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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => LAB Subwoofer Forum => Topic started by: Nate Armstrong on May 14, 2012, 12:48:01 pm

Title: Replacement Drivers t36
Post by: Nate Armstrong on May 14, 2012, 12:48:01 pm
I friend just purchased a used small pa system for small events

DBX drive rack pa
1 crown ce1000a
1 crown ce4000
2 Cerwin Vega v-152 tops
2 Cerwin Vega T36-750  ( 8 ohm )

he was told that one of the sub drivers had just been re coned. When we went to purchase the system one of the subs did not work.  The system was still purchased at a discount.  we are uncertain if the damaged sub is the newly re conned woofer,  or more likely the original sub is the one that is now damaged


after inspection of the sub enclosure the wiring was connected correctly , after testing the ohm load it has a .1 reading ( toast )

we have toyed with the idea of only replacing the damaged sub and seeing how the new sub works with the oem sub that still works properly.   I know its not a great idea mixing subs, but if we could find a driver that is very similar, would it be doable  temporarily, until we recoupe some of the money to purchase a 2nd driver.

Can someone recommend some good choices to replace the blown cerwin vega sub woofer ?  -thanks
Title: Re: Replacement Drivers t36
Post by: Ivan Beaver on May 14, 2012, 05:44:31 pm

after inspection of the sub enclosure the wiring was connected correctly , after testing the ohm load it has a .1 reading ( toast )

I would look closer again at ALL the wiring in the cabinet.

It is VERY rare (but I have seen it a couple of times) that a "blown" driver has a .1ohm reading.  Most of the time it reads an open (wires acted as fuses- to protect the amp).

It is possible that you have a short somewhere inside the wiring of the cabinet-causing the very low reading.
Title: Re: Replacement Drivers t36
Post by: Nate Armstrong on May 14, 2012, 08:56:47 pm
I attached the speaker directly to one side of the amp. Zero output.
Title: Re: Replacement Drivers t36
Post by: Ivan Beaver on May 15, 2012, 07:26:41 am
I attached the speaker directly to one side of the amp. Zero output.
And that is what I would expect with a .1 ohm resistance.

You FIRST need to find out what is causing that short.

Disconnect the loudspeaker DRIVER (I'm not talking about the cabinet terminals) and measure the terminals of the driver itself-without any wires hooked to them.

THEN you go from there to find the problem.
Title: Re: Replacement Drivers t36
Post by: Nate Armstrong on May 15, 2012, 09:24:22 am
the speakers and amp are 2 hours from me.   The reading was taken directly from the raw speaker and not the cabinet.  I feel it has been determined the speaker no longer functions. I am now looking for a replacement
Title: Re: Replacement Drivers t36
Post by: Ivan Beaver on May 15, 2012, 05:49:55 pm
the speakers and amp are 2 hours from me.   The reading was taken directly from the raw speaker and not the cabinet.  I feel it has been determined the speaker no longer functions. I am now looking for a replacement
Did you happen to look at the leadin wires (from the terminals to the cone) to see if they were touching?  I've seen that a couple of times.

I would suggest the best thing to do is the simply get the driver reconed.  That would be your cheapest way out-and would get the cabinet back to original functioning condition.

Are there drivers that would perform bettern in those cabinets?  Maybe.  But you may gain something in one area-and lose something in another.

The one thing you DON'T want to do with a horn cabinet-is to simply replace the driver with one that you "think" is better.  Often the result is worse sound-but people "think" it is better-because they did it themselves-so it HAS to be better-NOT.
Title: Re: Replacement Drivers t36
Post by: Chris Carpenter on June 01, 2012, 10:30:19 am
the speakers and amp are 2 hours from me.   The reading was taken directly from the raw speaker and not the cabinet.  I feel it has been determined the speaker no longer functions. I am now looking for a replacement
Absolutely what Ivan said; don't just drop a random driver in a cabinet, especially a horn, especially just one of a pair.

Getting it re-coned is probably your best option. These guys have a pretty impressive resume of re-coned Cerwin drivers: http://www.speakerrepair.com (http://www.speakerrepair.com)

If you have to replace, the proper driver is the FH18A (http://www.cimplesolutions.com/other/CV_International_Pro_Audio_Parts_List_2007.pdf (http://www.cimplesolutions.com/other/CV_International_Pro_Audio_Parts_List_2007.pdf)). Perhaps see if Cerwin Vega can sell you a replacement (I've never owned any of their gear, so I cant vouch for their service).
Title: Re: Replacement Drivers t36
Post by: Nate Armstrong on June 01, 2012, 04:16:11 pm
Thanks for all the help. ill let you know how it turns out
Title: Re: Replacement Drivers t36
Post by: Chris Gruber on June 04, 2012, 03:29:04 am
Absolutely what Ivan said; don't just drop a random driver in a cabinet, especially a horn, especially just one of a pair.

Getting it re-coned is probably your best option. These guys have a pretty impressive resume of re-coned Cerwin drivers: http://www.speakerrepair.com (http://www.speakerrepair.com)

If you have to replace, the proper driver is the FH18A (http://www.cimplesolutions.com/other/CV_International_Pro_Audio_Parts_List_2007.pdf (http://www.cimplesolutions.com/other/CV_International_Pro_Audio_Parts_List_2007.pdf)). Perhaps see if Cerwin Vega can sell you a replacement (I've never owned any of their gear, so I cant vouch for their service).
Actually the proper driver for the T36 is the L1815. Recone kits can be had here http://reconekits.com/cerwinvega1815-8.aspx and are available in 4 ohm and 8 ohm versions. These kits are decent, I used them in some T36s I used to have and they never let me down.
Title: Re: Replacement Drivers t36
Post by: Chris Carpenter on June 04, 2012, 07:56:28 am
Actually the proper driver for the T36 is the L1815. Recone kits can be had here http://reconekits.com/cerwinvega1815-8.aspx and are available in 4 ohm and 8 ohm versions. These kits are decent, I used them in some T36s I used to have and they never let me down.
L1815 is the original woofer, FH18A is the replacement.
Title: Re: Replacement Drivers t36
Post by: Gary on June 23, 2012, 01:31:45 pm
I friend just purchased a used small pa system for small events

DBX drive rack pa
1 crown ce1000a
1 crown ce4000
2 Cerwin Vega v-152 tops
2 Cerwin Vega T36-750  ( 8 ohm )

he was told that one of the sub drivers had just been re coned. When we went to purchase the system one of the subs did not work.  The system was still purchased at a discount.  we are uncertain if the damaged sub is the newly re conned woofer,  or more likely the original sub is the one that is now damaged


after inspection of the sub enclosure the wiring was connected correctly , after testing the ohm load it has a .1 reading ( toast )

we have toyed with the idea of only replacing the damaged sub and seeing how the new sub works with the oem sub that still works properly.   I know its not a great idea mixing subs, but if we could find a driver that is very similar, would it be doable  temporarily, until we recoupe some of the money to purchase a 2nd driver.

Can someone recommend some good choices to replace the blown cerwin vega sub woofer ?  -thanks
Hope I'm replying correctly, first time on a forum. The quickest way to verify a burned speaker is simply pushing in & out on the cone. If you feel rubbing it's fried hence the 1 ohm short. Someone mentioned the FH18 woofer. There is actually an American and a Chinese version of that speaker. Same basic parts except a small difference in the voice coil. I happen to have two freshly rebuilt Chinese fh18 8 ohm in stock. The customer left them over 30 days ago so they are now up for sale for to recover repair costs. $140. ea plus shipping. If interested I may be contacted @ info@musicmagic.biz
Title: Re: Replacement Drivers t36
Post by: Chris Carpenter on June 24, 2012, 05:37:18 pm
Hope I'm replying correctly, first time on a forum. The quickest way to verify a burned speaker is simply pushing in & out on the cone. If you feel rubbing it's fried hence the 1 ohm short. Someone mentioned the FH18 woofer. There is actually an American and a Chinese version of that speaker. Same basic parts except a small difference in the voice coil. I happen to have two freshly rebuilt Chinese fh18 8 ohm in stock. The customer left them over 30 days ago so they are now up for sale for to recover repair costs. $140. ea plus shipping. If interested I may be contacted @ info@musicmagic.biz
Close, but you need to put your WHOLE name as your display name, including surname.

Pushing in on the cone will check for debris in the voice coil gap, but a speaker can be fried without debris, and a speaker with debris can not be fried. So it's not a good indicator of fried voice coil.

Finally, you may have better luck putting your for sale items in the marketplace, or PMing the user. I don't think its against the rules posting in the thread, but you'll likely get a better response the other way.