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A questions concerning a 100W valve head and cabs

Discussion in 'Amps and Cabs [BG]' started by Dell, May 23, 2005.

  1. Dell


    Apr 7, 2005
    I aquired a little while back a custom Hiwatt 100W all valve head from an old bassist that has toured with them for many years using custom cabs and EV speakers. I am and have been looking for cabs that I can use with my newly aquired head but need to ask a question (I have searched and not found an answer)

    What would be ideal specs for a cab (I cant afford custom made, got to go for the mass produced) for a 100W valve head? It is switchable between 8 and 16 ohms, but I havnt seen any 16ohm cabs. I'm currently borrowing Hartke 1x15 and 4x10 (rated 350W I think?) cabs but they fart at anything above the volume being at 7. I know they are cheap cabs, is this why they are farting?

    I know John Entwistle used to run Sunn 2x15's off his Hiwatt 100 heads, but I cant find any of those anywhere :)

    Unfortunatly I'm not in a position where I can try out bass cabs, Music shops don't stock anything bass orientated (other than hartke and behringer it seems) and my head is too heavy to carry in to london (24Kg, not to mention they're a bit arsy if you actualy want to try something)

    So, as far as I can work out, I need sensitive cabs to get the volume from my low power amp, yeah? something like 100Db@1W/M?
    but what about wattage? If the cabs are rated too high I'm told they'll just fart, yet the Hartke are rated at 350W and are fine untill I get above 7 on the volume and they seem to be pushed too hard, so do I go for more than 350W?

    Oh and selling it to buy something else is not an option, it sounds like heaven and was owned by someone who I have looked up to since I started playing bass so Im not selling it to buy a 1kW head :)

    Thanks for your help guys and gals.
  2. ihixulu

    ihixulu Supporting Member

    Mar 31, 2000
    South Shore MA
    Realistically, with the volume at 7 you are entering the distortion territory for the amp so no cab is going to solve that issue. The farting is a consequence of running 100W.

    As far as cabs go, if you get cabs that are rated for more watts (over 200W each), you will be able to turn your amp up to 10 and go all day without hurting your cabs. Some of the modern cabs that are rated 300W and up for example sound "better" with more power but I think it has more to do with the headroom than the actual wattage. FWIW, I've run my Aguilar GS410, rated at 700W with a 130W MM HD130 and it sounded great. Not loud enough for many things but great tone.

    A note about Entwistle and others from that era: If you look at pics from the mid to late 60's you'll notice those guys didn't just use one 100W amp plus cabs but a wall of them, effectively compensating for the lack of wattage with more speakers.

    IMO, 100W is good for small gigs or a real buzzy hard rock tone. Your best bet is getting a modern 215 or even a 610/810 just so you can push the air.

    BTW, are you sure it's a bass amp and not a guitar amp?
  3. nonsqtr

    nonsqtr The emperor has no clothes!

    Aug 29, 2003
    Burbank CA USA
    You might want to check into the Bag End speakers.

    I sometimes use a "mini-stack" consisting of an S-15 and an S-12, in parallel (4 ohms total).

    That combination works great with a Marshall Major (valve), and an Acoustic 370 (ss).

    They're good speakers, robust, and nice sounding. Might be worth a check-out. :)
  4. Dell


    Apr 7, 2005

    Yeah, I know they had walls of amps back then, but lack of money and space in the van won't let that happen untill I'm signed :)
    The hartke cabs were loud enough for what I do, just about, and I know they're not the most sensitive cabs out there. Most venues I play have a PA to back me up anyway.

    Its definatly a bass head, I got it from a bassist of a long running metal band (incidently, its numberd "4" so he must have used to use atleast 4 of them) and it says 100 Bass on the front :)

    all the 2x15 cabs Ive seen are 4Ohm so I'd have to do it in seperate 1x15 cabs if I went that way. As for 6x10, Ive looked at these too, these are all 6Ohm... Do you think I could run that from a 8 Ohm output? The bloke who we're working with for our EP said it would just make the head run a bit hot?? not only that but the watts of the cabs really goes up with multiple speaker cabs.
    The Warwick 6x10 is 900W max (the 4x10 is 100DB/w/m so I assume this would be about the same) Could I get it re-wired so Im running 3 speakers on each output of my head? or would that make no difference? Or again, maybe 2 two 4x10 cabs rated at 350W each would be better?

    Cheers for your help.
  5. Dell


    Apr 7, 2005
    I dont think they have a distributer in the UK, atleast, I cant find any nor the bag end website.
  6. James Hart

    James Hart

    Feb 1, 2002
    Endorsing Artist: see profile
    I won't comment on cabinet choice....

    but I run 2 4ohm cabinets with a "series" cable (it's a Y cable I had custom made) for a total of 8 ohms to run with my tube head.

    Tube heads generally don't loose significant output because of running @ higher Ohms like Solid State stuff does.
  7. Dell


    Apr 7, 2005
    Thats an interesting idea, James. how many watts are your cabs and head rated at?

    Oh, and I just found this Eden Cab http://www.eden-electronics.com/products/cabs/indiv/d215xlt.asp
    4-8 ohm... how does that work? does that mean it is switchable? And as its only 400W I could run two of those cabs off my head if I decided to later.
  8. James Hart

    James Hart

    Feb 1, 2002
    Endorsing Artist: see profile
    Head is 400 watts of all tube (8x KT88) and my cabs are rated @ 850watt and 1000watts.

    yeah the Eden might work nicely... not sure if it switches, you might need to order it @ 8 ohms
  9. No... They blow up!!! Going LOWER with a tube amp is no porblem, but you LOSE output power. Going higher is dangerous, especially with a Hiwatt.
  10. 44me


    Jun 17, 2002
    Bedford, NH USA
    I think James meant that you can typically get the same power at 8 ohms as 4 due to the output transformer impedance matching. Hopefully all tube amp owners know not to run higher impedance loads than the amp's rating.
  11. James Hart

    James Hart

    Feb 1, 2002
    Endorsing Artist: see profile
    sure if you are dumb enough to exceed manufacture specs :rolleyes:

    Where did I say "Ignore common sense and factory limits if it suits you" in my post??!?

    *My* amp runs at either 4 or 8 ohms. I run 2x 4ohm cabs in series (8 ohm load) and have the same output as if I had 2x 8ohm cabs in parallel (4 ohm load)

    where if it was Solidstate, I could expect to be running at 2/3rds the wattage @ 8 ohms compared to 4 ohms
  12. Joe Beets

    Joe Beets Guest

    Nov 21, 2004
    I won't comment on the cabinet choice, but I do know something about farting. See if the Hiwatt head has a preamp or line out jack on the back. If so, run this to an external power amp. It should make T.O.F. (threshold of farting) just a bad memory. :smug:
  13. Old Hiwatt bass amps are going to be at LEAST thirty years old and likely isn't any operational literature for them, because there wasn't any written in the first place. 'Back in the day' tube amps and their operation were still pretty common knowledge. They're not anymore.

    Proper operation of tube amps runs contrary to what most bass players consider to be common sense. Solid state amp run best at rated imedance or HIGHER, any amp with an output transformer needs a speaker load equal or LOWER for safe operation. I doubt there are ANY published factory limits, especially that explicitly state HOW to hook up cabinets to the amp.

    Most Hiwatts have switchable output impedance from 16 to 8 to 4 ohms with a plug on the back, but he's already confused as to how to properly hook cabs to the amp. Since the taps are already there for equal power at the selectable impedance, there are lots more options that don't require potentially VERY dangerous series speaker cabling.

    Relax, James. I didn't mean to single you out. He's obviously gotten some bad info somewhere from the looks of this:

    ...because running a 6 ohm cab off an 8 ohm tapped amp output, decreases power and makes the amp run COOLER and put out less power, not hotter. Whoever gave him that advice is thinking like the Hiwatt is a typical solid state amp.

    Replying to that with what you said makes it look like you're endorsing his previous misinformation. Series wiring togther two cabs is going to result in a HIGHER net impedance and a higher probability of damage to the amp. Hiwatts run their tubes at nearly their operational limits, and a higher than expected speaker impedance WILL cause serious damage. I only wanted to underscore the danger.
  14. The 0x

    The 0x

    Aug 24, 2003
    Timonium, MD
    Entwistle NEVER used Hiwatts with Sunn 2x15s, he used Hiwatt 4x12s & occasionally Hiwatt 4x15s with them.

    But yeah, congradulations, i'm extremely jealous of you!!!! :bawl:
  15. Dell


    Apr 7, 2005

    Either way, I can't find those cabs in this country either :)
    The amp repair man phoned up hiwatt to ask for a wiring diagram and they said they had nothing from the original company and wasn't aware they ever made custom amps for this person I got it off.
    Anyway, thankyou for you input. Looks like the closest thing I can get to that 70's thing is with the Eden 2x15 8Ohm cab I mentioned above and look at getting another cab later.
  16. popinfresh


    Dec 23, 2004
    Melbourne, Aus
    If you want a Sunn 2x15, check ebay. They go quite often.
  17. Dell


    Apr 7, 2005
    Ive been watching ebay since feb and I havnt seen any available for the UK yet.

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