symbiotic
Tele-Meister
I have an original Blues Deville from, I think, 1996. It had some of the usual troubles over the years, such as failed input jacks, plate load resistors, and what finally made me gave up on it - channel switching relay failures. I put up with it for a long time because I am just that type but, honestly it just doesn't suit me anymore if it ever did. Very stiff and sterile I would say. So, I have definitely decided to use it as a donor to build something different.
So, what to build? I am inclined to make it into something Vox-ish. Specifically I am looking to the Mojotone NC3015 as a template to start from. Two channels; one is a volume-only single gain stage while the other is a top boost style preamp with CF-driven tone stack. I would add a preamp master to the top boost channel and also a post-PI master; either a simple crossline, or a Type 2/Lar-Mar style. The NC3015 already includes a Vox style 'Cut'. Also, no negative feedback.
Here is the thing stuck in my mind. I want to use the Blues Deville transformers. I want to replace the EL84 power section of the NC3015 with the 6L6GC tubes from the Deville. I want to use cathode biasing in the Vox style for its inherent compression. BUT the Deville power transformer, through diode rectification (which I would keep because, 2 octal holes and no 5V winding) delivers about 470V to the 6L6GC plates. How do I determine if this is feasible? Can cathode biasing be used at that plate voltage? I could maybe reduce plate voltage by 30V or so with zener diodes but, is that necessary or sufficient?
I look forward to input, just don't bother suggesting repairing the Deville circuit ;-)
(btw, I am aware the power supply dropping resistors would require component value changes to get the preamp values in the right range but I don't see that as a roadblock yet)
So, what to build? I am inclined to make it into something Vox-ish. Specifically I am looking to the Mojotone NC3015 as a template to start from. Two channels; one is a volume-only single gain stage while the other is a top boost style preamp with CF-driven tone stack. I would add a preamp master to the top boost channel and also a post-PI master; either a simple crossline, or a Type 2/Lar-Mar style. The NC3015 already includes a Vox style 'Cut'. Also, no negative feedback.
Here is the thing stuck in my mind. I want to use the Blues Deville transformers. I want to replace the EL84 power section of the NC3015 with the 6L6GC tubes from the Deville. I want to use cathode biasing in the Vox style for its inherent compression. BUT the Deville power transformer, through diode rectification (which I would keep because, 2 octal holes and no 5V winding) delivers about 470V to the 6L6GC plates. How do I determine if this is feasible? Can cathode biasing be used at that plate voltage? I could maybe reduce plate voltage by 30V or so with zener diodes but, is that necessary or sufficient?
I look forward to input, just don't bother suggesting repairing the Deville circuit ;-)
(btw, I am aware the power supply dropping resistors would require component value changes to get the preamp values in the right range but I don't see that as a roadblock yet)
