Fender Super Reverb Headroom

Discussion in 'Amps and Cabs' started by Mateoz77, Mar 7, 2015.

  1. Mateoz77

    Mateoz77 Member

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    Hi All,
    I'm new to your forum and am search for some help. I recently acquired a 1971 Fender Super Reverb amp (AA270 model) for quite a good deal. I immediately dumped some money into it and had it serviced. The tech replaced the capacitors and resisters and fixed the vibrato which was shorted out. Two issues remain, one, with some ringing tones, the amp will crackle in and out. It's like the sound when a tube is wiggled around. This only happens at louder volumes. Two, I get quite a bit of distortion at volume 4. By volume 5 it sounds like Crazy Horse. Now, before anyone tells me to just get a twin reverb amp, I really, really like this amp and it's tone is golden. And, I've read other posts by people who say they can get to 6 easily before it starts breaking up.

    So, would changing my tube configuration help? (It's got 2 - GT 12ax7r, 1 RCA 12at7, 1 fender 7025, 1 fender ECC (something else worn away) and it also says 7025. The power tubes are Sovtek 5881/6l6wgc.

    I don't want to spend the money, but I'd change out the speakers if it would make a huge difference. The ones in there are fenders with an old blue label on the back. I think original.

    Any advice is greatly appreciated! Thanks :D
     
  2. Blue Strat

    Blue Strat Member

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    The amp should stay reasonably clean until at least 6.

    Tubes will only help if one or more of the tubes is really weak. V6, the 6th socket from the right when facing the back, should have a 12AT7 in it. A 12AX7 will work but make the amp break up sooner.

    If one or more speakers is blown the amp will break up early. There are many internal reasons for the amp to break up early but I'm assuming that the amp tech would have addressed these.

    Speaking of the amp tech, have you raised these issues with him? Someone who's actually seen the amp is much more likely to have a theory on the problems than those of us who haven't.
     
  3. e???

    e??? Member

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    My friend has a 71 super. When he got it he had to have it serviced and it was quite the process. Many different options and ways to go with that, all kinds of things replaced and then they asked him how he wanted it biased or how loud on the volume he wanted it when it broke up. He chose around 7 or 8 so the thing had massive headroom. Did your tech go thru this stuff? I've had guys tell me things were unfixable, then brought it to a different tech, and 20 $ and 15 minutes later its good as new....
     
  4. MrKite89

    MrKite89 Member

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    No thoughts on the first problem, but you can give it more headroom in many ways in my experience: I'd change the output tubes with Tung Sol and the PI with a 5751, you can also put a 12AY7 in V1 if you want MUCH less gain...if this is not enough you can swap the speakers with a higher wattage, more efficient ones, so the speakers won't distort as easily and if they are more efficient they are also louder at the same volume on the amp, so louder clean tones at "3"...

    It depends also on the guitar you play: old Fender amps distort quite easily with humbuckers, even the Silverface models...if you have second input (-6db) use it!

    Another thing that I noticed, when I was helping a friend recording a guitar track, is that "distortion" is very subjective: acoustic pressure, timbre and your own ears have a lot to do with the perception of what we call "distortion", in fact he (my friend) said "this guitar is way too distorted" when I was thinking "oh, I hate this clean, sterile sound"! :D
     
  5. Mateoz77

    Mateoz77 Member

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    Thanks for the fast replies. To answer a few questions, my amp tech is a very kind, older gentleman who works primarily on old stereo equipment. While guitar amps are listed on his card, its not really his main thing. He doesn't, for example, have an electric guitar and I've had to bring mine over every time something needed to be tested that running his radio through my amp wouldn't indicate. I brought up increasing headroom and showed him how early it was breaking up, and he suggested changing out different tubes for different types and told me to look online for suggestions. Perhaps a new guitar tech might be my first step.

    I play a Fender Strat deluxe with two single pickups and one humbucker in the rear. I expect more growl from the humbucker, but I'm getting it all across the board. People talk about 4 being "plenty loud enough" and it is nice and loud, but far from blasting even sitting in front of the amp. And like I said, there's quite a bit of grit at 4 and full on distortion at five (equivalent of a my Catlinbread Formula 5 overdrive pedal cranked).

    I just pulled the face off the amp and discovered a lot of dust pile up. So, step one, dust it down. Step 2, try the suggested tube swaps. Step 3, find a new tech (or should this be step one? I'm in Reno in case anyone knows of a good one).

    Thanks again! Despite having played for 30 years, I'm realizing how very little I know about amp functions.

    On a side note, here's the kind of music I play if anyone's interested: www.mateoz.bandcamp.com
     
  6. swiveltung

    swiveltung Member

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    There's something wrong with your Super. Original speakers?
    One of our local jams a guy uses one as the host band. he's way too loud but it's perfectly clean all the time. he's on 7 and about to get fired! 3 of his speakers are original and one is a old oddball.
     
  7. zenas

    zenas Member

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    What capacitors did he replace? Check the receipt should be listed there.

    I wouldn't even mess a silverface untill I know every electrolytic is fresh. Not tested, not looks good no leaks, brand new.

    Also has the bias balance set up been modded yet? You can set bias by changing a resister but a pot is way nicer.
     
  8. stratzrus

    stratzrus Philadelphia Jazz, Funk, and R&B Supporting Member

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    Try authentic late distortion SED Winged "C" 6L6s and bias the amp just slightly cold. If everything else is working properly that should give you more headroom and absolutely killer clean tones.
     
  9. amphog

    amphog Silver Supporting Member

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    May be a speaker, or cracked baffle issue. A Super should be clean at 5 with single coils.
     
  10. Custom50

    Custom50 Member

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    If you're playing a strat and the amp is mostly stock it shouldn't be a gain machine at 4.

    I have a '67 bandmaster that's an overdrive machine when it's hit with a Les Paul...but I have it biased hot and disconnected the tremolo.

    A strat with a super should be pretty clean. It could be a number of things, taking it to another tech is a good 1st stop.
     
  11. OilsFan

    OilsFan Supporting Member

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    I'd say your first line of inquiry should be to find the right amp tech. That's not an easy thing to do. I'm in L.A. and still haven't found one I thought was truly great. Even some of the most well known guys here have done (or not done in some cases) some things that make the eyebrow raise up. Anyway, I have a 73 and it is biased on the hot side and is still very loud and clean up to 5-6 ish. You should be able to smoke just about any drummer on 4-5 and be clean.
     
  12. arcey

    arcey Supporting Member

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    If you love it and want to keep it, here's a way to make it right.
    Hook up another cabinet to find out if it is bad speaker.
    If not, call David Allen, and send him the chassis.
    Very nice sounding album you made there.
     
  13. fuzzface71

    fuzzface71 Member

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    My advice try to find a better tech. How can someone give back an amp, that he just supposedly fixed, still have problems?

    Any good tech will run the amp for awhile and check if everything is great.
     
  14. Blue Strat

    Blue Strat Member

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    The most important thing to note is that THERE IS SOMETHING WRONG WITH THE AMP OR SPEAKERS. Don't just start throwing new tubes at the problem before knowing what the problem is.

    OP, you'll either have to connect up to an external speaker cab to figure out if it's your speakers or not and/or have a qualified tech look at the amp. Don't modify an amp until it's working properly.
     
  15. Mateoz77

    Mateoz77 Member

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    Hi folks,

    Quick update in case anyone is interested (and more advice needed perhaps). So, I followed advice and got a new amp tech. Much, much better. Within minutes, he'd run a test and determined that my speakers were mostly shot. I also replaced the power tubes with Tung-Sol 7581As and the preamp tubes with Tung-Sol's as well.

    The amp tech found multiple problems with the previous tech's work, replaced the solid state rectifier tube (not sure if that's the right term) with a tube, changed a capacitor that was leaking (should these all be replaced?), and fixed some connections with resistors. I am not tech savvy at all, so I may be confused on exact details.

    I replaced the old speakers with two Celestion 10n-40's and two Rajin Cajuns.

    The long and the short of it: the amp sounds beautiful now (seems to be sounding better each day...speakers breaking in or is that a myth?)

    BUT, the amp's headroom is still short of the mark. It breaks up at four, not hugely, but gritty for sure. And by 5, it sounds like a great overdrive pedal. This isn't a problem when I'm playing at home. 4 is loud. But, I'm involved in a surf-rock project that is just getting underway and while competing with a drummer, I'm getting overdrive when I want clean. The amp tech wasn't entirely happy with the results either. He said he wanted it "studio clean" and wasn't sure what to try next (I think he mentioned changing the power supply). Anyways, I can live with the amp the way it is now, but I'm picky and would really like one more level up on the volume before overdrive (clean 4, slight breakup at 5). It feels like a poker hand I'm "pot committed" to, so I don't want to try and sell it to get a twin-reverb (plus I imagine I'd lose money on this). Plus, I really love this amp...just want a tiny bit more clean.

    BTW, I tried using 12AT7's in position 1 and 2. The result was quieter and cleaner (missing something). But, it didn't really help because to equal the same volume of the 12AX7, I had to turn it louder which resulted in overdrive as well.

    Advice? Thanks guys! (or gals . . . don't know why I assume this is all dudes).
     
  16. keithb7

    keithb7 Supporting Member

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    I have a 71 that's very clean at 4. No problem with a drummer either, when clean at 4. Hmm. Curios what is the sensitivity/efficiency rating on the speakers you bought? Original bias balance is still in place? Curious does the 71 use negative feedback? NFB resistor change may help.
     
  17. zenas

    zenas Member

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    Be nice to see some gut shots and a shot of the caps under the dog house. Also check your output transformer codes to make sure it's a SR OT. You never know what's been done on an amp that age.
     

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