User Manual - Gjika 10^n Guitar Amp Instructions & Proper Amp Voltages

Read this and watch the videos - protect your warranty!


GJIKA POWERS OF TEN (10^n) Guitar Amplifier with Gainmaster & Cable INSTRUCTIONS:

Thank  you for your purchase of a Gjika Amp. Here is what you need to know to  get the most out of this original design, high-power, single-ended Class  A guitar amp, and the accompanying Gjika Gainmaster, which allows you  to get a cranked amp sound at any desired volume.


IMPORTANT:  this is very important, did I mention this is IMPORTANT? Well it is, so  listen up, you need to have surge protection on your amplifier, and the  best way to do that is with a surge suppressor (like you use for your  computer and other expensive equipment). Get a good one. I have  information about that on my YouTube channel videos, if you want to know  more. For the purposes of this instruction manual, it will suffice to  say that if your amplifier is not protected by a surge suppressor, and  damage from electrical surges occurs, the warranty is void, and any  repairs will be made at your expense.

For optimal performance,  get a Variac, and plug it into the wall outlet, then plug your surge  suppressor into the Variac, and plug the amplifier, Gainmaster, and any  other equipment you will be using, into the surge suppressor strip. The  reason for a Variac is that you never know what the voltage is in the  wall outlet you are plugging into. These voltages vary depending on what  time of day it is, or where you live. The 10^n amp, Gainmaster, and  most all other modern equipment you may be playing through, is designed  to run at 120V. As a seasoned player, you will find that it is your  responsibility to make sure that you provide these devices with the  specified 120V. If you are using this amp overseas, you will need to use  either a drop box or a Variac to provide the amp and Gainmaster with  the specified 120V. If you are unsure of what to buy, communicate with  me and we can find the proper solution for your specific needs.


This  is also important, do not defeat your ground on the amplifier. If you  get two amps, to play in stereo, then use a HumX adapter for one of the  amps.

You will use the adapter that comes with the Gainmaster to  avoid a ground loop hum occurring. If you choose to use a HumX, that is  also acceptable.

TUBES: Save the boxes, note locations on the  preamp tubes (12AX7s) if you choose to remove them. The reason for this  is that I have selected them for tone and response for their respective  positions.

Your amplifier comes equipped with two 12AX7 preamp  tubes, which are pre-installed. It also comes with four KT77 power  tubes, which are interchangeable, so don't worry about which one goes  where, just install them according to proper tube installation  techniques, and you are good to go.

Your tubes have been  carefully selected for your Powers of Ten amplifier. If you decide to  remove these tubes for any reason, please mark the locations of the  tubes you have removed, so you can easily put them back where they go.  This is only important for the preamp tubes (12AX7).

REPLACEMENT  TUBES: if your power tubes fail, they must be replaced with a matched  quad of power tubes. Tubes all will eventually fail, and must be  replaced. When you need replacement tubes, it's best that you get tubes  that are within the testing results on the packages that the tubes were  originally packed with so SAVE THE TUBE BOXES. Again, when the time  comes, you can contact me and I will help you get the right tubes for  your 10^n.

The Gainmaster tube is a little different story, since  so much rides on it, it is subjected to even more rigorous testing and  only a small percentage of tubes are designated as being good enough  sounding to be Gainmaster tubes, and for this reason, I recommend that  you purchase them directly from me. I sort through hundreds of tubes to  select the best-sounding tubes for the Gainmaster, so you get the great  guitar tone that it was designed to provide. The good news here is that  because of design factors in the Gainmaster, this tube will last a long,  long, long time.


You do NOT need to replace  any of the tubes in the amp or the Gainmaster (such as to use vintage  tubes) because I have already tested these “Unobtanium” tubes in the amp  and Gainmaster, and they do not generally appreciably improve the tone,  and in most cases, are not as good sounding as the hand-selected modern  tubes I designed the amp to work with. Most of the good stuff is gone,  anyway. NOTE: I have the good stuff, and they are not what is in my  personal pair of 10^n amplifiers. My amps sport the same tubes you  received with yours.


You  may decide to try to get different guitar tone using different tubes in  the Gjika Powers of Ten (10^n) amplifier, but be sure to follow the  following guidelines:

EL34 power tubes may be substituted for the KT77 power tubes that the amp comes with.

Do not use other tubes – KT77 or EL34 ONLY.

MATCHED  QUADS ONLY. If one tube blows, it can be replaced, but the replacement  must be carefully selected to go with the remaining tubes of the  original matched quad. It is not recommended to mix and match tubes of  different types, manufacturers, or to randomly select the tubes.

This  amp is a high-current, Class A amp, and requires that the tubes be  optimally selected for this type of circuit. The Gjika 10^n guitar  amplifier works best with tubes that fall into a certain test range.  That's why I recommend that you get replacement tubes from me, or check  with me to make sure you are buying a good testing range for the amp.  Having a spare set is not a bad idea.


The  gold aluminum tube guard on the back of the amp serves the purpose of  protecting your tubes, and the fan that is used to cool this high-power  single-ended Class A amplifier. The tubes get hot, and should not be  placed near fabric such as upholstery or curtains or placed up against a  wall which will cause heat build up.

You will take the tube  guard off to put your power tubes in. The tubes are packed in the right  hand side (from the back) of the amp. You can operate the amp without  the tube guard, but that is inadvisable, so I recommend that you keep  the tube guard installed during all times when not changing tubes or  cleaning dust from the inside of the amp or fan.

It is possible  that the fan may build up dust, pet hair, etc, over time, so do be aware  that you can just shine a flashlight in there once in a while to make  sure everything is tidy inside, as the amp is open in back except for  the tube guard, and things can get in there.

SPEAKER CABLE: Your  Gjika Powers of Ten amplifier comes with a special speaker cable for  connecting your amplifier to a speaker cab. The length is 5' long which  is what I've found to be a good length for most players, but you may  want a longer cord at some point, and you can contact me to get a longer  cord, or to buy additional specific-length cables for use with multiple  cabs. I recommend that you only use my cords with my amps.

It is  also a good policy to always keep the cord ends plugged in the same  direction, so mark the end that goes in the cab and always put that end  in the cab. A zip tie works well for this. If you purchase a cab from me  along with the amp, I will pre-mark the end of the cable with a zip  tie.


The Gainmaster comes ready to go. It has  it's own power cord, and therefore you may experience a ground loop hum,  which will be eliminated by lifting the ground.

The Gainmaster  is an in-line signal-shaping device I designed to work with my amps.  It's main use is to obtain the cranked sound and feel of my amps at any  volume, even at extremely low “bedroom “ levels. Used in this manner,  practicing for long periods of time is less taxing on the ears, and your  relationships with neighbors and housemates, obviously... but if you  are in a position to turn up your Gjika amp loud, then the Gainmaster  can be used to access scorching gain levels with tons of harmonic  goodness. I designed it to work with my amps and I only sell them along  with my amps.

More than likely, most other amps would not be able  to accept the Gainmaster's high signal levels, because their front-end  designs may not be up to the task. So, if you try to use it with other  amps, you are on your own.

You will want to put devices such as  treble-boosters, wah pedals, and Uni-vibes and the like in front of the  Gainmaster. Time-based effects, such as delays and reverbs are placed  between the Gainmaster and your Gjika amp.

The Gainmaster runs on  a single 12AX7 tube and takes a one-amp fuse. Like any other device you  would use in your rig, and depending on your power supply ground  isolation, you would probably do best to lift the ground on the  Gainmaster to avoid ground loop hum.


IMPORTANT:  Make sure the amp is plugged into a cab before turning it on. You will  destroy the amplifier's power transformer if you leave it on without a  speaker hooked up to it, and void your warranty.




Two Raytheon-Style pointer knobs in front:

TONE on left:

VOLUME on right:

EQ switch in the middle of the two knobs:

Input jack on front

Begin  experimenting with your amp's controls at approximately even settings  (Tone and Volume) and start out low on the volume control. This amp is  extremely powerful, be careful.


Power switch on the back:

DOWN is ON position.

UP is OFF position.


There are 3 jacks to plug in speakers to your amp.

One is labeled 16 Ohm

Two are labeled 8 Ohm

Plug in speaker cabs as follows:

One 8 Ohm speaker cab – use either of the 8 Ohm jacks

One 16 Ohm speaker cab – use the 16 Ohm jack

Two 16 Ohm speaker cabs – use the two 8 Ohm jacks

If  you want to use two 8 Ohm speaker cabs, you will need to buy or build a  series box, which is just 3 speaker jacks wired in series. You would  plug both cabs into that box, and run a cable from the box to the one 16  Ohm jack on the amp.


Two  knobs on the Gainmaster control the level and the gain. I will give you  my favorite starting points – I set my level control around 1 o'clock,  this should start you at level to your clean signal or slightly boosted.  I set the gain control around 11 o'clock. These two settings should  give you a good cranked amp tone from bedroom volumes to fairly loud  volumes. For your maiden voyage, try your Gainmaster set this way, along  with the amp's volume and tone settings at 9 o'clock, and the EQ switch  in the down position. I generally leave this switch in the down  position, unless I am turning the amp's volume and tone up past 9  o'clock.

This is just a starting point for you to do your own experimenting.

Your Tubes and Transformers are counting on follow the instructions!

Your Tubes and Transformers are counting on follow the instructions!

Setting up Your Gjika 10^n

Please make sure you have at least a surge protector, but you should have a Variac preferably.  

Voltage for Tube Amps

Highly-tuned amps require a VARIAC for superior performance, and to keep from blowing up your tubes. Please watch this video and follow Bob's detailed instructions to protect your warranty and get the optimal performance from your 10^n. 

Variac vs Step-Down Transformer - Voltages for Guitar Amps

 Variac (autotransformer) or a step-down transformer, depending on your country's voltage - Voltage regulators - Variac? or instead of a Variac, you might choose to use a step-down transformer to get the necessary amp voltage requirement, which critical to the proper use of tube guitar amplifiers - 120V (or close to 120V) to power your electric guitar tube amps is ideal. These guitar amp instructions thoroughly explain  what you need to do to get it. 

These voltages are critical to running your amps.