AC50 FOR BASS?

Safe haven for everything low-frequency. Bass players unite in this forum.

AC50 FOR BASS?

Postby Frickengruvin on Tue May 16, 2006 9:14 pm

I've got a solid state rectified AC50 that is just sitting collecting dust (so to speak)....Is it problematic to use this as a bass head amp coupled with a jbl e140 (15" bass speaker)?
yesteryear's equipment is the salt of the musical earth!
Frickengruvin
Court Jester
 
Posts: 98
Joined: Thu Aug 02, 2001 7:01 am
Location: Sparks, Nevada

Postby gypsy moth on Wed May 17, 2006 1:28 am

it won't hurt the head to run a bass through it.
the questions are on the speaker end - can you adjust the impedance on the 50 to match the speaker? if not, that can kill your head.
do you know the max watts of the jbl? I expect it is more than adequate, but if not you could smoke it.
gypsy moth
King
 
Posts: 5294
Joined: Mon Oct 06, 2003 7:01 am
Location: in the midst of fanatics & zealots

Postby 1953Vintage on Fri May 19, 2006 1:53 pm

What gypsymoth said is right on: you won't hurt the amp by playing bass through it. But the speaker might be another issue.

Watch the cone as you play low notes and determine how much the cone moves in and out. That amp probably won't be able to control the JBL's cone very well at higher volume levels (especially with too much low-end EQ), and uncontrolled excursions can damage your voice-coil by slamming it into the rear of magnet's gap.

I've seen a voice coil jump so far forward that it completely cleared the magnet's gap and stayed there!! Bye bye speaker.

But at low to medium volumes, and with conservative use of low-end EQ, a 50-watt tube should sound fine for bass.

Good luck!
Visit the Sound City Site!
1953Vintage
Baron
 
Posts: 2592
Joined: Mon Sep 16, 2002 7:01 am
Location: Albuquerque

Postby Frickengruvin on Fri May 19, 2006 11:09 pm

Thanks for the input guys. I don't have the speaker right now, it is being re-coned. I bought it used in need of a re-cone. I thought I would put the question out there to determine whether or not I could get away with using it. It will mainly be for practicing purposes-I'm not planning on playing at stage levels with it. When I receive the speaker back, I will check it's rating.....
yesteryear's equipment is the salt of the musical earth!
Frickengruvin
Court Jester
 
Posts: 98
Joined: Thu Aug 02, 2001 7:01 am
Location: Sparks, Nevada

Postby 1953Vintage on Sat May 20, 2006 12:38 am

A stock JBL E140 has a 400W rating, but this isn't the issue. The real issue is the amp being a low-power tube amp with an inherently poor speaker damping capability. As long as you're careful, you'll be fine.

For more information (than any sane person would probably care to read) on speaker damping, click here.

Good luck!
Visit the Sound City Site!
1953Vintage
Baron
 
Posts: 2592
Joined: Mon Sep 16, 2002 7:01 am
Location: Albuquerque

Postby knuck on Sat May 27, 2006 5:33 pm

Well, I have two D140 JBL´s which is a much older speaker and I use them with my Marshall major 200watts of pure tube power and I have never had any problems with that so I dont really get this be careful on the speaker saying. I´ve been gigging like this for about 3years and no sign of any problems, just the best bass sound that I ever had.
About a year ago I used a borrowed AC50 for recording and I used the same speakers with that one and the sound was fantastic.
Just go ahead and crank it up!!!!
knuck
Certified
 
Posts: 202
Joined: Tue Feb 07, 2006 1:19 pm
Location: sweden

Postby Frickengruvin on Sat May 27, 2006 7:08 pm

Thanks for the input! I also through this question to Victor, and he also responded that the ac50 would work with no problems. Maybe someone can advise on who can build a ported cab for the 15 I have....Also, is it a good idea to put a tweeter or a 10' speaker in the cab also?
yesteryear's equipment is the salt of the musical earth!
Frickengruvin
Court Jester
 
Posts: 98
Joined: Thu Aug 02, 2001 7:01 am
Location: Sparks, Nevada

Postby knuck on Sun May 28, 2006 4:41 am

The JBLs are a bit bright so I dont think that you will need a tweeter or a 10" in your cab unless you play disco. :D
knuck
Certified
 
Posts: 202
Joined: Tue Feb 07, 2006 1:19 pm
Location: sweden

Postby speed on Wed Mar 28, 2007 2:44 am

AC50s were often used with Vox 1-18 cabs in the 60s for bass rigs. You can buy a repro 1-18 cab at North Coast Music.
speed
Certified
 
Posts: 174
Joined: Sun Jan 07, 2007 4:29 am

Postby Vortexion on Tue Jan 15, 2008 10:54 am

Nothing like resurrecting an old thread...

When I was a teenager, back in the 1970s, learning to play bass, I owned an AC50*

I played it through a pair of huge folded horn PA bins with 18" drivers that my brother (who ran a PA hire company) had given me.

Only one problem: when I was practicing at home, at what I thought to be a reasonable domestic volume level, the people two houses away were watching their ornaments walk along the shelves! :lol:

(* Why did I sell it? Why? WHY?) :cry:
Vortexion
Newt
 
Posts: 1251
Joined: Thu Jan 10, 2008 4:28 pm
Location: Norwich, UK


Return to Bass Talk

Who is online

Users browsing this forum: No registered users and 2 guests