Tweaking the Bugera V5 Circuit

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

  1. mpdunne79

    mpdunne79 TDPRI Member

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    Well I found my problem... Im an idiot. Lol.

    It usually helps if you by the right size capacitors. I had originally purchased 220 uf by mistake.

    Replaced the capacitors with 220 pf and the results are nothing short of amazing. I have the tone control on 5 and it sounds great. It made the tone control on my guitar come alive. It is actually useful now! When I'm playing coil tapped on my guitar (Ibanez AR325) it's almost too "trebley" and I'm using the tone control to roll off some of those highs. The humbuckers sound so much better too.

    It really wasn't difficult to add the capacitors or remove the other 2 caps. I highly recommend this mod if you're unsatisfied with the dark tone of the amp. However, use a volt meter to verify the amp is dead and properly discharge of any stored voltage.
     
  2. dmurado

    dmurado TDPRI Member

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    Phono Input as AUX input in V5

    Hi.
    Anyone has tried this before?
    I was thinking in implement this input just before the final stage in order to amplify the signal without the gain and tones controls modifying the input signal....I'm not sure about the values of the RC filter and the bese place to insert this input in the electrónic circuit
    Any help will be apreciated
     
  3. nymtber

    nymtber TDPRI Member

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    I'm new here, but I did (most) of this mod tonight to my V5. I removed C22, added 220pF across gain and volume pots, and added a 220pF cap across R24. I did not remove C13, change C14 or add a negative feedback loop.

    I have a Vintage NOS RCA 12AX7 in the preamp and a JJ EL84, both added and played before the modding.

    Doing only what I did completely changed this amp! I went from a very muddy, dark amp (that still had great tube tone) to a nice bright amp with oodles of tone and pretty good crunch. I can turn Tone down to 6 on the amp, and its still plenty bright! I have a Squier Affinity BSB tele with GFS Pro pickups, and never before has this guitar through this amp sounded so sweet. It sounds like a Tele again!

    So, do yourself a favor and do the upgrade. The components cost much less than $5, a soldering kit will set you back maybe $30 (I bought my soldering kit from RS 13+ years ago), and I used a "free" multimeter from Harbor Freight. It works...not fancy and not a Fluke, but it works. Not quite going to get Fender clean, but its plenty bright for me!

    Thank you SO much, tele_wah_fuzz for posting all the info! :)
     
  4. mvanstee

    mvanstee TDPRI Member

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    I don't think the infinium has the same problems. I would get the infinium and be done with it.
     
  5. Tommygun1

    Tommygun1 NEW MEMBER!

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    Tele-Wah-Fuzz, what great set of mods to this little beast. Like everyone else, I found the amp to be a bit muddy out of the box. The mods mentioned did brighten my sound a bit, but I was still wanting a more Fender sound out of it. I went with a 3 way switch and 2 different size caps for the bright cap across the volume and gain pots, and it's cool, but of course diminishes when the volume is cranked up. In my search for a bit better tone control overall, I did the following and found it to meet my needs a little bit better:

    1) lift the leg of R26 (22k) from the board where it connects to the tone pot.
    2) solder 2 10k resistors is series, and insert them from the land R26 was connected to, and to the raised leg of R26
    3) using a SPDT switch with center off, connect the center pole to the land on the board where you lifted R26. Connect one of the other poles (your choice) to the junction in the middle of the 2 series 10k resistors. Connect the other pole to the junction of the OTHER 10k and R26.

    What you'll have is a 3 position bright that's not affected by your volume settings, and with a slight boost/drop of mids depending on switch position. With the switch thrown in one position, you get the stock sound by shorting the 2 10k's straight to R26. In the other thrown position, you'll have what I call a 1/2 bright sound with a slight boost in mids by shorting one of the 10k's out. In the center off position, you'll get a way Fenderish scooped mids sound by having all 3 (42k total) resistors in line. With Strats, I find I can run my tone control around 2! Way brighter than stock. With HB guitars, I run the tone around 3 or 4 and keep the treble end much more usable. I suppose if you played with the value of C12 (4.7n), you could vary things some, but its a PITA, and I didn't see the need to go through all that.

    If anyone needs schematics, I can scan them and post, or just PM me.
     
  6. slickman

    slickman TDPRI Member

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    Hey Guys - I did the bright cap mod and added 100 pF caps to the volume and gain pots. Wow, unreal change. The amp sounds amazing now.

    I guess I am a little spooked about ripping out C22. Can someone let me know the benefit of taking it out in more detail? I think it sounds great now and has plenty of highs. So, I would only want to change it if it adds gain or volume.
     
    Last edited: Feb 20, 2015
  7. slickman

    slickman TDPRI Member

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    Never mind guys. Rainy day so I opened it up and took out C22. It does have a slight improvement and rounds out the tone a little.

    Thanks for the post. Great mod.
     
  8. agquake

    agquake NEW MEMBER!

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    I'm waiting on a back order of the V5 Infinum. Would anyone happen to know if the same mods will be necessary on this version (I saw someone post that they will not)? I've played the regular V5 and agree regarding the darkness. Thanks. :)
     
  9. soulman969

    soulman969 Telefied Ad Free Member

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    I'd suggest playing it for a bit and making that call yourself after you've broken it and the speaker in. There will always be some sonic changes as that takes place.

    From what I understand there aren't any changes that have been made in the tone stack but how reliable that information is I can't say for certain never having played the newer version.

    It seems that the major changes are using a different speaker and of course the "Tube Life Multiplier Technology" neither of which I expect to be major game changers for this amp.
     
  10. slickman

    slickman TDPRI Member

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    I have two of these now modded (run in stereo). Both with the Eminence Patriot 8" speakers and new tubes. These now sound ridiculously good. I definitely could gig with this setup and a distortion or OD pedal.

    One question for the group: One of my amps seems to be getting some interference from somewhere that comes and goes. It's not picking up a radio station but just curious if anyone else is experiencing that. There is a small hum in both of the amps (not bad) but the one seems to have a hiss and pop. My hunch is I have a bad ground somewhere or the tube is picking up something? Any help would be appreciated.

    P.S. the amp did this before the mod as well.
     
  11. slickman

    slickman TDPRI Member

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    And just as last time I answered my own question. You guys are great :)

    It was the power tube: Mullard that has gone south. I put in a new Tung Sol and she is quiet again.
     
  12. James64

    James64 TDPRI Member

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    Jensen C8R in Bugera V5 farts out ...

    I'm very happy with my decision to put a new 220 pf capacitor in parallel to the existing 220 pf capacitor in the Tone control part of the circuit. I tried a Bugera 12" Infinium (Turbo Sound) speaker cabinet, and it sounded awful! That thing sounded like a cheap toy. The stock 12" speaker in my Bugera V22 is so much better.

    Has anyone had a problem with the Jensen C8R 25 watt 4 ohm speaker???

    I finally decided to buy brand new C8R and put in my Bugera V5 5 watt amp. The Jensen gives me a beautiful VOX tone and it really made a huge difference in the overall frequency response range of the amp. It really did brightened it up a lot. I can now easily tell the difference between positions 2 and 4 of a strat.

    But, with a JJ 12AX7 installed (including tube dampening rings) and the tone on 7, I can't turn the gain and volume up past about 5.5 (together) without the speaker farting out (I use teles and strats). If the volume is on 10, I can't turn the gain past 3.5 without it farting. If the gain is up to 7, I can't turn the volume past 3 without it farting. Therefore, I can't really get much breakup. This happens whether the Jensen is installed in the amp or not.

    Is this normal? Am I asking too much of this amp/speaker? Does it need to be "broken in"?

    The original speaker (unique but a limited dark tone) would fart out only slightly (and I can only hear it if the speaker is out of the amp) when the gain and volume are both turned up past 8 (which I don't normally do).

    I put a 6.5" Jensen Mod 4 ohm 15 watt speaker in my little Fender Champion 5 watt amp (which has thinner grill cloth installed), and it doesn't fart out even with the volume on 10 using the High input.

    For the record, I bought the Jensen mail-order through MF, and they won't deal with it. At the moment, my only option is to ship it to the Jensen distribution center for testing.

    Thanks ahead of time!
     
    Last edited: Feb 25, 2015
  13. HelgeOlsen

    HelgeOlsen TDPRI Member

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    Try putting a 5751 in there. I have the C8R in mine along with a vintage 5751 and a JJ EL84. I don't remember the brand of the 5751 but it sure is an improvement from any 12AX7 I have had in there. Better range on the dials before the distortion takes over, brightened up enough for me as long as I stay away from the neck humbucker on my LP clone. If I want more dirt, I can put my compressor in front and push the volume from there. Some lovely tones are to be had with some tweaking :cool:
     
  14. James64

    James64 TDPRI Member

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    Thanks very much for the suggestion on trying the 5751 (70%)!

    Instead of my JJ 12AX7 (100%), I've tried an EH 12AY7 (45%). With the 12AY7, I have to turn the amp way up to get the little bit of overdrive break-up that I like. The 12AY7 really quieted down the amp (while not playing), and I'm happy with that tube. So anyone who isn't happy with the sound of the transformer, should try a 12AY7 or a 5751. I am planning on buying a 5751 for sure.

    Thing is, the Jensen C8R could not handle any overdrive/break up at all, whether the 12AX7, the 12AY7 or a peddle created it. I think it should be able to handle it! I'm very disappointed.

    The cheap stock speaker could handle break up. A lot of us use 5 watt amps to achieve the break up without going deaf and angering the neighbors. If all I wanted was clean, I'd fire up my Bugera V22 (which is awesome for clean tones).

    I brought the amp and the Jensen to a local amp repair guy. He used a tone generator, his guitar and one of his speakers, and felt that the Jensen wasn't performing like it should.

    I sent the Jensen back to factory to have them test it. Could be a waste of money, but I wanted to understand it.

    I put the original stock speaker back in. With an equalizer peddle, I can get pretty close to the Jensen anyway.

    For me, adding the extra capacitor in parallel with the existing capacitor made the best and cheapest difference. It really opens up the usage of the volume, gain and tone knobs. Second to that, choosing a 5751 or a 12AY7 will also to the same. Third, would be to try a different speaker. But in that case, I guess mileage will vary.

    By the way, I thought about a 10" speaker. It looks like you can simply remove that metal bracket (I'm not sure of its purpose), and then a 10" would fit. But, I think you probably need to make a new baffle board (changing the good looking amp) because the existing one would block some of the sound (and, I don't know if the air pressure would bounce back at the speaker and alter the sound). I wonder if anyone has tried a 10", and what they did to mount it.
     
  15. xtech

    xtech NEW MEMBER!

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    Hi,

    this thread has been very interesting. Kudos for the people involved and the insights and experience they brought.

    I have one doubt, before buying the caps: what voltage spec they should be? You only speak about the the capacitance, but what about their voltage?
     
  16. soulman969

    soulman969 Telefied Ad Free Member

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    I believe the stock speaker is intended to sound somewhat like a Jensen but neither are highly efficient speakers. The Emi 820h will perform far better in this amp and has very moderate break up characteristics. It won't fart out on you I promise you that.

    You can fit a 10" in there but it's crowded. One of our other members has done just that but it does require some changes to the amp cosmetically as well as making a new baffle. If you search the Bugera v5 Owners Club thread you'll find the posts where he shows how he did it. The posters name is harleysr.
     
  17. dronester1

    dronester1 TDPRI Member

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    I may attempt some or all of these mods as well, and I'll definitely give each careful consideration before I make the decision. I've done the tubes and also put in a Jensen speaker, and the amp's better, but still not quite "there"... Thanks for posting!!
     
  18. waldru

    waldru TDPRI Member

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    My idea is to try the bright caps first with non permanent wires and listen if the result satisfies me, I solder it permanently. Please report of your experiences with this mods.
     
  19. jupiteer

    jupiteer NEW MEMBER!

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    Hi - long time reader but first time poster here.

    First, I was experimenting with tube swaps which improved the sound slightly. Then I went for the Eminence Patriot 820H speaker (which is called "the chemp" within this forum) as an replacement for the stock Bugera speaker - and wow, this little thing completely changed. The boxy sound went away, and it got way louder (due to better speaker efficiency). It's a mod I can highly recommend, although the chemp is a little bit expensive here in Germany but it's worth every Euro I paid for it.

    Still curious, I tried some of the mods described by tele_wah_fuzz. In detail, I added bright caps (220 pF) to both the gain and the volume pot, removed C22, removed C13, and added a parallel cap (220 pF) to R24.

    Now, this little thing has turned into one of my best sounding amps. Playing bluesy stuff or classic rock style really sounds very impressive, round and tight. It's fun to play while it produces a vintage-like "tone and feel".

    In order to answer your question, waldru, try the mods I did and you won't be disappointed. Be careful when opening the chassis because of high voltages in there even after unplugging.

    Thanks to all people investigating into the "Bug" and posting the mods - I've learned a lot and I'm very happy having found this forum.
     
  20. Magnetoman

    Magnetoman TDPRI Member

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    Great thread! Thanks to all you guys modding and posting I have tried most of the main mods one by one over the 4 years I've owed it.

    Basically done everything but the neg feedback. I did add 2 small toggles to front: one to switch between 2 different bright caps(220pf/470pf) on the gain/volume and a switch to enable the bright mod overall. I have a couple guitars that like the browner tone the stock delivered. So this gives me 3 settings all in all.

    I have a Russian NOS Military 6N14N-EB 7189A / EL84M for the power tube and a Sylvania 12AV7 in the preamp socket both were packed in the 50's according to boxes. I never have really used the stock speaker I run into 2x12 cabinet with 2 Fender/Jensens dated 1965 and I love this amp! I like the AV7 in there I can get a little more use of the gain knob and seems to get along with pedals better. I have tried varieties of AX7''s and AU7's .

    Have any of you guys ever pulled the reverb unit to see if a effects loop could be added? 4 contact connector makes me wonder if that isn't really what that connection is.

    I am neither brave enough or have the confidence that it looks that way in the schematic to me lol But that would sure round this amp out to have a loop.
     
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