Charvel active mid boost schematic JE1200

[Ice-9]

Cool! I missed this. I have a model 4 - Charvel. I need to check if this is the same preamp. If so, thanks!!!! It will help me with fixing some problems it has.

No problem Aaron, I still have my Charvel model 4 which i've had from new, so if you have any questions about the active circuit ask away, It was my first "real guitar" and my dad bought it for me before he passed away, it's just one of those guitars that i would never sell.

[PRR]

> IC is a LF442CN

LF442 is, for all practical purpose, the grand-daddy of the TL072.

TI figured out how to get LF442 performance better and cheaper (smaller die area). TL072 soon became THE most popular BiFET dual opamp. LF442 still exists for some legacy and military applications.

"CN" is commercial grade plastic DIP. (LF442AMH selected Military Hermetric can is still available.... for $23!)

[askwho69]

i had a charvel/jackson guitar.. an it has different booster.. i doesnt have IC but tansistor.. sk30a i think.. i took the booster because i dont really like it  i will yours ice-9

[Ice-9]

> IC is a LF442CN

LF442 is, for all practical purpose, the grand-daddy of the TL072.

TI figured out how to get LF442 performance better and cheaper (smaller die area). TL072 soon became THE most popular BiFET dual opamp. LF442 still exists for some legacy and military applications.

"CN" is commercial grade plastic DIP. (LF442AMH selected Military Hermetric can is still available.... for $23!)

I believe in the this case the LF442 was used beacause it has very low power needs making it ideal in a guitar where you want a long battery life. I have had a batteries last for over a year in this guitar, and that was in the days when I used to gig 2 or three times a week and also jam and rehearse.
Wow $23 ! If it needs replacing i know what I will use (TL072) Then again i have just checked digikey and they sell LF442CN for $1.60

[HarryR]

Hello everybody,

i'm in the mood to discuss 

My aim is to get something like the (in)famous E.C.-midbooster,
that's why i was looking for a diy-circuit and why i found this forum ...

I analyzed the "charvel" circuit (thanks for the hint - LTSpice will be one of my favourite
tools in the future !!!).

Now im thinking about what i'm tryin to do and what a midbooster really is.

So, here's what i wanna discuss my friends ...

The frequences on my guitar go from 82Hz up to ~660 Hz
(excluding the harmonics now ..), where is the "mid" of our boosting ?

Slacker wrote
"You've got sets of boost going on, R7 going to vb gives a gain of 2 for frequencies up to about 7KHz where the filter made out of R5/C5 starts rolling off the response. C4/R6 then give frequencies over about 2.3KHz a gain of 3.2, so you get a peak in the mid frequencies."

2,3Khz and 7KHz are far above everything i will find on my strat (again : no harmonics discussed)...

As i first heard about midboosting, i was thinking about boosting  the d- and g- string (frequencies) ..

So, you will ask yourself, "what the hell does this guy" (me) really wanna know !?

Hmm, difficult to answer ... think about me as one who want's to design a midbooster
not knowing what i'm going to boost ...

Is a "midbooster" just a nonlinear amplifier with bandpass characteristics ?
What is the real "gimmick" on E.C.'s midboosting ?
Is a wha-wha doing the same, when leaving it alone in a preferred position  ?

Okay, enough questions for a good discussion i think  ...
and please remember - it's not for the discussion ...
i just wana build something to get a good sounding guitar .. 

Greets from
Germany

Harry

[familyortiz]

Yo,
   I love to build also but check this:  http://cgi.ebay.com/New-FENDER-Eric-Clapton-Mid-Boost-Kit-/300516677603?pt=LH_DefaultDomain_0&hash=item45f83097e3
I installed one in my Am Std Strat. Even without using the boost, the frequency response is expanded from any passive tone control due to the improved design using a ganged pot.
Enjoy,  M.O.

[HarryR]

Thanks for the reply familyortiz ... 

I will build it myself definitely .. because:

1) i'm building my own guitar including the electronics,
think i'll do it only once in life, so it should fit perfect to my needs
(or name it visions ..)   
2) i don't like tbx don't really know why.
3) the plan is :
3 singlecoils , wired through a brianmaylike wiring (3xpu on/off 2x phaseswitch, 1x serial/parallel-switch)
one volume- , one treble- , one basscontrol.
Then comes the midboost, which i can shortcut so it just boosts only (3dB).
the shortcut will be a pushpullpot so i can activate "prepositioned" midboost ..

See it a a classic strat, the switches expand the mixing of the pu's
the basscut expands the tonecontrol
the boost "eliminates" cabelcapacities
the midboost expands you know what ....
but it will sound like a "normal" 5wayswitched strat (maybe tele when bridge/neck activated) if i want it ..

And if i don't like it, no problem, i'll install a usual
5waysw 1vol 2 tone pickguard so only the
guitarhardway (body, neck, trem , tuner) is selfassembled the way i like it


greets Harry

PS.: Anyway, i'd like to know your opinions about "what is the trick with E.C.-midboost" 

[Ice-9]

I'm reposting the schematic for the Jackson JE1200 as it is one of the many images that went missing from my posts when photobucket changed its rules.


First the original image from the first post.





The second image I have redrawn in an easier format to follow, both are the same.

[adamandor]

Thank you!

[PRR]

What happened to C4 R6 and R12 ?

[Ice-9]

What happened to C4 R6 and R12 ?

Woops. I will re do that

[Ice-9]

Thanks to PRR noticing I had missed out C4, R6 and R12 from the second schematic, so here is a fixed circuit.