Lundahl LL1660 OPT Franks 6SN7 linestage

[Vinylsavor]

Hi !

As I mentioned above: At a certain point you should just start and build it. Then see how it works. Measure it and listen to it. Modify if needed and observe the changes that brings. This circuit is easy enough to get started.


If you want to know the currents. Look up the 6SN7 datasheet. Put the op points into the plate curves and get the currents from there.

Best regards

Thomas

 

[merlin el mago]

Thanks for all Thomas, only one question more: I see differents LL1689 models, wich one is the specific for my app & how should be wired?

 

[Vinylsavor]

Hi!

It is available for different currents. If you use one system of a 6SN7 only use the 10mA. If you use parallel 6SN7, use the 18mA (in that case the cathode R needs to be halved to 500Ohms).
Connection alternative Alt Q for 9:1 and Alt R for 18:1 for very low Zout

Best regards

Thomas

 

[merlin el mago]

Near 8mA

An externally hosted image should be here but it was not working when we last tested it.

 

[merlin el mago]

I see all these Lundahls LL1689 models, only to be sure for Senhs 300 ohms have to be wired Alt Q for 18:2, right?

LL1689-18 218-071-68 9+9 : 1+1+1+1+1. Interstage, for tube applications 18 90H

LL1689-AM-18 218-072-98 same as above, but amorphous core. NEW! Amorph 90H

Wich one?

 

[Vinylsavor]

Hi!

I just checked what I have: 11mA, 18mA, 25mA and 36mA. It is also available for PP or 9mA

11 or 9mA will be fine for half a 6SN7 the difference is negligible, the 11mA allows more room for experimentation with current.

The AM models are about twice as expensive. They have amorphous cores. I am not a friend of the AM versions. I prefer the standard cores sound wise.

to be sure for Senhs 300 ohms have to be wired Alt Q for 18:2, right?

You can easily try both and see what you like better. It is a matter of 5 minutes to change between 18:2 or 18:1

Best regards

Thomas

 

[merlin el mago]

Thomas you have pm.