Lundhal line input transformer question...

[sklimek]

Could someone recommend the Lundahl line input transformer equivalent to the
Jensen JT-11P-1 AND CineMag CMMI-15/15B line input transformers. I added a link to Lundhal and Jensen:

http://www.jensen-transformers.com/datashts/11p1.pdf

http://www.kandkaudio.com/transformers.html


I need to get two of these transformers and I'm having trouble comparing the specs for the Lundhal for comparative info.

Thanx - Stan

 

[KevinC]

The most closely matched transformer in the Lundahl line from an impedance standpoint is the LL1540. If you don't need the relatively high impedance service, there are a host of others that will do as well, many at higher maximum signal levels.

 

[sklimek]

LL1540...

The most closely matched transformer in the Lundahl line from an impedance standpoint is the LL1540. If you don't need the relatively high impedance service, there are a host of others that will do as well, many at higher maximum signal levels.

Hi KevinC, thank you. My amplifier input impedance is 100K, would R2 and R2 be replaced with 100K resistors and keep the RC damping network of 22K/1nF in place?

Stan

 

[KevinC]

Stan,

What is the output impedance of the source driving the amplifier? There may be a better transformer for your application than the LL1540, depending on what it is.

If you used the L1540 you may benefit from the terminating resistors. If you are installing the transformers in the amplifier, you could split your 100K input resistor into two series connected 50K resistors and then these would effectively take the position of the "R/2" resistors in the diagram.

 

[sklimek]

Stan,

What is the output impedance of the source driving the amplifier? There may be a better transformer for your application than the LL1540, depending on what it is.

If you used the L1540 you may benefit from the terminating resistors. If you are installing the transformers in the amplifier, you could split your 100K input resistor into two series connected 50K resistors and then these would effectively take the position of the "R/2" resistors in the diagram.

It is 3.3K output transformer into a 8 ohm speaker load, dual mono blocks. Hopefully that answers your question?

 

[KevinC]

I wasn't clear. I was interested in knowing what the output impedance of your preamp that is driving your amplifier is.

 

[sklimek]

I wasn't clear. I was interested in knowing what the output impedance of your preamp that is driving your amplifier is.

A 6H30 based preamp waiting to be built. I do know that the 6H30 can provide very low output impedance, but I can’t be exact at this point what the output impedance would be. Here is the preamp schematic I plan to follow:

http://digilander.libero.it/paeng/a_6h30s_line_preamp.htm

And a couple of Russian data shts for the 6H30:

http://headwize.com/images3/6h30a.gif
http://headwize.com/images3/6h30b.gif

Helpful?

 

[KevinC]

This preamp has a low enough impedance for a variety of transformers. The most sonically transparent of the choices is the LL1690, but the LL1540 will work, too.

 

[sklimek]

This preamp has a low enough impedance for a variety of transformers. The most sonically transparent of the choices is the LL1690, but the LL1540 will work, too.

Kevin Thanks!

BTW – here is a schem that uses your product as a power supply for the 6H30 that I’ll eventually get to as well.

Stan

 

[Tyimo]

Hi!
Can someone tell me how much inductance has the LL1540?

Tyimo