Search found 13256 matches
- Sun May 19, 2024 2:48 pm
- Forum: Dumble Discussion
- Topic: The Much Anticipated (?) Bluesmaster Build Thread
- Replies: 88
- Views: 2573
Re: The Much Anticipated (?) Bluesmaster Build Thread
Just OD; and with everything maxed out and PAB on. Worst (or best) case for starting an oscillation. Try chopsticking and see if you can make anything change. How would I drive the power amp with 102? Preamp out from 102 plugged into power amp in on BM? Would I use regular cables or speaker cables?...
- Sun May 19, 2024 1:11 pm
- Forum: Dumble Discussion
- Topic: The Much Anticipated (?) Bluesmaster Build Thread
- Replies: 88
- Views: 2573
Re: The Much Anticipated (?) Bluesmaster Build Thread
The OD section volume acts more like a master and the Drive like a pre-amp volume; but even cranked all the way up - still weak. If I dime the master, OD volume, and drive (and pre-amp volume) then switch on PAB - I get a high-pitched whistle (oscillation?). The strange preamp behavior could be an ...
- Sat May 18, 2024 5:43 pm
- Forum: Technical Discussion
- Topic: Can I Parallel 2 Mosfets in VVR?
- Replies: 30
- Views: 731
Re: Can I Parallel 2 Mosfets in VVR?
No slight intended, I just thought it made an interesting plot.
- Sat May 18, 2024 11:44 am
- Forum: Technical Discussion
- Topic: Replace overdrive pedal with real tube?
- Replies: 5
- Views: 145
Re: Replace overdrive pedal with real tube?
Guyatone tube pedal? There are a couple of versions: https://juggbox.blog.jp/archives/15803877.htmlSpeedypancake wrote: ↑Sat May 18, 2024 9:39 am Can you help me turn it into a simple overdrive circuit to replace the Guyatone pedal??
- Sat May 18, 2024 10:34 am
- Forum: Technical Discussion
- Topic: Can I Parallel 2 Mosfets in VVR?
- Replies: 30
- Views: 731
Re: Can I Parallel 2 Mosfets in VVR?
When the voltage drop across the MOSFET is larger, the voltage on the tube plate is smaller. When the voltage on the tube plate is smaller, the tube draws less current. So when the drain-to-source voltage increases, the drain-to-source current decreases. Let's graph that: MOSFET Dissipation 1.JPG T...
- Sat May 18, 2024 8:57 am
- Forum: Dumble Discussion
- Topic: The Much Anticipated (?) Bluesmaster Build Thread
- Replies: 88
- Views: 2573
Re: The Much Anticipated (?) Bluesmaster Build Thread
Well, it looks great, anyway! Your lack of OD may be some wiring error in the relay switching, and it seems strange that you have to set the volume and master very high to get decent volume. DC voltages look good except for the FET, which needs a bias adjustment. BTW, the "top" and "bottom" of the F...
- Fri May 17, 2024 3:43 pm
- Forum: Dumble Discussion
- Topic: 2nd Gen Build
- Replies: 72
- Views: 3260
Re: 2nd Gen Build
Seemed like I had a better balance between the channels too but that required maxing out the volume and keeping overdrive around 50%. Was a low dB test though and may not be reflective of normal playing levels. More fun later tonight after work.... I ran a simulation including source impedance for ...
- Thu May 16, 2024 10:51 pm
- Forum: Technical Discussion
- Topic: Taming amp gain in single channel deluxe reverb build
- Replies: 55
- Views: 2040
Re: Taming amp gain in single channel deluxe reverb build
Great! looking forward to seeing photos and maybe a sound clip.
- Thu May 16, 2024 10:48 pm
- Forum: Dumble Discussion
- Topic: The Much Anticipated (?) Bluesmaster Build Thread
- Replies: 88
- Views: 2573
Re: The Much Anticipated (?) Bluesmaster Build Thread
Good to hear you figured it out. Note in the Bluesmaster layout the switches shown are slide types, but the lug connections are shown as they would be for toggle switches.
- Thu May 16, 2024 10:17 pm
- Forum: Dumble Discussion
- Topic: Starting to populate the chassis....
- Replies: 114
- Views: 5513
Re: Starting to populate the chassis....
So I have a question. Using this board and this transformer The AC bias tap should be 60VAC, transformer puts out 45vac. Is this enough voltage or do I need to do something different to get 60 volts? Just have to reduce the 3k9 resistor to something smaller, maybe 470 ohms or so. Correction, 47 to ...
- Thu May 16, 2024 9:27 pm
- Forum: Dumble Discussion
- Topic: Starting to populate the chassis....
- Replies: 114
- Views: 5513
Re: Starting to populate the chassis....
Just have to reduce the 3k9 resistor to something smaller, maybe 470 ohms or so.
- Thu May 16, 2024 8:30 pm
- Forum: Dumble Discussion
- Topic: The Much Anticipated (?) Bluesmaster Build Thread
- Replies: 88
- Views: 2573
Re: The Much Anticipated (?) Bluesmaster Build Thread
Do you mean the OT primary connections/NFB?Raoul Duke wrote: ↑Thu May 16, 2024 8:02 pm Not hearing any weird noise from the PI or OT, so I guess V3b plate wire is ok where it is for now?
- Thu May 16, 2024 8:03 pm
- Forum: Technical Discussion
- Topic: Can I Parallel 2 Mosfets in VVR?
- Replies: 30
- Views: 731
Re: Can I Parallel 2 Mosfets in VVR?
It's the same as placing two same-value resistors in series to reduce voltage instead of one at the same total resistance. In the case of two resistors, half of the voltage is dropped in each one, current is the same, so half the power (V*I) is dissipated in each.
- Thu May 16, 2024 3:48 pm
- Forum: Dumble Discussion
- Topic: 2nd Gen Build
- Replies: 72
- Views: 3260
Re: 2nd Gen Build
Thinking about this more and running some numbers here is what I've come up with. Voltage dividers are linear (though a pot may have a different taper) meaning if you think of the divider as attenuating a certain percentage of signal voltage, it does not matter if that input is 10V or 50V, the rati...
- Thu May 16, 2024 10:57 am
- Forum: Technical Discussion
- Topic: Can I Parallel 2 Mosfets in VVR?
- Replies: 30
- Views: 731
Re: Can I Parallel 2 Mosfets in VVR?
At very low voltage the current draw is reduced. Power is I^2R, and the reduction in I^2 becomes dominant.Kagliostro wrote: ↑Thu May 16, 2024 9:01 am but I'm not able to figure why at 1/3 of the voltage as output the dissipation will not ne high