- Do rectifier types change the sound of an amplifier?
- Are tube rectifiers better than solid-state rectifiers?
- Do any amplifier models feature both solid-state and tube rectification?
The tube vs. solid state debate has resounded among guitar players for decades, with each party having their preference and reasons as to why one is better.
What does this have to do with rectifiers? Well, nothing really, as there is an abundance of tube amps that feature solid-state and tube rectifiers.
A rectifier has nothing to do with the build of the pre and power amplifier. Therefore, a rectifier type does not influence an amplifier’s category.
Even select amplifier models let you switch between either rectifier type on the fly, providing the best of both worlds.
Having established all this, what exactly does a rectifier do, and how does it impact your guitar sound on stage and in the studio?
Let’s find out.
Tube vs Solid State Rectifiers: Differences At A Glance
| Tube Rectifier | Solid State Rectifier (Silicon Diode) |
| Tube diode requires a transformer | Silicon Diode does not require its own transformer |
| Slower conversion of electrical current | Faster conversion of electrical current |
| Higher likelihood of failure | Rarely fails |
| Quiet | Can be susceptible to noise without modification |
| Loose and spongey feel with bursting sustain | Tight and punchy with added headroom |
What is a rectifier?
Simply put, a rectifier is a diode that turns alternating current (AC) into direct current (DC).
To understand the importance of this, you must know that any electrical current supplied by a wall socket is AC.
The problem with this is that all amplifiers run off of DC. Hence, a rectifier is required for an amplifier to work.
It’s easiest to think of a rectifier as an amplifier’s power supply, as it is not a direct part of an amp’s signal path.
Tube Rectifiers
If you own an early tube amp from the 1950s or 60s, chances are that its design implements a tube rectifier.
Even after the introduction of solid-state rectifiers, many manufacturers continued to use tube rectifiers until the price of solid-state components decreased.
These were the first vacuum tubes invented, and the first diode produced was a tube diode.
Despite being less commonly used than they were previously, tube rectifiers are still available in many amp models, especially vintage reissues.
So, what are the inherent characteristics of a tube rectifier that make some players fall in love with them?
Well, it has much more to do with feel than with sound. The tube diode is not a perfect component, but this trait produces some desirable qualities when applied in a musical context.
You see, tube rectifiers are inherently slower at converting AC to DC. This means the voltage will drop when you strike a note, and the tube rectifier will take a few milliseconds to catch up.
This creates an effect many guitarists and technicians call sag and compression.
This contributes to the feel many associate with classic tube amplifiers such as the Marshall JTM45, Vox AC30, and Fender Super Reverb.
Like describing colors, it is challenging to reiterate what sag feels like with words, but many players describe it as bloom or sponginess.
Some guitarists especially enjoy tube rectifiers as they feel that the combination of natural compression and tube sag results in some sweet bursting sustain, perfect for lead playing.
On the other hand, some players find sag to be an undesirable characteristic, preferring a faster and more precise attack supported by a tighter bottom end.
Tube rectifiers are somewhat unreliable due to their construction and design—a drop in the quality of modern tube manufacturing compounds this issue.
Regardless, tube rectifiers still boast a solid following among guitar players internationally and will remain in production for the foreseeable future.
Pros
- Feel and response akin to vintage tube amps
Cons
- More susceptible to servicing issues
- More expensive in the modern age
Solid State Rectifiers
Solid-state rectifiers came into prominence during the 1950s and have since become the primary choice when manufacturing modern amplifiers.
This is because solid-state rectifiers function perfectly from an engineer’s perspective.
The delivery of electrical current within a solid-state rectifier is considerably faster than that of a tube rectifier, with little to no fluctuation in voltage.
In addition to this, solid-state rectifiers rarely fail and only cost a few cents per unit. They also need fewer components to work as they do not require a dedicated transformer.
Many famous tube amplifiers utilize a solid-state rectifier, including the Marshall JCM800 and later iterations, Hiwatt Custom 50, and the Mesa Boogie Mark Series.
There are several characteristics that solid-state rectifiers will impart upon an amplifier’s feel and presence.
Firstly, amps with solid-state rectifiers tend to have a punchier response. This can be attributed to the speed at which this rectifier type can covert electrical current.
In addition to this, the bass response of amps with solid-state rectifiers tends to be tighter and less spongy. This may appeal to players in genres where tube sag would be detrimental.
Lastly, solid-state rectifiers provide more headroom, making it seem that amps with a solid-state rectifier sound somewhat louder than their tube rectifier counterparts.
One of the downsides of a solid-state rectifier is that it can inherit more noise than a tube rectifier, though this can be remedied by adding a few resistors and a capacitor to the circuit.
Pros
- Less likely to fail
- More headroom
- Cheaper to purchase
Cons
- Some players may miss the spongey response of a tube rectifier
Dual Rectifiers
A few manufacturers have successfully incorporated both rectifier types into their designs, maintaining this feature in their circuits for years.
Amplifiers such as the Mesa Boogie Dual Rectifier and Laboga Mr. Hector Duo Master both feature a switching system that enables users to switch between each rectifier type while the amplifier is on standby.
This means that players who prefer a different rectifier type for various types of playing no longer have to dedicate themselves to a single diode.
For example, a rock player may prefer tube rectification for lead playing and solid-state rectification for tighter rhythms.
So which is better?
- Your playing style and preferences determine which rectifier type best suits your needs.
- For example, a blues player may prefer a tube rectifier’s subtle compression and sponginess for their playing style. Finding that a solid-state rectifier sounds somewhat sterile for the music they play.
- On the other hand, a death metal guitarist may find that a tube rectifier is way too saggy in the bottom end to keep up with staccato rhythm playing. This will cause the bottom end to fall out on heavy chugs, resulting in a mushy and imprecise tone.
