possible big problem on surf 1.2

[Mohamed Ghitas]

Here is my Schematic and the PCB Artwork.

Thank you

can i use the output to the speaker directly without using TL026 ??

How much deep it can detect ??

[chemelec]

The TL026 is an Audio Output Transformer to Impedance Match to the Speaker.
It is NOT Advisable to connect the speaker Without this Transformer.

can i use the output to the speaker directly without using TL026 ??

How much deep it can detect ??

Only Heaven Knows.

[chemelec]

Updated Schematic.

[WM6]

Updated Schematic.

You suggest that primary of transformator should be 500 Ohms?

[chemelec]

You suggest that primary of transformator should be 500 Ohms?

That Mode Transformer is 500 to 16 Ohms
But Both the Primary and Seconday are Center Tapped.

I Chose to use the 500 Ohm Primary and 8 Ohms to drive an 8 Ohm speaker.
Works GOOD and Quite efficient.
A person Could use the 16 Ohm output if it were more suited to there speaker or headphones.

Also because my Volume control drives the signal to the base of the transistor, The Transistor Current is Lower and more constant than the Origional Circuit.

Gary

[WM6]

Nice idea, thanks Gary.

[chemelec]

Correction, That "TL026" Transformer is made by "MOUSER".
(NOT Mode.)

[6666]

Hi Gary
I am interested in this connection what does it do ?
thanks

[chemelec]

The DOTS mean that Wires are Joined.

[6666]

Hi Gary
I am just interested in why you have that connection, as on the surfs we are making that connection is not there on the schematic's ???

[chemelec]

Yes I see what your saying Now, THANKS.
SORRY, I GOOFED and I will get it Corrected.

[WM6]

..... I will get it Corrected.

Regarding this correction, PCB layout you posted (in post #45) is OK, or need corrections?

[chemelec]

It is Correct.
It is the one I Used to Create the Assembled Board you also see.

[WM6]

Thank you. Good work as allways from you.

[chemelec]

I GOOFED on Assembly of the PCB.

On my Previous Picture, you will see I put a .1 Cap where the 1 Meg Resistor should go.
Strange that it Worked so GOOD with that cap.

I Just Corrected it and Other than Resetting the Offset, It appears to work just as good.

Using one of my Flat Wound, 400uH Coils, it Detects a 4" by 6" piece of Circuit Board at 16 Inches.

But not very sensitve to a Gold Ring.
Too High of Inductance.

Take care.....Gary