Search found 13243 matches
- Thu May 16, 2024 3:48 pm
- Forum: Dumble Discussion
- Topic: 2nd Gen Build
- Replies: 63
- Views: 2895
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: 22
- Views: 493
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
- Wed May 15, 2024 6:28 pm
- Forum: Dumble Discussion
- Topic: Robben Ford & His Dumble Overdrive Special
- Replies: 23
- Views: 875
Re: Robben Ford & His Dumble Overdrive Special
I see it has the pro tour option, 12 chassis mounting bolts ;^)
- Wed May 15, 2024 2:16 pm
- Forum: Dumble Discussion
- Topic: The Much Anticipated (?) Bluesmaster Build Thread
- Replies: 70
- Views: 1995
Re: The Much Anticipated (?) Bluesmaster Build Thread
Yea, sorry for the diversion. If you went ahead and wired the rest of it up you'd have been fine. Hopefully the learning was worth the trip!
- Wed May 15, 2024 2:04 pm
- Forum: Dumble Discussion
- Topic: The Much Anticipated (?) Bluesmaster Build Thread
- Replies: 70
- Views: 1995
Re: The Much Anticipated (?) Bluesmaster Build Thread
That's it. I seem to recall the same question coming up in your 102 build.Raoul Duke wrote: ↑Wed May 15, 2024 2:00 pmMakes sense - the second ground reference wasn’t in the circuit - so it compensated by pushing all the voltage to one (grounded) side. Do I understand that correctly?
- Wed May 15, 2024 1:54 pm
- Forum: Dumble Discussion
- Topic: The Much Anticipated (?) Bluesmaster Build Thread
- Replies: 70
- Views: 1995
Re: The Much Anticipated (?) Bluesmaster Build Thread
Do you have heater leads connected between the two sockets? If not that would explain it. I thought I saw a back/white twisted pair.
- Wed May 15, 2024 1:45 pm
- Forum: Dumble Discussion
- Topic: The Much Anticipated (?) Bluesmaster Build Thread
- Replies: 70
- Views: 1995
Re: The Much Anticipated (?) Bluesmaster Build Thread
That says that the 150R from 2 isn't connected to ground.
- Wed May 15, 2024 1:24 pm
- Forum: Dumble Discussion
- Topic: The Much Anticipated (?) Bluesmaster Build Thread
- Replies: 70
- Views: 1995
Re: The Much Anticipated (?) Bluesmaster Build Thread
Yes. If you disconnect the PT heater leads you should measure ~150R to ground from pins 7 and 2. There are two diodes and a resistor across those pins, but that shouldn't affect the measurement significantly. P.S. If you measure pin 2 or 7 to ground with the heater leads connected, you should see ~7...
- Wed May 15, 2024 12:56 pm
- Forum: Dumble Discussion
- Topic: The Much Anticipated (?) Bluesmaster Build Thread
- Replies: 70
- Views: 1995
Re: The Much Anticipated (?) Bluesmaster Build Thread
I’ll go over everything one more time, but I’m fairly certain that I don’t. Is it safe to measure heater voltage with the leads off the socket and just hanging in the air? No problem. Measure across the leads since you have removed the ground reference. The only other thing I wonder about is the te...
- Wed May 15, 2024 11:06 am
- Forum: Dumble Discussion
- Topic: The Much Anticipated (?) Bluesmaster Build Thread
- Replies: 70
- Views: 1995
Re: The Much Anticipated (?) Bluesmaster Build Thread
Ok, replaced the heater ACTs with 150R and fired it up. Now I have 6.2vac on pin 2 and 0 on pin 7. With or without tubes you should get about 6.3 across the heater string and half of that from each side to ground. Are you sure you don't have any part of that network grounded other than the 2x 150R?
- Wed May 15, 2024 10:57 am
- Forum: Technical Discussion
- Topic: Illinois brand capacitors still bad?
- Replies: 29
- Views: 1076
Re: Illinois brand capacitors still bad?
The 10u 160V IC cap's ESR is not out of line. Check the chart that came with your Peak. Are there caps with lower ESR? Sure, and in some applications such as SMPS with high ripple current it's necessary for adequate life. Those old Mallory's appear to be good, but if that amp is going to be a player...
- Tue May 14, 2024 8:10 pm
- Forum: Dumble Discussion
- Topic: The Much Anticipated (?) Bluesmaster Build Thread
- Replies: 70
- Views: 1995
Re: The Much Anticipated (?) Bluesmaster Build Thread
Do you have 150k resistors to ground from pins 2 and 7 instead of 150 ohm?
- Tue May 14, 2024 6:58 pm
- Forum: Dumble Discussion
- Topic: The Much Anticipated (?) Bluesmaster Build Thread
- Replies: 70
- Views: 1995
Re: The Much Anticipated (?) Bluesmaster Build Thread
Heater voltage was 2.9vac at pin 7 and 6.9 at pin 2 - but 6.2 measured across 2 &7; panel light consistent with this as well. Don't understand this... If pin 2 to pin 7 is 6.2, I would think pins 2 and 7 should both be ~3.1 to ground. Is the only load you have on the heater circuit the panel lamp? ...
- Tue May 14, 2024 5:14 pm
- Forum: Dumble Discussion
- Topic: 2nd Gen Build
- Replies: 63
- Views: 2895
Re: 2nd Gen Build
My thought was keep the load similar to the Second Gen to preserve its character, and allow some plus/minus on the level coming out of the OD wrt the fixed divider in the Second Gen layout. The main point is, however you do it, the Ratio control provides for adjustment of the OD output without going...
- Tue May 14, 2024 2:30 pm
- Forum: Dumble Discussion
- Topic: ODS 102 with 2x KT88s and built-in Dumbleator
- Replies: 33
- Views: 899
Re: ODS 102 with 2x KT88s and built-in Dumbleator
Looks good now.