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Advice on Tube/Valve bass amplification

Discussion in 'Amps and Cabs [BG]' started by minnikin32, Sep 11, 2004.


  1. I have noticed there is no one stop advice thread for people moving from SS to Tube/Valve. So Here I have drawn up a few points to help people upgrading their rig, valve or not, and for some who are have bought their first valve bass rig.

    * THE SOUND: Firstly you moved to Valve because you wanted a solid rock or a punchy warm bass sound, didn't you? Remember the reason you move to valve is the same reason guitarists use valves, they produce harmonics different to solidstate, and they sound much more desirable to that of solidstate clipping (YUK! :spit: ) which sounds worse that scraping your fingernails down a blackboard! i.e. valves can be overdriven without sounding sh*t. And just like valve guitar amps, valve bass amps sound better LOUD! You cannot use this in a bedroom without blowing windows out/annoying neighbours, or with it sounding weak and wimpy. :eek:

    * RACKMOUNT HEADS: If your head is rackmounted, shell out a bit more for a shockmounted flight case, NEVER get a plastic moulded case. These amps get VERY hot and easily melt thermal-mould plastics.

    * CASES: Get a case for your head, even if it's rack or not. Line it with hard foam (not furnishing foam). Ask your local flightcase manufacturer.

    * YOUR BACK: Get wheels for it, a trolley or wheels on a case. Your back with thank you. If you need to take it upstairs, make sure the handles on the case are positioned on the case so you don't have to monkey-walk on the stairs, this is very dangerous, especially with heavy items such as valve bass heads.

    * POWER RATING: Yeah, the amps are rated at 300/400 watts, this means nothing whan you compare them to solidstate heads. A 300 watt valve head push like a 900 watt solidstate head. Make sure your cabinet can handle the extreme transients that the valve head outputs.

    * SPEAKER LOAD: Another thing about the cabs, solid state heads usually have a minimum impedance/load, like 4 ohms for example, which means you can put cabs that add up to 4/8/16/32 ohms on the amp if you like, even have them disconnected (the impedance of air!), Valve amps require you have a fixed load, usually selected by a switch on the back (the SVT handles 4 or 2 ohms, which means you can't just plug a signgle 8 ohm 4x10 in). If you ignore this, this puts undue stress on the power valves, shortening their life, or even blowing them instantly. Plan your cabinets carefully. Remember 8 + 8 ohms in parallel = 4, 4 + 4 ohms in parallel = 2, This means if your amp is in 4 Ohm mode, you can connect 2x 8 ohm speakers or just one 4 ohm speaker. :eek:

    * TEMPERATURE: This is what I done with my SVT2-PRO... I installed two 80mm fans on the back of my rack pulling air out of the SVT 2, and had them running slower than usual (cold air + hot valves = smash! well, weakens the glass!). This kept the rack cool and when disconnecting at the end of the night, didn't burn your fingers. (unless you'd like to fry up some bacon and eggs on top of your amp at the end of a tiring gig!) :rollno:

    * GLOWING GLASS: I know it's expensive, always take an entire spare set of valves, pre and power, to gigs and studios. And usually, try and get power valves in matched pairs or sextets (for SVTs and similar) or dozens (400+s). I'd reccomend finding the brand of valves in your amp before buying. If you fancy a change, I'd reccomend Electro-Harmonix (excellent and mid priced), or Groove Tubes (expensive but guaranteed to impress). After you get you amp revalved (power section), get it 'biased', with some SVTs, you can do this yourself, with others you may have to see an expert. :(

    * VALVES/TUBES?: For our American friends, I apologise if you are a little baffled to why I call tubes 'valves'. It's because I'm from the UK, we call them valves over here, sorry for the confusion! :D This will help if you get tubes imported from the UK (hotrox.co.uk is pretty good selection and value), or even valves from the US (for us Britons!)

    * IS IT WORTH IT?: I know the weight, the expense, the reduced reliability, fragility and the additional maintenance are all daunting factors when moving from SS or Hybrid to All-Valve, but remeber you are doing out for a reason, the sound YOU want! If clean hi-fi SS suits you, go for it. If grinding powerful Valves are your thing, also go for it! However, I used to have an SVT2-PRO, and had shifted from that to an SVT3-PRO, just because of the weight difference, and sounds very very cool, having an all tube preamp and power amp driver section. Hybrids are a pretty good happy medium for the undecided!

    If you think some of this advice is incorrect, I have missed something out, or you have further questions about valve amplification, please reply on this thread. I sure myself and other users would be happy to help. :)

    Best of luck everyone! :hyper:

    Glenn Minnikin
    glenn@minnikin.com
    United Kingdom
     
  2. Selta

    Selta

    Feb 6, 2002
    Pacific Northwet
    Total fanboi of: Fractal Audio, AudiKinesis Cabs, Dingwall basses
    +1

    I vote for this to be sticky'd! Lots of good info here, especially for people who, like me, are recently or will be moving to valve/tube soon...
    Ray
     
  3. While it's admirable that you're sharing your love for tube bass amps, you're not doing anyone any favors with this post, which contains loads of misinformation and is not as you claim, a "one stop advice thread for people moving from SS to Tube/Valve." Here's why:

    The difference in harmonics has more to do with amplifier class and the fact that the amp has an output transformer than device type. It's a popular myth otherwise, but a myth nonetheless.

    This is ENTIRELY, completely false. Amps of all types have to pass UL inspection the United States to be sold in most places. Part of that means that they DON'T spontaneously melt objects close to them. While tubes DO get hot, they're surrounded by evacuated glass envleopes whose specific purpose is to KEEP them from burning. Yes, some of the heat from their operation IS conducted through their bases and the tube sockets to the amplifier's chassis, but it is NO more than the heat produced by a typical solid state bass amp. I'll also remind you that shock cases are just wooden boxes laminated with plastic or vinyl with aluminum support rails and NO MORE flameproof than a typical molded plastic case, not that it's an issue anyway.

    This is ludicrous. If you can CARRY around 150+lb cabinets, a tube bass head is nothing. You can also CAUSE serious damage to ANY amp head by rolling it around on a wheeled case which subjects it to far worse vibrational stress than even the loudest cabinet. If you do have to wheel it, make sure it's in a shock rack with large rubber casters, but considering most tube bass amps weigh at MOST 20 lbs more than their s/s counterparts, there is NO need. If the weight bothers you THAT badly, consider a different amp.

    Tube amps can peak out at much higher wattages than their s/s counterparts, but they're NOT going to trash cabinets any more. Follow the cabinet's rating and don't worry about it.

    The biggest thing you neglected is that the danger with tube amps is to go HIGHER than the rated output impedance. Tube amps typically tolerate 100% mismatches either direction, but with a higher than rated load, this causes a dangerous rise in plate voltage of the tubes and can destroy the amp. It's the opposite of s/s, where it's lower loads that damage an amp.

    Unless your tubes go into complete runaway in a MASSIVE amp, their envelopes are not going to be affected in the least by operation. If your amp does "lose" its bias (which will cause the MOST heat) for whatever reason, the HV fuse will blow. BTW, repeated heat stress of glass envelopes usually STRENGTHENS them. Besdies, if your amp is getting hot enough to exhibit what your describe, there is something BADLY wrong with it.

    While tube dealers may endorse this view, it's false and potentially dangerous. If your amp is "blowing" tubes, there is something wrong with it and it needs service, PERIOD. I have yet to see ANYONE ever pop out a "spare set" of transistors and "retransistor" a s/s amp that has blown its output section. And it's also patently obvious from your recommendations by now that you have NO business endorsing the idea that an amp owner can bias an amp themselves. Solid state amps require biasing too, but I have yet to see a neophyte attempt that either. If your amp is not stable enough to gig without worry, there is something wrong with it. Musicians played many gigs with tube amps for decades without carrying around spare parts.

    Thermionic valve- no big deal.

    ...none of which actually EXIST!

    I think I've made my position known.
     
  4. James Hart

    James Hart

    Feb 1, 2002
    toms_river.nj.us
    Endorsing Artist: see profile
    Thanks for the corrections Psyco!... I'm stepping into the world of modern, giggable tube amplifiers shortly, I might become a bother with questions.
     
  5. Hooray, this post IS starting to become a one stop information shop on valve bass amps! Just a few points of my experience with valve bass amps.

    A fellow SVT2-PRO user had their's in an SKB rack, the plastic went all soft and mishapen. He ended up not bothering with a case.

    My amp lived quite happily on some quality castors, in an non shock rack. But I wouldn't ride the poor thing over a cobbled road!

    I thought that no matter the situation, there should always be a backup. Basses?... Take spare strings.

    Infact, I did change my amp because of the weight, my roadies consist of myself, my dad and his mate, both aged around 60 (so they would complain!) I'm only 21, so I was happily hauling the beast around myself. I ended up with an SVT3-PRO (which I prefer over the SVT2 sound wise!), much lighter for the wrinklies to carry (I love my dad really!)

    That was a better and more accurate explanantion of speaker loads on valve amps than mine, excellent!

    Apparently there was nothing wrong with the heat from my amp, I asked Ampeg they said it was normal!

    And I wouldn't be a neophyte, I have been playing bass for 11 years and used an SVT2-PRO for 5 years (I hired a 400+ bfor a week before that, but couldn't afford one, it was a beauty!) Might not be a bass veteran, but 11 years is quite long for a 21 year old!

    All the above information is from MY experience. That's all. I gladly accept your critisism, I find it most informing. Thank you for opening my eyes (no, seriously!).

    I just hope we could all be friends in this forum, people have helped me out already, and I'm really enjoying this forum, I just thought I could put something back into it.

    If you would prefer I delete my post because it is misinforming and contains myths and untruths, and feel it would misguide, just say the magic words!

    Glenn Minnikin
    glenn@minnikin.com
    United Kingdom
     
  6. It shouldn't. That's the same stuff the ARMY carries high explosive ordinance inside! If an amp is getting that hot, there is something SERIOUSLY wrong with it.

    It's a time/taxes thing; vibration can break solder connections and unseat tubes. It won't instantly kill your amp, but it is NOT good for it.

    I don't take spare strings to gigs either. If I can't trust a piece of equipment to stand up to how I play, I fix or replace it.

    An SVT3Pro isn't all that light either; I've had one.

    Did you tell them it was melting SKB cases?

    You're a neophyte when it comes to AMPS! You're offering advice from a position that you don't understand. I've been FIXING amps for thirteen years and playing bass for eleven myself. Considering the subject is an amplifier, experience should relate to THAT, not to playing bass.

    I believe you and based upon my experience working on the things can surmise some things from your posts that point to reasons as to why your info is not a hard and fast rule, so I point that out.

    The discussion itself is good because it points out and debunks a lot of popular misconceptions. Even if a viewpoint is wrong, it's important that others see it and understand why it's wrong. The politically correct police who want everyone to "get along" with no disagreement are missing the point. I like lively discussions and while I'm not the most popular poster here, I'm VERY easy to get along with.
     
  7. Yep I guess there was!

    It lasted for 5 years... and still going. The castors were pretty good and had nice rubber tyres.

    What happens if you snap a string in a gig? Ring your dealer for a new bass pronto? I want a dealer like that! I like to eliminate all eventualities, Murphy's Law...

    It isn't that light, but a damn load lighter than a SVT2-PRO

    Heh heh heh! I think that might have been a noggin scratcher!

    Yep. Point taken.

    I'm glad you think it was a good idea to start this discussion. There can be disagreement, and people can get along. Critisize and discuss WITHOUT the attitude and more people will listen.

    Yeah me too. I hope you are verey easy to get along with, there is few bass players I can talk to over here in the North of England, so these forums are always buzzing and I can feel free to express opinions and recieve advice.

    I can only critisize on one thing. Your advice is fantastic, and very informative and to the point, but looking at your posting history, your attiude stinks. Look, I totally understand the way you post, to the point, and make sure it's noted. But take it easy, we are all friends and fellow bassists here! It just makes it easy for everyone to get the information they need fast without the aggro.

    Anyway, went a little off topic, this is about VALVE BASS AMPS. Advice (accurate and bogus) and questions go here!

    All the best

    Glenn Minnikin
    glenn@minnikin.com
    United Kingdom
     
  8. Selta

    Selta

    Feb 6, 2002
    Pacific Northwet
    Total fanboi of: Fractal Audio, AudiKinesis Cabs, Dingwall basses
    I'd think it'd be a plesant idea to maybe delete this thread and start a new one with correct and complete information. That way newbies don't have to read 20 replies to get everything, and there's no...conflict, for lack of a better word.

    I'd also suggest that there be a few other, sticky'd posts, such as "I need a new/louder/beginner" amp and "Ohms, Watts, Cabs, Heads and Racks" or something. I don't know...just seems to be alot of repeats.

    My $0.02

    Ray

    Edit: Maybe also one on power, such as what's enough for which situations? I dunno. Or one massive FAQ thread, though people ignore those it seems...
     
  9. Removal would be a good idea. I apologise for giving sh*tty info.

    Glenn Minnikin
    glenn@minnikin.com
    United Kingdom
     
  10. It quite possible for an amp to run too hot for a long time without it destroying itself. It significantly shortens tube life, though. Rubber tires are also what I suggested.

    If I didn't know better, I would take that as a sarcastic response. ;) :p

    I've only broken one string, a low E on my Jazz, in all my gigging, and it was worn out. I didn't have a back up bass, so I just detuned the other strings and adjusted my playing to compensate. It sucked; lesson learned. Since then, I don't take worn-out strings to gigs and haven't had any problems. My plucking technique makes Billy Sheehan look sedate, BTW.

    Amps are not consumable items; they either work or they don't.

    Please point out an exmaple of my exhibiting this elusive "attitude." So far, the only sarcasm has been from you, and I got the joke, so what's the big deal?

    Please tell me how you've managed to divine my "attitude?" This is a forum of words. Whatever emotions you attribute to those words, YOU brought with you. If my response to your post offended you, I'm sorry. I take offense to having someone else tell me what "my attitude" happens to be, especially when they have no idea, so I'm telling you now; I am open to technical discussion. Personal observations, like the one you just made, you can keep to yourself if you want to keep things friendly. Not only is it wrong, it's a violation of forum rules.

    If I understood exactly WHAT was so "aggro," I wouldn't post it, but I cannot be responsible for things you "read into" them. If you really "totally understand the way I post" you'll know there is no intended malice.
     
  11. OK OK OK OK OK!

    Look, I'm sorry, I was misguided. It was just the way you post as though you look down on people like they know nothing, and you knew all. In your above posts there appeared to be malice, as though to say "ha ha you are al wrong, I am always right". About amps, you might be though!

    To tell you the truth, the word neophyte used casually is EXTREMELY offensive where I live, especially between two people who should considered equals. I should have backed off and looked at the big picture. Even better, should have ignored it.

    I am really sorry from the bottom of my heart for questioning your attitude, and offending you, only as I was offended myself. I forgot that we are here to discuss bass (bass amps to be more precise), not to get at eachothers necks.

    And yes, that was sarcastic! Just I believe in taking backup and spares, like many people do. Especially when it came to valve amplification (and even more especially when daft guitarists spill beer down the back of their amp and shatter the valves!). If you don't take spares and things, and that worked, good on ya!

    Anyhow... is this thread about VALVE AMPS or WHAT?

    Glenn Minnikin
    glenn@minnikin.com
    United Kingdom
     
  12. Selta

    Selta

    Feb 6, 2002
    Pacific Northwet
    Total fanboi of: Fractal Audio, AudiKinesis Cabs, Dingwall basses
    *shakes head*....

    [Monty Python voice]

    And now for something completly different

    [/Monty Python voice]

    let's get back on topic at least?
     
  13. Yes indeed. Actually I do have a question. I haven't head much about the Eden valve head they make, VT300 or something, has ANYONE had any experience with it? I'm interested in getting one for studio use and for an alternative sound. I'm looking mostly at lower powered valve amps like the ampeg B15, but this one just seemed interesting!

    Glenn Minnikin
    glenn@minnikin.com
    United Kingdom

    PS. Damn! If only the [Monty Python voice] tags worked!!!
     
  14. Fred Labbidie

    Fred Labbidie Guest

    Apr 22, 2004
    It's an interesting quandrey. People post their experiences, draw conclusions from them, and get others to chime in with their anecdotes and what they believed happened to them.

    It's a woefully inaccurate way to discuss anything technical.
    However, this is "talkbass". It's pretty much a bunch of Bass Player yakking to each other. If we were in a bar there wouldn't be any more accurate or factual information in the discussion.This type of bull session works better for subjects that don't involve math.

    I do think that people should post what they have experienced, and if they posit something as fact that is not true....they can respectfully corrected. I don't have a clue to what you think and feel, Mr. Psychobassguy. Your posts always have a lot of good info. Maybe just a little more fiber in your diet. :eek:
     
  15. IvanMike

    IvanMike Player Characters fear me... Staff Member Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    i'd love a valve amp - i really like the ones i've tried
    a few reasons why i dont have one
    #1 i cant afford one now
    #2 i'm pretty happy with my current tone (alembic & demeter pres into a stewart 2.1 amp), stewarts are kinda GIGO amps
    #3, my guitar player is a valve junkie - swaps tubes, rebiases tubes, plays with 3 or 4 different amps, power brakes, finds that the "sweet spot"/"brown sound" (i.e., where the amp distorts slightly on the attack and fades into a nifty tone) happens at a volume way too loud for practical club use, etc, etc, etc.............
    i'm bad enough as it is, i dont need more worries when it comes to tone and GAS :p
    i'm sure one day i'll get a valve power amp (or 2), just not now
     
  16. An enema! That's a little extreme!

    Yes, it's the Eden VT300B, if anyone knows anything about it.

    Cheers

    Glenn Minnikin
    glenn@minnikin.com
    United Kingdom
     
  17. If your happy with your sound now, and your amp works for you, stay put. Why fix something when it isn't broken?

    Glenn Minnikin
    glenn@minnikin.com
    United Kingdom
     
  18. Selta

    Selta

    Feb 6, 2002
    Pacific Northwet
    Total fanboi of: Fractal Audio, AudiKinesis Cabs, Dingwall basses
    Because you can ;). My acoustic works fine for me, but I wanna go tube, and a bit more agressive (a sound I can dial in with two pedals that I own mind you), but if i can do it otherwise, hey why not :p.

    Ray
     
  19. Fred Labbidie

    Fred Labbidie Guest

    Apr 22, 2004
    Too extreme, after I thought about it. I never knew anyone who had that Eden amp.
     
  20. I suppose, a plus with valve power stages is that they FEEL completely different to SS. You can't hear it (i'm some situations) and you can't measure it, I just had a different feel what I had the SVT. It's more exciting, but don't ask why it just is, honest!

    Glenn Minnikin
    glenn@minnikin.com
    United Kingdom