Building kit and would like to add this.  Nik does not have a layout, but referred me to schematics on site.  Only layout which has this switch in it is the OTS FM Modern Eagle, but values on that are different than for the HRM BM.  It would appear simple enough to add the extra components for the switch as per the FM Modern Eagle layout diagram, but I am not versed in amp design so cannot confirm this would be functional for the HRM BM.  Can anyone help verify that this will work?

I've searched this forum and at Amp Garage, and while there is plenty of discussion over the merits of having a LNFB switch, there are no applicable layouts which I could find for the HRM BM.

Thanks in advance!

Mark

has anyone tried these tubes?  Highly recommended to me for the dumble Bluesmaster circuit by Brandon of Bludotone.  I have MM transformers, and have verified w/MM that the PT and OT will "easily" run them w/no issues.  In most locations, PT OT ability to handle the higher heater current is only issue flagged as concern.  I'm not a circuit designer, so hoping someone can say whether or not this tube would present any issues in the Ceriatone HRM Bluesmaster cirucuit?  I've searched through the forum and have seen no answer already noted, although a few folks seem to have tried the tubes.  Many Thanks!