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Can I really use the same preamp for Bass or Guitar…..?

In the case of the Frog Fx1 tube preamps, absolutely. It is being used around the world for guitars and bass guitars with excellent results. In fact, it has been used for pedal steel guitars, lap steels and some Alembic F2b preamps are used for string instruments (I don’t know if the Frog is yet, but there is no reason it couldn’t!). I have also used it with my acoustic guitar with a Piezo pickup installed.
It is being used to create the bass sounds of a Disney musical that runs 8 shows a week in Hamburg, Germany. It is also being used to create the ethereal sounds for David Gilmour/Pink Floyd tribute bands in The Hague, Netherlands and Illinois, USA as well as many other bands all across Europe, USA, Canada and even some in Japan. There are about 200 of these “Frog” type preamps all over the world, that are either using my DIY Frog 2.0 and 2.1 tube preamp PCBs that have been built by gutsy DIY’ers or complete, hand-built units built by Mark Price in his little shop in Sibley, MO (a distant suburb of Kansas City, Missouri, USA).

How can a preamp for guitar be used for bass or visa versa?

The beauty of this preamp design is that it is a full-range preamp and has EQ for Bass, Mid and Treble. The Studio version and the Ruggedized version both have a Mid Boost and Bright switch. The Mid Boost is unique to the Frog compared to the Alembic F2b only having a bright switch. With the full range of controls and various ability to boost mid or high frequencies, you have all the tools you need to dial in your sound as illustrated by the range of users of the Frog Fx1. There are probably many preamps that aren’t crippled for use for one type of instrument or another, I just hope you will consider the Frog Fx1. Soon, I hope to create a more Bass centered preamp, however, even it will have full range capabilities but will have some specific features that Bassists need more than others.

Another unique feature of the Frog Fx1 Studio or Ruggedized tube preamp…

A while back, I had a band member that brought in a KLON Centaur and used it in front of his Fender guitar amplifier and I fell in love with the overdrive sounds that the KLON could make. I decided I would add two switchable clipping options to my preamp. I say it is based on the KLON Centaur, not because I added a solid state operational amp, or used the same diodes to get the clipping, it is because I placed the clipping section at a similar place in the circuit as did the KLON. That is, right after the first preamplifier stage. One of the clipping options offers a more “overdrive” sound, and the other is more of a “fuzz” sound. It is all very dependent on the type of pickup and how hard the pickup is driving the first preamp section (attack). The clipping feature is probably more useful for a guitar compared to bass guitar. There is one user, Patrick from Ohio, that recently stated: “ …I didn’t think I would find the clipping circuit useful and it may be my favorite feature….I believe it’s (the preamp) going to be more versatile than I had originally thought….ITS REALLY WONDERFUL. I want to integrate it full time into my pedalboard.”

So, sound is in the “Ear” of the individual, but I have to say, time has proved that the Frog Fx1 is extremely versatile and can be used for any instrument with a pickup.

Go to frogpedals.com to look at your options or join us on http://www.facebook.com\frogpedals for more up-to-date commentary and activities around the Frog product line.

Why do I need a preamp?

What does a preamp do?

A preamp or preamplifier prepares the signal coming from a pickup or other instrument for additional amplification.

Here are 3 MAIN reasons to use an instrument preamp:

1. It can boost a low signal
2. It can clean up a signal so that it sounds better coming through the amp
3. It can adjust the signal (e.g. volume control or equalizer)

For example, a pickup that’s plugged directly into an amplifier is a “passive” pickup. A pickup with a preamp, on the other hand, is an “active” pickup.  But then there is a cable (or some other device) between your instrument and your amplifier.

A note about cables:  A preamp can enhance tone that is lost by long cables, but make sure whatever instrument cable you use, it is fairly high quality.  I say fairly high, because, I believe you can pay too much for a cable.  There is the issue of diminishing returns on what you spend.  If you spend 10 times as much for one cable over another, but only gain 2% better/cleaner/ sound, was it worth it?  Can you even hear the difference?  That of course is up to you.  I do think you can buy a quality cable and not spend a fortune.

A good passive pickup should produce warm, full, tone.  Active pickups are usually louder and brighter and the preamp allows you to shape the sound of the pickup in a number of ways: volume, bass, mid, treble, gain, etc. You can assume, the more expensive the preamp, the more features and control it gives you over your overall sound.

In addition to controlling the output of your pickup, preamps can also improve their sound. If your pickup output is too low, the sound is thin, the signal is unbalanced, the signal is noisy, then a preamp might solve your problems. Most basic preamps will provide volume control and an equalizer (tone stack).  In other words, an instrument preamp is an electronic device that provides an end-to-end solution for taking the signal from a guitar and preparing a tone-shaped signal ready for further amplification.

It can be used to directly drive the signal into a power amp, meaning, a non-guitar/PA amplifier.  In fact, that is exactly what the Alembic F2b back in the 1970’s was used for.  They had Alembic F2b preamps directly connected into McIntosh audiophile power amplifiers.  Each instrument had its own stack of preamps, power amps and speaker columns.  Be careful though, some preamps are not able to drive a power amp based on the power amps input sensitivity.  The Frog Fx1 Tube preamp, based on the same Fender/Alembic F2b circuit is very much capable of driving a power amp directly.

One thing to watch out for when considering a preamp is noise. Whenever a signal is amplified, the goal is to keep the signal-to-noise ratio as low as possible. That makes sense because a little bit of noise from the pickup or the preamp can become a lot of noise when the signal is amplified and loud. In order to avoid introducing extra noise from a preamp, it’s good practice to place the preamp as close to the signal source as possible.

Additionally a preamp can be an effective way of overdriving an amp, where the instrument alone wouldn’t have enough power.  They are especially great for amplifiers that have a tube input stage as the first stage.  It can produce a nice creamy overdrive to sometimes an intense distortion sound depending on the output capabilities of the preamp.  The Frog Fx1 Tube Preamp has a lot of output capability for these features!

Many times, people confuse preamps with DI boxes.  A DI is not a preamp and a preamp isn’t necessarily a DI.  A DI, or “direct injection” box, converts an audio signal from unbalanced to balanced, and sets the output level and impedance of the signal specifically for connection to the input on a mixer.  Having said that, there are devices that have elements of both inside, but don’t assume that a preamp will function as a DI box or visa-versa.

A little terminology lesson:

Gain (or Drive) refers to the amount your signal level is increased. It is critical to understand how much a preamp can increase your gain, because each device that you send your signal to (power amp, mixer, instrument amp head, etc.)  has specific requirements for signal levels that are required for optimal results.  Not all preamps can drive a power amp. Some preamps have little or not gain. Others may be designed to boost the signal level enough to overdrive the input of a tube amp. Preamps have a gain control, while others have a fixed amount of gain. Typically, they will have a “volume” knob which just passively turns down the signal level at the end of the preamp circuit.

Tone can include anything from EQ controls, to “warmth” or other subtle qualities, to outright distortion. Some people want lots of tone changing and EQ controls, others want transparency, and others, everything in between.

Impedance can be described as the efficiency of the signal transferring from one piece of gear to another. An ideal impedance relationship is a very low output impedance number connecting to a very high input impedance.  If your instrument or device has an output impedance that is too close to the input impedance of the device you’re connecting it may result in your signal being too weak. That weakness may result in a lower signal level or a dull tone.

Another spec you can look for in a preamp is dB gain (amount the signal is boosted). A “clean boost” pedal may commonly offer 20 or 30 dB of gain, but it may take 50 or 60 dB gain to bring the output of a bass or guitar up to the level needed to drive a typical power amp.

Another factor to consider is if the output of the preamp is balanced or unbalanced. An unbalanced signal uses a regular instrument cable containing two wires, typically with a 1/4″ plug on the end. A balanced line uses three wires, and may have an XLR (microphone type) plug or a TRS (stereo) 1/4″ plug. You need to verify which of those types of connection is most ideal for the next item you’re going to plug the preamp into. There are some devices which can receive both balanced and unbalanced connections, but you cannot assume that about any one piece of gear. The instrument input of an amp head is unbalanced; most pedals are unbalanced; a DI output is balanced; many rack mount processors are balanced.