Grateful Dead Music Forum

Happy Friday Rukind family! I'm sure this question has been asked a million plus times but I couldn't find and posts relative to my set up question.

Ok so I acquired a MC2100 not to long ago and I would like to use it in conjunction with my Alesis imulti mix 8 mixing board in order to power two 15'' pa speakers and a 2 floor wedges in my home jam room. The only problem is I have no clue how to hook this thing up. Can someone point me in the right direction about how to accomplish this?

Question 2: Do you think it's wise to bring the mac to an amp tech and have a 3 pronged grounded plug installed and maybe easier speaker connections installed or am I over thinking this?

As always thanks for you help. The board continues to be an invaluable resource for newbs such as myself while exploring the vast and wonderful world of all things Grateful Dead related.

Peace love and hugs...

Duhigg

I wouldn't worry too much about the grounded AC plug. Just be sure that your mixer is safely grounded, then the connecting audio cords will create a ground path for the amp too.

I would figure out the impedance of the speakers, most likely each speaker is 8-ohms. Then if you use one half of the Mac for the mains (run in mono obviously), that means it's a net 4-ohm load. So connect one PA main to the 4-ohm tap on channel 1 of the Mac. Then jumper the second PA speaker from the first one. Next, do the exact same thing with the monitors but with the second channel of the Mac.

This setup will give you 2 mains in mono, and then 2 monitors that share the same monitor mix.

Brad

Brad to the rescue again. Dude your a busy man on this board.

Ok what your wrote makes total sense however the mains are a 1/4'' mono plug hook up and the mac has some oldschool screw type hook up for speaker connection. Does that make sense?

This is where I'm a bit confused. Thanks again Brad. You don't live in Charlotte, NC by chance do ya?

Duhigg

Yes,

the Mac's use the terminal strips for speaker connections. You need to strip your speaker wires for that end. Go to Radio Shack or similar and get some "lugs". The lugs will crimp and solder to the raw, stripped wire ends. The black wire would go to "com" or common or ground on the Mac terminal strip. Then the white or other lead will go to the screw terminal of your choice. In this case, with the two speakers daisy chained creating a 4-ohm load, you'd connect that wire to the 4-ohm screw. Same on the other channel.

Something like this: http://www.radioshack.com/product/index ... Id=2103309

They say crimp, but I like to crimp and then solder. I think the screws on the Mac are #6 (6/32). Just be sure to get a lug that has a fat enough entry to handle your speaker wire gauge.

And NEVER have the amp on while the speaker connections are being made. That's an easy way to create a short and hurt an amp. Connections first, power second. (sorry for the Duh. But sometimes a good Duh can prevent a bad DOH!)

Brad

Brad,

You my fried are the Beezzzz Kneezzz! Thanks again for all your help. If you ever stroll thur the Queen City of Charlotte, NC and need a place to crash.... hit me up...

Duhigg

P.S. Thanks for the tid bit of advise. I can already assure you that I would have most likely made that mistake. Connections first....power second- check!

I found this the other day...
Pretty cool:

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... K:MEWAX:IT

Not needed if it's sitting at home really, but I like em anyway.

NeebruM wrote:I found this the other day...
Pretty cool:

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... K:MEWAX:IT

Not needed if it's sitting at home really, but I like em anyway.

I use banana plug spade adapters on my MC2105 - A word to the wise when constructing your cables - I nearly fried one of the channels on the MC2105 because the speaker wire terminated to two beautiful (and thick) gold plated male banana plugs (4ohm and GRD).

Because the 4 Ohm and GRD terminals are so close together on the back of the MC2105 the two male banana plugs were touching ever so slightly. After about 5 mins of playing my brand new rig all sound cut out The top of the MC2105 was super hot - I have since placed non-conductive material between them....but that was a scary learning experience!

[quote="jkstraw]Because the 4 Ohm and GRD terminals are so close together on the back of the MC2105 the two male banana plugs were touching ever so slightly.[/quote]

I use the gold plated banana lugs that screw onto the terminals also. They can be pretty close together when on the lower ohm setting (only about a 1/16" gap).

I found that sliding one one from the top and the other from the bottom creates a larger gap between the ends (closer to 1").

Jim

jkstraw wrote:
Because the 4 Ohm and GRD terminals are so close together on the back of the MC2105 the two male banana plugs were touching ever so slightly. After about 5 mins of playing my brand new rig all sound cut out The top of the MC2105 was super hot - I have since placed non-conductive material between them....but that was a scary learning experience!

Yeah, that's one of the quickest way to ruin an amplifier or maybe burn your house down. Speaker output leads must never short, ever, ever, ever!. Be thankful that the Mac had the Sentry Monitor to save your amp!!!! It would have fried for sure. Never even think about letting speaker leads touch eachother. That's a golden rule with amplifiers. It's dangerous and expensive.

Brad

Good thing you didn't disconnect your Sentry Monitor!

See the shame I am willing to endure to save someone the same embarrassment

Thank goodness I told this tale AFTER buying my SMS Classic

Good news is how much I have learned getting my rig to the point it is at

Thanks for all the great advise everyone. I'm assuming it's personal preference in regards to hooking it up so I think I'm going to stick with Brad's original suggestion and go with the "lugs" approach.
Thanks

jkstraw wrote: See the shame I am willing to endure to save someone the same embarrassment

Thank goodness I told this tale AFTER buying my SMS Classic

Good news is how much I have learned getting my rig to the point it is at

And that was just a mild lashing, but a warning for all!!!

I get even more adamant when it comes to guys working on tube amps with high voltages. There are actually some guys who never were taught the one-hand rule. That means that when probing or poking around in a live amp, one hand should be behind your back. This is an easy way to keep your beating heart from completing a circuit.

Brad

I have some of those lug adapters for my 2105 and discovered that when using the 8 ohm taps, the distance is perfect for standard banana plugs!

Back in my ignorant youth, I ran my 2105 into some pretty stupid loads, including a speaker cabinet with 2 15's which I ran separately but the cabinet had a metal jackplate so the grounds were connected. The amp would play for about 20 minutes, get hot enough to fry an egg and then shut off until it cooled off. I also suffered shorts numerous times with sketchy homemade speaker cables before I learned how to solder properly. These amps are damn near indestructible!

Also, it's worth noting that while transistor amps of yore hate short circuits, tube amps don't mind them nearly as much but absolutely hate open circuits. Never play your tube amp without a speaker connected. Modern transistor amps usually have protection circuits that keep them from melting down under short circuit conditions. I suppose there might be some modern hifi amps that don't have this protection with the idea that there shouldn't be anything between the output devices and the speaker.

None of this is by way of saying that you shouldn't observe care in speaker wiring. It's best not to press your luck. I consider myself to have dodged a barrage of bullets.

I figured it was the least I could do and let ya'll know my progress. Well she's up and running and sounding awesome! Lugs ended up being the avenue I chose and it's working GRATE! I used the crimp lugs that had heat shrink tubing and I couldn't be happeir with the result. My MAC thanks you for all the great advise and most of all the DO-NOT'S Now all i need to do is have my twin preamped! However this endevor will be one I leave for the professionals. Well I'm off to



Duhigg