Musicman StringRay 2band/3band onboard preamp ??

[vanessa]

you are totally right !! I will send the prototype to my mate to see if he can backtrace it using he's MM. I hope we can get this one right.

How about it! I don't understand why no one has ever done this before?

I do have two other questions, on my schematic of the 6 string guitar it shows the 1K resistor after the 25k VOL pot. I also see the the wiper of the TREBLE pot after the 220K resistor not before. Could you verify both?

[Mcgiver69]

yes there is on 1k resistor then a 10n cap and after them the 25k pot. Bear in mind that maybe your guitar's preamp might not be the same and the values might be diferent too. All I know is that the schematic I posted before contains all the right values taken from an actual 2band MM and if I'm not wrong it didn't work because my mate made a mistake in one track or two.

[vanessa]

Updates by forumites. It has been suggested that the C1 cap polarity should be reversed for a better engineered circuit. Any input is gladly appreciated!

Also the taper on the R2 pot is said to be reverse audio C taper.

See updated schematic next

[vanessa]

Here is the latest and I believe to be the final version of the 2 band EQ. Any input is greatly appreciated. If someone could trace theirs out and or verify the components to this schematic that would be fantastic. A big THANK YOU to all that helped out on this one!

[Mcgiver69]

Ok this are the lastest news about this project, I tested it with my mate and seems to work fine, the simulation of the circuit shows that it works but there's something unusual and is that there is a bit of interaction between bass and treble, maybe that's why the characteristic MM sound but my mate says that this doesn't happend in other circuits.

What do you think

Next step is building one to try it out or maybe breadboard it ...... I'll let you know !!

[kriwil]

Ok this are the lastest news about this project, I tested it with my mate and seems to work fine, the simulation of the circuit shows that it works but there's something unusual and is that there is a bit of interaction between bass and treble, maybe that's why the characteristic MM sound but my mate says that this doesn't happend in other circuits.

What do you think

Next step is building one to try it out or maybe breadboard it ...... I'll let you know !!

Any update for this anyone has the 3 Band version??

[vanessa]

Well I have had this confirmed by two sources that have had (or have) access to this 2 band EQ. The thing I've found is most players of the 3 band version use the mid for mid cut only (slap bass). The people who prefer the 2 band over the 3 prefer the 2 band's deep bass (finger or pick style).

A friend of mine asked me to build him a 2 band version (full bass) but with a mid cut switch for slap bass use (I have yet to build it, but will soon) in order to have the best of both worlds. I had a separate post while ago that addressed tagging a mid cut switch that the Q could be set via a trimpot internally then you could have the desired mid cut you wanted at the flick of a switch. Most players of the 3 band have a preferred mid cut setting that corresponds to their rig to get the best sound for slap use.
You might find this circuit better (faster) than trying to ask someone to reverse engineer their 3 band. I've not seen a schematic and from what I've heard it's not that great of an improvement over the 3 band (just more bells and whistles). From what I've come across is the real big difference in tone (besides the 3 band's mid cut/boost, and the 2 band's bass boost) is the 3 band uses a TL062 chip over the LM4250CN (a lot more noise from this chip). You could put in a TL061 and have the same "Hi-Fi" low current as the TL062. They are the same one being single and the other being dual opamp. From what I've read people used to swap out the LM4250's for a similar type chip back in the day as an upgrade mod.

Here's the mid cut thread:

http://www.diystompboxes.com/smfforum/index.php?topic=46161.0

[vanessa]

Edit:

"You might find this circuit better (faster) than trying to ask someone to reverse engineer their 3 band. I've not seen a schematic and from what I've heard it's not that great of an improvement over the 3 band (just more bells and whistles)."

It should be:

You might find this circuit better (faster) than trying to ask someone to reverse engineer their 3 band. I've not seen a schematic and from what I've heard it's not that great of an improvement over the 2 band (just more bells and whistles).

Improvement over the 2 band (not 3 band).

[Mcgiver69]

Has anyone tried this circuit yet? I've been out of business for a while but as soon as I have a space to work (moving houses right now) I'll build the circuit but if someone has done it I would appreciate the feedback.

Peace.

Mac

[Nikolay]

Mcgiver69 please give us updated link of the circuit again. I can't find it..
Thanks

[StephenGiles]

Is this arguements or abuse?

[Nikolay]

a little bit info, taken from a friend:

Having recently bought several Ernie Ball StingRay basses (a fretted and a
fretless), I was eager to learn as much about them as possible. Having heard
and read that the 2-band EQ is better than the 3-band EQ's, I managed to
evaluate both from a technical viewpoint. I only have the 3-band versions so
I could not make direct comparisons, yet I would like to offer the following
to those who might be interested---WARNING: the following is a very dull
technical discertation.

The 2-band and 3-band EQ's share several features, including an op-amp
design (as opposed to a discrete design like a Sadowsky or newer BassLines).
The 2-band EQ uses a strange (to me) LM4250 single op amp with simple tone
circuits. The circuit appears to have been designed somewhat empirically
with non-symmetrical component values. The pots are simple audio-taper and
configured for boost only. The circuit is fully AC decoupled as it runs off
a single battery.

The 3-band EQ is worlds apart and features a low-current dual JFET op amp.
The tone circuits are text-book symmetrical and closely match those in a
National applications handbook with some key differences---the treble
control is configured "wide-open" which explains why only a small rotation
off center results in a drastic treble boost. The pots are 50K linear taper
with center detents, both boost and cut are "equally" available.

Yet both my basses seem to have very little bass in the flat (center
position) mode. You have to crank the bass full up to get a meaningful
boost. The reason? There is a filter at the input to the circuit!

Unlike the 2-band EQ (as well as Sadowsky and others), the 3 band EQ employs
a 2-pole (12 dB/octave) Butterworth high-pass filter at the input. It is 3
dB down at about 58 hz, which pretty much knocks off all the fundamental of
your low E, F, and G. The steep slope actually competes with the bass boost
circuit, leaving you with only a few dB extra with the boost cranked fully
up. Strange, but easily revised.

I guess I could have left well enough alone, but some simple mods readily
improved the performance:

- ---There are two .0082 uF input caps in series to pin 3 of the op amp that
set the frequency. Changing them to something larger will lower the
frequency. I used .022 caps with good results. In contrast, the 2 band EQ
uses a single 1.0 uF which sets the high-pass frequency at about 1 hz.

- ---There is a small value cap, .0022 uF directly across the pickup's input.
My guess is that it limits the very highs from overloading the preamp. I
removed it, but I heard no significant difference. BTW, I've never seen this
on any other type of preamp.

- ---The op-amp is not ideal for this application. As noted by Len Moskowitz
earlier, a significant noise reduction is available from the newer op amps
such as Analog Devices AD 822. This device is also a "rail-to-rail" design
and will yield several more volts of output headroom. Use it if you got
it--I like it much better.

- ---There are 2 resistors in the input filter that set the damping as a
Butterworth type. If you change the 250K resistor at pin 2 of the op amp to
about 360K, the damping is now a Bessel type with better transient response
and a slower rolloff. Again, not necessary but I feel better about it.

- ---Another mod that would be nice but again not quite necessary is to revise
the bass control to boost-ONLY. You change the pot to a standard 50K linear
taper, and tie the wiper to the outer leg (the leg that is in series to pin
1 of the op amp). At the lowest setting, the bass is now flat; boost as you
crank the knob clockwise.

- ---The final mod is a bit harder to implement, but you can get much better
adjustment resolution in the treble control if you place resistors in series
with the pot's outer legs. Try about 5-10K on both legs. This will limit the
maximum boost to about 12-15dB which is fine, and you

I would love to hear from those who have other enhancements for the
StingRay. In particular, I'm still looking for a tortoise-shell pickguard!!

PS: IF SOMEONE HAVE THE UPDATED SCH PLEASE SEND ME. Thanks