the Nash 112? I'm not so sure it would be a match as far as location of the components on the PCB.

George

*Peavey states that 400's (I assume) after a certain serial number have this modification incorporated at the factory[/quote]

[Jack Stoner]

The preamp board in NV112 is essentially the preamp board from a NV400 with tone mod.

What is a plus for the NV112 is the Ken Fox OPA2134 chip replacements. Cleans the amp up nicely.

[George Erdman]

The preamp board in NV112 is essentially the preamp board from a NV400 with tone mod.

What is a plus for the NV112 is the Ken Fox OPA2134 chip replacements. Cleans the amp up nicely.

Hi Jack, thanks for the input. Just a bit of ambiguity to sort out here...are you saying the 112/1000 PreAmp boards already incorporate the factory Tone Enhancement modification? That would certainly make my job easier!

I guess what's confusing are the factory instructions to the modification shows a 400's PCB which considerably different in layout from a Nash 1000 Preamp PCB which I have in the project Nash 112 I'm trying to resurrect and improve on...



vs the Nashville 1000/112 Preamp Board.



You'll also notice that instead of 5 OpAmps in the 112/1000 boards the 400 shows 6!

I'm sure I'll sort this out but it may be that I have to look at the actual schematic to see where the substitutions occurred vs relying on the factory call sheet for the various Tone Enhancement substitutions that identifies the new components' physical location on the board...for instance I don't believe C1 is the same capacitor on the two boards simply because the two boards are laid out differently.



Maybe Ken Fox will surface for air and sort me out or I'll call Peavey! but regardless thanks again Jack!

[Jack Stoner]

What I recall from Mike Brown at Peavey, the 1000 preamp section was designed from the nv400 preamp with the tone mod. The 112 uses the same preamp board.

The NV400 tone mod (designed by John Lemay) was to revoice, as Peavey calls it, because of the speaker change. The original NV400 used a 1502-4 Black Widow speaker and the original unmodified amp worked/sounded perfect with that speaker. Peavey changed to the BW 1501-4 with a different response and the EQ had to be changed (voiced) for the new speaker. The same 1501-4 is used in the NV1000. Along came the NV112 using the same preamp with a custom designed 12" speaker (Eminence). Thus no additional NV400 type tone mod is needed.

I'm an ex amp tech and experimented with op amps and speakers in the NV112. Both the Eminence Travis Toy 12 speaker or the Telonics TSNEO12 speakers are a big improvement, or the less expensive OPA2134 chip replacement is the only "mod".

FWIW new NV112 comes with a custom Celestion speaker.

[Pat Chong]

Hello George,

I'd agree with Jack, as the only mod for that amp is op-amp and/or speaker replacement.

There were 3 different PV NV-400 versions available (according to the SGF grapevine). The 1st and 3rd versions did not require mods, only the 2nd version, which, (pbpbbbb) I had.

The PV NV-112 comes in 2 versions, made in America or China. The Chinese version requires desoldering the op-amp chips to remove them, the American version uses chip sockets. In agreement with Jack, I do not believe it requires circuit mods replacing resistors or capacitors.

The reverb circuit is a different story. It is still available from Bob Metzger, but I'm not sure if it applies to the NV-112. It adjusts the frequency responce of it's op-amps to be a little more trebely-sounding and increases the gain of the output op-amp, which increases feedback.

I don't know if there have been as many complaints on frequency/reverb responces on the NV-112 as I've heard about the NV-400.

Hope you get your amp fixed......

.......Pat

By the way, the capacitor values in the Nv-400 tone contol circuit that were changed, these new values are already in the Nv-112 circuit.

[Donny Hinson]

The NV400 tone mod (designed by John Lemay) was to revoice, as Peavey calls it, because of the speaker change. The original NV400 used a 1502-4 Black Widow speaker and the original unmodified amp worked/sounded perfect with that speaker. Peavey changed to the BW 1501-4 with a different response and the EQ had to be changed (voiced) for the new speaker. The same 1501-4 is used in the NV1000.

Not exactly. Peavey was having far too many “under warranty” speaker failures with their high-power amps. To reduce the number of failures, they purposely reduced the bass response in those amps. This helped with the speaker failures, but the result was the infamous “Peavey honk”, a tone that was shifted heavily towards the midrange frequencies, and not a lot of bass response. Then John Lemay came up with a mod kit that restored the full bass capabilities of the amps, and was having so much success with them that Peavey decided to come up with their own version of a “mod”. However, Peavey was still concerned with speaker failures (even with their high wattage capability Black Widow speakers), so their mod was designed to restore most (but not all) of the bass response in the newer amps. Both mods included newer-design op-amps (with a higher slew rate), which smoothed out the tone slightly, and also reduced circuit noise.

Mike Brown explained all of this right here on the forum many years ago.

[Jack Stoner]

The NV400 tone mod (designed by John Lemay) was to revoice, as Peavey calls it, because of the speaker change. The original NV400 used a 1502-4 Black Widow speaker and the original unmodified amp worked/sounded perfect with that speaker. Peavey changed to the BW 1501-4 with a different response and the EQ had to be changed (voiced) for the new speaker. The same 1501-4 is used in the NV1000.

Not exactly. Peavey was having far too many “under warranty” speaker failures with their high-power amps. To reduce the number of failures, they purposely reduced the bass response in those amps. This helped with the speaker failures, but the result was the infamous “Peavey honk”, a tone that was shifted heavily towards the midrange frequencies, and not a lot of bass response. Then John Lemay came up with a mod kit that restored the full bass capabilities of the amps, and was having so much success with them that Peavey decided to come up with their own version of a “mod”. However, Peavey was still concerned with speaker failures (even with their high wattage capability Black Widow speakers), so their mod was designed to restore most (but not all) of the bass response in the newer amps. Both mods included newer-design op-amps (with a higher slew rate), which smoothed out the tone slightly, and also reduced circuit noise.

Mike Brown explained all of this right here on the forum many years ago.

Wrong, the first NV400'S USED THE 1502-4 speaker the same speaker used in the Session 500 which Peavey sold as a 350 watt bass speaker The blown speakers were the JBL D130 that was originally used in the Session 400. Peavey, according to Mike Brown developed the 1501-4 to be a high power clone of the D130.

[Richard Sinkler]

The NV400 tone mod (designed by John Lemay) was to revoice, as Peavey calls it, because of the speaker change. The original NV400 used a 1502-4 Black Widow speaker and the original unmodified amp worked/sounded perfect with that speaker. Peavey changed to the BW 1501-4 with a different response and the EQ had to be changed (voiced) for the new speaker. The same 1501-4 is used in the NV1000.

Not exactly. Peavey was having far too many “under warranty” speaker failures with their high-power amps. To reduce the number of failures, they purposely reduced the bass response in those amps. This helped with the speaker failures, but the result was the infamous “Peavey honk”, a tone that was shifted heavily towards the midrange frequencies, and not a lot of bass response. Then John Lemay came up with a mod kit that restored the full bass capabilities of the amps, and was having so much success with them that Peavey decided to come up with their own version of a “mod”. However, Peavey was still concerned with speaker failures (even with their high wattage capability Black Widow speakers), so their mod was designed to restore most (but not all) of the bass response in the newer amps. Both mods included newer-design op-amps (with a higher slew rate), which smoothed out the tone slightly, and also reduced circuit noise.

Mike Brown explained all of this right here on the forum many years ago.

Wrong, the first NV400'S USED THE 1502-4 speaker the same speaker used in the Session 500 which Peavey sold as a 350 watt bass speaker The blown speakers were the JBL D130 that was originally used in the Session 400. Peavey, according to Mike Brown developed the 1501-4 to be a high power clone of the D130.

That's the story I heard too, from a few sources, one being Mike Brown. I was lucky with the JBL in the Session 400 I had. It was amp portion that failed several times for me. I ended up retiring the chassis as it would keep dying and just used the JBL in the cabinet as a speaker for a rack system I used for a while.

[George Erdman]

My God! My cup runneth over...to all of you, Jack, Pat, Richard, Donny, thank you!.

Personally speaking my curiosity is that of a cat or, more to my mother's announcement..."Curious George, the monkey, lives in my son..."

If I ever had questions about what I could or could not do with my 112's, (or select "Peavey Nashvilles" as a topic on "Jeopardy") I believe that itch has been scratched quite thoroughly and I could "come on down" to compete (yeah I know...different game show). I totally appreciate the 400, 1000 and 112 history lesson and I hardly consider this game show trivia. I can stop spinning my wheels searching for something that doesn't exist in the 112's...well more to the point it exists, but Peavey incorporated lessons learned in his later Nashville models, the 400 being first, followed by the 1000 and then the 112.

Between this thread and Bob Metzger's generous email sharing his own history lesson on Peaveys approach to reverb design, (his modification being exclusive to the 400 and based on his desire for an "airier" reverb a la Fender) I can now focus on the logistics of resurrecting the patch board of my currently defunct 112 project amp...anyone ever repopulated a PCB before? that conforming coating looks to be quite a bitch to remove in order to patch funky traces and soldering pads.

Which leads me to another question...the Patch Board of the 112 has three 4560 OpAmps in addition to the 5 on the preamp board. I'm changing out the preamp boards' pampas but has anyone ever put the newer TI 2145AP's on the patch board?

Again, many thanks,

George

[Donny Hinson]

I agree with you Donny. Peavey has been great to steel players but many of their steel amps have had that "honky, nasal" sound, some of it from cutting the midrange in a solid state amp and some from the extreme lack of bass. Certainly noticeable on the C9th tuning and somewhat on the E9th tuning. To my ears the 1501 and 1502 speakers sounded very similar in the Session 400, I've had both. Thanks to Lemay for waking us up! Both the Lemay and the Peavey factory mod make HUGE differences in the EQ, nothing subtle there and very noticeable with either the 1501 or 1502.
02 April 2006

John LeMay's original "mod kit" had nothing to do with speaker voicing. It was simply designed to restore the full-range sound that the amp was capable of. (The early Peavey mod kit was very similar to Lemay's.) Mike Brown mentioned that the early mods were to remove most of the bass roll-off that had been designed into the amps. Much later, Peavey came out with a "tone enhancement" kit that contained many more components (mostly larger capacitors) that aimed to "re-voice"* the amp. To me "voicing" an amp is just a euphemism for giving a "certain tone", anyway. When we're talking strictly about clean signals (no distortion), the only thing "voicing", "re-voicing", or "emulation" does is to change the EQ, and I'd much prefer to have a tone control network that can give me any EQ that I want. As opposed to a bunch of preset EQ emulations or circuit designs that limit (focus?) the amp capabilities.

It's only when distortion, sag, EFX, and other characteristics (normally desired by guitarists) are introduced that "voicing" really works. But anyone that thinks that you can make a modern, open-back amp sound like an old Fender Bassman has never heard the two live, and side-by-side.

Voicing schmoicing, gimme controls with knobs!

[George Erdman]

....It's only when distortion, sag, EFX, and other characteristics (normally desired by guitarists) are introduced that "voicing" really works. But anyone that thinks that you can make a modern, open-back amp sound like an old Fender Bassman has never heard the two live, and side-by-side....

Donny I have a 6G6 Bassman head and matching blonde/oxblood 2x12 close backed cabinet. From what I can tell it's the "B" revision...is this the kind of old Bassman to which you're referring?

[Donny Hinson]

George...yes, egg-zackly!