I bought a Bugera V5 last week. Playing through an eq pedal I was getting some really good sounds out of it. However, by itself, it's just way too dark and muddy. I did some searches on the internet to see if anyone had some mods for this little combo. There is a lot of people changing the speaker but nothing much regarding the circuit. I did find one mod (here at tdpri) with a bright cap across the volume pot; this helps quite a bit and I used this as a starting point. This weekend I spent some time with it and I think I have it where I want it. I'm not an amp tech but rather a hobbyist. I attached a pdf of the schematic and the mods I have done. Its cropped to maintain resolution to post it here but you can find the full one if you search for it on google. There are plenty of highs now and it really growls when overdriven. I've gotten it sounding so good, it's earned itself a few Sozo caps Here is what I have currently done to it: Remove C22 - this is small 47pf cap that dumps some high end to ground before the signal even reaches the pre-amp tube. I'm not sure why this is there but it doesn't help. It can be easily cut off the board. No de-soldering required. Remove C13 - This is a common mod found in the Epiphone Valve Jr. called the jp1 mod. Its a jumper wire to a electrolytic cap and when cut, it removes the electrolytic cap from the circuit. With it removed helps brighten the tone as well as increase the gain. On the Bugera V5, it will need to be de-soldered and removed. Add a bright cap across both the gain pot and volume pot. This is the major problem causing the muddiness. Many amps have these and it beyond me as to why the circuit designers left these caps off. Anytime there is a signal crossing a 1m pot, and the pot is less then maxed, its going to attenuate those higher frequencies. Installing a small cap across the lugs of the pot fixes that problem. In this case on the Bugera V5, you need to flip the circuit board upside down to add the caps to the two center lugs of the pots. The two outer lugs are ground. I'm using 220pf for both the gain and volume. Depending on how bright you want it to sound is up to you. Anything from 100pf - 500pf will be a good choice. Higher the value of cap, the brighter the tone. Keep in mind the more the pot is turned up, the less influence the bright cap will have. With the pot maxed, the cap is obsolete and out of the circuit. Add another small cap parallel to R24. This cap lets some highs pass around the 470k resistor. There is of course C14 which is 220pf that feeds into the tone control pot that does the same thing. But the cap fixed across R24 will allow you back off the tone control on the amp and still retain clarity. Again, I used a another 220pf cap. This will need to "piggy-back" R24, so solder it directly to the 470k resistor. By now the Bugera should be sounding really good. With the extra caps in place there will be lots of clarity and more humbucker friendly. One last mod I made for additional brightness was to swap out C14 (a 220pf cap) for a 470pf cap. This is the cap that feeds into the tone control pot and allows you dial in your those highs. I wanted this extra treble when using humbuckers with the amp's gain and volume set to ten. Finally I installed a negative feedback loop. My goal here was to keep that raw sound but tidy it up a bit. So I settled on a 2.2m resistor. See the attachment for its placement. If you want to reduce the gain and give the amp a cleaner sound, reduce the resistor to something like 22k. That's what I have done so far and I'm really happy with how the amp sounds now. I can plug my strat into it and get bright surf tones as well as the ZZ Top grind with humbuckers. The next mod I suppose will be a speaker upgrade. I hope this helps anyone with a Bugera V5 who is up to this. There are not many mods for it so I thought I would share. Remember to drain the electrolytic capacitors of current before attempting this!