First question, do you have the user manual for the amp? That may be helpful in dialing in the amp.
If the amp does not have the sound, it could be related to a few things. Mostly with the preamp tubes. If the V3 or V4 tubes have been used for some time, the tone will change.
Also if this was a used amp, it could be due for some cleaning. You need to remove the chassis from the head shell to do this. It is also helpful if you have access to compressed air.
things you will need:
Acetone, in a can or even nail polish remover will work.
Small amount of silicon oil
Q-tips (small cotton swabs on a paper stick).
Compressed air from an air compressor or from a can of air used for cleaning computers.
After you remove the chassis, placed it with the tubes facing up onto a flat surface, Remove all of the tube shields, followed by the preamp tubes. Keep them sorted in the position you removed them.
Look at the tube shields first, it should have a black rubber o-ring. It if is silver in color, that is aluminum dust, you can clean that off with some oil on a paper towel or cloth. WD-40 or any silicon based oil will work. Remove the o-ring to clean them and place them back on to the shields.
The next thing to look at is the area around each preamp tube socket. If you see any metallic dust on the PCB around the socket, that is why the bass is not present, I had this issue with the Roadster not too long ago.
Take a Q-tip and saturate the one end in acetone. You will need to collect as much of the aluminum dust around the tube socket as possible. No rubbing needed, just press the Q-tip down onto the area, if you can move it ok but try not to strip the cotton on the pins and leads of the components poking through the PCB.
Do this around all of the preamp sockets.
When you have cleaned up as much as you can using the Q-tips, it is time to use compressed air.
The Best is from an air compressor and a spray nozzle, even an air brush would work if it is small enough. The trick is to disperse the left over dust with the force of the air. Try to do this with the chassis on its side. Compressed air in a can may result in liquid coming out that will frost up on the PCB surface, it should evaporate. Try not to pool too much fluids on the Board surface. Why I recommend compressed are from a compressor but it will do the trick. Do not worry about the liquid from the compressed air can, it is not conductive. I have used that to chill active parts while they were operating and conducting current. However, the trick is to disperse as much of the dust that has accumulated from many tube changes or removal of the tube shields. Getting as much up with an acetone dipped Q-tip will help remove most of it. Do not use alcohol as that will not fully evaporate and may leave behind a residue.
Put the preamp tube back in and see if that fixed the issue. If not, it may be due for some new preamp tubes.
Had similar issue with the Royal Atlantic too, That trick fixed the problem with lack of tone or gain.
