Lots of people – manufacturers and end-users alike – boast about the “transparency” of a particular device. Manufacturers like to use that buzz-word as a marketing ploy, but after spending the last few years evaluating tons of gear, I’ve learned to be very wary of manufacturers,’ and especially end-users’ claims of a device’s “transparency.” So to test out their claims, I’ve come up with a little test that doesn’t require measuring voltages or impedance curves or force you to perform complex mathematical analyses to prove a device’s transparency.
In fact, the test is so simple that when I tell you how to perform it, you’ll probably laugh! But believe me, to me this test is the ONLY transparency test that matters!
First off, let’s establish what we mean by “transparency” so we have a common reference from which to build. What seems to be the prevalent perception about transparency is that it is a function of both tone and dynamics; that is, a device’s transparency means that when it is engaged, you still hear your original tone, and you feel or perceive the same or similar dynamics of your original signal. Notice, no calculations or measurements. And mind you, I’m not just making this up. Go to any gear discussion board and search on transparency, and invariably the descriptions you will be given will be based upon what people hear. So given that reference point, let’s get into the test, shall we?
The Transparency Test
- Attach your device where it is supposed to sit in your signal chain, but do not engage it.
- Play a simple riff or strum a chord and remember what you just played with the device disengaged to establish your base tone.
- Engage the device.
- Play exactly what you played in Step 2 in exactly the same way.
- Make a note – either mentally or by writing it down. Are your tone and dynamics retained?
- Repeat steps 2 to 5 with a variety of settings on the device.
The test is so simple, you may be chuckling right now. But once you’ve done the test, if you’ve detected an audible difference in tone and dynamics, then the device isn’t transparent. I’m sorry, but there’s no arguing that. But lack of transparency is not necessarily a bad thing. But what we’re really talking about then is what’s acceptable tone, and there is a HUGE difference between what’s acceptable and what’s transparent.
Take, for instance, the Ultimate Attenuator. I hate to keep on picking on this device, but I’ve always had problems with the manufacturer’s and user’s claims of the Ultimate Attenuator’s transparency. This is an incredibly popular attenuator – probably the most popular out there. People love it, and as you know, I will never fault people for purchasing gear that sounds pleasing to them. So if the tone that the UA produces is acceptable and pleasing to you, keep on using it!
But let’s be clear here: The UA is NOT transparent. There is no way it can be transparent simply because once you hook up your amp to the UA, you are immediately hit with a non-reactive, 30 ohm, fixed resistor that essentially flatlines the load that your amp sees. This is compensated for by the UA’s built-in solid state amplifier, but that is the amp that is now reacting with your speaker. All the original amp is doing at that point is providing a base signal that is then re-amped with the solid state amplifier to produce the output signal. An amp’s tone is a function of its reactance with the speaker. In the case of the UA, it is the solid state amplifier that is providing the reactance with the speaker. But hey! The UA sounds good to lots of people, so I won’t knock the device itself. But what I’m illustrating here is the difference between acceptable tone and transparent tone.
So let’s circle back a bit. The point of this article is that you should be wary of people’s claims of a device’s transparency. If you do the test above, and find that the device really isn’t transparent, then you have to ask yourself if the tone it produces is acceptable to you? If it is acceptable and pleasing to you, that’s really all that matters!
Guitar Gear 
It’s pretty ironic: the first thing you tell us is that the only way you can truly tell if a device is “transparent” is by listening, but then you tell us that the UA can’t be transparent because it loads your amp with a non-reactive, 30 ohm, fixed resistor, which you then go on to explain in detail, without once making reference to the sound you hear.
Now, it may be that you can hear the difference, in which case, by your definition, it’s still not transparent. But the reason you’ve *given* is exactly the kind of mathematical analysis you warned about at the start of the article.
I do understand and agree with the point in your last paragraph though.