Yamaha - NE-1 Parametric Equalizer

Silent Fly · Post by **Silent Fly** » 25 Aug 2009, 16:27

Here some detailed gut shot with component values.

: Main board (components side)

: Main board (back)

: Main board (mix)

: Input board

: Q control board

lolbou · Post by **lolbou** » 25 Aug 2009, 16:33

That's cool silentfly!

Did you start reversing it? Or shall we go for it?

Silent Fly · Post by **Silent Fly** » 25 Aug 2009, 16:37

lolbou wrote:That's cool silentfly!

Did you start reversing it? Or shall we go for it?

I hopeless in tracing circuits. Please feel free to start without me.

The switch in the Q control board should be this.

The output is grey (signal) and white (gnd) wire.

I don't know the value of C11 but if we can't guess it looking at the schematics I will measure it.

lolbou · Post by **lolbou** » 25 Aug 2009, 16:38

I've just seen your link, sorry, there's one extra position?

Silent Fly · Post by **Silent Fly** » 25 Aug 2009, 16:41

In the 3 position version, some terminals are dummy. You can find more details here.

lolbou · Post by **lolbou** » 25 Aug 2009, 17:16

Cheers,

Any clue about the diode below the IC?

Dirk_Hendrik · Post by **Dirk_Hendrik** » 25 Aug 2009, 17:30

lolbou wrote:Cheers,

Any clue about the diode below the IC?

Runs from pin 8 to 4. Suggests reverse power supply protection. Therefore it's value is of limited importance for tracing the circuit.

Silent Fly · Post by **Silent Fly** » 25 Aug 2009, 17:32

Dirk_Hendrik wrote:
lolbou wrote:Cheers,

Any clue about the diode below the IC?

Runs from pin 8 to 4. Suggests reverse power supply protection. Therefore it's value is of limited importance for tracing the circuit.

I agree - something like a 1N400x should be ok.

lolbou · Post by **lolbou** » 25 Aug 2009, 20:29

Version 0.0...

NE-1 - schematic 0.0.pdf: (87.59 KiB) Downloaded 692 times

Hope there ain't no big mistakes in it... ANd if someone has a better way to draw the Q-switch (to make if easier to understand) let me know!

BTW, I think the two pots were mislabelled (freq and level)... But what about values?

Silent Fly · Post by **Silent Fly** » 25 Aug 2009, 21:20

Apologies. You are right lolbou. The labels are wrong.

The values are correct. The double pot is A50K (freq) and the other one is A20K (level)

SPeter · Post by **SPeter** » 25 Aug 2009, 21:20

Some clips here!
Enjoy!
http://bass.forumeiros.com/reviews-f10/ ... -t2571.htm

lietuvis · Post by **lietuvis** » 25 Aug 2009, 21:33

The 47K resistor goes to ground,LED goes from positive via 10K,and switch is wrong.
In SHALLOW position should be C7 shunted by C5,R4 shunted by C6 and R7 in serries.
In DEEP position like there is no C5 and R7
In NORMAL position C7 is shorted and R4 shunted by C6.
hope this would help.

lolbou · Post by **lolbou** » 25 Aug 2009, 21:41

A LFO+LED/LDR could be added in to be used in place of the frequency pot to give a sort of auto wah...?

Silent Fly wrote:Apologies. You are right lolbou. The labels are wrong.

I had a hard time thinking on both sides of the PCB too... Where's left from right

?

lietuvis · Post by **lietuvis** » 25 Aug 2009, 22:43

This is what I have traced ,switch from top SHALLOW then DEEP and NORMAL

DimebuGG · Post by **DimebuGG** » 26 Aug 2009, 02:25

I'm a little confused in the configuration of the rotary switch. Anybody?

BTW, lietuvis's tracing is correct.

george giblet · Post by **george giblet** » 26 Aug 2009, 03:56

Pretty much identical to the Robin Tomtlund's trace of the "Fender JB Special preamp"!!! (probably 9 years old now)

http://hem.passagen.se/robin2/effects.htm

lolbou · Post by **lolbou** » 26 Aug 2009, 06:36

lietuvis wrote:The 47K resistor goes to ground,LED goes from positive via 10K,and switch is wrong.
In SHALLOW position should be C7 shunted by C5,R4 shunted by C6 and R7 in serries.
In DEEP position like there is no C5 and R7
In NORMAL position C7 is shorted and R4 shunted by C6.
hope this would help.

DimebuGG wrote:BTW, lietuvis's tracing is correct.

Back on it for next version...

DimebuGG wrote:I'm a little confused in the configuration of the rotary switch. Anybody?

Lieutevis made a better job on drawing it though!

RnFR · Post by **RnFR** » 26 Aug 2009, 06:37

i'm not quite sure why pot 1 is a dual. anyone have any idea?

lolbou · Post by **lolbou** » 26 Aug 2009, 06:58

Version 1.0:

NE-1 - schematic 1.0.pdf: (90.31 KiB) Downloaded 505 times

Any better?

RnFR wrote:i'm not quite sure why pot 1 is a dual. anyone have any idea?

Some second order filter (two RC networks)for better selectivity in frequencies?

analogguru · Post by **analogguru** » 26 Aug 2009, 07:28

A similar filter configuration canbe found in the Ibanez ST-9, the Ibanez STL and the Pearl OD-5. All from the (early) 80´s.

analogguru

Yamaha - NE-1 Parametric Equalizer [schematic]