Subwoofer amplifier

[mikef]

In my pool area I have Bose environmental 251 speakers driven by a Marantz MCR 612 networked audio player

The Marantz has a subwoofer-out RCA connector

I’d like a bit more bass, so have a passive 10” outdoor sub (being outdoor, active sub isn’t an option) rated at 200W. I need a subwoofer amp to drive it with RCA in and speaker pair out

I bought a cheapo Chinese Douk G4 subwoofer amp off Amazon which has the right connections but is a bit weedy - it’s spec’ed at 100W but performs like it’s half that…

I’d like to find a 200W-ish subwoofer amp with RCA line in and speaker pair out at a reasonable price (less than the £500 cost of the Marantz), but am having no joy - a KEF KASA500 does far more than I need and costs more than the rest of the system put together

Any suggestions what I could look at?

[rex]

Have a look at the Behringer range. Fans can be noisy so best put in a different room but more power than you would ever need. Bought mine about 12 years ago and still running strong.
I have the EP 4000 but the NX 1000 may be all you need

[mikef]

Thanks - I’m looking at images and not seeing RCA input though

[Crackie]

mikef said:

In my pool area I have Bose environmental 251 speakers driven by a Marantz MCR 612 networked audio player

The Marantz has a subwoofer-out RCA connector

I’d like a bit more bass, so have a passive 10” outdoor sub (being outdoor, active sub isn’t an option) rated at 200W. I need a subwoofer amp to drive it with RCA in and speaker pair out

I bought a cheapo Chinese Douk G4 subwoofer amp off Amazon which has the right connections but is a bit weedy - it’s spec’ed at 100W but performs like it’s half that…

I’d like to find a 200W-ish subwoofer amp with RCA line in and speaker pair out at a reasonable price (less than the £500 cost of the Marantz), but am having no joy - a KEF KASA500 does far more than I need and costs more than the rest of the system put together

Any suggestions what I could look at?

It would be good to know a little more about the passive 200w sub you have..........the impedance of the sub could be why it sounds quieter than you're expecting.

The Texas Instruments chip used in the amp is a TPA3116 . it is rated 100w into4 ohm loads but only rated 50W into 8ohm loads........I've used a few of the Douk amps and they usually follow TI's own chip application notes very closely............i.e. they deliver the TI data sheet specs. https://www.ti.com/lit/ds/symlink/tpa3116d2.pdf?ts...

This is the data sheet for the chip used in the Douk G2..........it could be ideal but knowing more about the electrical impedance load of the sub would help to confirm. https://www.ti.com/lit/ds/symlink/tpa3255.pdf?ts=1...

Douk G2 https://www.amazon.co.uk/dp/B07TTMN51V/ref=emc_b_5...

Edited by Crackie on Sunday 3rd July 23:36

[VEX]

OSD Audio do some and they are due to come to the UK soon. CE certification permitting.

V

[benz0]

mikef said:

Thanks - I’m looking at images and not seeing RCA input though

It doesn't need to have RCA in.. you can use an RCA to 'whatever' cable which will work just fine

[mikef]

Crackie said:

It would be good to know a little more about the passive 200w sub you have..........the impedance of the sub could be why it sounds quieter than you're expecting.

The Texas Instruments chip used in the amp is a TPA3116 . it is rated 100w into4 ohm loads but only rated 50W into 8ohm loads..

Edited by Crackie on Sunday 3rd July 23:36

That's probably it - subwoofer spec is

• Impedance - 8ohms (per voice coil)
• Power - 200W max (per channel)
• Frequency response - 40-200Hz
• Lower 3dB limit - 50Hz
• Upper 3dB limit - 110Hz
• Crossover - 150Hz

[Douglas Quaid]

Behringer a800 is fanless so silent.

[Crackie]

mikef said:

Crackie said:

It would be good to know a little more about the passive 200w sub you have..........the impedance of the sub could be why it sounds quieter than you're expecting.

The Texas Instruments chip used in the amp is a TPA3116 . it is rated 100w into4 ohm loads but only rated 50W into 8ohm loads..

Edited by Crackie on Sunday 3rd July 23:36

That's probably it - subwoofer spec is

• Impedance - 8ohms (per voice coil)
• Power - 200W max (per channel)
• Frequency response - 40-200Hz
• Lower 3dB limit - 50Hz
• Upper 3dB limit - 110Hz
• Crossover - 150Hz

Do you have a link to the manufacturers site? The sub driver looks like a twin voicecoil design ( might have two separate drivers ); consequently it may have the option to drive them individually or in series or in parallel. i.e. 8Ohm + 8Ohm or 16Ohms in series or 4Ohms in parallel. The 16Ohm series option is very unlikely.

If there is only one set of terminals on the sub enclosure then wiring the coils individually isn't an option and it's likely that they are parallel. In that case the sub will be 4 ohms which doesn't explain why things are quieter than expected.

The power spec does mention 200W 'per channel' though.........does it have two sets of terminals?

[mikef]

Polk Sub 100 outdoor subwoofer

[Crackie]

mikef said:

Polk Sub 100 outdoor subwoofer

Polk do specify the design as an 8 Ohm product, with an 88dB sensitivity............the Douk amp will only be delivering 50W into the Polk's impedance. As suspected, that 50W of power, in conjunction with 88dB sensitivity, is why it isn't playing particularly loud.

An amp capable of 150 - 175W into an 8 Ohm load would be ideal. The Douk G2 I linked to yesterday would work well.............it also has adjustable input sensitivity to help match is with the sub out from your Marantz.

[rex]

mikef said:

Thanks - I’m looking at images and not seeing RCA input though

Just looked. The EP4000 has RCA inputs as that is what I use. Have checked the NX 1000 and you are correct there is no RCA inputs. My apologies

[stevoknevo]

I've got an XTZ A2-300 power amp that's 150w/8ohm and has a huge damping factor that'll get a proper grip of the sub - they're a direct seller so import costs will sting on €368, they tend to sell on eBay for £300ish, but there's a pair on the Wam for £275 each including delivery (tiny, about the size of a ream of A4 paper, class D so power efficient and run cool, absolutely solid case and some of the best speaker binding posts I've ever seen, RCA input and a trim knob for volume matching - I don't know if that pair are still in warranty but if they are all you need is the receipt for XTZ to honour it - I asked them directly before buying my one)
https://www.hifiwigwam.com/forum/threads/pair-of-x...

[mikef]

I thought I would update this thread, as I now have my perfect subwoofer amp thanks to a poster here

No connection with American Audio other than as a satisfied customer for the OSD SMP200 subwoofer amp used for my outdoor subwoofer



OSD Amp on lower shelf



Spot the subwoofer…

[VEX]

I can! But then I know what i am looking for!!

Very hidden in plain sight.

[Miserablegit]

Very good- you could hide it further by twisting ivy around the cabling!