Bugera V5 Schematic?

[cebreez]

Hi... Im Terry..... Im new to this forum. I was wondering if anyone has the schematics to the new Bugera V5 amplifier. Just need it for some comparative studies. Im modding a Crate V5 and want to know how the circuits compare seeing as how the Bugera has a far better sound.

Thanks,

Terry

[cebreez]

Been looking all over the internet for the Bugera V5 schematics and found nothing. Seems to be a closely guarded secret. If the price for them was just a little cheaper I would just pick one up and study the board myself. Have seen one picture of the circuit board online.

[cebreez]

Okay let me make this easier. Can someone point me to some good input circuits for guitar amps... tube or solid state. I know just enough about electronics to be scary. All of the tube amplifiers I've seen are basically the same animal. More power= more tubes= more bias circuitry= more tone control circuitry... and so on. What im trying to figure out is the best input circuitry to stoke the fire in the belly of the beast. Eventually what I want is a fantastic little practice tube amp that wont cost $1000 dollars or even $500 for that matter.

[tunghaichuan]

Okay let me make this easier. Can someone point me to some good input circuits for guitar amps... tube or solid state. I know just enough about electronics to be scary. All of the tube amplifiers I've seen are basically the same animal. More power= more tubes= more bias circuitry= more tone control circuitry... and so on. What im trying to figure out is the best input circuitry to stoke the fire in the belly of the beast. Eventually what I want is a fantastic little practice tube amp that wont cost $1000 dollars or even $500 for that matter.

I'm not sure what you mean by input circuits. Do you mean preamp circuits?

The Bugera V5 is a fairly simple amp. One 12AX7 preamp tube and one EL84 power tube. In this regard it is probably similar to the Valve Junior or Blackheart Little Giant.

It has reverb built in, but I bet it is solid state driven as there aren't enough preamp tubes for tube driven reverb. It also has an attenuator to get crunch at lower levels. The reverb and attenuator add complexity.

My 'net research showed that Behringer is pretty tight with their schematics.

What exactly are you trying to achieve by rebuilding the Crate amp? High gain? OD at lower volume levels?

[cebreez]

Fuller more rounded tone (more bottom and top end) and better headroom. What makes the Bugera V5 sound so much better than the Crate V5? The Crate V5 has an op-amp in front of the 12AX7 preamp tube I assume for conditioning the incoming signal but it also contains the tone circuit which sucks. I like the op-amp being there because I can work around it while leaving the tube portion of the circuit pretty much intact. I hope I'm saying that right.

[tunghaichuan]

Fuller more rounded tone (more bottom and top end) and better headroom. What makes the Bugera V5 sound so much better than the Crate V5? The Crate V5 has an op-amp in front of the 12AX7 preamp tube I assume for conditioning the incoming signal but it also contains the tone circuit which sucks. I like the op-amp being there because I can work around it while leaving the tube portion of the circuit pretty much intact. I hope I'm saying that right.

The op amp is for preamp gain. It takes the place of a 12AX7. You might try upgrading the speaker, but that might be a tall order with a 10" speaker. I haven't heard a single ten that I've liked. They tend to be bright and lacking in bottom end, especially in small cabinets.

Part of the problem is the EL84 tube. They tend to be bright, even a tad shrill in single ended circuits. They also are very sensitive. A single cascaded 12AX7 preamp tube puts out more than enough signal to drive the EL84 to full power. That is why there are voltage divider resistors in the Valve Junior. The Blackheart Little Giant gets around this by suing a three band EQ that eats up a lot of the signal.

Because the amp is PCB based, without a lot of experience, it can be hard to physically modify the amp. So You're stuck with component values changes to the circuit.

You might try a lower gain tube swap for the 12AX7. A 5751 or a 12AY7/6072 are both similar to 12AX7s but lower gain. Other types are lower gain, like the 12AT7 and 12AU7, but they're really not in the 12AX7 family. But you could try them to see if you like the tone, however.

Hopefully, Jim P. will weigh in. He is the man when it comes to Crate V5 mods.

[jim p]

On getting a Bugera schematic Bugera is Behringer and they do not send out schematics. The Bugera does have solid state reverb I traced out the amp and posted a schematic over at Sewatt once upon a time (bug era). The speaker in the Bugera and the Crate are both not great the Crate is real bad the Bugera is dark. For a 10 inch you can consider an Eminance Legend 10516 which is 16 ohms that is what the output transformer in the Crate is really wound for or look at Weber speakers. For Crate schematics Crate will e mail a PDF to you no problem. As far as tone, op amps in the front end lead to a cold sound to me so I would get rid of it. The op amp is used as the volume control in the amplifier and to give a treble boost to work with the tone control located between the two triodes in the preamp section. If you remove the op amp to regain the brightness for the tone control you can use a 470nf cap for the cathode bypass of the input stage triode. There is a thread on the Crate over at Sewatt and Sewatt is a good site to go to relative to amp building and mods.

[cebreez]

Thanks jim p. You are the man!! But Im still toying with keeping the op-amp and I struggle with the technical ability to explain why. I am expecting a pcb in the mail anyday now for the "Professor Tweed". Are you familiar with the circuit? Its featured at runoffgroove.com. Granted it uses transistor instead of op-amp but is similar to what I am trying to accomplish. My point is to let the 12ax7(or 12at7) and the EL84 act as nothing more than the power amp and completely change the op-amp circuit to function as a true pre-amp controlling the gain and drive and eq but with much more finesse than the existing circuit. Except to swap out the tubes, (probably with Electroharmonix), I would like to do as little as possible to the tube section. I will definitely check back over at Sewatt. I didn't see the thread the last time I was there. Thanks again jim p.