ANYBODY HERE EVER DO THE T-TOP MOD ON GIBSON 490 PICKUPS?

[toomanycats]

I'm asking because they're in my Gibson B.B. King Lucille, and I'm not entirely happy with them. Don't get me wrong, they're not terrible, though they're not my preferred tone, which I usually get by using vintage output, unbalanced coils, and no wax potting.

I've come across mention of the so called "T-Top mod," named so because it's supposedly an easy way to get the 490s to sound similar to 70s Gibson T-Top pickups. I've read that it can get Jimmy Page's 70s tone.

This mod involves replacing the A2 magnet in the pickups with short A5 magnets. That's it, simple as that. I've been leery to change the pickups outright in my Lucille because, being an expensive "investment" guitar, I want to keep it original. I figure a simple magnet swap is easily reversible, not even necessitating any disturbance of the control cavity.

So anybody here have any experience with this T-Top 490 mod?

[Chocol8]

I haven’t done a mod to those specific pickups, but I have changed magnets in humbuckers a number of times. It is very easy to do and it does change the tone a bit. It will not change an overwound pickup to a more clear vintage wind. It will not give you the integration with a loud amp that you get from un-potted pickups. What you can expect is a slight boost in output and a slight change in frequency response.

[toomanycats]

I haven’t done a mod to those specific pickups, but I have changed magnets in humbuckers a number of times. It is very easy to do and it does change the tone a bit. It will not change an overwound pickup to a more clear vintage wind. It will not give you the integration with a loud amp that you get from un-potted pickups. What you can expect is a slight boost in output and a slight change in frequency response.

Yeah, I've done magnet swaps countless times myself, but I was wondering if anybody had done this specific one, and if it was all that some make it out to be.

What I've noticed about the effect of a magnet swap, apart form the frequency response, is the perceived stiffness and sustain. Ceramic magnets sound tight and super clear, which is obviously good in some applications, high gain metal for instance. The weaker ALNiCos sound rounder, softer, smoother, and spongier, which may result from less magnetic string pull.

Supposedly the 490s are very similar to 57 Classics, both having balanced coils, wax potting, and A2 magnets. The 490s just have slightly greater output, what is often called a more "modern" voicing.

Ironically, what is required in the T-Top mod is to go in the opposite direction that I normally go. I'm used to ripping out ceramics and A5s and putting in A2s. In the case of the T-Top mod you go from A2 to A5, in other words, from weaker to stronger. That's why I'm so curious if anybody here has tried it, because it seems counter intuitive to me. To decrease the output in something that is already A2 I'd usually be thinking A3.

[honyock]

I believe my first set of 490T/490R had that done to the bridge pickup, but that information has been lost to the great MOFO purge and it was like a year or two into my playing so I can't remember anything about the results.

I've done even more on my LPJ completely changing the base plates to allow standard nickel covers in place of the black plastic active look, on another set I even went so far as pressing out slugs and installing hex head set screws like a Super Distortion look.


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[Chocol8]

The mod makes sense in terms of what a 490 and a T top are. I just looked up the 490r and they are speced at 7.4K wind which is really close to the nominal 7.5k of the T tops. The T Tops used the short rough A5 magnet, so putting the same magnet in a pickup with very similar winding should sound very much like a T top. The 490T should have wider spacing and is probably a little hotter than the R but still in the T top neighborhood with the rough short A5 swap.

That won’t necessarily be the sound you are after though, as it will be a bit hotter than typical vintage PAF. The A5 should add a little brightness which will offset the darkness from extra winds, but overall, it will be higher output than a vintage wind with A2 and a 70’s tone vs 50’s.

[jtcnj]

Necro Bumpski!!

@toomanycats What did you end up doing here, if anything?

I just scored a used 490R/T set and and when they arrive, I will set will be attempting to cut a rough cast A5 (thanks @mozz !) down to the "short" length, put it in the 490R, and put it in the bridge of my Firefly V.
Hell, I might put the T in the neck for kicks.

Looking for the UFO era Michael Schenker ballpark, but I'll take the nod to Page tone too.

[mozz]

I think I sold you some A2. That had to be a year or more ago, so it doesn't fall under my short term memory loss, it's under WTF I can't remember sht. If you get them mixed up some phones have a magnetic sensor, just use a big spacer between the mag and the phone such as a piece of wood. You should be able to tell the strength difference from the readings, or just see which sticks better to the fridge.

[toomanycats]

Necro Bumpski!!

@toomanycats What did you end up doing here, if anything?

I just scored a used 490R/T set and and when they arrive, I will set will be attempting to cut a rough cast A5 (thanks @mozz !) down to the "short" length, put it in the 490R, and put it in the bridge of my Firefly V.
Hell, I might put the T in the neck for kicks.

Looking for the UFO era Michael Schenker ballpark, but I'll take the nod to Page tone too.

I didn't do the mod. The reason why is because . . . and I cannot believe these words as I type them . . . I got rid of my Gibson Lucille. I just couldn't completely bond with those pickups, and I wanted to leave a guitar like that completely original. Plus I ended up never using the stereo output (impractical live), or the Varitone. The BB was traded for a Gibson SGS3, which is a three pickup SG with all gold hardware and a sideways Vibrola. Plus I got some cash on my end. The SG has 57 classics and I play it much more than I did BB . . . though part of me still misses BB.

I'm fighting an entirely different battle with the SG. Let's just say that the Gibson Sideways Vibrola is a totally non-functional piece of engineering crap. It seems that the only way of pleasing me is to put a good old fashioned Les Paul in my hands.

Now I'm anxious to see how your T-Top mod comes out.

[jtcnj]

I think I sold you some A2. That had to be a year or more ago, so it doesn't fall under my short term memory loss, it's under WTF I can't remember sht. If you get them mixed up some phones have a magnetic sensor, just use a big spacer between the mag and the phone such as a piece of wood. You should be able to tell the strength difference from the readings, or just see which sticks better to the fridge.

You're right! It was A2.
It's my I cant remember sht.
I have some A5s, dont recall if rough cast or not, or if it really makes a difference beyond internet hype.

[mickey]

I think I sold you some A2. That had to be a year or more ago, so it doesn't fall under my short term memory loss, it's under WTF I can't remember sht. If you get them mixed up some phones have a magnetic sensor, just use a big spacer between the mag and the phone such as a piece of wood. You should be able to tell the strength difference from the readings, or just see which sticks better to the fridge.

You're right! It was A2.
It's my I cant remember sht.
I have some A5s, dont recall if rough cast or not, or if it really makes a difference beyond internet hype.

CRS Syndrome seems to afflict everyone beyond some age, however the good part is that "brain farts" become "senior moments" when you become a senior citizen.

[mozz]

We had a girl at work, whom when walking to another room we would stop her and ask some irrelevant question. She would answer usually, then continue to walk to the other room, turn around, go back to her seat. When she finally remembered what she was going for, she would get up and go finish it. It was like only 1 thought could process. Pretty sure she smoked a lot of reefer.

Anyway, if you find a good way to cut magnets let us know. I think grinding is about the only solution without shattering it.

[jtcnj]

Anyway, if you find a good way to cut magnets let us know. I think grinding is about the only solution without shattering it.

Good point. I realize they are brittle.
I was going to use a grinder with a cut off wheel, but reading on this I found the heat can demagnetize it.

[BatUtilityBelt]

I was going to use a grinder with a cut off wheel, but reading on this I found the heat can demagnetize it.

Yup. Heat totally destroys magnets. I found that out soldering to a nickel plated magnet.

[mozz]

You can buy 2 NEO magnets and then recharge them. I have a electric magnetizer but i think @Andrewsrea can provide info on how to remagnetize them.

[tonebender]

I have modified the more "affordable" Gibson models but I would be reluctant to modify a Lucille. I had a vintage Lucille for many years but never changed a thing. So my 2 cents is, Let It Be, just like the Beatles said.

[Jaymo]

I'm fighting an entirely different battle with the SG. Let's just say that the Gibson Sideways Vibrola is a totally non-functional piece of engineering crap. It seems that the only way of pleasing me is to put a good old fashioned Les Paul in my hands.

I can’t find any fault with this. The heart wants what the heart wants.
A Les Paul is a good thing for the heart to want.

[jtcnj]

I'm still meaning to do this, to cut down an A5.
I am going use one of my grinders with metal cut off wheel, taking only a light pass at a time and letting it cool in between.

from what I have read, standard is typically 2.5" and short 2.25".
I havent measured the ones I have.

Anyone know if this is correct?

[glasshand]

from what I have read, standard is typically 2.5" and short 2.25".
I havent measured the ones I have.

Anyone know if this is correct?

The ones on sale at Philadelphia Luthier Supply generally seem to be either 2.5" or 2.05": https://www.philadelphialuthiertools.com/bar-magnets/

...but then there are some at 2.444" also: https://www.philadelphialuthiertools.co ... p90-qty-2/

...and crazyparts.de has them at 2.371": https://www.crazyparts.de/pickup-making ... -short.php

[jtcnj]

Necro -Bump x2!

Gibson 490R in the bridge of Firefly V.
Got A5 magnets from Philadelphia Luthiers.
I cut one end of the magnet like mentioned above - cut off wheel on an angle grinder - from 2.5" to 2.25".
I cleaned up the end and squared it up.

I was concerned the heat would demagnetize the end of the magnet to some degree.
In several rounds, I made 2 light scoring passes each time, cooling in between rounds by grabbing it and letting go repeatedly with my thumb and 1st finger.
It was too hot to hold onto the first time or 2 for each round: I could feel it was hot, let go and kept repeating. I didnt get burned.

I dont know if I FUBAR the magnetism, it seems ok.
Very general observation type test: I stuck and pulled each end off the metal work bench several times, and could not tell a difference in strength.
I put it down and picked it up without looking so I did not know which was the cut end.

The pick up works fine but is pretty bright. The bass strings are not weak sounding; it is just a bright sounding pick up.
I dont recall if the cut end is at the bass or treble strings.

I have not had enough time to play it to evaluate the tones. It sounds good in general.

It is out of phase with the neck, so I will rotate it the magnet 180°, swapping where the cut end faces, instead of flipping it along the long axis. I should hear a distinct change in brightness if the magnetism was affected.

I put the new magnet in with the same orientation as the existing 490R magnet, but the Firefly pickups are reversed.

I didnt take a pic of the magnet and the cutoff: here is the cut off piece and the magnet that came out of the pickup.

[Rollin Hand]

I didn't do the mod. The reason why is because . . . and I cannot believe these words as I type them . . . I got rid of my Gibson Lucille.

[Partscaster]

Fwiw, I'm seeing 2.25" a5 bar mags at Phil Luth right now. They label them as Filtertron mags. $5.49 ea.

[golem]

If you're curious enough, I'd be willing to pay @andrewsrea to try it on my 490R/T set in my LP Studio. We can see if he's willing to record a before and after demo for you.

edit: I only just now see that @toomanycats got rid of his Lucille!

[jtcnj]

Fwiw, I'm seeing 2.25" a5 bar mags at Phil Luth right now. They label them as Filtertron mags. $5.49 ea.

The filtertron magnet is .25" thick.
The humbucker magnets are .125".
I dunno if that works.

I'm gonna flip that magnet later today or tomorrow and will report back.

[andrewsrea]

I'm asking because they're in my Gibson B.B. King Lucille, and I'm not entirely happy with them. Don't get me wrong, they're not terrible, though they're not my preferred tone, which I usually get by using vintage output, unbalanced coils, and no wax potting.

I've come across mention of the so called "T-Top mod," named so because it's supposedly an easy way to get the 490s to sound similar to 70s Gibson T-Top pickups. I've read that it can get Jimmy Page's 70s tone.

This mod involves replacing the A2 magnet in the pickups with short A5 magnets. That's it, simple as that. I've been leery to change the pickups outright in my Lucille because, being an expensive "investment" guitar, I want to keep it original. I figure a simple magnet swap is easily reversible, not even necessitating any disturbance of the control cavity.

So anybody here have any experience with this T-Top 490 mod?

First, sorry you sold your Lucielle! Second, 1960's to late 0's T-tops are probably the most underrated pickups on the planet. S

That said, Gibson marketing wants you to believe the 490's are the sister to the T-top but that is not close. First, T-tops were one size-fits-all. No special differences between neck and bridge models. Second, they were manufactured for tight consistency and affordability. They were shooting for 5K tight and even turns per coil for a total of 7.5K DCR at 72 degrees F. I have seen a few as 7.3K and some as much as 7.7K, but keeping temp consistent - they are most likely to be dead-on 7.5K. They have a powerful 2.25" (not the PAF 2.5") Alnico 5 bar magnet, which are more resistant to demagnification and were not wax potted. They are exceptionally sweet in the neck and can cut in the bridge position.

Note that when replacement pickups hit the market in the late '70's, 30% to 40% of these T-tops went into storage and 10% were turned into DiMarzio PAFs for Hamers.

490's range from 7.9K to 8.3K neck and 8.2K to 8.7K for the bridge and have the long A2 magnets. They are typically matched bobbins and IMHO, the coil wire they use currently doesn't have the copper content that the old T-tops or the '57 Classics have. Which makes them mid-focused and boxy in the neck position. 490s are potted.

Funny this thread came up, because a friend of mine was just considering having me rewind his neck pup on a 2022 Gibson Tribute. I popped an A4 magnet in and did 50's wiring, which helped but is still not my cup of tea. I am thinking of doing my partial coil cut trick to unbalance the coils which will change the resonance frequency to a brighter more single coil sound. If that doesn't work for him, I'll strip the coils and do a re-wind.

[andrewsrea]

I have some A5s, dont recall if rough cast or not, or if it really makes a difference beyond internet hype.

Somewhat internet hype and some not. In my experience, tone performance is basically the same for rough vs. smooth bar magnets of the same dimensions and composition (some sellers incorrectly rate their Alnico numbers based on Gauss measurements, instead of the mix of metals which were used). IMHO, the difference comes with potted versus unpotted pickups. For me rough magnets and soft Butyrate bobbins are a must for low or unpotted pickups. They grip better to the other components of the pickup and are much more resistant to unpleasant microphonics. Using the ABS bobbins with a smooth magnet with no potting is a guaranteed microphonic pickup.