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1/4' vs. Speakon

#9
I posted this a while back, but its buried in a thread that also has a major flame war or two in it, so I extracted it.....

Back to 1/4 inch jacks.........(I almost feel I should post this elsewhere under its own heading, but it's on-topic)

I should say that we do make amps with 1/4 inch jacks, including the B2R which has 350 watts at 4 ohms, and either 1/4 or speakon depending on destination. So I suppose I am hypocritical....

I don't like 1/4 inch jacks for speakers, de-facto standard or not. I would put a speakon on everything. But the reality is that 1/4 inch jacks are out there and demanded.

Here is my case against them.

The standard type of 1/4 inch jack has a pretty poor current rating. The usually quoted one is 5 amperes. Some of them don't have a rating, because the cheesy manufacturers (typically but maybe not exclusively in China) don't even rate them.

The connection in a 1/4" jack is made by what is usually a two-point contact between the tip of the plug and a contact in the jack. There is the strong chance for higher contact resistance, and various sound-related effects that go with that.

As a side point, even well-respected manufacturers are going to China with their 1/4 inch jacks, and quality is suffering IMO as a result.

OK, at 5A then.... since power equals I^2* R, you start to get to 5A (5 squared being 25)at a power of 25*4=100 watts at 4 ohms. So with a 100 watt 4 ohm amp you are reaching the current rating of the jack. You *probably* will not play at 100W all the time, so you are likely fine.

At 350W 4 ohms, you are getting up towards 10 amperes RMS, which may or may not cause significant heating in a 5A connector, depending on how you play, power-wise. Peak currents are close to 14A. Now that 5A gets hit a lot more often, if you use the power.

If you have a 2 ohm rating of say 800W and a couple cabs, the peak current is almost 30A, and rms is 20A. Not a great idea to daisy-chain them off one 1/4 inch jack........probably you will lose quite a bit of that power through the contacts.

Maybe the power is not lost as heat, but it still is lost just as an effect of increased resistance. At 2 ohms, tenths start to count. Every 0.2 ohm would have used 80 watts. In reality 2.2 ohms simply draws only 727 watts instead of 800, at equal output voltage....still a loss, and a reduced damping factor, if you are considering that much-abused rating.


The Speakon, by contrast, has a line contact almost an inch long. It is rated for at least 4 times the current rating of a typical 1/4 inch jack, which suggests both a power capability 16 times larger, and a considerably lower contact resistance.

Your choice as to which you want. With all I say, the 1/4 inch jack is still out there and actually works pretty well, considering.

Sorta like the bumblebee, which is supposed to be aerodynamically incapable of flying, but doesn't know it.


Added note:
I should have mentioned that in many types of 1/4 inch jack, the first thing the 1/4 inch plug does when you insert it in the jack is to create a short circuit from tip to sleeve against the barrel of the jack.

Same thing if it falls or is pulled out and lands on anything else made of metal, like a mic cord connector. That is especially true of the all-metal type where the "handle" is a screw-on metal sleeve..

That can make some amplifiers unhappy, although any decent one should be protected. And you generally have no signal as you plug in speakers. Still....

Just another reason not to use them on speakers.
Click to expand...
 
#10
Thanks for the info!

I asked because I'm in the market for a power amp right now. I've pretty much narrowed my choices down to a Carvin DCM1000, Qsc RMX1450, and if I can find one for a good price, a Crown CE1000. The Carvin has 1/4 outputs, but the Qsc doesn't.

Also, if I get the Qsc, will I need a certain type of Speakon to run in bridged mode? Will I need a special chord for the Carvin?

Jerrod, thanks for digging up that post; it was VERY informative.
 
#12
LiquidMidnight said:
Thanks for the info!

I asked because I'm in the market for a power amp right now. I've pretty much narrowed my choices down to a Carvin DCM1000, Qsc RMX1450, and if I can find one for a good price, a Crown CE1000. The Carvin has 1/4 outputs, but the Qsc doesn't.

Also, if I get the Qsc, will I need a certain type of Speakon to run in bridged mode? Will I need a special chord for the Carvin?

Jerrod, thanks for digging up that post; it was VERY informative.
Click to expand...

To run in bridged mode you will have to have a speacial speakon cable wired 2+, 1+ at one end (amp side), and 1+, 1- at the other end (speaker end). This can also be done with a cable with banana ends at one end, then whatever you need to go into the cabinet.

If you go the speakon cable route, I highly recommend getting it off here: http://www.procablesnsound.com/ . Great guys to work with, and by far the highest quality cable Ive ever had. Was about 25 shipped I believe.

About the Carvin, Im not sure, but Id highly recommend QSC, mines performed wonderfully.
 
#16
DMB said:
Yeah, I had a cable end snap on me, and he offered to fix it for free, I just had to ship it to him.
Click to expand...

That's awesome to know. Fortunately I haven't had any problems... I was very pleased because I ordered something he didn't have listed on his site, but he said he could make 'em and then created a webpage just for me where I could place my special order.
 
#17
I had an instructor for a while and I asked him the same thing and whether or not it made a difference in the sound. He, Trip Wamsley http://www.tripwamsley.com, took out several cables: 2 speakons that were different because of their construction/ materials, and a regular 1/4 inch speaker cab cable. Using the same bass, amp head, and cab he played through each. While I do not remember the real details, almost 2 years ago, there was a distinct difference in the sounds. One being more clearer, one sounding more full and rounded, and then the 1/4 sounding almost as good as either one but did lack some clarity.
Overall I was impressed but he explained it best by saying that most people would never hear the difference so it's your choice. I agree.
 
#18
For my DIY cab, I chose a Speakon because I like the idea of not being able to short out the conductors to ground, or to one another, in any amplifier mode.

For 1/4" I recommend using only Switchcraft. Type 270 is the standard plug. Type 70 has a bigger shell, and screw terminals. You can take the screws out and solder fairly heavy wires into the screw holes. It is probably the speaker connector of choice if you want to use 1/4". On the other end, the jack of choice is type 11, the good old open frame with heavy duty spring contacts. All of these are at Invalid Link Removed for reasonable prices, along with most types of Speakon connectors.
 

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