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Discussion in 'Glowing Bottle Tube Amp Forum' started by chucker, May 17, 2021.
how does this tube affect sound?
It makes the other tubes light up.
is solid state rectification then as good?
It depends on the tube, the power supply of the amp, and what you’re after as a musician. It affects feel more than sound, as the rectifiers only job is to convert ac to dc power (to “rectify” the voltage off the power transformer). Solid state is more efficient at doing that than tubes, but both have their benefits.
if you’ve ever played a 5e3, they have kind of a slow response, which is known as “sag,” due to the 5y3 rectifier dropping a lot of voltage into a power supply that doesn’t really have a lot of capacitance (the filter caps literally can’t keep up with the voltage that’s being put into them). It can feel thick and sticky, like the notes take a bit longer to come out of the amp. It’s because the amp is struggling to get enough voltage to run the power supply. I love this, others don’t. Ymmv, it’s really personal taste based on your style and application.
Diodes (solid state) will make the feel stiffer and more responsive (think Marshall super lead/jcm800), because the lower voltage drop to a generally higher capacitance power supply makes it easier for the amp to draw in current. If you play fast and a ton of notes with high gain, this might be better for you, but maybe not.
no better or worse in this case, just different.
What @JamesAM said. The rectifier tube converts AC from the wall to DC to the amp, and exactly which one you use (and which one the circuit is designed for and the power transformer can get along with) does make a difference in sound and feel. Even rectifier tubes of the exact same type and brand normally supply slightly different voltages.
somehow thick and sticky sounds appealing.
Um, sag happens a lot more on the internet than in amplifiers. A tube rectifier, properly spec'd, will provide enough voltage until the amp is really, really cranked and stressed. Ya'll use yer master volumes and overdrives and compressors and talk about "sag" that probably is mostly in your head. IMO.
Um, I plug straight in to a 5e3 and crank it to 10/12 with no pedals and PAFs. It sags plenty, even with increased filtering.
Appreciate your insight into my mind and gear though, thanks
I had a 5E3 tweed Deluxe during the loud years...sometimes I could gig it, but mostly had to chain it to me Pro Reverb for adequate horsepower.
Then I fell in love with a '63 Vibroverb RI (in 1990).
Stick with me...I'm on track....
There was something about the way the notes JUMPED out of the VV that hooked me...it was so responsive.
But, after awhile, I realized there was something about my Deluxe that I missed...this is how I discovered sag and bloom...the tube rectifier.
I feel it.
I sometimes use my right hand fingers, and if I really snap a string and hit the amp hard, it's almost like a triggered volume pedal ...the sag is that obvious.
Sticky...I like that.
Sag is real, it exists and has significance. More, you can hear the difference in current production vs NOS. SAG, it is real, it is audible and you can just about feel it.
Paul wasn't really talking about 5E3's on 12, more the guys with bigger tube amps who imagine they hear sag at any volume.
Peace. You make a good point- the tube is only half the equation. my ac15 has an ez81 and is stiff as a board thanks to the crazy high filter values.
Yup, yup, yup. Guys cranking 5F1s, 5E3s, 6G2s, GA5s, etc. can relax. I know what you know.
Most amps, on the other hand, don't actually "sag" under most circumstances. Yet I see long dissertations about AC30s, Super Reverbs, etc., and I say, nah.
Deleted. Why stir things up?
Obviously that is not totally true because changing loudspeaker and output transformer impedances come together with music. Loadline is a tool to design circuits and current/voltage does not follow it when amp repeats music. There come spikes which some are more vertical and some more horizontal and they don't always pass the idle point. Obviously music spreads the loadline to an oval area both side of it.
Power stage does not transfer power to loudspeaker when it idles at bias point and although it is significant in A-class and RMS current might be at its max the music brings current peak needs which tube rectifier power supply can not deliver fully and this can change sound more pleasant.
I have not built tube rectifier to A-class amp yet but when I do I try to get an oscilloscope picture of current/voltage behaviour.