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Placing amp on top of cabinets

Discussion in 'Amps and Cabs [BG]' started by chardin, Jun 17, 2003.


  1. chardin

    chardin

    Sep 18, 2000
    I have an Eden WT-400 that I put on top of my Bag End cabinets for easy access to the controls. Will the vibrations from the cabinets cause any damage to the amp? What about the tube in the pre-amp?
     
  2. Funkateer

    Funkateer

    Jul 5, 2002
    Los Gatos, CA
    I asked Aguilar tech support this same question. They do not recommend putting any tube equipment on top of a cabinet. Decreases tube lifetime. Vibrations will also be transmitted to tube filaments and this will end up affecting the sound (e.g. microphonics). Having said this, at home, I have my all tube head sitting on top of a 3" thick piece of foam which sits on top of the cab. I don't play terribly loud at home, so this is probably OK. For a gig, I would probably not stack.
     
  3. NJL

    NJL

    Apr 12, 2002
    San Antonio
    i put my rack on top of a keyboard stand.

    my svp-pro makes a nasty pop/crackle noise when vibrated.

    with a keyboard stand, the controls are a little more easier to get to for me
     
  4. jondog

    jondog

    Mar 14, 2002
    NYC metro area
    This makes perfect sense, I don't know why I never thought about it. Maybe the manufacturers should stop making their heaeds the same width as their cabs to discourage people from putting it on top like everyone else.

    My rack is too heavy to be putting on top of my cabs. It has a permanent dolly and stands upright, || instead of =. It's low to the ground, so it's not easy to tweak controls, but I try to control tones w/ my hands and the bass and that works fine. I want a PV DPC . . .
     
  5. Mcrelly

    Mcrelly

    Jun 16, 2003
    Minnesota, USA
    But it looks cool! :D like mine 21" wide rack, 14" wide cabs :meh:
     
  6. Funkateer

    Funkateer

    Jul 5, 2002
    Los Gatos, CA
    The Auralex products seem to be designed to isolate cabs from the floor. Are you using it between cab and head too?
     
  7. jdombrow

    jdombrow Supporting Member

    Jan 16, 2002
    Colorado Springs, CO
    Another inexpensive isolator is a sheet or two of 1" bubble wrap under the head (or some good soft foam, as mentioned earlier).

    JD
     
  8. Mcrelly

    Mcrelly

    Jun 16, 2003
    Minnesota, USA
    is it really necessary to isolate cabs from the floor in a gig situation? I like the sound/vibrations coming through my legs from the wood stage! :p
     
  9. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    Personally I find it funny that bass players are concerned about vibrations from their cabs, but probably cart their thing around in a skb type rack that offers no protection from bumps in transit.
     
  10. I'm not sure I would buy an amp that can't take a little vibration from the cabinet it sets on. Combo amps seem to last forever and they are almost setting on top of the speaker itself. IMO you might get a little more life out of a tube amp by isolating it from vibration but it doesn't seem like it's worth all the effort. Anyway, the sooner your amp wears out the sooner you get relief from GAS. :D
     
  11. rayzak

    rayzak

    Jan 13, 2001
    Louisville, KY
    Woahh, good point jbplayer. I've got an Aggie tube head and it's stayin' put... on top.:bassist:
     
  12. The Gramma works equally as well "between" the rack and cab. I have one for the floor and one for in between. Looks a little odd, but so do I...

    Bubble wrap didn't even come close to working for me, I tried it. I've tried various methods of isolating and the believe me the Gramma works better than anything I've tried. I do have some 2" thick foam used for insulating and it was a runner up, but again the Gramma was MUCH better.

    Some would say this is an exspensive item for the actual material your getting, but I'm convinced that Auralex foam is different and must have some properties that most building/insulating type products you get at your local Home Depot etc don't carry.

    There are several post on the Gramma, do a search.
    If you actually use it for it's intended purpose to "decouple" the cab from the floor you will notice a much more focused low end without the annoying rumble you get on hollow stages. If you like that, well your all set then. :cool:
     
  13. vanselus

    vanselus

    Sep 20, 2000
    Boulder, CO
    None
    How exactly can you quantify a difference between materials placed between the speaker cab and head? How can you tell the Gramma is MUCH better?
     
  14. rumblethump

    rumblethump Supporting Member

    Mar 25, 2000
    Pioneer CA. 95666
    I'm not sure I would buy an amp that can't take a little vibration from the cabinet it sets on. Combo amps seem to last forever and they are almost setting on top of the speaker itself. IMO you might get a little more life out of a tube amp by isolating it from vibration but it doesn't seem like it's worth all the effort. Anyway, the sooner your amp wears out the sooner you get relief from GAS.)

    Although there are a few tube Combos, most seem to be SS or hybrids (tube pre, ss power). If you ever have to replace 4 or 6 6550s (check out the prices on NOS GE's), you might then see the value of the effort. In the 60s I was replacing 6L6s in my Showman every 2 to 3 months. No isolation between the cab and amp. Nowadays, I have a Sunn 2000S that still has the tubes that I bought it with 3 years ago and I use a 3" piece of foam between amp and cab. Tubes can last a very long time if you just make a little effort to protect them.
     
  15. My ears. I didn't use any measuring devices to "quantify", my oppinion. All I know is it stopped the vibration I mentioned earlier in the thread. Maybe "MUCH" was too much. How about A Lot, HA!
     
  16. bucephylus

    bucephylus Supporting Member Commercial User

    Aug 18, 2002
    General Manager TecPadz LLC
    My first amp was a nearly new silver face Bassman sitting on top of a 2x12 cab. No question for that unit that the vibs from the cab did make the power tubes microphonic over time. I never noticed an issue with the pre-tube. For more recent gear, I don't really know, but tubes haven't changed all that much. For my current rack which uses a PLX power stage with an Alembic F1X and ART Tube Channel pres, I went out and bought two gardening foam pads at the hardware store to go between the rack and the cabs. This noticeably cuts down on the mid to high vibs which cause rattles and probably could endanger the circuitry. I figure that's good enough. If not Darwin kicks in and I'll find another piece of gear that does work. So far, in 3+ years no issues. BTW the foam kneeling pads store in the empty slot in the rack during transport.

    - pt
     
  17. jondog

    jondog

    Mar 14, 2002
    NYC metro area
    You must not play very loudly, there's a lot of vibration going on, especially over time. I cannot count how many things have vibrated off the top of my rig over the years -- manymany beers/drinks, pedals, ashtrays, rack lids (one landed exactly on the power strip switch during a gig), DIs, a guitar combo (twice, survived the 1st fall so put it right back up there and broke it for real the 2nd time), tape decks, you get the idea. I have finally learned that the top of my cab is a high vibration zone and that I should not put stuff on it if I want it to stay there.

    I have also learned that stuff vibrates off of a Tolex cab more quickly than a carpeted cab.

    My tube head (Sunn Sorado) lives in a road case. To play it the case top comes off and the bottom stays, like a tray. Between the rubber feet on the tray, the foam inside, and the feet on the head itself, I can put my head on my cab without vibrating it off. The tubes would probably be ok too.
     
  18. vanselus

    vanselus

    Sep 20, 2000
    Boulder, CO
    None
    Yeah you'd think we were smarter than that, but I finally learned my lesson too...

    Put an open can of Sprite on top of my SKB holding a Demeter 201 and a Stew 2.1... wouldn't you know it, damn thing tipped and ran down the front...


    ...right into the cooling vent on the front of the Stewart! :eek:

    that really ups the resale value :p
     
  19. Suburban

    Suburban

    Jan 15, 2001
    lower mid Sweden
    Not so strange. During transit, the gear is turned off, thus much less sensitive. MUCH less.



    Un-:confused: ---:D