Help me understand the different twin reverb methods

Discussion in 'Amp Central Station' started by tesla005, Sep 6, 2019.

  1. tesla005

    tesla005 TDPRI Member

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    Hi. I'm in search for a twin reverb amp and I'd like to know about the differences between the different versions of the amplifier. As far as my knowledge goes, the first version is the blackface, 85w, from 1963 to 67. Then, after the cbs takeover, from 1968 to 1972, they were silverfaces without master pots and 100w of power (or 85???). From 73 to 75, they added a master vol put, but how did this simple addition altered the identity of the twin reverb. Many people say that because of the master volume pot the tone was degraded. From 76, it was the ultralinear region and the power was up to 135 w,but the tone got worse. I am mainly interested in the silverface models, because of my low budget, and of course before the ultralinear. What is the difference between the non master volume silverface and the master volume one? Can I just solder some wires and bypass the pot, and do some mods to convert it to blackface?
     
  2. Wally

    Wally Telefied Ad Free Member

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    Greetings, fellow Earth-man?
    If you are wanting a TR for cleans...and why else would you want one, right?.....and budget-constrained, then do consider a ULTR.
    Properly set up, they are very good amps. And...they can still be modded to offer more versatility....like a Normal channel with effects and tweed Sonics. Be advised that the Dual Showman Reverb amp’s are the same amp but in head form.
     
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  3. tesla005

    tesla005 TDPRI Member

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    Yes, but I don't want to buy ultra because I have heard both versions (pre ultra and ultra) and the deference is not at all subtle for me. I just want a simple silverface and I am capable of getting one with master pot and one without one. I only want to know the differences.
     
  4. tubelectron

    tubelectron Tele-Meister

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    None. And choose a Master Volume one rather than a non-MV : you'll thank me later ! ;)

    My Venerable mid-late 70s SF TR:

    [​IMG]

    -tbln
     
  5. Wally

    Wally Telefied Ad Free Member

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    Tesla, ime, until one knows that two amps that have the same basic topography and tube compliment have been put into proper working condition and have been biased to the same plate dissipation...and are run through the same speakers, the comparison is not valid. I have owned almost every TR between 1963 and 981. What I have not owned, I have worked on. All were in proper order, and all of them sounded great. One can take a 1963 BFTR hat has been serviced and is sounding great and with a small adjustment that takes about 4 seconds from the outside of the amp——the bias pot—-turn it into something that sounds like the worst solid state amp you could wish not to hear.
    Example of comparisons....I had two 1974 100watt SFTR’s in for recap and full service. The amps had the same power tubes and were biased to the same point. One amp had orange K120 JBL’s in it. The other had stock Utah’s. The amps sounded nothing alike...one very warm and musical while the other was thinner, harsh, and brittle. I then ran each amp through the other’s speakers. The sound stayed in the speakers....the amp that had been harsh and brittle was warm and musical with the Utahs. The amp that had been warm and musical was harsh and brittle when running through the JBLs. And.....the results of the comparisons stood up under tests with strangers. There was no doubt about the difference and why the difference existed.
    Would I prefer a BFTR in good condition to an UL?? That depends on what purpose I had for the Amp. There are applications where the ULTR can be superior to the BFTR, imho and ime.
    Just sharing....good luck with the hunt.
     
  6. Wally

    Wally Telefied Ad Free Member

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    There is one big and beneficial difference between a non MV and a MV Fender. With the MV, there is a place on the front panel in which to install an adjustment pot for the negative feedback resistance after you pull the useless MV circuit out!!! (;^)
     
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  7. Les H

    Les H Tele-Meister

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    I don't know the ins and outs of the master volume twin vs the non MV twins. But I do know after playing my ex father in laws master volume twin I thought it sounded great and prompted me to buy a Twin Reverb Reissue thinking if his was supposedly the bottom dweller Twin that the 65 Reissue was going to be awesome. But it's not..... Not even close to how good his sounded. It boils down to trying them out and seeing what you think.
     
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  8. Milspec

    Milspec Friend of Leo's

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    Rule number one: Don't listen to all the forum noise about how bad the MV amps or the UL Twins are for tone...it is all biased dribble.

    I replaced a '67 Twin with a '79 Twin that had a bias pot installed and set to blackface specs, I sold the '67 a month later. The UL Twin is the best bargain out there for a Twin and maybe even for all of the SF amps to date. It will give you everything that the early SF Twins can give and a little bit more with a smaller price tag. If you really don't want a MV screwing up the tone, just do what most of us do and dime the dial as it takes it out of the circuit. You could also just have it removed for that matter.

    Leo Fender's evolution in his amps was to get louder and cleaner with every series moving along those lines. CBS era had some bad quality control, but they took the Twin in the exact same direction by making it cleaner and louder than before. I am not so sure Leo wouldn't have built it the same way actually. For bell-like tones, great cleans, and a terrific reverb, any of the SF era would do great with the cheapest ones being the later years with the MV control and UL transformer.

    Just don't rule them out or you will be leaving money on the table.
     
  9. tesla005

    tesla005 TDPRI Member

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    Ok thanks for you answers, I'll get any sftr I find in my country (Greece) and I will remove the volume pot, and if it is not ultra linear I will maybe order a mod kit and convert it into a blackface.
     
  10. Wally

    Wally Telefied Ad Free Member

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    Imho, and ime...there is no reason to ‘blackface’ a ere are some aspects that some players prefer in the SF circuit....like the .01phase inverter cap. I used to revert the power supply back to NF specs, rebuild the entire PI, circuit, and revert the biasing circuit back to blackface...blackface it. Now, I simply recap, do good general service, and install a bias voltage adjustment pot to the bias circuit so that one can the bias voltage and still have the balancing circuit there. This allows one to install unmatched power tubes or to provide a slight imbalance in the circuit which some players like. Note: the first changes to the circuit in the Sf amps happened in the summer of 1968. Fender did a strange mixed biasing....and imho those cathode biasing resistors need to be cut out of the circuit.
    Fwiw and imho, the early amps have better cabs. I might hold that difference to be more important than any circuit changes. I don’t like the separate grille boards that are Velcro-attached compared to the one-piece baffle/grille boards that were used until sometime in 1970.
     
  11. Dacious

    Dacious Poster Extraordinaire

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    +1. There's honestly more difference in a new set of good caps well biased tubes and decent speakers than between BF and SF amps.

    I BF'd a Vibrolux Reverb and found while the reverb and tremolo did sound fuller, the slightly smoky warmer tones didn't for me and I actually preferred the 5U4 to the BF-spec GZ34. The differences were minor. A lot of guys get the amp serviced and retubed when it is BF'd and a lot of the 'wow' is got with fresh components and a service. Speakers were sometimes crappier during CBS era.

    Buy any SFTR for the right price, leaves you more for maintenance and speakers.
     
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  12. BobbyZ

    BobbyZ Doctor of Teleocity

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    I can't comment on the ULs because I've not spent enough time with them, only played them here and there. Don't remember hating them.
    Currently I have a 65 blackface and a 76 100 watter. That 85 to 100 watt thing is CBS marketing. I can't see where they got an extra 15 watts.
    The real deal blackface should be my favorite but it's not. It would be if I switched speakers around, the 76 has inefficient Radio Shack Utahs that I like.
    Personally I keep the MV on 10 and the pull boost pushed in all the time. Some people like those two functions but they are a small minority, that probably do evil things to kittens. ;)

    You get into the real early silverfaces, non MV and you'll pay more. You might pay more and get every one's favorite "dog turd" caps and the 68 circuit too. There was also a reduction in voltage in the early ones. (it's on the schematics)
    For cheap money I'd go with the late 100 watter with the value reduction that comes from that push pull master knob and the "inferior" cab construction. Then replace all the Ecaps and add a trim pot to the bias balance pot. These already had the grounded cord, if it's in good shape you're done.
    My SFTR set me back a cool 300 bucks. The similar one I just did for a guy set him back $600 but he got orange D120Fs too.
    Oh also worth noting there were two different chassis styles. One uses shorter screws through the top and a few across the back side. Doesn't affect the sound I just prefer the BF style if given a choice. Saves a minute or two putting the chassis back in, don't have to keep the springy nut things lined up.
     
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  13. umasstele

    umasstele Tele-Afflicted

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    For what its worth- I have a bone stock Twin Reverb that is "AA769," and it sounds more like a twin reverb than anything I've ever heard. Don't hassle yourself about the internet hype or non hype...play 'em loud, play 'em clean.

    This isn't meant as a dig at anybody- wonder how many people would avoid or "hate" the UL twin's if the internet didn't exist?
     
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  14. Lawdawg

    Lawdawg Tele-Meister

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    I have a '73 SFTR. The pull boost is unmitigated garbage no doubt about it. But over the years, I've come around on the MV and genuinely find it to be a feature not a bug for these amps. No reason to take out the MV in my opinion.
     
  15. T Prior

    T Prior Poster Extraordinaire

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    silly season .

    If you can locate any SF Twin for a reasonable price, and its in good shape. JUST buy it. With or without MV, with or without the UL Output Trans.

    The 85 to 100 watts thing, well there are no active components to suggest that change but there is a theory. A paperwork spec, the primary transformers are rated at 125 VAC or so, Leo probably rated everything at 110 VAC, which was the common language back then. Its a math equation. You don't find 15 watts without changing active components in the circuit. BUT you can find 15 watts with a math equation.

    THE UL / OT is wired to the output stage differently than the typical OT which supposedly allows for a higher output from the 4 x 6L6's, in common mans terms this also may be a mathematical equation. Its possible this is all marketing as suggested above.

    Doesn't matter, these are all great amps if you are looking for FENDER cleans. Typically people commenting on overall tone are basing this on which speakers are in the amps. Speakers indeed cause a dramatic change in tone .

    Oh yeah, the new RI's , they say TWIN , they look like TWINS etc, they are not bad, but they are not the same.

    Just buy whatever SF TWIN that crosses your path, you will love it ! SF Twins are perhaps the best deal on a used amp around the planet. Original Fender breadboard point to point design and manufacture , plus easy to bring back to 100% operational condition. They are not TOO loud but they are pretty heavy !

    good luck .
     
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  16. Silverface

    Silverface Poster Extraordinaire Ad Free Member

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    If you don't know the differences WHY do you want a Twin?

    And unless you play very loud and clean IMO you are shopping for the wrong amp only because the name is well known.

    A Twin Reverb is WAY too much amp for most club work. It's unusual that a Twin can be turned up enough to drive the output stage and speakers enough for decent tone. This results in a thin sounding amp (especially at home!). It doesn't matter which one - ALL of them are generally "too much amp" unless you play large halls with no miking, or outdoors (also without the amps miked)

    I service and tweak amps and a Twin is not a good platform for typical club volume modifications. I have n ot seen one used around the Los Angeles area for at least 10 years.

    Most players use amps like Deluxe reverbs, and if they want a "big" amp as a backup or for large venues they might have something like a Super Reverb.

    I just can't imagine that the situation is that much different in Greece than it is here, and a Twin - which is not a bad amp - is the WRONG amp for your use.
     
  17. RoscoeElegante

    RoscoeElegante Friend of Leo's

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    All due respect to the glorious Twin Reverb, and to the great advice/perspectives on this thread, but tesla005, consider not only the Dual Showman noted above, but also the Bandmaster Reverb head. It's not the Big Grail of cleans that the Twin is, but its cleans are similarly glorious. And you can push it into various degrees of breakup much easier, as it's "only" 40 watts.

    As emphasized several times here, speakers are key. Use an efficient pair with a Bandmaster--Eminence 1218's, say--and you've got serious volume and punch. Go softer--WGS 12 C/S's, say--and you've got smooth depth with good backbone.

    So when you check out the Twins (or similar stuff) available, be really careful not to pass on an affordable amp just because its sound is ratty, or brittle, etc. Identify speakers whose tones you like, and try to play a prospective amp through them.

    Good luck!
     
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  18. BobbyZ

    BobbyZ Doctor of Teleocity

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    Twin Reverbs. . . . .
    You either love um or hate um. :)

    Played a while yesterday after completing a plumbing project on my Avion. Replaced all the plastic pipes with new PEX. If you've ever had a camper with plastic pipe from 1983, you'd do that too.
    Anyway I started out with a Princeton Reverb then went to the SFTR shorty after. Seems every time I start out with something else I end up with the SFTR before long.
    I'm always harping about the Radio Shack Utahs in that amp. Those things give me about one more number higher on the volume knob than anything modern I've tried. That makes a difference. Someday I'm going to try Mavericks in the BFTR, pretty sure I'd like those.
     
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  19. Telecastoff1

    Telecastoff1 Tele-Holic Silver Supporter

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    For nice, clean Fender sounds at any volume from a whisper to all-out tree shaking, you simply cannot beat a Silver Face Twin Reverb. In my neck of the woods, they are still being played and seen on stages everywhere. These make great pedal platform amps as well, so you can use your favorite pedal(s) for playing distorted that won't deafen your crowd or club manager. We still play SF Twins in our band from small American Legions to large outdoor events, and we haven't had a volume issue at anytime, anywhere. We just don't play loud in small venues, but we still get our tone and sound we like. Just because the power is there doesn't mean you have to use it. The Twins sound great at any volume.
     
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  20. Paul G.

    Paul G. Friend of Leo's

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    One of the nicest Twin Reverbs I ever played was in a rehearsal studio in NYC, I can't remember which one. It was a SF, with a master volume (but no pull boost) and had Celestion speakers in it. It sounded so fat and warm, you didn't need to drive it (as if you could). I remember plugging my 1960 Junior into it and just being floored by that amp.

    Again, often the difference between an ok amp and a great one is in proper service, bias and the right speakers.
     
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