Celestion V-30 clone on Ebay, check this out.

[Slobrain]

Just got 'em in and have 'em in-parallel on a 9vac filament transformer...probably bump up to 12vac in a couple of hours.

They have a removeable rubber gasket on the backside of the frame...pretty nice. However, the main gasket is quite thick.....gonna have to get another bolt about 1/8 - 1/4 longer for one of the t-nuts....apparently one is a bit too short (Avatar cabinet).

Don't sound as close to the BV30V as I had thought..They seem rather bright..but breakin should help a bit.

Hey TD,
How long you running the 9VAC transformer on these for breakin?

I never tried that method but if it works sure beats trying to break em in the old way by just cranking the amp for hours and making the wife and neighbors mad...

SLO

[TD_Madden]

a couple years now.....and I've let 'em run overnight before.

I use the formula on Ted Weber's site to figure what volatge to set it at....think the latest was that with 2 of the 8ohm/60-watt speakers in parallel the setting should be just a bit more than 12.5vac.

Seems to work ok....until the transformer gives-up!

[TD_Madden]

picked-up another "at&t answering machine" tranformer at RatShack....120vac to 9. 10, 12, and 13vac @ 800ma.

$17.

I spliced the wire to some zipcord with a 1/4" jack on the end. Back in business.

[Slobrain]

a couple years now.....and I've let 'em run overnight before.

I use the formula on Ted Weber's site to figure what volatge to set it at....think the latest was that with 2 of the 8ohm/60-watt speakers in parallel the setting should be just a bit more than 12.5vac.

Seems to work ok....until the transformer gives-up!

Hey TD,
what would two 16 ohm speakers in parallel would be what voltage?

Thanks

SLO

[TD_Madden]

From Ted Weber's page (http://www.webervst.com/sptalk.html):


From: Jeff Brinson

I recently purchased a replacement 12" speaker for my amp. I like its tone, but it seems a little shy on the low end and a little tight overall. Is there anything I can do to loosen it up or improve its tone? I've heard of people beating on the magnet and other methods, but I'd like to know what you suggest.

Jeff, most speakers are a little tight when new due to the stiffness of the cone surround and spider. After several hours of playing at high levels, they begin to loosen up and have more overall body and sound projection. I've heard of beating on the magnet also, and quite frankly, I'm not sure what benefit it is supposed to yield. An AlNiCo magnet is a metal alloy, so it conducts electricity. This means that physical shock will cause the magnet to induce an electrical current into itself, which will in turn generate a magnetic field, and that field, if strong enough, can partially demagnetize the magnet. A ceramic magnet, on the other hand, is essentially non conductive and therefore has a very high resistance. That's the reason powdered ferrites are used in high frequency coils and transformers, so currents won't be induced in the core and adversely affect the transformer action at high frequencies. Ceramic speaker magnets are also made of powdered ferrites. If a person was purposely trying to decrease some of the magnetism of a speaker, the intent is probably to lower the self damping of the speaker itself thereby allowing the speaker resonance to add some low end. In my opinion, that's a poor method of increasing the low end.
OK, on to 'breaking in' a speaker. If you really want to speed up the breaking in period, the easist method is to connect the speaker to a filament transformer. Having said that, let's look at the precautions you need to take. Since you will be driving the speaker with a steady state signal, you don't want to drive it at its rated power or it will burn up the voice coil. 1/3 power rating is a safe figure to use. So, let's say you have a 50 watt speaker and it is 8 Ohm. 1/3 power is about 17 watts, and at 8 Ohm, that works out to be around 11.5 volts. Using a 12.6 volt transformer will put 20 watts into the speaker. I wouldn't have a problem with that in our products, but just to be safe, you might want to go with a 6.3 volt filament voltage, which will put about 5 watts into your speaker. Another option is to use a variac into the primary side of the 12.6 volt filament transformer and dial in the voltage you want on the secondary. That way, you can dial in the 11.5 volts we originally calculated at the 1/3 power level. I'd also suggest performing the operation in a garage or closet, because listening to the loud 60hz hum from the speaker will grate on your nerves very quickly. Also, if you leave the speaker out of the cabinet, the rear radiation of the speaker will cancel alot of the front radiation and reduce the noise. You need to lay the speaker face up though, so the cone can move as much as possible since the whole idea of this operation is to loosen up the cone and spider. Laying the speaker face down would trap air between the cone and the surface of the table and restrict cone movement. You're going to be surprised how much the cone moves and how loud the speaker is, even at 1/3 power.
Here's the math for determining the correct voltage to use in case you have a different wattage and impedance rating than our example above:
1. Take the power rating of the speaker and divide it by 3.
2. Take that number and multiply it by the speaker's Ohm rating (4, 8, or 16)
3. Use your calculator to find the square root of that number.
4. The result is the voltage you need to use to drive the speaker at 1/3 its rated power.


2 16-ohm/60-watt speakers in parallel at 1/3 power is 17.88854VAC

[Slobrain]

Hey TD,
Thanks for the info. I just bought a used Marshall 4x12 1960 B cab on Thursday and I'm thinking about replacing the T12-75's with some of those vintage 30 clones. The voltage thing should be good enough to break em in without pissing off the wife

SLO

[TD_Madden]

well, I do it in my bassment, but you can still hear the rumble ;-)
...make sure you do it with them OUT of a cabinet to lessen the effect.

[Slobrain]

Well, I just bought 4 more of these excellent v30 clone speakers for my Marshall cab.

Seems guys over at plexi palace have been raving on these speakers. Others on the net raving too so I figure I bertter get some more before they run out.

http://cgi.ebay.com/12-inch-VINTAGE-...QQcmdZViewItem


I wonder if Bruce ever got his and how he liked them?

SLO

[bob p]

Brush some acetone on the speaker paper around the surround and down about 2 inches but don't get it on the dust cover over the voice coil.
A couple wet coats over a 5 min period should help loosen it up a bit faster.

Hijacking for a minute, Bruce do you know what compound the speaker people use to attach the cones to the surrounds? or the surrounds to the frames? i know its black, and it looks like its pretty thick and painted-on.

the reason that I ask is because i just finished performing a re-foam on a 10-inch JBL consumer audio woofer. those kind of speakers use that annoying arched foam surround that rots apart and needs to be replaced. the kit that i used provided a "synthetic copolymer resin adhesive" which looked an awful lot like white glue to me. pretty disappointing. next time I'd rather use a better adhesive. thanks.

[bob p]

will using the acetone make the surround-doping gummy/sticky?

Gotta pickup another RatShack answering-machine power-supply (120vac - 9/11/12vac) as mine gave up the ghost..... ;-)

i've used acetone to remove surround dope on speakers. i use a Q-tip. the acetone will make the surround dope gooey and slimy for a very brief period, until the acetone evaporates. once it evaporates, the dope is dry, and you'll never know the acetone has been there.

[eyesonly]

to a 2x12 with my jcm800 and these vintage 30 clones. these are not broken in yet.

http://www.anniemac.info/sounds/vint...0%20clones.mp3

Oh dear! . What JCM800 model is it and what's the cab made out of?

[gtrboy]

the cab is an ampeg 2x12 made out of ?????? the marshall is a modded 2204.

[eyesonly]

the cab is an ampeg 2x12 made out of ?????? the marshall is a modded 2204.

Oh gee 2204.

Well it certainly has some grind on it. Sounds very Vintage, or is that Veteran

You must be loving that setup.