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Will my amp handle two 4 ohm speakers?

SX828POWER

SX828POWER

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Hello All,

As I have mentioned before, I am going to be building an 18" sub for my room and plan on using a dual vc driver such as an old CV Stroker. The thing is, I noticed that the driver is 4 ohms per voice coil, so if I power both voice coils with the speaker a channel of my amp in mono, will the sub be putting a 2ohm load on the amp? Or would it be an 8 ohm load? Don't laugh, but I plan on using a Sony STR-7065 receiver that is kinda beat, but still sounds very good lol. If the load is 2 ohms, then will the amp be able to handle just that sub?

Thanks,

-Johannes
 
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Does the woofer have separate connections for each voice coil? I'm just asking, because I've used some dual voice coil subs in the past, but they all just had one speaker wire connection, and a singular impedance rating for the whole sub.

If it does have separate connections, then you would have the choice of running series or parallel.
 
SX828POWER said:
Hello All,

As I have mentioned before, I am going to be building an 18" sub for my room and plan on using a dual vc driver such as an old CV Stroker. The thing is, I noticed that the driver is 4 ohms per voice coil, so if I power both voice coils with the speaker a channel of my amp in mono, will the sub be putting a 2ohm load on the amp? Or would it be an 8 ohm load? Don't laugh, but I plan on using a Sony STR-7065 receiver that is kinda beat, but still sounds very good lol. If the load is 2 ohms, then will the amp be able to handle just that sub?

Thanks,

-Johannes
Click to expand...

What does the speaker have for terminals? It really depends on how you wire it. Likely it has A +/- and B +/-

Wire in series, Amp to A+, A- to B+ then B- to Amp, and you will be around 6-8 ohms. (my math isn't installed right now.)

Wire Parallel Amp to A+, A+ to B+ and Amp to A-, A- to B- and you will be down around 2-3 ohm.
 
Only thing I can affirmatively say is that the Sony is definitely not designed to handle a 2 ohm load - if that's the resulting impedance of your subwoofer project.

If its on its last legs as it is, there's no surer way of killing it off for good.
 
Actually that Sony STR-7065 receiver was a decent unit in it's day.

I re-read your post.
If each VC is 4 ohms, and you connect them up as you suggest with one channel per VC, The amps will see a 4 ohm load. According to the rear panel that receiver is stable into a 4 ohm load so you should be safe if you keep the amp at perhaps -3 db's (1/2power) to keep the amp from clipping or running out of current. It should be well ventilated with clean heat sinks too.
 
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Yes the woofer does have two terminals. There is one for each VC. The receiver is not in bad shape functionally at all though. The amp is very robust, and has more than adequate heatsinking. I would add a fan for good measure though. It is just scuffed up physically. I think I am going to give wiring it in series a shot. Would this require wires out of only two individual terminals on the amp? Like the right of left side of speaker A?

I'll attach a pic of the sub:

Thanks guys,

-Johannes
 
Hey Charles,

Okay, so wiring the left channel's terminals to VC 1, and the right channel's terminals to VC 2, will keep the load at 4 ohms? This is what I had planned to do, so that I was not only using one channel of the amp. I know that the amp can handle 4 ohms, because it powered both my old Advent speakers and some bigger Pioneers without an issue.

Regards,

-Johannes
 
SX828POWER said:
Yes the woofer does have two terminals. There is one for each VC. The receiver is not in bad shape functionally at all though. The amp is very robust, and has more than adequate heatsinking. I would add a fan for good measure though. It is just scuffed up physically. I think I am going to give wiring it in series a shot. Would this require wires out of only two individual terminals on the amp? Like the right of left side of speaker A?

I'll attach a pic of the sub:

Thanks guys,

-Johannes
Click to expand...

Yes, you would be using only one channel. I don't think it is wise to operate any amp, Tube or SS at full power without a load. You could use an 8 ohm resistor in the other channel for the load. But I think you would be safe using one channel per VC so both channels get used, the way I suggested in post #6.
 
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SX828POWER said:
Okay, so wiring the left channel's terminals to VC 1, and the right channel's terminals to VC 2, will keep the load at 4 ohms?
Click to expand...

Yes. It's just like running a pair of 4 ohm speakers. Since there are two amps (L and R channels), they are each seeing a 4 ohm load.

Also there is no problem with running a SS amp with no load on one channel, but using both channels as you propose is much better anyway, as you have twice the power at your disposal.
 
Excellent! Sounds like my crazy plans may actually work. Thanks for your help guys! When I get it all going, I shall post the finished product.

Regards,

-Johannes
 
Yeah, seriously, series or parallel? Unless you're dealing with multiple (more than 2) drivers, it's one OR the other.
 
If you plan on powering only the sub from your Sony using one voice coil per channel then you should be okay but the sub is the ONLY speaker you can drive with that amp. If you plan to run your main speakers as well the amp will see less than 4ohms and damage/destruction will result.
 
Don't run it in parallel.

As mentioned connect one channel of amp to one vc, and the other channel to the other vc to run your amp at 4 ohms per channel.

Most amps and receivers can handle 4 ohm loads and connecting in this way gives you all the power of the amplifier, not just half as the 8 ohm parallel suggestion would do.
 
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Yes, the correct answer to keep 4 ohm load is connect one vc to the left channel and the other vc to the right channel.
 
SX828POWER said:
Yes the woofer does have two terminals.
Click to expand...
I sure hope you mean two pairs of terminals. Your picture isn't very informative since it only shows one side of the woofer. From the pictures I've found online, it looks like the Stroker series was available in both single and dual VC.
 
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