Vintage MIT MI-330

Hemihead, it upsets me to learn that you encountered someone who simply perpetuated the misinformation started long ago by audio sales people, and I stand by my explanation!

It's especially upsetting to me in this case because the "source" of this myth was someone at MIT, whose owner, Bruce Brisson, is the person who (while working for MonsterCable) invented the so-called "Shotgun" single-ended interconnect; and I would expect his people to know better!

Try and understand WHY it's important to have the GROUNDED end of the shields of ALL the single-ended interconnects in a system, attached to the preamp. It's called "Star Grounding" (Google it for an explanation) and is the most direct/effective way to drain off any noise intercepted by the shields.

The fact that implementing this configuration (often) results in the arrows pointing "backwards" on the interconnects between preamp and amp is unfortunate, but that's how it is.

Most people can understand the reason for this practice (of having all shields grounded to the preamp) if it's explained to them clearly. And they can also easily understand that an audio signal is an "alternating current" which of course flows back and forth in both directions! But if you're still unconvinced, why don't you try your amp/preamp cables in BOTH directions? Turn up the volume control on an unused input, stick your ear in the speaker, and then decide which "direction" results in the least background noise?

Or maybe you should call back to MIT cable and ask to speak to Mr. Bruce Brisson directly! ;~) I'm sure he will give you the same (correct) explanation he gave me (in person!) back in 1988, when he left MonsterCable to start MIT . . .
.

OK ! Let clear this up !! I just picked up a pair of MIT MI 330 plus cables that a friend gave to me . Of course I googled them and came across this post! Then called MIT !! Spoke to "no Name " and told him about this post.
He said , that the arrows are in the direction of the signal ! That means those of you who have the arrows pointed to your amp are correct ! Just like any other cable ! The end with the box is the end that should have the braided soldered to the RCA plug ! The other end stays floating !!

When in doubt go right to the source!!

Hi Forrest,

Generally speaking, speaker cables are non-directional. Some have shields, but they are passive (i.e., not electrically connected to either of the signal conductors.)

Some manufacturers (and consumers) say they can hear a difference depending which way the (speaker) cables are oriented in their system. Personally, I can't understand from a physics point of view why this would be. But if you're one of those who does hear a difference, then the arrows (or other markings on the cable) can come in handy for making sure that if you have to remove the cables from your system for some reason, that you re-install them in the same orientation.

So let me restate for the record, that (in my ever so humble opinion ;~) arrow markings on audio cables only have a functional purpose when the are applied to SINGLE-ENDED SHOTGUN-TYPE INTERCONNECTS. And (unfortunately, these days) even with that type of cable, manufacturers sometimes DO NOT follow the convention of pointing the arrows toward the grounded end of the shield. So it's always best to double-check with the manufacturer, or as I suggested above, remove the connector barrels and check visually.

Neil
.

I see that I'm late to the table by about a year, but stumbling upon this thread, I find all this information to be very interesting and quite useful.

I've used the original MIT MI-330 interconnects for many years with all the arrows pointing the the *wrong* direction! I bet you can guess what I'll be doing this afternoon when I get home. Sheesh!

But all this brings up one other question. Which way should the arrows point on the old MIT MH-750 "Music Hose" speaker cables? Now I'm thinking towards the amp. Is there shielding in these cables as well that's tied together on one end but not the other like the MI-330s?

Thanks for pointing me in the right direction!

MP, Joe was only quoting me. Here's the deal: A music signal is alternating current, just like wall current AC, except at all kinds of different frequencies beside 60 Hz.

Yes cables do "break in" but that has nothing to do with changes in the metal of the conductors, but rather with changes that take place, over time, in the INSULATION material where it meets the metal conductor, when current runs through the cable (in EITHER direction, BTW!) These 'changes' in the metal-to-insulator interface (SOMETIMES!) result in audible changes in the sound. Why? Because of SKIN EFFECT. Skin effect is the term that describes the tendency of high frequencies to want to travel on the surface of a conductor rather than through its interior. So changes RIGHT AT the surface of a conductor (where it mates with the dielectric insulator) could (POSSIBLY!) affect the timing and phase relationships between the high and low frequencies of the music signal as it propagates from one end to the other. That's the theory anyway. It IS certainly true, that when people DO (say they) experience an audible 'change' as a cable 'burns in', it usually has to do with a 'relaxing' of high frequency harshness (they say! ;--)

Back to the arrows. Bruce Brisson invented the 'shotgun' single-ended RCA interconnect (while he was working at MonsterCable and before he founded MIT cable). This breakthrough design (used in 90% of all single ended interconnect today) consisted of two signal conductors surrounded by a braided shield. The ORIGINAL single ended RCA interconnect consisted of only a SINGLE center conductor, with a braided shield around it (like your cable TV coax.). But that meant the shield also acted as one of the two signal conductors, and so had to be connected at each end (duh!) If the shield DID intercept any hum or RFI, it went straight into the amp or preamp along with the music! Bruce's idea was to use TWO music signal conductors (double barreled 'SHOTGUN') and surround them BOTH with a shield. But NOW since the shield didn't have to carry a (music) signal, it only had to CONNECT TO GROUND AT ONE END in order to drain away hum and interference -- thus keeping the hum and interference from becoming part of the music signal!

With me so far? OK, so from the very beginning, they began to mark wire used in shotgun interconnects with arrows WHICH POINTED TO THE END OF THE CABLE WHERE THE SHIELD WAS CONNECTED TO GROUND! This was helpful to know, because in a music system (just as in an individual component) you get the quietest background noise/hum level if all grounds, shields, circuit boards, chassis, etc. terminate at ONE POINT! This is called "star-grounding" and in the best of all possible worlds, the preamp should be the only piece of equipment that is actually connected (by its power cord's ground pin) to the actual electrical ground of your house. The grounded noise from all the other "stuff" should be forced to drain back through the preamp's grounded power cord -- and not have any other 'grounds' of their's connected to the house's ground -- because that's what creates GROUND LOOPS, which act like big antennae for RFI and hum from transformers, etc.

With this in mind, you'd want the hum and interference picked up by the shield on your interconnects to drain right out through the preamp; in which case you'd want the end of the interconnect cable, where the shield connects to ground, to be plugged into the preamp -- WOULDN'T YOU?? ;--)

SO -- assuming a given cable maker is following the convention Bruce set up back in the mid 80's, the rule of thumb would be: "All arrows point to the preamp" ;--) If you're not sure that the arrows on your cable point to the grounded end of the shield, call the manufacturer. If they don't know what your talking about, the arrows on their cable are just "me too" decor, and don't mean anything. If you can unscrew the barrels on the RCA connectors, you can usually see (if) the shield is indeed connected to the RCA ground ring (along with one of the two signal conductors) at just one end of the cable and not the other.
.

Hello Joe,
With regards to the "interconnect" connection, between the Amplifier and Preamplifier, are you saying the arrow head should point in the direction of the pre-amp not the amplifier ? Or should the arrow head be pointed in the direction the music flows, and pointed towards the amplifier from the preamplifier.

All the best...
MP

"The arrowhead end of all interconnects should attach to the preamp (including the pair between the preamp and amp.) The directional arrows have nothing to do with "current flow", since in AC (like a music signal) the current flows back and forth equally."

Thank you so much. I've been trying for years to get a straight answer on what goes where on directional cables and you've explained it beautifully.

The (original) MIT 330's are still great cables, just like the Straightwire Maestro and Maestro II. The boxes came later, and are an unnecessary electronic affectation IMO (unless of course your running lengths over 15 ft.)

I have a whole bunch of the stuff, but it all needs re-terminating. BTW, the arrowhead should point to the end of the cable where the shield is joined with the RCA ground 'ring', while the other end of the shield is left unconnected (floating).

The arrowhead end of all interconnects should attach to the preamp (including the pair between the preamp and amp.) The directional arrows have nothing to do with "current flow", since in AC (like a music signal) the current flows back and forth equally.