External Amp for DIY Tempest

Theon · 05-10-2004, 06:09 PM

I am toying with the idea of powering a DIY Tempest with an external amp. Can I use any stereo amp to power the sub, or will I need an amp with certain inputs?

The crossover of my Yamaha receiver is set at 90Hz and is unadjustable.

Thanks.

Mike SJ · 05-10-2004, 06:27 PM

TimForman · 05-10-2004, 06:42 PM

I've been using an external pro amp for a couple of years and it's fine. There's plenty to choose from like QSC, Pyle Pro, Crown, etc.. A older stereo amp will work fine. Some of the old Realistic receivers had hefty power supplies and work nice if you can scrounge one up at a thrift store.

Theon · 05-10-2004, 11:10 PM

Thanks for the responses guys. Here is what I think would work: Sub out on my primary receiver to any input (CD, Cassette) jack on my external sub amp. Then I use speaker cables between my external amp and the subwoofer. Sound good?

One thing I'm unsure of: since the Sub out on my receiver is giving out a mono signal, how would that affect how I hook up my sub? As I understand it, the Tempest is a dual-coil woofer and I would benefit from having an external amp powering it through two channels (more power).

Brian Fellmeth · 05-11-2004, 02:28 AM

This just came up in another thread. Yes, you can split the sub out line and plug them into the R and L RCA inputs of the receiver, say CD, Aux, anything but phono if it has one. Then use both the R and L speaker wire posts- one pair to each voice coil. Do not reverse the polarity. That way you will use both channels of your stereo amp and get the most out of it.

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Theon · 05-11-2004, 07:25 AM

Thanks Brian.

One more question (for now): should I just drill/cut a hole one in of the walls of the sub big enough for the speaker wire to pass through? I'm building a sealed sub so I'm unsure to as how this will affect it's performance.

TimForman · 05-11-2004, 08:37 AM

Use
terminal posts.

Bhavesh · 05-11-2004, 08:41 AM

Theon,
Using speaker terminals would add a really nice, professional touch to your sub. The one I got from Parts Express had its own gasket so there's no need to worry about air leaks.

Plus this way you have the option of using the shorting bars to wire it in parallel if/when you buy a better amp.GOLD PLATED BI-AMP TERMINAL

Theon · 05-13-2004, 08:44 AM

Ok, I bought a "Y-coupler" which I hope will separate a mono signal into stereo (part # 274-511 at radioshack canada). I also bought a terminal cup similar to the one Bhavesh recommended above. At the back of the cup, there is a bar connecting the negative terminals and another connecting the positive terminals. Since I want to wire my Tempest in parallel, should I keep these bars? I am planning to do as Brian sugessted and run one pair of wires to each voice coil.

Also, I am unsure on how to physically connect the Tempest to the terminal cup. I am going to use speaker wire, but will I need spades or some other connector to acheive a reliable connection with the Tempest?

TIA

Brian Fellmeth · 05-13-2004, 10:02 AM

Quote:

Ok, I bought a "Y-coupler" which I hope will separate a mono signal into stereo (part # 274-511 at radioshack canada).

That will work.

Quote:

Since I want to wire my Tempest in parallel, should I keep these bars? I am planning to do as Brian sugessted and run one pair of wires to each voice coil.

If you do it my way, you will remove the bars. You are not wiring in parallel or in series. You are using a separate amp for each voice coil- each channel of the amp is only driving a single VC at an 8 ohm load. In fact, having the bars in would be a very bad idea- the amps would then see each others output as part of thier load rather than jist the passive 8 ohms of a single VC. Again, be sure the polarity is correct or the sub will be very quiet- one amp woll be pulling the cone one way while the other pulls in the opposite direction resulting in very little actual movement.

Quote:

Also, I am unsure on how to physically connect the Tempest to the terminal cup. I am going to use speaker wire, but will I need spades or some other connector to acheive a reliable connection with the Tempest?

This can be done with any spade type thing that is very snug on the lugs, but I strongly recommend that the speaker wire be soldered to the lugs on the driver and on the terminal cup. If necessary, dragoon some friend or relative who knows how to solder to help you. There will be so much energy and vibration in that cabinet that I would not trust any connection based on friction alone.

Theon · 05-13-2004, 10:40 AM

Brian, thanks for the quick and thorough response. As I don't have a friend or relative to solder for me, would a tight connection and electrical tape work? (I hope that question didn't reveal my complete ignorance...:b )

Also, does the Tempest driver come with any connectors?

Finally, running each channel at 8 ohms would equal a 4 ohm load total? (I want a 4 ohm load since my amp isn't very powerful).

DustinF · 05-13-2004, 05:44 PM

I don't believe you need a "Y-coupler" to seperate the mono signal.

You run speaker cable from your stereo's left speaker connection to one of the voice coils on the Tempest. Then run another speaker cable from the stereo's right speaker connection to the other voice coil.

In your stereo's setup menu, make sure it's set to stereo. If it's a 5.1 receiver then make sure the speakers are set to large, turn off the center speaker and sub output and rear speakers.