Raleigh Audio Line Stage Impedance and Gain
(Original version)

 The Line Stage has options for different gains and output impedances. There are two ways to get different gains and output impedances. First, the board is wired so jumpers can be installed to change the transformer ratio. Second there are two different transformers that may be used, the LL1674 or LL1676, which are identical except for their winding ratios. Although there are several variations, I had to pick one as “standard.” The “standard” version of the Line Stage has 6.5dB of gain and an output impedance of 1000 Ohms.

 

Input Options 

Option

Transformer

Potentiometer

Ratio

Gain *

Input

Impedance

Note

1

LL1676

10KΩ

1:1

0dB

10KΩ

 

1a

LL1676

50KΩ

1:1

0dB

50KΩ

 

2

LL1674

10KΩ

2:1

-6dB

40KΩ

Standard

3

LL1674

10KΩ

4:1

-12dB

160KΩ

 

* The gain numbers above are in addition to a base of +24.5dB.

 

Output Options 

Option

Transformer

Ratio

Gain *

Output

Impedance

Note

4

LL1676

2:1

-6dB

4KΩ

 

5

LL1674

4:1

-12dB

1KΩ

Standard

6

LL1674

8:1

-18dB

250Ω

 

* The gain numbers above are in addition to a base of +24.5dB.

 

Option Combinations 

Options

Total Gain

Input Impedance

Output Impedance

Note

1 & 4

18.5dB

10KΩ

4KΩ

 

1 & 5

12.5dB

10KΩ

1KΩ

 

1 & 6

6.5dB

10KΩ

250Ω

 

1a & 4

18.5dB

50KΩ

4KΩ

 

1a & 5

12.5dB

50KΩ

1KΩ

 

1a & 6

6.5dB

50KΩ

250Ω

 

2 & 4

12.5dB

40KΩ

4KΩ

 

2 & 5

6.5dB

40KΩ

1KΩ

Standard

2 & 6

.5dB

40KΩ

250Ω

 

3 & 4

6.5dB

160KΩ

4KΩ

 

3 & 5

.5dB

160KΩ

1KΩ

 

3 & 6

-5.5dB

160KΩ

250Ω

 

 

Option Wiring 

Option

Cut trace between pins:

Add jumper between pins:

1, 2, 4, 5

None

None

3

6 and 10, 7 and 9

6 and 9

6

1 and 4

2 and 4,  1 and 5