Rivera Fender Concert mods

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by doc, Feb 18, 2005.

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  1. mike.mcglone

    mike.mcglone Member

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    Re. Hot transformer ... I beleive the transformer getting hot represents a fault, mine did get hot until I serviced it now it just gets warm.
     
  2. Bigbud

    Bigbud Member

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    Gentlemen: I've come into possession of a Fender Concert (Rivera era) Amp, 12" speaker. The first thing I did was change the speaker - I put in a Jensen Mod 12-70, a definite improvement over the stock item.

    While I'm pleased with the clean tone on the first channel, the second channel is disappointing. I'm appealing to the collective wisdom on this board to point me in the right direction. I'm looking for Fender clean on channel 1 and Marshall grit on channel 2. Any ideas? I'm not an amp tech and I would have the work done by a competent tech.

    I'm also contemplating switching from 6L6 tubes to KT-77 tubes.

    Cheers!
     
  3. epluribus

    epluribus Member

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    Hey Bigbud, welcome aboard!

    Hoo, a Fender/Rivera Concert, what a great amp! The speaker is definitely a good idea, but before you mod many other things, really take some time to get to know the amp. The Rivera channel gives you tons of control over gain structure at so many points between gain stages. Super-versatile, but it's easy to overdo. Man, there's all sorts of goods in that #2 channel, clean and driven. Oh yeah, and get to know the mid control and the mid-boost too, lotsa turf there.

    At this point, do a search for the Deluxe Reverb II over about the last year to eighteen months and you'll find all sorts of great stuff about dialing these things in. (I have a DRII.) The biggest caveat here is that these weren't generally designed to have low end that goes down into the basement--they're supposed to get wooly below bottom A, IMHO. If you "fix" that, you may find you miss it. (I did.)

    But for a quick start before The Search--don't twist all the knobs at once, you don't have enough power. It'll get muddy and harsh. On a DR II (I forget what the Concert has, but it's the same idea.) if you crank Volume, Gain, Master Volume and Bass all at once, it's an ugly chainsaw of an amp for sure. But give any one of those some breathing room and the whole thing settles down significantly, even while still being heavily saturated. With that in mind, generally I start with a clean tone about where I want it, then get the power section cookin' the way I want with the MV, and dial in the preamp and tweak EQ after that. You'll end up with better balance in the workload of each gain stage, and you'll be surprised how low the dials are actually set even though the amp is crankin' pretty good.

    BTW, though the DR II can do an okay knockoff of hi-gain sound, it really isn't cut out for serious hi-gain. I like it tons for blues, country, old-school hard rock, and those terrific cleans on Ch 2, but EVH is pushing it.

    --Ray
     
  4. Bigbud

    Bigbud Member

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    Ray, thanks for the advice. I will take the time to put the amp through its paces.

    Steve
     
  5. Fuchsaudio

    Fuchsaudio Member

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    We're only doing mods by appointment at this point, but the Concert (and Fender-75) are amongst the better Fender platforms for mods we've done. Should you want to get into the ODS territory a little more, drop me a note.
     
  6. covertops

    covertops Member

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    Andy
    Can you describe/give prices of some of the mods available for the concert II? And, what speakers have you found work well in the 2x10" config?

    I really want to make this amp sing!

    thanks,
    Josh
     
  7. SCOOTERGUY

    SCOOTERGUY Member

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    Hello everyone! I finally have a real Amplifier! I've been playing a Carvin tube Amp for years just settling. It was OK but lacked in many ways, plus it is a noisy amp. Everyone around me had Fender equipment and I became very dis-satisfied with my Carvin.
    Then I bought a Rivera Concert II from my daughters boyfriend. He owed me some money & could not pay back. It worked for both of us. He did not know what he had. Someone gave him the amp in a non-working condition.
    It just needed an On/Off switch & now it works awesome.
    The tone is incredible! Plus it is whisper quiet. I'm not used to that! Even though this Amp is 25 years old it is QUIET! I Love it. My American Strat with Kinmans sounds great. The other day I had it cranked up and a neighbor lady caddy corner to me started yelling at me (We're trying to sleep!) OOPS!
    I dont think I will do any mods for a while just enjoying the stock tone!
    The question I have is Should I re-cone the stock speakers or replace them ? I have the 2 x 10" set up. I've been searching for the right choice buy there are too many options. I'm looking for a speaker that has a better low end bu still retains the Fender tone. The original speakers do not have any tears but sound like they do when I play hard. The low end just falls apart. Otherwise they sound fine. Maybe its the pre-amp tubes?? The 6L6 power tubes are Sovtek and are new. The pre-amp tubes are most likely original. I will replace them but again I'm confused about what tubes to put in. I was thinking JJ tubes from Eurotubes. Any Suggestions???
     
  8. covertops

    covertops Member

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    Scooterguy,
    You're in the same boat as me. The stock speakers are junk but I'm not sure what to replace them with either. I'm either going with a weber 10f150 and 10f150t slightly doped as per Ted Weber's recommendation or an eminence Ragin Cajun and Legend 105. The problem is that I've read conflicting ideas about the two setups. Granted either would be a significant improvement over what's in their now.
     
  9. SCOOTERGUY

    SCOOTERGUY Member

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    Covertops,

    I went on the eminence site and listened to all the speakers and I thought the Ragin Cajun sounded the best.

    Arent Weber Speakers really expensive?
    Also, I'm new at this but you are going to put in two different speakers in ?
    What would be the purpose for that?
    Educate me!
     
  10. Bigbud

    Bigbud Member

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    For you guys looking for 10 inch speakers, donèt forget Celestion. They have the Vintage G10 and the newly released 10" Greenback.
     
  11. epluribus

    epluribus Member

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    Very reasonable, IMHO. Cruise the speaker websites and check prices. Ted's a lot more affordable than several of the other aftermarket brands, and his speakers are terrific.

    --Ray
     
  12. John Phillips

    John Phillips Member

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    Wrong way round - replace the power tubes and leave the preamp tubes alone.

    :)

    Really.

    They're all clearly in good condition if the amp is quiet. It's one of the biggest myths in the amp world that tubes 'need replacing every so often'... no they don't - they need replacing when they fail or start to get close to it, and old-production preamp tubes can last decades. It really makes me sad to think how many of them must have been thrown out by people who thought they should give their amp a new set of tubes 'just because', and put in crappy new-production tubes instead... like those Sovteks.

    OK, Sovteks are not all that bad, but they will definitely not give the best performance in that amp. Ideally you want old-production (NOS, or New Old Stock) US-made 6L6GCs for it, although they're getting rarer and more expensive now. There are several reputable sellers who specialise in them, including a member here, 'Blue Strat', who has a link to his website in his signature (and no I don't work for him! ;)). If not, JJs do have a good reputation. A slight problem is that these amps do not have adjustable bias (it's a 'balance' or 'matching' control instead) and the JJs may run outside the right range - although a good seller should be able to select a set which will be OK.

    The speakers are the weak point in these amps though - there are a lot better alternatives, at least starting with the reissues Jensens, but also Weber and possibly Celestion (although a little dark for that amp probably). You'll need to use at least 30W-rated speakers (each), and preferably 50W - these amps really put the power out when they're cranked up, which is why the stock speakers flap so badly.

    Hope that helps - and please don't throw out your preamp tubes, even if you do decide to change them!
     
  13. Fuchsaudio

    Fuchsaudio Member

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    Most times, the old tubes sound better ! If they have 85 or 90% of their original as-new gain, and the noise floor is low enough, leave them alone. There's a good bet they will sound sweeter, warmer and rounder than most anything made today, especially Chinese tubes. That's no matter who put their name on them and "tested" them.

    Power tubes are more important for good clean headroom and reliability. Put your money there, and into adding a "real" bias control. I'd even consider wiring it for two separate bias pots, instead of bias/balance.
     
  14. donnyjaguar

    donnyjaguar Member

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    Man, it sounds like a lot of people have a lot of different opinions on this amplifier!

    The biggest issue I had with it was the crappy sounding second channel when using overdrive. My modification of moving the tone stack to the end of the chain resolves this in fine style. I owned the amplifier for ten years before I changed anything and I can say with confidence I will not put channel two back to stock. I constantly get positive comments and nods of approval from other players when jamming. And I assure you my playing skill isn't the reason. Haha! :)
     
  15. epluribus

    epluribus Member

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    Now that's cool, several friends suggested doing that. As I've not really spent a lot of time working with tone stacks yet, I'm not familiar with all the peripheral circuit issues involved in re-locating one later in the signal path--personally, I'd love to make the placement switchable. Anyhoo, any chance you have a schematic? (Might not do it to my DR II, but it sure will be handy for my next FrankenAmp.)

    --Ray

     
  16. Bigbud

    Bigbud Member

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    My amp tech just performed the Donnyjaguar mod to channel 2 and it rocks! He also "blackfaced" channel 1 and now, this amp is a keeper. There is a lot of hidden potential in this amp. A definite sleeper! I might try various speakers just for fun.
     
  17. rust_preacher

    rust_preacher Member

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    I got me a 12" Weber California Ceramic with the large dome. Works like a charm, rocks on single-coils. I use pedals to get more gain or distortion and use Channel II as a dirty lead, most of the times.:AOK

    Jyrki
     
  18. Bigbud

    Bigbud Member

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    Gentlemen, I just tried my amp with THD Yellowjackets and I just love it! The only thing left is to try various speakers, but so far this Jensen Mod 12-70 speaker coupled with the Yellowjackets is spot on.
     
  19. cestlamort

    cestlamort Member

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    I'm realizing now that my power tubes seem to be slowly giving up the ghost... Do I understand you correctly that the concert II is a fixed bias amp? Would I still need to take it in for a "bias" (or match or whatever) for new power tubes?

    Thanks!
     
  20. donnyjaguar

    donnyjaguar Member

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    I modified mine years ago with two controls for bias. One for balance and the other level. This way I could run EL34 tubes and did so for many years. In fact this was the first modification I ever performed on a tube amp long before I heard of it elsewhere.
     
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