• TalkBass has been independent since 1998. Add your voice.
    Create a free account to reply to discussions, view embedded media, and browse with fewer display ads.
    Join freeLog in
    Want zero display ads or expanded classifieds tools? Compare plans.

Are sealed cabs recommended for tubes heads?

PaperbackRyder

Supporting Member
Apr 21, 2007
919
1,068
69
Maynard, MA
Are sealed cabs the choice for a classic tubes head?
I am thinking classic SVT, V4, Showman heads. The original cabs for these heads were all sealed, given the available tech in those days...
IDK the tech details, but something to do with damping factor, cone control etc. SO...
Do tube heads work best with sealed cabs? If so, is it because the speaker cones aren't as free to move in a sealed cab, as they are in a ported design...and tube heads were designed with this in mind? Thanks.
 
Are sealed cabs the choice for a classic tubes head?
I am thinking classic SVT, V4, Showman heads. The original cabs for these heads were all sealed, given the available tech in those days...
IDK the tech details, but something to do with damping factor, cone control etc. SO...
Do tube heads work best with sealed cabs? If so, is it because the speaker cones aren't as free to move in a sealed cab, as they are in a ported design...and tube heads were designed with this in mind? Thanks.


FYI, Ported cabs can be designed to work well with tube amps.

I have some Genz Benz 1288Ts that get along with all of my tube amps. These cabs are voiced to be somewhat warm and they are not hyper-focused. The lows are very even, with all of my tube amps.

I also have a pair of EV TL405s loaded with EVM18Bs. I think they sound better than the GB1228Ts with some of my tube amps. My vintage SVTs sound great through these cabs. They don't work well with all tube amps though. With an Aguilar DB359 they have a resonance at G#1 (about 52hz). The resonance is not horrible, but it gets on my nerves.

My understanding is the resonance corresponds to the upper peak in system impedance.

This chart shows the impedance with the standard tuning. My cabs are tuned lower in step-down mode, which I believe would alter this curve somewhat.
upload_2022-11-26_20-15-34.png

Notice there is an impedance peak in the mid 50hz range.

The best advice is try before you buy. I would not recommend totally avoiding all ported cabs, as you may miss a really great amp/cab combination.
 
  • Like
Reactions: Arthur U. Poon
Are sealed cabs the choice for a classic tubes head?
I am thinking classic SVT, V4, Showman heads. The original cabs for these heads were all sealed, given the available tech in those days...
IDK the tech details, but something to do with damping factor, cone control etc. SO...
Do tube heads work best with sealed cabs? If so, is it because the speaker cones aren't as free to move in a sealed cab, as they are in a ported design...and tube heads were designed with this in mind? Thanks.


SVT heads are pretty tight even with a good ported cab but yeah the sealed cab does make them "quicker" but I'll use them with ported B-15 cabs sometimes and they sound good. Any good tube head should sound good with either if they're also good. The original Showman cabs weren't very rigid and didn't control the cones as well as Ampeg cabs, Ampegs were made with thick 9 ply plywood, the Fenders I think were particle board, so you can't really make blanket statement like that. I had drinks fall off the top of many Fender cabs back in the day, never from an Ampeg cab.
 
have to be completely honest here.....and keeping in mind that I have been fortunate enough to play nearly every brand on the market...but I have come to the realization that sealed cabinets are the way to go. Right now I am playing an Ampeg V4B with the 2X12 cabinet and couldn't be happier - both for the less weight (old man) but more importantly, the tone. However, when it comes to needing a tad more "umnmph", I go with my Acoustic 370 and 402 cab (loaded with Eminence 15s). But as in everything, YMMV.... Happy Holidays!!
 
have to be completely honest here.....and keeping in mind that I have been fortunate enough to play nearly every brand on the market...but I have come to the realization that sealed cabinets are the way to go. Right now I am playing an Ampeg V4B with the 2X12 cabinet and couldn't be happier - both for the less weight (old man) but more importantly, the tone. However, when it comes to needing a tad more "umnmph", I go with my Acoustic 370 and 402 cab (loaded with Eminence 15s). But as in everything, YMMV.... Happy Holidays!!

I was under the impression that the Acoustic 402 was ported, not sealed?
upload_2022-12-2_14-38-55.png
 
Indeed! The 402 is ported....but I rarely use it any longer. I prefer the Ampeg rig..but yes, occasionally I need to go a little "bigger" so that's when I grab the 402 and the 370. As for the weight as listed above for the 402 cab - Either I have learned to handle it better or the weight is not correct...yes, when I changed out the original speakers with the eminence speakers it did increase the weight but (although I can't swear to it) before hand, it felt light as all get out.......weird..