When the volume of the amplifier is turned up, the amplifier produces more bass so it may become necessary to adjust the bass control down to compensate for the increase in volume. This is also true for high frequencies to a certain extent.
All Two-Rock amps are designed to maintain fullness, tone, and feel even when turned down to relatively low volume levels. This is attributed to the meticulous design of our master volume circuit, and its interaction with both the output stage and preamp stage of the amplifier. That being said, our amps will sound even better and be more responsive dynamically when they are pushed harder, ie running the master volume above 10:00 which hits the power tubes harder and causes the output stage to impart its character into the overall tone and response of the amp.
All guitars, regardless of pickups, will sound great through a Two-Rock. Many TR amp users say they were finally able to hear the true sonic characteristics of their various guitar/pickup combinations once they played through one of our amplifiers.
Yes, although we do not make an amp specifically for acoustic guitar amplification. It’s important to note that speakers designed for electric guitar amps do not reproduce as broad of a frequency response as PA speakers, or powered speakers, so even though our amps can work very well with an acoustic guitar, speakers and cabs designed for electric guitar will not accurately reproduce an acoustic instrument’s high frequency response.
We currently do not offer any kind of mod services on our amplifiers, but check with Two-Rock customer service if you have questions on fit and function of your amp. Many of our earlier models have been customized and modded over the years, so let’s chat about what you have and what you’re interested in changing.
Over the years we have tried several different speakers such as the Celestion Creamback and the Celestion G1265, but our go-to speaker is now our own proprietary 12” TR12 which is loaded in all of our 12″ equipped cabs..
There are many types of speakers out there and we fully encourage you, the end user, to consider trying different speakers, and ultimately choose the ones that best suit your needs.
Effects loops are best for patching in time based effects ie: delay, chorus, reverb etc. The effects loop is not designed to work with distortion/overdrive types of pedals!
Most Two-Rock amps have one of the following types of effects loop; Passive Insertion Point or “Passive Effects Loop” (most of our amps have this type of effects loop), Half Buffered Effects Loop, or Fully Buffered Effects Loop.
Yes you can but there are a few important things to note; Even though our amps have 3 different speaker output jacks, it will damage the amplifier if used with an impedance load of less than 4 ohms! Make sure you know what each of your speaker cabs ohm rating is. Most cabs are either 8 ohms or 16 ohms but some are 4 ohms. You can combine any 2 cabs that are 8 or 16 ohms but not 4 ohms. This includes using your combo speaker in combination with an additional speaker cab. If you have a 4 ohm speaker cab it can only be used individually with the amp! When combining 2 speaker cabs you must use only the one 4 ohm speaker output jack on the amp! The easiest way to do this is by using a 1/4” “Y” adaptor which allows you to connect both speaker cabs to the one single 4 ohm speaker output jack on the amp. The one exception to this is if you have two 16 ohm speaker cabs, then you can connect them to the single 8 ohm speaker output jack on the amp.
EG: two 1×12 cabs rated at 8OHM. With both cabs running into the Y cable you will get a 4 ohm load. In combos you can take the internal speaker and plug it into the Y cable and add another speaker cabinet again creating a single load to insert in the 4 ohm speaker output jack on the amplifier.
The Two-Rock amplifier models listed below are available in three different power configurations:
Power Configuration Options
*All of the amp models listed above are solid state rectified with the exception of the 50w dual tube rectified power option, only available on the Classic Reverb Signature.
Power Configuration Description and Comparison
The 100/50w version has true half power switching capability made possible by our proprietary output transformer which maintains proper impedance and bias when switching from 100 watts down to 50 watts so there is no compromise in feel or tone.
A common misunderstanding about “half power” is the idea that it should be half as loud as the full power mode but that is not actually the case. When switching from 100 watts to 50 watts, it’s the clean headroom and perceived feel that changes most noticeably. In half power mode (50w) labelled as Low on the rear panel power switch, you still have plenty of volume on tap but the amp can be pushed into breakup more easily while still retaining its dynamic responsiveness. The 100/50w version does have the sparkle and punch that the 6L6 power tubes are known for, and being a 100 watt amp it definitely feels bigger with more authority even when turned down to lower volume levels. The 100/50w version gives the player the flexibility of having both wattages with no compromise in tone or feel. When switched to 50w mode (half power) it is still loud, clean and punchy sounding, and while the difference in volume is not that significant it does lower the threshold of clean headroom.
Our straight 50 watt model uses a 2 x 6L6 power section. The hi/low switch on the 50w version switches the power section of the amplifier between fixed bias (Hi) and cathode bias (Low). When switched to the Low position, the touch sensitivity and feel are enhanced and the amount of available clean headroom decreases without lowering the perceived volume significantly. The 50 watt version of the Classic Reverb Signature adds a dual tube rectified (2 x 5AR4) power section which gives the amp a more bouncy feel, forgiving low end response, and subtle compression when the amp is pushed hard.
The 40/20w version is very similar sounding to the 100/50w however there are some subtle differences other than the output wattage and volume. The 6V6 tubes have their own tonal character and personality, i.e. slightly looser bass response, less aggressive mids and highs. There is still plenty of sparkle and clean headroom on tap but you can drive the 40/20w into clipping more easily than the 100/50w thus achieving natural amp break-up at lower volume levels. At higher volume levels the 100/50w delivers much more “authority” and punch to your tone as expected but that’s not as apparent when the amp is set to lower volume levels. The 40/20w does give you the advantage of being able to run the amp in its “sweet spot” for better sustain and some overdrive while still not being too loud, especially in the 20w (half power) mode. The 40/20w can still be quite loud with a significant amount of clean headroom depending on how the controls are set.
Why Do I Need or Want a Reverse Polarity Speaker Cable?
Most reverb amps are wired out of phase. We inadvertently brought attention to this many years ago by wiring our Two-Rock cabs out of phase in order to match our reverb heads so you could then use a standard speaker cable and still maintain the correct speaker phase. When mismatched, there is a very subtle difference and slightly less low end but it WILL NOT DAMAGE your head or cabinet if you run an amp head wired out of phase with a speaker cabinet that is wired in phase, or vice versa.
A reverse polarity speaker cable is an optional way to match an unmatched amp and cab, simple as that. If both the amp and cab are out-of-phase then they stay matched with a standard speaker cable, if the amp and cab are both in-phase then the same applies. The out-of-phase, (reverse polarity) speaker cable is only needed to correct a mismatched amp and cab.
Current Two Rock amps that are out of phase:
-Classic Reverb Signature
-Studio Signature
-Silver Sterling Signature
-Joey Landreth Signature
-Vintage Deluxe
Current Two Rock amps that are In Phase:
-Bloomfield Drive
-Traditional Clean
-TS1
-Burnside
All of our speaker cabinets have a label inside to tell you if it is in phase or out of phase. Most of our speaker cabinets are wired out of phase with the exception of the Traditional Clean, Bloomfield Drive, and TS1 cabinets that are wired in phase.
Check your instrument and speaker cable connections, power cable connection and AC outlet the amp is plugged into, and then check the pre and power tubes.
Most likely one of the power tubes has gone bad. If you have installed a new set and reset the bias and the fuse is still blowing please contact us immediately and leave the amp off.
This type of noise is most often caused by a malfunctioning preamp tube. Easiest way to trouble shoot is to use a new 12AX7 preamp tube and swap one tube out at a time starting with the V1 position tube, then play test the amp before moving on to the next tube. If that tube does not fix the issue, then replace it with the original tube and try swapping the next tube in line. If the noise goes away the tube you pulled is bad and can be discarded. If you go through all the preamp tubes and still have the noise you may need to purchase a new matched set of power/output tubes and install them into the amplifier, (see tube installation section for details). Please contact us before taking this step so we can help verify that it might be necessary to replace the power tubes. The amp must be re-biased after installing new power tubes. If the same noise problem still exists after checking all of the preamp tubes and replacing the power tubes, the amp will need to be looked at by a qualified technician.
Our amplifiers are designed and built with great attention to detail, build quality and component selection during all phases of construction with the goal of creating some of the finest guitar amplifiers available anywhere.
As with all vacuum tube based analog amplifiers, it is common that some circuitry and or components can introduce minor levels of noise into the audio signal path. Due to the inherent levels of signal gain in all stages of the amplifier, a very slight amount of noise emanating from a component
can be amplified to a level that we will notice when the amplifier is powered on and switched out of standby. This can include hum, hiss, static, buzzing, and even occasional pops or crackles. Those of us with years of experience playing and owning tube guitar amps have dealt with these noise issues repeatedly and are not surprised by them. If this is your first amp of this type, and or you are new to the world of tube guitar amplification, then any stray noises can seem very alarming and might even cause you to think that there is some kind of defect in the amp. This is understandable, and it’s good to be aware of your amp’s behavior and idiosyncrasies.
While some of these noise issues may be perfectly normal, other more prominent noises might be due to one or more of the tubes having developed a slight problem. We source the best vacuum tubes available in large quantities for use in our amplifiers. These tubes are measured and tested both before we receive them as well as during our building and bench testing procedures. Since they are electromechanical devices, some tubes will randomly develop noise problems, and possibly even fail after the amp has been shipped to its final destination. We can easily solve the majority of these noise problems with a simple tube swap which can be performed by anyone with a moderate level of mechanical ability. It is common for tube amp owners to become accustom to changing tubes occasionally.
Amp heads with tube driven spring reverb circuits will also experience a minor level of noise specific to the reverb circuit, especially when the reverb controls are set to higher levels, due to the reverb tank’s proximity to the amplifier’s transformers especially in amp heads. This is to be expected and is not a defect in the amplifier.
We understand your concern regarding hum and buzz created in our amps by the reverb circuit. This is an overview of the design and implementation of our reverb circuit, along with tips on minimizing the audible hum.
The reverb circuit in your amp is a true tube-driven analog effect. Along with several other analog components, this circuit utilizes a tank with springs and magnetic transducers. With the tank mounted in an amp head cabinet, these transducers, which operate very much like the pickups in your guitar, are in close proximity to the power transformer of the amplifier. This puts these transducers within the “magnetic field” of the transformer that actually encompasses several feet around the transformer itself. Proper positioning of the reverb tank in relation to the transformer reduces the hum to acceptable levels. However, at extremely low amp volume levels, and high reverb level settings, the hum can become much more noticeable. At mid to higher volume levels such as live performances (stage level), the amount of hum that is present within the reverb circuit is far less noticeable.
It’s important to keep in mind that electro-mechanical, magnetically coupled reverb circuits are a 100% analog, 75+ year old design. There is something magical and organic about the sound and feel of a well implemented spring reverb that many players love. That said, modern digital effects processors and pedals do allow us to mimic those analog sounds while also eliminating most of the real-world EMI, noise, and other interference common to those classic designs. In some instances when noise issues are more critical, outboard digital effects will be more suitable to use especially for low-level listening and or recording as opposed to live performances. Our decision to implement vintage reverb technology was based entirely on the tonal advantages with regard to live performance settings, where the level of noise created by the circuit was far below the signal level.
Here are a few tips on reducing reverb hum when the amp is played within a home environment or studio setting:
Remove the tank from the head shell and place it as far from the output transformer as possible. This may require longer RCA connector cables. Experiment with the position of the tank in relation to the head cabinet. Rotating one end of the tank away from the head cabinet may reduce the hum even more. If necessary, you can also use the above mentioned longer dual shielded RCA cable to extend the tank further from the amp.
Another option is to turn down the reverb completely and use a digital reverb in the amp’s effects loop. There are many great sounding reverb and time-based pedals as well as rack systems that many of our artists use just for this reason.
We hope you have found this information useful. As always, if you have any further questions, please feel free to contact us.
The recommended tube types that you can use are:
Typically the only tubes you may need to replace in the near term are the power tubes. If the amp is currently performing well, then no tube replacement is necessary. The preamp tubes tend to last for many years and only need to be replaced if they exhibit any signs of failure. Tubes are very easy to change out but there are a couple of things you have to pay attention to so as not to damage the tubes or the tube sockets when removing and replacing them. It’s also important to note that the amp must be re-biased after installing new power tubes. We currently use 6L6GC-STR power tubes for our 100/50w, 50w, 35w, and 28w amps, but any good quality 6L6s will work well in our amplifiers.
For our 40/20w amp models any good quality 6V6 tube sets will work well.
It’s very necessary that you replace them with matched sets, either a pair or a quad, when you purchase new power tubes!
Replace your power tubes when:
This depends on the type of amp and the wattage range!
While we generally encourage players to experiment with different tubes, it is recommended to only use replacement tubes similar to what was installed by Two-Rock. Be careful when considering other variations of the power tube type that your amp requires ie 6L6, 6V6, or EL-34. Not all variations have the same specs and some of them can’t handle the plate voltage of the amplifier.
Below is a list of comparable tube types:
Current Amp Model’s Bias Settings
Silver Sterling Signature:
Classic Reverb Signature:
Joey Landreth Signature:
Traditional Clean, Bloomfield Drive, TS1, Studio Signature, Vintage Deluxe, Burnside:
Legacy Amp Model’s Bias Settings
BIAS PROCEDURE
Make sure the speaker is connected properly, then power up the amplifier.
Set the rear panel power mode switch to Full or Hi DO NOT apply any signal to the input during the biasing procedure!
Insert volt meter’s positive probe into the bias test point socket (located underneath the chassis)
Connect volt meter’s negative probe to chassis ground
Switch amp out of standby and allow a few seconds for the circuit to stabilize
Set voltmeter to millivolt scale (or lowest volt scale 60 millivolts =.060 volts.)
Observe the display on the meter to see the current bias setting. If an adjustment is needed, use a small flat blade screwdriver inserted into the bias adjust pot and adjust by turning bias screw SLOWLY in very small increments until the desired setting is achieved on the meter. Then wait a few moments for the bias to stabilize and re-adjust if necessary. You may need to repeat
this procedure a couple of times. It is ok to play test the amp with the meter connected.
Bias Instruction Video:
LINK TO VIDEO
Feel free to send an email to our info@two-rock.com email via the contact page on our website if you need assistance in troubleshooting any issue your amp may be having. If after troubleshooting your amp via our phone/email assistance we were not able to resolve the problem, then we would recommend that you send the amp to us for service. It is ideal to ship the amp in its original box and packing foam. If we feel a local tech can do the necessary service and or repair, we will work with him/her to be sure the problem gets resolved.
Send to:
Two-Rock Amplifiers
619 Martin Ave., Suite 5
Rohnert Park, CA 94928
707-584-8663
It’s best if you do ask us for one before you ship the amp to us, but it’s not a problem if you don’t.
Please include a detailed note or a copy of emails exchanged with the service dept. about the issue with your amp. Include your return address and phone number. After your amp has arrived, we will notify you when the repair has been completed. The amp will then be shipped back to you.
Turn the treble, mid, and bass controls all the way up. Now hit bypass. You’ll notice the amp doesn’t get louder(or gets very slightly louder) and has more mids. Now back off the tone controls gradually while switching in and out of bypass until you find that perfect level of boost.