Fodera, Sadowsky, aguilar, and other bass preamps

Stompboxes circuits published in magazines, books or on DIY electronics websites.
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darmstat
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Post by darmstat »

Does anyone have a schematic for the Demeter BEQP ?

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darmstat
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Post by darmstat »

Rcustoms....it looks like the 3 band bass EQ of the Seymour Duncan bass preamp. Bass (boost)90hz, mid cut 575hz, bass 32hz, mid 650hz, and treble 5khz. Using a bandpass EQ filter.

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rcustoms
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Post by rcustoms »

darmstat wrote:Rcustoms....it looks like the 3 band bass EQ of the Seymour Duncan bass preamp. Bass (boost)90hz, mid cut 575hz, bass 32hz, mid 650hz, and treble 5khz. Using a bandpass EQ filter.
maybe i found many circuit based on.like jackson electronics guitar eq booster copied for esp and other brands
http://www.rcustomspedals.blogspot.com
guitars,pedals and amps.
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darmstat
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Post by darmstat »

Rcustoms...I have this for a schematic so far. It is rough so be gentle....lol

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Post by rcustoms »

darmstat wrote:Rcustoms...I have this for a schematic so far. It is rough so be gentle....lol
looks so good,good work ,is the definitive schematic or rev 1
http://www.rcustomspedals.blogspot.com
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Post by rcustoms »

rcustoms wrote:
darmstat wrote:Rcustoms...I have this for a schematic so far. It is rough so be gentle....lol
looks so good,good work ,is the definitive schematic or rev 1
the last model of fender basses(i don't remember which one) use this little demon,recently i install one, on an ibanez sound gr and is amazing what he does with a cheap pickups.
http://www.rcustomspedals.blogspot.com
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Post by lars-musik »

Just in case someone's still interested: Here's a pcb I did for the Silent Fly’s Sadowsky Preamp schematic on the third page of this thread. I liked the sound a lot better with J201 transistors, drain voltages adjusted to about 4.4 V each. Replace R4 and R7 with trimmers to adjust the voltage.
Cheers, Lars
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SF_sadpre.png

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Duckman
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Post by Duckman »

darmstat wrote:Rcustoms...I have this for a schematic so far. It is rough so be gentle....lol
The 1M resistor at the input... goes to ground or to Vr?

Edit: I mean, in the Curbow schemo

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Post by flood »

looks awesome baja, I might just give this a spin. wondering if I should try my buffer-before-blend concept with this design... it worked fantabulously with the Music man design.
In the interest of full disclosure, I am Animal Factory Amplification.

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Post by lietuvis »

Hi all, I came across the Yamaha BB604-605 bass service manual with schematic.The preamp has built in NE-1 parametric EQ for midrange control. Original PCB is double sided so I redesigned to single side PCB. I have not built it yet but have plan to do. On my PCB I designed the way that IC's are mounted on track side :oops: , but if legs are bent backwards it will fit as normal. If there are interest to make this preamp feel free to use or modify these files. The PCB is drawn on Sprint Layout 6.
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BB604 605.rar
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BB604_605_E.pdf
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Top is original yamaha pcb layout<br />Bottom is what I came up
Top is original yamaha pcb layout
Bottom is what I came up

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i2k
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Post by i2k »

EWS Trilogic here : viewtopic.php?f=7&t=16263&p=232387&hili ... ic#p232387

But no conclusion at the end. Perhaps they need Mr Bajaman magic touch ?

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darmstat
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Post by darmstat »

Curbow Eq

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deltafred
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Post by deltafred »

Not my work, all credit goes to khutch on Talkbass.

See http://www.talkbass.com/threads/fender- ... es.934190/

Image

Image

Image

Image

(Apologies for the huge pictures.)
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gogata
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Post by gogata »

bajaman wrote:okay - here are some graphs :wink:
the first is normalized to all controls flat (mid way)
then: full bass boost, full bass cut, full mid boost, full mid cut, full treble boost, and finally full treble cut.
enjoy :D
bajaman

Hi, i don't know how to read these grafs on page 5. I'm curious what is center frequencies of these preamp.
Thanks for help!

Are C13 electrolitic or no ?

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EddieTavares
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Post by EddieTavares »

Guys

What about using charge pump to increase the available voltage adding more headroom? Does it short the battery life?

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Post by lietuvis »

Hi here I traced Bartolini MK I onboard preamp using pictures from web , maybe some one do have one and can measure or already know smd capacitor values?
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MK1 Wiring.jpg
mk1.jpeg
Bartolini MK 1.jpg

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clintrubber
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Post by clintrubber »

lietuvis wrote:Here is another interesting bass preamp (has minor errors) with variable low pass filter and switchable Q found on other forum.
Just curious which forum that was, I don't remember ...

(based on the file-names I'm fairly sure I did make those scans from a Dutch magazine)

Bye

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Post by lietuvis »

clintrubber wrote:
lietuvis wrote:Here is another interesting bass preamp (has minor errors) with variable low pass filter and switchable Q found on other forum.
Just curious which forum that was, I don't remember ...

(based on the file-names I'm fairly sure I did make those scans from a Dutch magazine)

Bye
Well it is you by the name on the other forum, thank you for sharing, but if you want it to be removed ask administrators to delete it.

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Post by clintrubber »

No problem at all, only glad it might be of use. Was just curious where I had posted it - DIYSB ?

Have a good wknd

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Post by clintrubber »

Silent Fly wrote:Based on the indications supplied. It should be correct:
Sadowsky-pre (1.1).gif
Digging this Sadowsky preamp up from page 3.
It makes sense to have treble-cut as well, and that has indeed been added as the VTC (Vintage Tone Control...)

So you have four controls in total: Bass-Boost, Treble-Boost, Volume and Passive-Tone (Treble-Cut).

There are reasons for putting the Passive Tone control before the preamp,
as well as for putting it after the preamp.

Just curious, anybody an idea what the original does here ?

Image

Bye

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