Tweaking the Bugera V5 Circuit

Discussion in 'Shock Brother's DIY Amps' started by tele_wah_fuzz, Jan 19, 2014.

  1. esteewee

    esteewee TDPRI Member

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    As I've mentioned in the big V5 owners thread, I did the bright cap mod on a V5 Infinium. And undid it.
    The amp does get brighter, but not when the volume is dimed, so I found it not very useful. Also it's hard to dial in a tone when there's effectively three knobs that control the tone.
    The other mods are too hard for me to do on the Infinium, since the components are so tiny.

    A speaker swap did do wonders though, with a Jensen C8R the amp is bright enough for me. Although a bit harsh when overdriven. Maybe it will get smoother when the speaker is broken in.
    I also like the Joyo/Harley Benton American Sound in combination with this amp.
     
  2. BadBen

    BadBen TDPRI Member

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    Funny you mentioned the Joyo American Sound. I've started running a Joyo AC Tone in front of mine. Definitely a cheap, easy way to brighten it up.
     
  3. granny

    granny TDPRI Member

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    Hi guys, i bought an (barely) used old version of Bugera V5 and did the mods and now I do experience from time to time some kind of low volume static that comes and goes, much like when you're tunning an old radio. It seems it's not related to the guitar input because it's there even if I unplug the guitar cable. If I work around the volume/gain knobs it doesn't always feel related - sometimes goes lower sometimes does not.

    Am electrician told me that C22 (the 47pf capacitor that i removed) it's way too small to influence anything and usualy it's there at the begging of input signal in order to clean the static.

    Do any of you experience this issue? Thank you, George.
     
  4. Fiat_cc

    Fiat_cc Tele-Holic

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    I had an amp that started doing similar things. Eventually figured out my power tubes were getting old. Old filter caps can also create noise...

    When my tubes started going bad it was like a wind in the trees kind of sound (could also be described as AM radio tuning sound). It started out as a very intermittent problem, and got more and more constant with further use over a 6 month period, until it was driving me nuts.

    Filter caps in my experience tend to be a more humming type sound, although I've heard crackling sounds related to leaky caps too.
     
    Last edited: Feb 27, 2017
  5. granny

    granny TDPRI Member

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    Thanks for your feedback. I'm waiting as well for some replacement tubes and will report back. Meanwhile I mounted the C22 back to it's place but the problem still remains. I will check the big caps as well but considering that the amp has very little use i doubt any of them are faulty. Most likely I figure it's one of the tubes..thanks again.


     
  6. Fiat_cc

    Fiat_cc Tele-Holic

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    As far as I know, electrolytic caps are more likely to go south through lack of use. They dry out when not used regularly.
    A tube is a very real possibility though.
     
  7. Guitargod-NOT

    Guitargod-NOT NEW MEMBER!

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    Can someone please help me. I took the chassis out of my bug v5 to add bright caps across tone and vol. I was told I would have to turn the PCB upside down to do this. Does this mean I have to disconnect the gain,tone,vol n reverb? as I can't get it out. I was also told to remove c22 and c 16 please help me
     
  8. Guitargod-NOT

    Guitargod-NOT NEW MEMBER!

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    Can anyone help me. How do I get underneath the board to do the bright cap mod. Also I can't find c22 and 13. Please help. 1488287783008-1778408055.jpg 1488287783008-1778408055.jpg
     

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  9. esteewee

    esteewee TDPRI Member

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    no offence, but if you can't figure out how to remove the pcb (just take everything from the front panel off), maybe you shouldn't mess around in a tube amp. It's pretty dangerous stuff.

    Anyway, you seem to have a V5 infinium, which is different than the first version. So C22 may not be called C22 on your board. Another big difference is that the infinium has an SMD board, which has very small components, it's very hard to mod such a board.

    I have an Infinium as well and I'm really not gonna try to mess around with those tiny resistors. The volume and gain pot mods are fairly easy though.
     
  10. granny

    granny TDPRI Member

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    I replaced the EL84 and the static sound is gone. Thank you!
     
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  11. Tom Freeman

    Tom Freeman TDPRI Member

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    So I did a few mods mentioned in this thread last summer, and it definitely improved the sound of the amp. However, I've been really getting into building my own pedals and modding amps lately, and I thought I'd revisit the bugera. I recently made some changes to an epiphone valve jr, and stumbled upon this:

    http://ashbass.com/AshBassGuitar/vjr/xls_194___octal_schem.pdf

    After looking at the schematics for the two amps, I realized that many of the mods here could be applied to the V5 as well. I'll have to check my notes again to see exactly what I did, but I chose to "marshallize" it as I already get all the fender tones I need from my blues jr. Anyways, I'm sure I'll open it up and tweak it even more later, but I'm very impressed. Great crunch and lead tones in a small package. If I had another v5, I'd also try doing some of the vox mods.

    I'll update if I see the need to do so, but here's as much as I can remember changing:

    C22-remove
    C14-raise to 470p
    C13, C9 - remove (could reinstall them on a switch for a bass cut/boost control if desired)
    R22 - jumper (affects input gain - could experiment using a dpdt switch between stock 22k and lower values)
    R20, R13 - lower to 820 ohms (I put in 1k each, but may lower it down to 820 - doing this adds more crunch apparently, while the stock value is supposed to be clean and neutral. Higher than 1.8k apparently adds distortion, but I haven't experimented with that yet)
    C15, C10 - Change to 22n
    And of course, the tried and true: New tubes and upgrade the speaker (I put in a Celestion 8-15)

    Some things I want to try, and hopefully will get around to doing, include:

    Altering the stock values of R26 and R24
    Increasing C1 and C4
    SLIGHTLY lowering R8
    Putting some kind of hi cut fliter around R25 or the reverb pot (for those who find the digital reverb too bright)

    These last few ideas are just that - ideas - so try them at your own risk. However, I can vouch for the list of mods that I've tried already, and it should be easy enough to play around with any component values if you want to tweak the sound more to your taste.
     
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  12. tombob

    tombob Tele-Holic

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    I'm starting on a VHT Special 6 now but I would like to pick up one of these V5s after I get through with my VHT. I've seen these for $120 which is a steal for a tube amp and the demos I've listened to don't sound bad to start with. The reverb isn't the best but for lower volume, sit around the living room jams a little reverb goes a long ways to fill out your tone.
    I'm thinking I'd either build a new baffle and put a 10 in speaker in (unless it so small it sounds too "boxy" even with a good 10" speaker) or build a head cab for it. A 1x10 combo would be handier but I have a feeling a head cab and 1x10 cab might be the way to go.
    Seeing all the great mods on here makes me want to get one of these even more now. The one other thing I'm thinking about trying in one is one of those el84 to 6v6 socket adapters, just to see what difference it would make.
     

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  13. James64

    James64 TDPRI Member

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    Crontron, if you are still around, can you give us some more feedback on the R26 resistance change that you made? That change interests me a lot! Is it really noticeable? In other words, if you played a few riffs or chords at 40k, and then switched it to 22k, is it easy to tell. A noticeable change to increase the bass slightly and scoop the mids sounds like the ticket for me

    I've done the following:
    1) Installed a Jensen C8R. Made a HUGE difference and I highly recommend it! I had tried a Jensen Mod 8-20, that speaker made a difference but it wasn't much and not worth it to me.
    2) Swapped the tubes. I tried a JJ 5751 but prefer the EH 12AY7. I'm also using a JJ EL84. I can tell that the amp sounds smoother and richer, but I wouldn't say that the tubes made a significant change in brightness.
    3) Put a 220pf cap across C14. I could hear the difference.
    4) Put a 220pf cap across R24. It seemed to make a smaller difference than doubling the C14 capacitance.

    Love the amp now.

    I haven't done the "bright cap" mods across the gain and volume pots because they are ineffective if you dime either pot. Though maybe I should.

    Also, if anyone has done this changes one at a time, does the removal of C13 make a noticeable difference? Maybe that's my next move.

    Has anyone tried putting a cap across R14 or R15?

    Thanks to everyone for the help!
     
  14. esteewee

    esteewee TDPRI Member

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    So, after 9 months of owning the little bug, I'd like to share my experiences. I was somewhat underwhelmed at the beginning but I'm starting to love the amp more and more.
    By the way, I've got the infinium version which is hard to tweak because of the small components.

    -a speaker swap does wonders, cause the stock turbosound one is very dark. My amp has got the Jensen C8R. I found it a bit harsh at the beginning but it sounds pretty good now. Apparently the P8R and the Eminence 820 sound even better, I don't know, haven't tried them.
    - the bright cap mods don't work for me, cause they only work at low volumes, when you dime it the effect is gone.
    -I get the best sound when I dime the volume knob and use the gain to set the level. This is a pretty important one to get a good tone.
    -I'm starting to like the stock reverb more and more. This may be a side effect of using the gain and volume knobs like I described before because I was a little underwhelmed by it at the start.
    -I've tried lots of overdrive pedals. (There's lots of pedals I didn't try of course). When I tried a Tube Screamer, I fell in love with the Bug. In fact, the Tube Screamer is the reason why I wanted to post this. It just works so well with this amp.
    - for clean sounds, I've got this €30 harley benton American Sound that I like. You can shape the mids and add a little edge which is pretty cool.

    So there. I went from underwhelmed to loving it. And I suspect the gain/volume played a big part. Also, speaker and tube screamer. Enjoy!
     
  15. jackaugust

    jackaugust NEW MEMBER!

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    Totally easy Infinium mod you will not regret if you're a Tele or Strat player - forget all the aforementioned changes except one: adding a 220pf cap across the middle lugs of the gain pot.

    After you do it you will hold your hands up and high five yourself because you will have opened up your amp to the most juicy and heavenly blues tones you ever heard from a 5 watt amp. Enjoy, my brothers.
     
  16. James64

    James64 TDPRI Member

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    Jack, but isn't there no effect if the gain is on 10? From what I am hearing, the effect should be bigger with low gain, and diminish as you turn the gain up? Also, do you feel that it brightened it up on the high end (sparkly) without effecting the high mids?
     
  17. scout2112

    scout2112 Tele-Holic

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    Here's a summary of the mods that I've tried (as discussed in this forum):

    Remove C22.
    Remove C13.
    Add a 220pF cap parallel to R24.
    Replace speaker with Jensen C8R.
    replace tube w/ JJ EL84 (much clearer, 'raspy' distortion is gone)
    replace tube w/ 12AY7 (much cleaner, little to no overdrive)
    Add a a 220pF cap across both the gain pot and volume pot (bright cap mod.)

    Of the above, I found that with ALL of the mods it was far to bright and tinny (playing with Strat). I ended up going back in and removing the bright cap mod and leaving everything else. Now it sounds just great. It's still a wee bit too bright in certain upper midrange frequencies, but am able to easily fix that with a minimal EQ adjustment. Overall very happy with the tweaking.
     
  18. Guy Lorshbaugh

    Guy Lorshbaugh TDPRI Member

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    I know everyone's this, but I gotta thank you for sharing! I already liked this amp, now it's a MONSTER!
     
  19. TurkeyTuggin

    TurkeyTuggin TDPRI Member

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    I just ordered the same speaker and some JJ Tubes. ECC83 and an EL84. Hoping for good results.
     
  20. dragonfly66

    dragonfly66 Friend of Leo's

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    I was looking at the Jensen C8R speaker swap, but going to try the cap on the gain pot first. I like the V5 Infinium right now, but it is sort of boomy/bassy. I play with P90s mostly.
     
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