My amp (DNA Starlett) can run a few different rectifier tubes:
5AR4
5U4G
274B Aqua (a more robust 274B).
Does anyone have any idea what the sonic differences would be between these tubes or if it is even meaningful? The amp is designed for the 5AR4 (currently a new production Genalex) but the designer stated that the other options would be fine as well.
Internet searches just get me a bunch of stuff regarding guitar amps, which hasn’t helped me at all, or just non comparative reviews of various individual rectifiers.
Here are some data sheets. The 274B is the standard version. I don’t use rectifiers except having one in my TV-7 A/U tester. Maybe you can compare the specs and glean something useful…
Here is my understanding of it, as someone who is not an EE but likes to read too much:
You know how people usually say the input tube usually makes the biggest sonic difference, followed by the power tube, and lastly the rectifier tube? That’s because the input/power tubes are in the audio signal path, and I believe the rectifier tube is not. A rectifier converts AC to DC. Its part of the power supply, and converts the AC from the wall into DC.
Both methods (tube or diode) usually require a smoothing capacitor or choke (or both) to get a steady DC voltage after rectification.
Have a read.
I’ve always been extremely wary about people who claim that rolling rectifier tubes have made a huge difference in how their amp sounds. I’m sure it can make some kind of difference, but assuming the power section of your amp is built well, any difference should be very minor. If it is NOT minor, then the DC being fed to the rest of the amplifier has dramatically changed. That kinda scares me.
Now, I suppose you could rectify an audio waveform, but I’m not sure why you would want to. You would be removing half the signal and adding it back in as it’s inverse. It would mess things up.
My suggestion would be to look for long life / military versions of those tubes so that you get one that will last forever instead of falling down the sonic OCD rabbit hole.
Rectifiers became a thing in guitar amplification with the rise of Mesa/Boogie. This firm specializes in ultra-high-gain buzzy and distorted heavy metal amps, and was popularized by Metallica back in the 1980s. A fuzz pedal will also square off the waveform and produce a rumble-strip or chainsaw output. Just what I want for vocals and acoustic instruments!
The polar opposite in the guitar world is Fender, which has focused on very clean and neutral amps. They just do a simple job and and rely on external pedals/effects for distortion. Audiophiles generally seek something much closer to the Fender output than the Mesa/Boogie output.
Thats a good point in that I dont really think it should make much difference either which is why I posted and also why I havent really chased any rectifiers other than just getting a back up for my current one (a $30 genalex). Some posts I have come across suggest huge differences but I wonder if its an amp issue or simply the replacing of a garbage tube.
I was aware of the location in circuit and the general workings of the rectifier but relating it to the overall design of the power section and its role in the overall functioning of the amp is an interesting one. I have a sense that the designer of my amp is a pretty thoughtful guy and I think he is an actual EE in the audio industry, or at least along those lines, so Im not worried about design issues around the power supply.
I might track down a Mullard or Amperex 5AR4 at some point just to try and if I can get a JAN version than great, but those tend to have an uncharge. I have come across some people who have stated that they have had Mullards last decades .
Came here to see if anyone was gonna mention this, but as an owner of a Single Rectifier which quite oddly only offers the diode rectification option, I couldn’t tell you the difference firsthand. There are lots of demos on YT of the Dual which offers tube or diode mode for this and generally it affects the dynamics of the amp, with the tube rectifier leading to a more compressed “feel” to use a guitar player term
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