Recent Posts

91

Tube Amp Building - Tweaks - Repairs / Re: I'm writing a new book - suggestions?

« Last post by scstill on September 02, 2025, 08:21:34 pm »

hopefully in large print :-)

92

Tube Amp Building - Tweaks - Repairs / Re: Questions about Rehabilitating a 65 Super Reverb

« Last post by Dumbmonkey on September 02, 2025, 06:51:48 pm »

Hi Tubeswell,
I measured that 220k resistor with the reverb level all the way down across the actual resistor and got 481k.
Man, I wish I could figure out what the heck is going on here...

93

Solid State / Re: Unfamiliar with solid state amps, so maybe a dumb question...

« Last post by scstill on September 02, 2025, 06:32:12 pm »

these days my ear drums hurt at <5 tube watts

having said that is there a "standard" as to the loudness difference between tube and ss wattage??

Here is what Gemini says...
"A solid-state amp needs roughly two to three times the wattage of a tube amp to reach a similar perceived loudness, meaning a 50-watt tube amp is often compared to a 100- to 150-watt solid-state amp, though this is a subjective comparison based on tone and distortion characteristics, not pure volume. A key difference is a tube amp's smooth, gradual distortion and compression at higher volumes, while a solid-state amp's distortion is often harsh at high levels."

94

Tube Amp Building - Tweaks - Repairs / Re: Hum and Buzz in Cordovox Build

« Last post by scstill on September 02, 2025, 06:07:45 pm »

100ohm
rectifier side: 0vac; 442vdc
1st tap side: 0vac; 428vdc
14v drop; 0.14amp; ~2w
no voltage change whether MV low or annoying

95

Solid State / Re: Unfamiliar with solid state amps, so maybe a dumb question...

« Last post by shooter on September 02, 2025, 05:50:39 pm »

100Watts of what electrons dissipating or ear-drums hurting??


swapping out transistors is pretty simple, it's all that tedious specification stuff that gets complicated.  hence a schematic, parts list......

96

Solid State / Re: Unfamiliar with solid state amps, so maybe a dumb question...

« Last post by scstill on September 02, 2025, 05:48:52 pm »

Why can't you just play into the 100w cabs just don't turn amp volume up to 10.
I also understand that SS amps are more forgiving on mismatching impedance.

97

Solid State / Re: Unfamiliar with solid state amps, so maybe a dumb question...

« Last post by pdf64 on September 02, 2025, 05:46:20 pm »

With solid state, as load impedance reduces, power output increases.
So at a guess, 150W at 4 ohms may be 100W at 8 ohms and 75W at 16 ohms.

I really doubt it'll be 150W with a 16 ohm cab.
So it might be safe to use.
But, always bench check, don't assume.

98

Tube Amp Building - Tweaks - Repairs / Re: Hum and Buzz in Cordovox Build

« Last post by shooter on September 02, 2025, 05:43:44 pm »

with amp on and annoying, measure both AC n DC on BOTH sides of the 100 ohm between rectifier n 1st PS tap.


do the ohms law for current across that 100 ohm.


post it all

99

Tube Amp Building - Tweaks - Repairs / Re: Hum and Buzz in Cordovox Build

« Last post by scstill on September 02, 2025, 03:54:57 pm »

drawing error on the cap?  or is it wired wrong like schematic?

Cap is wired correctly, drawn wrong. Will change the diagram.

100

Tube Amp Building - Tweaks - Repairs / Re: Hum and Buzz in Cordovox Build

« Last post by tubeswell on September 02, 2025, 03:51:09 pm »

drawing error on the cap?  or is it wired wrong like schematic?