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JDO · March 24th, 2003, 11:07 AM

i emailed david allen last night. here's what i wrote.

hello david,

there has recently been some discussion going on over at the tdpri amp board about your raw control. we're wondering what exactly it does. i know that it takes out the tone stack but how?

is it a pot that lets you dial in as much as you want of the tone stack, or is it a switch that bypasses the tone stack?

also, do you mind if we know how it's done? yours' are the only amps i've seen it on so i don't know if it's an issue or ownership or anythign like that. if so i understand. if not do you mind if some of us over there know about it. what i'm learning from the discussion it sounds like a really cool/useful option to have. it would be a great thing to have in a homebrew.

thanks for reading. and thanks for the help you give freely over at the webervst board. if i ever get the money i'll defenetly buy one of your kits.

clean as a whistle,
dean

here's his response.

The Fender blackface tone stack is a “subtractive” type of tone control network. It bleeds off the frequencies you don’t want and lets the rest go to the next gain stage. It is also very inefficient and robs the next gain stage of quite a lot of the signal. The RAW control gradually increases the impedance of these “thrown away signals” trying to go to ground thus forcing them to go on to the next gain stage. There is a dip in the tone stack about 300-400hz where the curve of the bass control overlaps the curve of the treble control. At first the RAW control brings this dip back to unity for a flatter response and then from there, it raises the entire curve which is perceived as gain.

Due to its popularity and time spent tweaking it, I really don’t want to hand over the design at this time. I hope you understand.

Sincerely,
David

don't know if that helps any of you in this discussion. i was slightly disappointed when he said that it's something he wants to keep for now but completely understandable. this might also be something that some of you want to keep in mind if you have a schematic from one of his kits.

March 24th, 2003, 11:07 AM	#9 (permalink)
JDO Tele-Holic Join Date: Mar 2003 Location: Pittsboro, NC Posts: 597	i emailed david allen last night. here's what i wrote. hello david, there has recently been some discussion going on over at the tdpri amp board about your raw control. we're wondering what exactly it does. i know that it takes out the tone stack but how? is it a pot that lets you dial in as much as you want of the tone stack, or is it a switch that bypasses the tone stack? also, do you mind if we know how it's done? yours' are the only amps i've seen it on so i don't know if it's an issue or ownership or anythign like that. if so i understand. if not do you mind if some of us over there know about it. what i'm learning from the discussion it sounds like a really cool/useful option to have. it would be a great thing to have in a homebrew. thanks for reading. and thanks for the help you give freely over at the webervst board. if i ever get the money i'll defenetly buy one of your kits. clean as a whistle, dean here's his response. The Fender blackface tone stack is a “subtractive” type of tone control network. It bleeds off the frequencies you don’t want and lets the rest go to the next gain stage. It is also very inefficient and robs the next gain stage of quite a lot of the signal. The RAW control gradually increases the impedance of these “thrown away signals” trying to go to ground thus forcing them to go on to the next gain stage. There is a dip in the tone stack about 300-400hz where the curve of the bass control overlaps the curve of the treble control. At first the RAW control brings this dip back to unity for a flatter response and then from there, it raises the entire curve which is perceived as gain. Due to its popularity and time spent tweaking it, I really don’t want to hand over the design at this time. I hope you understand. Sincerely, David don't know if that helps any of you in this discussion. i was slightly disappointed when he said that it's something he wants to keep for now but completely understandable. this might also be something that some of you want to keep in mind if you have a schematic from one of his kits. __________________ clean as a whistle