Blade guitar preamp  [schematic]

Pickups, wiring schemes, switch techniques and onboard active electronics for guitars and basses
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roseblood11
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Post by roseblood11 »

alexradium wrote: if anyone is really interested i can post some pics of the actual circuit and perhaps try to trace it if i have the time and patience
:applause: :applause: :applause:

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alexradium
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Post by alexradium »

C1 47u
C2 100n
C3 22n
C4 10n
C5 4u7
C6 4u7
C7 470p ceramic
C8 22n ceramic
C9 4u7
C10 4u7
C11 4u7
C12 4u7
C13 4u7
C14 3n3


R1 1M
R2 1M
R3 1M
R4 10K
R5 470K
R6 10K
R7 10K
R8 470K
R9 10K
R10 10K
R11 6,8K
R12 10K
R13 this is maybe inside the goop underside
R14 470K
R15 10K
R16 100K
R17 100K

VR pots are 50k
diode is 1n400x
input is green wire
mid out should be white,bass/treble the red,black ground,all part of a shielded cable
then red and black bring 9vdc from battery
purple and black is the switched ground from the input jack
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DSCN2616.JPG
DSCN2621.JPG

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azzzardo
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Post by azzzardo »

Hi, have this VSC in my Blade California Custom

can you tell me which VSC modl is it?

I' d like to have a schematic of it
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Ben N
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Post by Ben N »

For stompbox use, is there any reason not to use a common dual opamp type?

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alexradium
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Post by alexradium »

Ben N wrote:For stompbox use, is there any reason not to use a common dual opamp type?
you can use the one you want,those for guitar are known to be very low consumption,in a pedal you maybe don't have this need.

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Post by alexradium »

azzzardo wrote:Hi, have this VSC in my Blade California Custom

can you tell me which VSC modl is it?

I' d like to have a schematic of it
schematic is in the first page

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harmaes
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Post by harmaes »

I'm working on VERO layouts for the Blade VSC preamp and I'm also trying to create one for only the Mid-boost part of the preamp which I think is very nice!
Since I'm a beginner I'm learning as I'm going, working with bread board layouts and schematics and trying to create veroboard layouts from there.
It would be great if I could get some help with the layouts I'm creating!

The schematic for the Blade VSC preamp:

Image

I've created this vero layout for it. I've verified the mid-boost part for it so that's correct. The EQ (Bass/Treble) part is not confirmed yet.
If you could please check the above schema and the vero layout below to check if it's correct that would be great? Also, if there's a better way to layout the vero or some tips/tricks to share please lemme know.

Image

I have a ne5334 opamp lying around and I breadboarded it for only the mid-boost part. Sounds nice. Here's the diagram:

Image

I've attempted the following vero layout but it doesn't work (the opamp is working correctly, the mid-pot doesn't seem to do anything: no gain, no mid freq boost)? Any idea what's causing this? I've looked over it for a number of times and can't seem to find the issue.

Image

Here's another vero layout for you with the Storm DIY layout creator:

Image

As I've mentioned, I'm learning from building simple circuits. I'd like to bring in some of the work I'm doing for the vero layouts of the Blade VSC preamp. They're not finished yet and it would be great if you could give me some leads to finish them so we can share them with the FSB forum!

Thanks,

Harry

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harmaes
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Post by harmaes »

Correction on the schematic (lines were crossing on the Bass VR):

Image

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harmaes
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Post by harmaes »

These vero layouts both work (verified by myself):

Mid-boost:

Image

EQ (Bass/Treble):

Image

They can probably be smaller. ;) I will place these in an enclosure with another boost circuit (Demeter Fat) so I don't need them to be small.

Have fun with it. :D

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Post by roseblood11 »

Am I missing something or is there still no schematic for the version with the quad opamp?

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roseblood11
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Post by roseblood11 »

harmaes, can you upload the layouts and the schematic again, please?

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Post by roseblood11 »

What value and taper is used for the volume pot in the Blade Stratocasters? Should be different from the typical A250K, as the input of the VSC is always in parallel with the pot?

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Post by jt »

In my Texas standard strat it was a typical A250k.

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Post by alexradium »

circuit is in true bypass,standard strat pots.

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roseblood11
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Post by roseblood11 »

It isn't a true bypass. The input of the VSC circuit is always connected to the wiper of the volume pot. See the switching scheme on page 1.

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Post by roseblood11 »

I just want to build the mid boost part into my new stratocaster. So I only need a single opamp. Which one should I choose for a little better audio quality, more headroom, lower noise...? I think the LF441/442 was chosen because of the very low current consumption, but as this is gonna be astudio guitar, I don't really need that...

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roseblood11
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Post by roseblood11 »

Nobody is interested in this... :roll:
I'll try the TLC271 and the OPA134

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Post by phatt »

I think you will find there will be no difference for such a simple audio circuit which is just a preamp with tone control.
Of course if you are building equipment that is way above the audio spectrum there may well be great benefit in sussing out the performance specs of different chips.

Even if you use a chip with the lowest noise figures, bad design and layout will destroy any advantage.
If there is any difference in the audio band I doubt it would even be audible. YMMV
LM833 is a very good chip,, TL062 is low power consumption but bandwidth is lower (which can be an advantage)

Just remember that while on-board actives have an advantage they do tend to extend the bandwidth and that can present a whole new set of problems to solve. IMHO too much bandwidth for guitar is a catch 22 :hmmm:
Phil.

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sonnyv2
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Post by sonnyv2 »

I just bought a R3 strat (1991?) with the VSC and I'm loving it.

To conserve battery life, can anyone tell me if I should unplug the guitar cable, leave the preamp switch in the center position, or do both?

How will I know when to replace the battery? Will the sound degrade or squeal?

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roseblood11
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Post by roseblood11 »

The sound will be distorted, at first only when you pick harder.

The power is switched off by unplugging the cable, it's a TRS jack that cpnnects ring and sleeve if a cable is plugged in.

The mini switch only switches the audio signal, not the power.

-----------

I always liked the treble/bas boost of the VSC, but never had a use for it. The mid boost was ok, but I like the EMG SPC circuit much better. I added that to my Warmoth strat, with a gain knob and true bypass switch as external controls. That's much more useful than the VSC. When the pot is ccw, the circuit is a linear buffer and then you can dial in the amount of boost while you play. I even use it to give single notes more distortion after I hit the string.

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