Vintage vs. Modern Ampeg

Discussion in 'Amps and Cabs [BG]' started by LarryJ, Sep 29, 2002.

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  1. LarryJ

    LarryJ banned

    Dec 12, 1999
    Encino, CA (LA)
    Well, I don't really mean "versus"..
    But I'm curious----
    Since I am enamored with the tone of my new V4BH-
    What are the differences between the older Ampegs, the SVT's V4,s etc. and the current line?

    I'm referring to actual differences in the circuitry that voice the amps differently.
    I was under the impression, that except for cosmetics, the tube circuits were the same-if so why is there an opinion that vintage SVT's are louder, stronger, whatever. Same w/ the B-15R-
    I know they added atweeter/midrange, and it's higher powered, so there must be some re-design there. Anybody know? How about Psycho-Bass Guy?
    I know that you are an encyclopedia re: tubes.
    What has SLM done differently?
  2. I am also interested in hearing about the differences between the old and new svt classic all tube heads. (opinions are welcome but I am mainly interested in the electronic differences)
  3. LarryJ

    LarryJ banned

    Dec 12, 1999
    Encino, CA (LA)
    OK, I'm waiting.....

  4. The SLM era SVTs and V4s have different preamps than the old ones. The original SVTs had a bunch of tubes that aren't readily available these days. 6C4s, 12DW7s, etc. When SLM introduced the SVT classic they redesigned the preamp to use all 12AX7's (I think, haven't had one apart in a while). The actual circuitry is quite different from the originals. As an example the older SVTs and V4s didn't have master volumes, the new ones do. I think the SVT's power section is pretty much the same as the old ones with modern components of course. I'm not sure about the V4, but I think the new ones use 6L6s for power tubes where the old ones used 7027s. I think the quality of the individual components, transformers, caps etc isn't quite what it was in the early days as well. That being said, the SVT Classic is a great sounding amp, but it doesn't do justice to the old ones. IMO of course:D
    I'm sure Psycho and some other guys who know more about it will chime in eventually......
  5. Modern = Good
    Vintage = Gooder

    Personally, I don't think you could go wrong with either, but they are just so damn heavy.
  6. IMO, the difference is the result of goals and ideals strived for (and in place already) at the given time of manufacture. Like most everything else, I believe that the older amps were built at the tail-end of the era of: "Let's build the best amp we can, at the highest-quality, for the most reasonable price." Now we're in the beginning of the new era of: "Let's take this quality, proven, and time-tested design and see how we can build and sell more of them cheaper and faster." It has become a very fine and exacting science. And unfortunately there is no turning back. I know this is not the response you're seeking (sorry) and to that end you should wait on the authority, PBG.
  7. LarryJ

    LarryJ banned

    Dec 12, 1999
    Encino, CA (LA)
    'S Cool, your reply makes a lot of sense.
    As I get older I realize how things are built to be
    disposable & obsolete today, in many cases.
    I had heard that the Ampeg cabinets today are not as substantial as before, but both my V4 and SVT 48 seem very well constructed and solid.
    I'm not an engineer, so I can't claim to follow differences in schematic- I do know that 6l6's today
    replace 7027's etc.As far as capacitors & transformers etc. that's a design factor.
    I have a Mesa as well, and they state as a company policy how it is more profitable to design and sell a solid state circuit than a tube design.
    Ampeg is one of only a few that has continued their all-tube lines. IMO-nothing sounds as rich as tubes. Just wondered what made a 70's SVT or V4
    different & why.
  8. I heard that also and was very curious. I happen to have one of each right now. I've had the newer "Classic" (a misnomer) for a few years. I just got an old "straight-back" ('70-'75 most likely). I've not been able to test for sound yet cuz my head's not ready yet but the speakers are certainly different. More importantly I have conducted the old "Knock Test". It's similar to the "kick-the-tires" test on cars. Knocking on the new cab sounds like knocking on cardboard compared to the old one which sounds like knocking on real wood. As for the circuitry, I'll go as far as to ask/say where did three tubes and at least ten pounds go?? Kinda like lite-sabers. The new models just don't look as heavy as the old ones. I wouldn't do battle with anything less than a vintage lite-sab...I mean SVT. :D
  9. LarryJ

    LarryJ banned

    Dec 12, 1999
    Encino, CA (LA)
    Well, I'm sure that SLM uses different woods than were used 30 years ago, still it seems stronger than particle board anyway.
    The finish on my components is well-done, nice tolex,(I hate carpet), solid metal corners,tight grill, etc.
    And irrespective of vintage sounds, the new V4BH
    gets the job done, I mean it sounds GREAT with the 4X8. Overall, I think the quality is there- both the market & manufacturing process are different from the "old days"- the 70's- damn. I'm getting old, I guess:D
  10. Tapp


    Aug 29, 2001
    USA, Mississippi
    I have not worked on the new SLM Ampeg stuff but from what I hear the old Linden/Magnavox 60's,70's, Ampegs are made much more sturdy. I know that my old B-15 and SVT are made on "tech-friendly" circuit boards where I don't have to worry about the traces lifting too easily. The circuit board material is nice and thick too and the components are easy to get to for replacement if necessary.

  11. well, i really LOVE the old stuff, but the people who got the old stuff wont give it a big guy so i dont mind the im setteling for an Eden insted of a Vintage 8X10...need the mid boost
  12. LarryJ

    LarryJ banned

    Dec 12, 1999
    Encino, CA (LA)
    Thank you PBG for the data.
    SVT's are a bit overkill for what I do, so I chose a
    new V4BH.
    I'm very pleased with its tone.I'd like a chance to play through a vintage model and see what I might
    be missing.
  13. [​IMG]

    That's an original one, at least an original Magnavox era one.

    It's the reason I always say 100 Watts is enough for just about any indoor gig. I got it back in 1988, and ran it through a Distex 18" sugar-scoop cab that was 4' tall, 2' deep, and 2' wide. I never turned the amp up past 10 o'clock on the volume knob, and I was playing with (3) Marshall 50 Watt half stacks.


    Psycho, take a look at that input circuit on the original V4B. I doubt the new ones have that same straight line input to the first tube grid with a 5.6Meg grid resistor. I'm convinced that is the reason a Jazz bass sounds so good through a V4B. That high impedance makes the Jazz Bass Tone control act different from any other amp (except maybe some other Ampegs). It's like even when you turn the Tone on the bass down, you still have sparkling highs coming through. It's the best. I've been meaning to add that exact preamp section to my Bassman 10 / 2-15 combo amp to see if it gets me near an Ampeg fliptop sound through a Fender Bassman.

  14. LarryJ

    LarryJ banned

    Dec 12, 1999
    Encino, CA (LA)
    I understand only the basics of the schematic,
    but commenting as a player:
    The combination of my Sterling & its preamp,
    plugged into a modern V4BH and a (now-discontinued) SVT-48HE is incredible.

    PBG, do the ultra-low & ultra bright circuits function essentially the same between old & new?

    Also, the "presence" switch on the new VB4-
    it adds a great glass-like "sheen" when switched,
    especially when combined with either or both
    of the ultra switches- Is that a feature of the new models?

    No doubt there was a better grade of manufacture
    employed 30 years back, but I think SLM is still doing their thing pretty well.
  15. LarryJ

    LarryJ banned

    Dec 12, 1999
    Encino, CA (LA)
    I'm not defending SLM. Certainly their marketing people are going to try & capitalize on the Ampeg
    history, as does Fender,etc.
    CAD design is probably necessary to meet cost/profit requirements as are the choice of components etc.
    I appreciate the interesting input-it answered a lot of ?'s I had.
    Still, looking at & playing throught the new V4 is a pleasure for me. I think they managed to keep at least some of the old Ju-ju sound there.
  16. metron

    metron Fluffy does not agree

    Sep 12, 2003
    Lakewood Colorado
    Hey tube amp lovers! I would like to resurrect this thread because Ive been wondering to myself lately wether or not a vintage SVT is that much better than the new CL I have. Obviously ABing would be the best bet and Ill do that in the future but Im looking for some info. Mark Reccord mentioned that theres a difference in the preamp and that could explain a lot of why the old ones sound "better" then the new ones. The power section is the same in the old and new.

    My question would be circuit related for those who have worked one the new or old ones. Would I be correct in assuming that resistors and caps wouldnt make much difference in tone? Whats the difference in the preamp topology? Could the new ones be worked on to make them more like the old ones? Thanks in advance for any information.

    PS Be as technical as possible. Im versed in circuit design but tube amps are more of a mystery to me and I would like to learn more! :)
  17. metron

    metron Fluffy does not agree

    Sep 12, 2003
    Lakewood Colorado
    Anyone have any info? I know this subject had been talked about a lot but Im looking for more info from those who are technically inclined. Thanx!
  18. I can't add any SVT specifics since I don't have one, but I think the main differences lie in the preamp circuit topology differences, which includes slightly different tube choices and surrounding R's and C's, and probably a big portion is due to output transformer differences. Besides all that, I've come to realize that speakers are just as important to overall sound and response as my beloved tube amps, so there may be a lot of difference chalked up to the older speaker cabs and their drivers.

    As far as different cap and resistor types affecting the sound (given that they are equal value), maybe a teeny-tiny bit (not near as much as hi-fi nuts seem to think), but for the most part there are other things that swamp those tiny differences. I wouldn't think the new SVT's could be easily transformed into an older one since I'm sure the new ones use a circuit board (as did the old ones I think, although slightly different circuit as mentioned above) and PCB's make it a bitch to modify. Also you'd need to change the output tranny to an older one to really nail it. A lot of distortion in tube amps comes from the output tranny and how it reacts to the overdriven tubes, and this boils down to metallurgy which all points to one thing - if you want an old one, buy an old one. :D

    Having said all that, even though I'd prefer an old SVT, I wouldn't kick a new SVT out of bed unless it wanted to play on on floor. I'm sure some good tones can be had out of those things since it's more the player than the amp anyway.

  19. rickbass

    rickbass Supporting Member

    I rent Ampeg SVT's when I have to go way out of town to play. These are made by St. Louis Music.

    I'm also old enough to remember the Selmer SVT's. The Selmers were definitely a step above, especially when it came to tone. Not that new SVT's don't sound good....they just don't measure up to the "real deal."

    Several of my friends worked at St. Louis Music's factory in Ferguson, MO (I grew up in St. Lou).

    Kornblum, the CEO of that company has always done everything on the cheap - Crate amps, Alvarez guitars, Electra get the idea. The one thing they spent extravagantly on were European violins.
  20. The power sections are NOT the same. That info was contained in my original post which I deleted some time ago when I expected to be leaving the forum. Anyhoo.

    Real SVT's have bigger power and output transformers and run their tubes very differently from the SVT CL. They use two 12BH7's as cathode follower drivers which are FAR more current capable than the single 12AU7 of the SVT CL. They run at higher plate and screen voltages, which in turn, generate more power out of their tubes. The SVT CL has several current limiting relays in its circuit designed to protect it in case of a tube fault. SLM did this in the design because they bought bulk unscreened tubes (cheap) initially and failures were common. Rather than have a bunch of warranty work, they constipated the amp so that if it loses an output tube or tubes, it doesn't get damaged; doesn't sound as good either.

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