Tube or solid state rectifier in tube guitar amp?
There's lots of talk among gear enthusiasts about the differences between amps with solid-state and tube rectifiers. Some players prefer one or the other or even claim one is better than the other. So what is the big deal anyway?
What does a rectifier do?
Becasue the guitar amp's circuitry(such as tube) requires DC voltage to operate. But power from wall plug is AC, power supply of amplifier have to convert AC into DC. So, one good performance rectifier is needed here.
After AC from wall plug enter an amplifier, it pass through the amp's power transformer bumping the voltage up to which needed by tubes, then to the rectifier. A bridge rectifier is consist of tube or solid state diodes. The Diode like 'valve' or 'gateway' that forces current to flow in one direction, so converting to DC. It is important to note that the rectifier is not in the signal path of an amplifier but rather the power supply.
Although the rectifier itself is not actually in the amplifier's signal chain, meaning your guitar’s signal does not pass through the rectifier at any point. So what's this big debate over solid state vs. tube rectifiers? If the guitar signal doesn't even pass through this part of the amp, how could it even affect the amp's tone?
When we introduce tube rectifier, we have to point that the tube diode was invented more early. In fact, the tube diode was the first tube ever invented. This is actually the biggest part of why many players live by the idea that tube rectifiers are superior to solid state rectifiers (sonically speaking),because many people are accustomers to its performance although this is the power defects in fact.
Tube has internal impedance and a voltage drop across them. The power of tube rectifier is smaller also. When load become big suddenly, the current delivery will be a slight delay and voltage will drop for a few milliseconds while it catches back up. This is known as "Sag". In fact, we met "sag" in the daily life also. When a refrigerator or an air conditioner power on suddenly, the light of home will be flash instant.Many electronic devices must avoid this situation happened.
But what does sag mean for sound of guitar amp? When a player is hitting big chords, sag leads to a singing sustain and touch sensitivity at high volumes and mild compression at lower volumes. This really gives players the classic compression that defines the traditional tube amplifier sound. Players often describ the sound and playing feel using "bloom", and "spongy" . Many amps have become famous from this sound; Fender Deluxe Reverb and Super Reverb, the Marshall JTM 45, Vox AC30, etc.
Different tube-rectified amps have different voltage requirements, and thus use different values of tube rectifiers. The 5Y3 rectifier tube, used in a Fender Tweed Deluxe, is a small rectifier tube that produces less DC voltage and thus exhibits more sag/compression. Heavier-duty tube rectifiers include the GZ34 (5AR4) and the 5U4G; these tend to have a quicker response and supply more voltage which means they will exhibit a tighter sound with less sag.
Solid state rectifier
Solid state technology came about in the 50s -- in the case of rectifiers, it was in the form of a small silicon diode. These quickly became less expensive than tube rectifiers and were thus used more often. They also have no internal compression, and are said to work more 'perfectly' in the world of engineering. Solid state rectifiers have much less, if any, voltage drop and can deliver more current more quickly (which is why they are used in higher wattage amplifiers, where tube rectifiers are rarely seen in amps over 40 Watts).
Sonically, this yields a tighter sound with much less sag. A more solid low end with lots of headroom is typical (which is great for metal players/fast pickers). The drawback here is obviously that with little to no sag, many players miss that vintage compression and spongy playing feel. Preamp and power tubes will also exhibit some sag of their own when hit hard enough, so even solid state-rectified amps containing preamp and power tubes will have some sag if pushed pretty hard, but it will typically not be to the extent of a tube-rectified amplifier.
Here again, many famous and popular amps were designed to use a good solid state rectifier: Fender Twin Reverb, Carr Rambler, etc. Even Mesa Boogie's ever-revered Dual Rectifier allows the user to switch between tube and solid state rectifiers.
Tube vs solid state rectifier
Like with many aspects of personal guitar rigs, this all has to do with taste. Some players will require the tight and quick response of solid state rectifiers, where other players want the heavy sag and blooming compression of a tube rectifier.There is no right or wrong answer here. It is always best to take your primary guitar into a shop and play as many amps, first hand, as possible. You might be shocked to learn that out of five amps, your three favorites all contained a solid state rectifier
Tube rectifiers are far less reliable than their solid-state counterparts but you can swap them for different types for different feels.