Class D amp for dual coil 8 Ohm sub

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TimsUsername

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Joined 2016
#1
Hello all,

I have a nice dual coil 8 Ohm sub laying around and would like to use it as a separate amplified sub in an 2.1 setup.
But I run into some problems finding a matching amplifier (or a set of 2) capable of driving the sub.
My understanding of DIY audio is limited (let’s call me a serious interested newbie).

sub: 2x75W RMS @ 8 Ohm. ,2x150W peak (From an old good sounding cambridge THX 550)
To keep the amp temperatures low I like to drive it as it is (2x8 Ω).
Or is this a wrong approach?


I was thinking of TDA8920 that delivers 2 × 210W @ 8 Ω (V DD = 41 V; V SS = -41v ) and lowering the voltage to +/- 30V to have 2x 150W @ 8 Ω (to extend life time. wrong approach again?)

Or any of these and good idea: TAS5630 (but can’t find a 2x300W @ 4 Ω / 2x150W@8 Ω version yet)
or 2x IRS2092 (100W 8 Ω) (danger of clipping?)

Or the best question of the day:
With (aliexpress) amplifier (or set) would you recommend to fiddle around with?
A link would be extremely welcome!


Note: each coil (of the 8Ω dual col sub) will have his own channel or amplifier.
The line in will be mono, this shouldn’t be a problem.


Thanks in advance, your helping me out big time!
 
#3
I don't get why you insist on running a separate amplifier output to each coil. If you parallel the coils you lower the supply voltage requirement.

IRS2092 and TDA89xx have single ended outputs anyway. To avoid bus-pumping they would need to be ran bridged, which means you might as well parallel the coils.

A TAS5630 PBTL board is cheap, only requires a single rail supply, and is capable of enough power to shred that sub...

https://www.aliexpress.com/item/F98...32605424058.html?spm=2114.01010208.8.8.XXa1S8
 
#5
First of all I thank you for discussing this with me.
I am completely new to this "sport" and am learning on the fly while combining the components for my first build.
From copying a build from someone wont give me much of an opportunity to learn something new. So thanks again to question my initial thoughts!.
This is how I learn 🙂

@ theAnonymous1
I read on this forum it is wise to avoid higher voltages on class D amps.

If I use an amp (the one you linked) that delivers exactly the required watts i have to juice it with the max voltage, asking 100% performance of the amp (=48V with 10% THD*).
Therefor I selected 2x IRS2092 IRFI4019H (running it at 75% of its limit @45v ) & maybe lowering the THD with it
Or is this not the way to go?


The bus pumping issue:
I was in the assumption a use of a rectifier would avoid this.
NOVER-Electric-Capacity-Rectifier-Loudspeaker-AIO-Board. (I realy have to read into this stuff but don't get is yet. Will google it the moment this post is written 😛 )

Don't take me wrong, I like to learn as fast at possible. I'm not fixed on my layaut. I just like to understand.

@ Globulator
Indeed, 4 terminals. caled DVC (Dual Voice Coils).
I believe more common in the car audio.
 
#9
Okay
Lets sum the items up:

Sub: 2*75 RMS-300W 8Ω / equal to 2*150 RMS-600W

Power supply 33v 300W (45v afther rectification)
or
Power supply 33v 500W (45v afther rectification) ?to have some more roof?

Rectifier (AC dual 34V max.)
34v not to close to the 33v power suply?

Or rectifier & protect seperate:
Rectivier
+
Speaker protection / start delay or start delay 2

And to controle it:
Low pass filter

2x Amp:
IRS2092

I hope to order the items soon since I have to nice discount today.
Waiting on theAnonymous1 to reply first
If you like I will post the build & hopefully on the pictures no smoke :worried:, not even a little 😛
 
#10
Globulator said:
One to to try it I guess 😀
Click to expand...

Jeah! lol.
But I'm still a bit afraid of the smoke, fire and explosion thingy 😉

scottjoplin said:
I know what you are saying, but I think sometimes these dual coil drivers are driven with L&R separately when used as car subs
Click to expand...

I read that these drivers came to existence because of the lower available power that the amplifiers delivered those days.
2 amplifiers on one driver was a solution.

Currently there used to be more all round (can be used as 4Ω/8Ω).
I don't know what you mean with "L&R separately", what I do know it is preferable to have the same signal to each coil (so more or less 2xmono).
It is arguable if its a problem if its not the exact same singal.

In my case is did not have to go with the DVC, I had him laying around and know its a good sounding driver.
 
Last edited:
#11
TimsUsername said:
Jeah! lol.
But I'm still a bit afraid of the smoke, fire and explosion thingy 😉



I read that these drivers came to existence because of the lower available power that the amplifiers delivered those days.
2 amplifiers on one driver was a solution.

Currently there used to be more all round (can be used as 4Ω/8Ω).
I don't know what you mean with "L&R separately", what I do know it is preferable to have the same signal to each coil (so more or less 2xmono).
It is arguable if its a problem if its not the exact same singal.

In my case is did not have to go with the DVC, I had him laying around and know its a good sounding driver.
Click to expand...

What is the make and model number? Is it a car subwoofer?
Usually the car ones have 2 4Ohm coils which can be wired in parallel for high current car audio amplifiers or in series to use with bridged amps or separately for two as you intend. I have heard of them being wired separately to left and right channels but also heard that this might not be advisable.
 
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