I was told that the L pickups would distort the pre on the M, hence the underwound pickups on the M.
But I haven't tried this myself.
But I haven't tried this myself.
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If I recall correctly, the pickups used in the M-series were carefully matched to the preamp. From the text back then:
"Leo's MFD™ humbuckers have always been the heart of the iconic L-Series. In the all-new M-Series, these powerhouses are voiced to fully exploit a studio-quality 18v preamp system specially designed by G&L's R&D wizard Paul Gagon. With an LF442 chip, 100v poly caps, 1% metal film resistors and big, fat signal traces on the mil-spec circuit board, this preamp reveals everything the player and the instrument have to offer."
On the BassesByLeo site, Paul Gagon describes the M-series preamp this way:
"Back in July I was asked by Todd (TDR1138) to talk about the preamp used in the M-Series basses.
I have been trying to figure out the best way to cover this without going deep into the weeds and boring
the pants off of everyone. I want to keep this post focused on what the preamp is, does and how to alter it.
I promise......there will be no math!
This preamp design is based on the Baxandall Active EQ circuit. Most particularly, the 3 band EQ type.
A Google search of "Baxandall Active EQ" will give you a wealth of information on the history of the circuit,
inventors, and one crap load of math calculations for finding frequency centers. We're not going to go down
those roads. It gets a bit hairy. My goal here is to dig right into the preamp and look at what it's doing
and what you can do about it.
Let's begin. First off, there are 2 different circuit boards used in the M-Series basses. The one that is used on the M-2000 and M-2500 is called the BEQ3 (Bass EQ with 3 bands). The one that is used for the MJ-4 and the MJ-5 is called the MBEQ3 (MJ series EQ with 3 bands). OK, not overly creative on the naming of the PCBs but marketing was never my strong point. The only difference between these 2 boards is that the MBEQ board has adjustable gain on the front end before the 3 band EQ circuit. This was done because the split-coil J-Bass type pickups used on the MJ basses are so much weaker than the MFD pickups."
I have been trying to figure out the best way to cover this without going deep into the weeds and boring
the pants off of everyone. I want to keep this post focused on what the preamp is, does and how to alter it.
I promise......there will be no math!
This preamp design is based on the Baxandall Active EQ circuit. Most particularly, the 3 band EQ type.
A Google search of "Baxandall Active EQ" will give you a wealth of information on the history of the circuit,
inventors, and one crap load of math calculations for finding frequency centers. We're not going to go down
those roads. It gets a bit hairy. My goal here is to dig right into the preamp and look at what it's doing
and what you can do about it.
Let's begin. First off, there are 2 different circuit boards used in the M-Series basses. The one that is used on the M-2000 and M-2500 is called the BEQ3 (Bass EQ with 3 bands). The one that is used for the MJ-4 and the MJ-5 is called the MBEQ3 (MJ series EQ with 3 bands). OK, not overly creative on the naming of the PCBs but marketing was never my strong point. The only difference between these 2 boards is that the MBEQ board has adjustable gain on the front end before the 3 band EQ circuit. This was done because the split-coil J-Bass type pickups used on the MJ basses are so much weaker than the MFD pickups."
There's circuit diagrams there for both the M-series preamp and the MJ-series preamp, the two varying by only a couple of resistors. Here's the one for the M-series:
So the LF442 chip used in this circuit is a JFET input dual low power op amp (vs the simple LM4250 single op amp in the L-series preamp) and you can see the two halves in the circuit above. Here's his in-the-bass diagram.
There's lots more about the design of the preamp on that page, but it's clear it was extensively tweaked to achieve what it does—and I suspect that plopping the higher-windings L-series pickups in might overload the input stage on this preamp since it was the input gain that was increased for the lower output MJ-series pickups (those two changed resistors).
The most interesting thing I found on that page was that the three BMT controls are interactive to some extent and that tweaking one changes the response of the other controls. I had assumed (I don't know why) that they were pretty independent.
Anyway, a little fuel for the fire.
That makes perfect sense. But it would have been easier (and cheaper) to add a resistor in parallel with C5 to pad the input, rather than winding all new pickups. I wonder if G&L tried it both ways and felt that the underwound pickups just sounded better.
Interesting that the M series uses a Baxandall tone stack...
Oh no, don't look now, it's the GAS again!
Interesting that the M series uses a Baxandall tone stack...
Oh no, don't look now, it's the GAS again!
I'm guessing that the underwound pickups sounded interestingly different: that is, it's flavour rather than just signal level. In Ed Friedland's A/B videos with the L- and M- basses (all controls flat, volume up) they sound both similar—that MFD goodness—and (to my ears at least) quite different. MFDs seem a bit quirky: e.g. that tonal change as you reduce the volume control and so on. Whenever I read Paul Gagon's stuff, I get the impression that he's an inveterate tweaker of things as much as a circuit designer. So I expect that the M-series preamps are a kind of best-fit that he found. The Baxandall tone stack isn't anything remarkable really; I think the L-series passive B/T design w/wo the preamp is more idiosyncratic. BTW, I had an MJ-5 and never really cared for the pickup/preamp pairing in that one. The pairing's really good in the M-series. (Sorry about the GAS, but it's deserved in this case.)
I think that's right. The M's series-only, underwound pickups provide an extremely flexible middle ground between the L's series and parallel settings. The native tone is more like the L's series mode, but less intense, and you can adjust from there with the EQ to approximate the series and parallel tones from the L, and get an enormous array of other tones. With the EQ, they didn't need to provide a parallel mode, and it may have been easier to optimize the preamp when having the pickups locked in a single wiring mode.
Whatever the rationales, it sure works!
Yes, I find that when the M's mids are boosted, it comes pretty close to the sound of an L in series. Not quite, but in the ballpark.
I bought a new G&L. I noticed that the saddle lock screw is there, but really not tight. I can (and did) do several turns to tighten it.
I did this too with other new G&Ls.
I wonder, am I overtightening these screws? Are tight are yours? I guess it is hard to discuss this over the net...
I found that there is a difference, when I tighten them. Notes are more focused. I just hope I'm not putting too much strain on that little screw...
I did this too with other new G&Ls.
I wonder, am I overtightening these screws? Are tight are yours? I guess it is hard to discuss this over the net...
I found that there is a difference, when I tighten them. Notes are more focused. I just hope I'm not putting too much strain on that little screw...
snug is your friend, as that screw is small and pointed downwards, if you loose it, you'll never find it.
that's my approach.
that's my approach.
I've loosened that screw on all my GL's, as I found the sound a bit strident with it tightened.
Part of that was the Daddario rw strings, which i replaced, but the design really already has great note definition even with the bridge lock screw loosened.
Setup advice I found on bassesbyleo.com/forum says the saddle lock screw should be snug but not tight. That being said, if you're having to do several turns to tighten it, that's not right. I don't know why a new G&L would leave that loose unless it has something to do with shipping. I personally have found that if I overtighten the saddlelock screw after doing a setup, it throws off my intonation and my action slightly.
The purpose of that screw is to get the entire large G&L bridge to act as a single, large mass that (in principle at least) shouldn't rob vibrational energy from the strings. For that to work, the screw has to be reasonably tight: enough to enable effective mechanical unity.
The "screw" is actually two parts: (i) an Allen type set screw threaded to match the hole in the side of the bridge and (ii) a nylon cap which compresses as the screw is tightened against the G-string saddle. As noted by @Holdsg, they're pretty easy to lose if you don't pay attention, but you can buy a pack of replacements from the G&L store. I have a bunch of G&L basses and guitars so I keep a pack on my workbench.
While the advice above varies, I've not found any issues with stridency of tone or loss of intonation when tightening this screw. Indeed, since the very fine saddle movement produced by tightening is lateral rather than along the string, the intonation effect seems to lack a mechanism. My personal experience is that the instrument sounds "tighter" with better note articulation and sustain with the bridge locked.
[Note that this bridge design strategy—which is also used in other makers' bridges—is the opposite of the strategy where individual strings have their own, isolated bridge pieces.]
Thank you for this explanation. I just checked and mine was loose. I never paid attention to this, not having had my L2500 very long.
And, for your tagline: WORF: It is screeching... pounding...dissonant. It is not music.
RIKER: Worf, it's better than music -- it's jazz!
--Star Trek, The Next Generation
...considering that Worf loves Klingon Opera, that is saying something!
I personally have found issues with over-tightening that set screw. Admittedly, it's worse on my cheap little Steinberger Spirit XT-25, which doesn't even have set screws to adjust the intonation. I just have to move the saddles with my fingers or some needle-nosed pliers, get them where I want them, and tighten the saddlelock set screw. A lousy system not worthy of the Steinberger name that's stamped on the bridge, but Gibson's destruction of that brand is another subject. Here's how I snug that set screw on my G&Ls and the Spirit: I snug the set screw until I feel tension, then I use the thinnest feeler gauge in my set (available at any auto parts store) to see if the bridge saddles are all touching the ones next to them. If they are, I stop tightening. If they're not, I snug it a little more and repeat the process. Once the gauge tells me they're snug and secure, I stop. I also double-check where the saddles are at visually. That works for me, and the entire process takes a minute or less. However, if you're not having any problem with it, just tighten, play, and have fun!
Personally, I tighten more than that: until I get the sense that the nylon tip is being compressed. That tip keeps the metal tip from grinding into the saddle piece and helps to give some haptic feedback for when the system is being compressed together.
Thanks for this and I'll definitely be ordering a set, since my SB-2T is missing the locking set screw. Any idea where to find the nylon cap?
The caps come with the screws: one cap for each screw. When you put them in, the cap precedes the screw into the hole. They're attached. It'll be obvious. Pinky promise!
OK. Hard to tell from the photo if there was the nylon cap on those or not. Appreciate it! Thanks.The caps come with the screws: one cap for each screw. When you put them in, the cap precedes the screw into the hole. They're attached. It'll be obvious. Pinky promise!
Totally agree with you on this but can't understand how the nylon (acting more as an insulator) would be the best choice to mechanically couple the bridge saddles to the bridge body. One would thing that the metal edge of the set screw (or end of the screw filed flat) would offer a more solid coupling effect.
OTOH, I wonder how much any of this really matters. One of these days I'm going to remove the stock set screw and see if I can hear any difference. I do like the idea of not counting on the springs for maintaining intonation and any screw helps keep the entire assembly in place.
