Dumble Lite schematic?
Moderators: pompeiisneaks, Colossal
Dumble Lite schematic?
I see there is a Layout for a Dumble lite in the file section, is there a schematic that goes with this some place?
Re: Dumble Lite schematic?
Nope, but it's just a Hybrid-A with a few switches removed.lbradshaw wrote:I see there is a Layout for a Dumble lite in the file section, is there a schematic that goes with this some place?
Re: Dumble Lite schematic?
Cool, thanks.
Also, are you using a lower voltage power supply for the 6V6's?
Also, are you using a lower voltage power supply for the 6V6's?
Re: Dumble Lite schematic?
I've used three different power supplies ranging from 290-0-290 to 340-0-340. (Brownnote has used as high as 350-0-350.) No issues so far using JJ 6V6's. For Brownnote's kits we settled on 325-0-325 @200mA, 6.3V @5A, 5V @3A with a 47V bias tap. OPT will be 8k primary, 4/8/16 secondary Vibrolux-style iron.
Re: Dumble Lite schematic?
Can you describe the tonal differences with the different voltages?Normster wrote:I've used three different power supplies ranging from 290-0-290 to 340-0-340. (Brownnote has used as high as 350-0-350.) No issues so far using JJ 6V6's. For Brownnote's kits we settled on 325-0-325 @200mA, 6.3V @5A, 5V @3A with a 47V bias tap. OPT will be 8k primary, 4/8/16 secondary Vibrolux-style iron.
Re: Dumble Lite schematic?
There's a slight difference in feel that you would only notice in a direct comparison. At moderate recording volumes I can't hear the difference at all. At higher volumes, the 350V PT seems to provide a little more headroom and a tighter feel. At the opposite end, the 290V feels a little looser and breaks up a little sooner, but we're not talking about a huge difference. It's probably the kind of thing that Dogears would notice, but mortals like me would overlook.
We went with 325V because it allows us to put 300V on the PI to keep it stiff, but keep the plates of the 6V6's at around 415-420V. As you know, when you drop the plate voltage, there's not a lot of wiggle room in the dropping string to tweak PI voltage. 325-0-325 seemed like the best compromise.
As an aside, I have a switch in my Brownnote 18watt Lite to change from 290V to 215V. Even with a 75V swing (90V on the plates), I can barely hear the difference at moderate volumes. Cranked to 2 o'clock there's a wee bit smoother breakup with the 215V position, but only noticeable if I flip the switch back and forth.
We went with 325V because it allows us to put 300V on the PI to keep it stiff, but keep the plates of the 6V6's at around 415-420V. As you know, when you drop the plate voltage, there's not a lot of wiggle room in the dropping string to tweak PI voltage. 325-0-325 seemed like the best compromise.
As an aside, I have a switch in my Brownnote 18watt Lite to change from 290V to 215V. Even with a 75V swing (90V on the plates), I can barely hear the difference at moderate volumes. Cranked to 2 o'clock there's a wee bit smoother breakup with the 215V position, but only noticeable if I flip the switch back and forth.
Re: Dumble Lite schematic?
Thanks for the info.