Recent Posts

81

Tube Amp Building - Tweaks - Repairs / Re: First amp build

« Last post by AlNewman on September 06, 2026, 04:34:48 pm »

Yes that's the correct way to calculate current.  You can use either plate voltage or cathode voltage, (PI gets a bit trickier using cathode voltage).  You can also look at the power rail and see what resistors feed what parts of the circuit and take one measurement for that section.

82

Tube Amp Building - Tweaks - Repairs / Re: First amp build

« Last post by Mongrel714 on September 06, 2026, 04:02:13 pm »

There's voltages on your build schematic.  You can find out what current the pre amp and phase inverter are supposed to draw.

Just wanted to verify that I'm going about this the correct way, looking at the Tube town schematic,
Find the plate resistor for pre amp tube, take the B+ voltage before the resistor, then subtract the voltage after the resistor, then divide by the value of the resistor itself, gives you the current.
First preamp tube
B+4:260v subtract voltage after 100k resistor:195v =65v drop
65v divided by 100,000ohms=0.00065mA
Do this on all pre amp and PI tubes then add together to find total current?
Or is it the 1.8v, 2.8v, 1v, 50v (PI) below the tubes?

83

Solid State / Re: DC to AC Inverter

« Last post by shooter on September 06, 2026, 03:26:43 pm »

how many amps does your pump draw?  you can pick up a 700-1kW invertor far cheaper than building one, even better buy a 12VDC pump n ya don't need an invertor, just a solar panel n a charge controller, that's how I did my setup.

84

Solid State / Re: DC to AC Inverter

« Last post by dpm309 on September 06, 2026, 12:54:00 pm »

Thanks Shooter, I'll check it out. I have a ton of components (diodes, resistors, IC, transistors, vero board) from my pedal building stash and would like to find a schematic to do a DIY inverter. Didn't find anything online yet but will keep looking.

85

Tube Amp Building - Tweaks - Repairs / Re: Pro- amp planning

« Last post by Mike-p on September 06, 2026, 11:59:08 am »

Ok thanks sorry I will. So will playing through the trem channel without the trem engaged sound exactly like the normal channel?

86

Tube Amp Building - Tweaks - Repairs / Re: Pro- amp planning

« Last post by acheld on September 06, 2026, 09:36:09 am »

OK, I'm confused.

Could you sketch a block diagram of what you want to do?   No schematic, just blocks with intended function.

87

Tube Amp Building - Tweaks - Repairs / Re: Pro- amp planning

« Last post by HotBluePlates on September 06, 2026, 09:17:27 am »

... I want to use 4 preamp tubes so I thought, v1 and, V2 are doing the same thing, so can I scrap one and switch the output. ...

If you only want 1 Channel, and Harmonic Trem, why do you need to switch anything?

Fender already had this in what they built:  erase everything of the Normal channel from the Input JAcks up to the 0.05µF and 1MΩ resistor that feed the Phase Inverter Input Cap.

  - Signal "goes through" tubes used to mix the Dry & Trem signals, but...

  - No trem is added unless the Footswitch allows the oscillator to run:  No oscillator, no-trem


You don't need to "mix" or "switch" anything (except in a manner to enable/disable the oscillator).

88

Tube Amp Building - Tweaks - Repairs / Re: Pro- amp planning

« Last post by Mike-p on September 05, 2026, 05:31:57 pm »

Maybe I used the term incorrectly. I want to use 4 preamp tubes so I thought, v1 and, V2 are doing the same thing, so can I scrap one and switch the output. Is that single input two channel maybe?

89

Tube Amp Building - Tweaks - Repairs / Re: Pro- amp planning

« Last post by sluckey on September 05, 2026, 05:16:47 pm »

You said you only wanted one channel, or so I thought.

90

Tube Amp Building - Tweaks - Repairs / Re: Pro- amp planning

« Last post by Mike-p on September 05, 2026, 05:11:26 pm »

I'm sorry I'm really trying hard to understand your reply. I asked AI in case I was being stupid but no help.

 The normal channel simply goes triode-tone stack and volume- triode - .05 cap- 1m resistor- coupling cap-PI

Can I not switch the signal before the 1m resistor to EITHER feed v4 phase splitter OR 1M -PI cap.

The 1M resistor is doing what exactly? Correcting impedance between channels? Like a mixing resistor?

If I'm being too stupid for an answer please send me in the direction to improve my understanding. I have the new merlin book and the entirely of the internet to consult.

Thankyou.