Zobel to MC Transformers

[Dr. ODD]

Hi,

I am just building a fine House for my LL 1681. I am adding swichabel load resistors and I am thinking about adding swichabel Zobels (fixed resistor, swichabel Caps) too. I am wondering why Jennsen and Sowther are recommending Zobels and Lundahl does not. Are there differences in winding or something else which are mattering in this case?

I will use it 1:26 to mach a SPU Cassic A

Bernhard

[SY]

Why make it switchable?

For me, I began my MC preamp design with the transformer. I loaded it with a capacitor to simulate the Miller capacitance of the first stage, drove it with a source impedance equal to that of my particular MC, then played with various resistors and Zobels as secondary loads to get the response as flat and extended as possible.

Any transformer will benefit from this.

[Dr. ODD]

Swichabel because

1) I have a second cartridge wich I want to use from time to time.

2) I fear that I could hurt the transformer when I solder new resistors and caps to often.

3) Your describtion looks like you measured the response. I fear this is beyond my knowlege. Do you think I can find the right values whith listening tests or do I have to learn how to measure this?

Bernhard

[SY]

I didn't measure the response directly, I used a square wave and adjusted for a compromise between HF peaking (seen as ringing on the edges) and bandwidth-limiting (seen as a sluggish rise and rounded edges).