Tube or Solid State???

Discussion in 'Amps and Cabs [BG]' started by iceblinko, Oct 1, 2003.

  1. iceblinko


    Jul 15, 2003
    hello all! I recently bought a good ol' Ampeg SVT classic. sounds amazing with my fender p and my ampeg 8 x 10. yes, i'm VERY happy with the sound and blah blah blah. BUT... i was recently talking to someone about tube replacements. he was telling me that i'm going to have to replace them like every 3 months or so. now my band tours for about 5 weeks at a time. when we're home, we play on the weekends. i don't know if i have the money to be keeping up with this tube maintenence!
    my question is this, should i just sell this thing and go with one of the ampeg svt 3 or 4 pros? they both have a tube pre-amp, and i can just plug my mighty sansamp bass driver into it too. i dont' know what to do! i neeeeeed help! how much of a difference would it be if i buy one of these other solid state amps? and how much is it to re-tube an svt classic? and one final quesion... how long do these tubes take to burn out? thanks for your time. sorry for the drunken rant.

    xo tom
  2. Lockout


    Dec 24, 2002
    Every 3 months? That doesn't seem right..

    I'd say maybe once every couple years at the most. Could be wrong, but 3 months seems like quite an exaggeration to me. :)
  3. Your friend doesn't know what he's talking about. A set of decent tubes can last for years, even in an SVT, as long as you keep the bias adjusted. I'm still using the original Magnavox coke bottles in my '76 SVT and they're just fine. There's no set time to replace tubes, you replace them when they stop performing well. You should get at least a couple of years out of a set of power tubes.
  4. I've got preamp tubes that are 30 years old and still quite serviceable. I've also got 30 year old 7027A power tubes that are still OK, even with the high voltages Ampeg puts on their V4's......I've also got a 40 year old guitar amp that still has its original 50L6 power tube (as well as its original preamp and rectifier tubes).

    The "3 month" figure your friend quoted is completely bogus. The Svetlana tube site has a technical article that quotes 2000 hours of use, IIRC, for beam power tubes such as the 6550.
  5. nonsqtr

    nonsqtr The emperor has no clothes!

    Aug 29, 2003
    Burbank CA USA
    Yep, ditto. I still have the original RCA's in my Bandmaster and three of the original preamp tubes in my Portaflex. Man those old tubes last forever. The new ones are more variable, I'm guessing you can count on maybe five years or so if you don't abuse them. Depends on the manufacturer and species, some of them get microphonic over time and have to be replaced pretty much on schedule, so maybe your friend had bad luck with the particular brand he was using (for instance, I would stay FAR away from any Chinese tubes, they've been known to take entire amps with them when they go) :):):)
  6. I'd say more likely it was a salesman at a music store speaking authoritatively on a subject he knows nothing about, the B.S. factor at play. It's hard for me to spend five minutes in a music store without hearing at least 12 tons of it.
  7. All-tube power amps, or all tube amps per se, are great, but heavy on maintenance ... preamp tubes are easy and cheap to change, they go on for years without deteriorating in quality, but power amp tubes are a different deal.

    The power stage can have anything from 4 to 8 tubes, like KT66s (or 88s, I forget) and these cost some ... plus there's the need to get them matched and biased, so it takes a qualified tech to do the job.

    Also, power amp tubes don't last as long, especially if you place the amp head on the cab and play - the vibrations, when the tubes are hot, are the quickest way to shorten tube-life. As I stated before mine are rack mounted in a SKB, it has a shock mount system in it so I get a lot of time out of my tubes.

    Tubes are probably the single most sought-after part for old Ampeg amplifiers. Some of the tubes used have since become very rare and expensive. Ampegs have used 7027a, 12DW7, 7199, 7591, 6BK11, to name a few off the top of my head, that command premium prices. These tubes are still available, if you look hard enough. Don't expect to just walk into your local guitar shack and find them. Keep an eye on the internet newsgroup Fortunately, interest in tube circuitry is on the rise, and factories outside the United States have begun to add some of these tubes to their production lines. The 7199, for instance, is being manufactured in Russia and is marketed by Sovtek, although it's been reported that the Sovtek 7199 is not a true 7199, but is merely pin compatible. (Supposedly their 5Y3 isn't a true 5Y3, either, and I've read the same of their 5881; it seems that many old Soviet tubes are similar to desired types, but not quite the same, but they number them as such anyway.) I have also seen the 6BK11 listed in Sovtek advertisements. They've been receiving requests for a run of the 7591, so it wouldn't surprise me if that was to appear soon as well.

    ;) Treena
  8. Not true. Once a tube amp is up and running there is NO maintainence involved, period, end of story. When its power tubes wear out after about 25 years, it needs a cap job and a rebias, just like a ss amp would need a cap job, new output and driver transistors, and a rebias.

    Any reputable tube dealer should be able to supply a set of matched tubes and a bias job is not that difficult to perform. As I stated earlier, ss amps require biasing as well, but no one has gone plastering that in transistor ads in guitar magazines so most folks aren't even aware of it. It's just "something that the amp repair guy takes care of."

    Dirty little secret here: if vibrations are strong enough to cause microphony in power tubes, they're also strong enough to crack solder joints and unseat IC's in ss amps. Vibration is bad, period, not just for tube amps.

    You forgot to give Aspen Pittman credit for that. That last paragraph is lifted from The Tube Amp Book, which he wrote. Aside from the VERY useful schematics, most of the book is just pretty pictures and total Groove Tubes ad BS.

    Besides, most of the "info" in that statement is outdated. Sovtek has been marketing a 7591 and 7199 for the past two years (not that ANY Ampeg bass amps ever used them or the 7199 either). A 7027 is nothing more than a 6L6GC with its grid connections pinned out an extra pin. The 6L6GC is a direct substitute for ALL Ampeg amps. A 5Y3 is low powered tube rectifier and not used in bass power supply circuits either and is in VERY strong NOS supply. SVT's use 12DW7's and 12BH7's (currently made by both EI and JJ electronics) and V4's and B15's use 6SL7's (currently made by Sovtek). B15's also use a 5AR4 rectifier which is currently made by several manufacturers. Modern SLM Cratepegs don't use ANY "weird" tubes, so if you've got an SVT CL or V4BH, you've got nothing to worry about.

    If you're going to use a line, credit the author so that it can be put into proper context. Pittman was a salesman for Acoustic amps in the 70's pushing their s/s amps for years before he began cashing in on the emerging tube craze in the 80's. Many of his technical claims are ridiculous and ring more of sales pitch that true information (see my above post). Part of the reason that people think tubes need replacing every five minutes is because of his advertising which is designed to sell his tubes, not tell the truth. :eek: ;)
  9. Excerpts from original article in VTV #5

    Ampeg Bass Amp

    ;) Treena
  10. Psycho, I'm offended that you didn't remember my beloved B25B. :D You've been climbing around those 300 Watt + monsters too much and forgotten about the low-powered jewels.

  11. I'm not registering to just to be able to log in to the site, but I would be VERY interested to see the date of the article. I have version 4.0 of Pittman's book and the Ampeg bass amp paragraph is produced in its entirety in it and not credited to someone else. Wouldn't surprise me if it's stolen, though.

    I also fail to see the relevance of the VTV article. I have known about Red Bank tubes for awhile. I don't have any amps that require a super rugged 6L6 type or even use EL84's at all and I have been preaching the gospel of overpriced vintage tubes for quite awhile myself. Why that link?

    I don't even LIKE Genalex KT88's; they're too midrangey. Telefunken ECC83's are great, but not in every circuit. And before the GE 6550A was developed, the Tungsol 6550 was the only tube that could even approach the level of abuse the latter variant could take. Hammond organ guys put the price of it through the roof.
  12. Crap! I haven't even seen a B25 in ten years. That's why they publish skits, huh? Doh!
  13. metron

    metron Supporting Member

    Sep 12, 2003
    Anyhoo... keep your SVT CL iceblinko! No need to replace tubes for a long time. I personally didnt like any of Ampegs hybrid stuff (svt4, svt5) IMO you cant go wrong with the CL! :bassist:
  14. Oh yeah. The SVT3 and 4 Pro models are boat anchors, IME. I used to own a 3Pro and have worked on a few 4 Pro's.
  15. You could always have a reputable tech check the amp before you go on a 5 week tour just for your own piece of mind. Other than that I wouldn't worry about it until you notice that something is not right. As long as you don't abuse your head the tubes should last a very long time. For example, I just picked up a nice clean 1976-79 used but not abused Ampeg B25B last month. I took it to a very well respected tech here in Boston to have him go over it and give it some TLC. He told me that the Magnavox 7027A power tubes were still good and they probably are the originals but since the amp was serviced last in 1987 he couldn't say so for sure. So the tubes have at least 16 years on them....
  16. iceblinko


    Jul 15, 2003
    thanks a bunch to all that posted~! i hope what you guys are saying is right. i do A LOT of playing. shows or practice every night or at least once a week. so i hope they can last. does anyone know about how much it is to replace these tubes? this same friend told me that it was about 300. thanks again everyone!!

    xo tom
  17. Bruce Lindfield

    Bruce Lindfield Unprofessional TalkBass Contributor Gold Supporting Member In Memoriam

    I've noticed this in other threads - I think the point is that if you lift large chunks of text from another source, then you should put that in quotes and credit the source - not try to pass it off as your own!! :meh:

    Very bad form!!
  18. metron

    metron Supporting Member

    Sep 12, 2003
    I think this is about right. Probably $200-$300 range. I dont know about the quality of the Groove Tubes that come in the SVT-CL but if your bias is set properly they should last a long time.

    Only about $150 to $200 for the tubes themselves if you know how to bias the amp and don't have to pay a tech to do it.

    They should last for years as long as they are treated nice - mainly, don't drop your amp. Tubes don't die every few months like some folks like to think.

    My Ampeg V4B is still putting out full power with tubes that are 13 years old.

  20. notanaggie

    notanaggie Guest

    Sep 30, 2003
    Tubes definitely last for a long time if not beat on.

    If you run flat-out power amp distortion, they WILL go out in weeks or months, but somehow I doubt you'll do that........

    As far as replacing, you might get stuck witrh whatever the shop decides you'll pay......But it probably should NOT take over an hour to do it, even with a clean-up and look-over. If a problem shows up, then who knows.

    BTW, Ampeg is sitting on a supply of new old stock US made that from my secret source guy there....I don't know if you can get them or if they are holding for endorsers, or what. I haven't ordered a tube from them.

    As far as Ampeg and tubes, the only real issue is the multi-section tubes that were used back when the TV company owned them.
    Anyhow, they are stuff like like a 12AX7 half with both sides of a 12AT7 all in one bottle, wierd things you'll never find new. Only made for that manufacturer, never before or since.

    Good freakin luck....someone needs to make an adapter board or something for those.
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