Subwoofer connection/Rotel RA1572MK2 review

[Helix Hifi]

I see Rotel RA1572MK2 has two subwoofer outputs. Two mono outputs. So you can add one, two subwoofers. Then it we’ll be stereo, I assume. I am wondering why most people use two RCA cables from the subwoofer to the amplifier pre out. What exactly is subwoofer outputs? Is it better then pre out, speaker terminals?

You see. I’m considering buying Rotel RA1572MK2. Simply because it’s very powerful, and Rotel is very conservative measuring watts. Bit tired of owning Marantz the last two years, want to try something else. And of all the amplifier I had, I never owned Rotel before. Whether it is bright sounding or not...This I need to decide my self.

Going to borrow one this weekend. Otherwise it most likely we’ll be Yamaha AS1200. Hopefully this two amplifier we’ll be one off the last amplifiers I buy. Or I’ll stick with my current amplifier.

I’m hoping SvS Pro 10 can be added in my system next year. Rotel also has pre out, two pair off speaker terminals. And of course two mono subwoofer out. The hifi shop can hopefully take my current amplifier as trade, so then it could be worth it.

I’ll always have soft spot for Marantz, but I’d like an amplifier with more oomph in the sound. Rotel also has Dac. It’s handy to have. Plus the power 200 watts in 4 ohm, 120 watts in 8 ohm. Outstanding build quality too. The transformer!

 

[Helix Hifi]

Wondering which connection is best when the amplifier has two mono subwoofer outs. Should I just use them?

 

[Khazul]

As far as I can tell the sub outputs are simply stereo summed to mono versions of the pre-outs and so may be more convenient for connecting to many subs.

If you wanted to have stereo subs, then you would still use the pre-outs instead.

I used pre-outs from my A-S2100 (previous generation model up from the 1200) to L+R inputs on my sub as my sub has separate LFE and L+R line level inputs. However many subs do not separate these which many matter if you also want to do something funky with the LFE from an AVR as well (I used to dual connect my sub to both the AVR and my amp, but it is complex to set this up right and requires a bit of luck too).

Also you may want a sub with a crossover that can be set as low as 30Hz or so with the silver 300. The common 40Hz lower limit may make integration difficult.

 

[Helix Hifi]

As far as I can tell the sub outputs are simply stereo summed to mono versions of the pre-outs and so may be more convenient for connecting to many subs.

If you wanted to have stereo subs, then you would still use the pre-outs instead.

I used pre-outs from my A-S2100 (previous generation model up from the 1200) to L+R inputs on my sub as my sub has separate LFE and L+R line level inputs. However many subs do not separate these which many matter if you also want to do something funky with the LFE from an AVR as well (I used to dual connect my sub to both the AVR and my amp, but it is complex to set this up right and requires a bit of luck too).

Also you may want a sub with a crossover that can be set as low as 30Hz or so with the silver 300. The common 40Hz lower limit may make integration difficult.

Let’s say I wanna connected one subwoofer to one off the subwoofer outputs. Well it be mono if I do the the same on pre out? I mean just one RCA cable. If I do the opposite on both subwoofer outputs, pre outs (two RCA cables) it’s going to be stereo?

It’s subwoofer basically mono singnal, regardless if you use two RCA cables?

Subwoofer connections is confusing. Some prefer high line sound, some low line sound.

 

[Khazul]

It’s subwoofer basically mono singnal, regardless if you use two RCA cables?

Yes - they are both mono outputs, so just one cable needed to a line input on a single sub.

If you use one pre-out instead, then it will only get the left or right channel which is not what you want if using one sub. For pre-outs you need to use both to a sub that has line L + R inputs, or run them to separate L/R subs which is what quite a few people do with the little REL T5 subs.

While many tracks are mixed with low end bass to mono (using a mid/side mode EQ), not all are so you always need a feed from both channels either to separate left and right subs or summed mono to a single sub.

High level input are just internally converted to low level and passed via the same crossover as any line inputs (if available). Sound will be the same regardless unless something odd has been done.

 

[Helix Hifi]

I see, little lost... From understanding RA1572MK2 has two subwoofer mono outputs. Label one and two, not left, right. You know this. Sorry for nagging.

I have no intention of using dual subwoofers in the beginning, I don’t know if we’ll use subwoofers at all. But it’s nice to have this options. Not many amplifiers have subwoofer outputs. My plan is to use on subwoofer. Then perhaps two.

So do I need two connect two RCA cables from both the amplifier mono subwoofers outputs to the the two subwoofer inputs on the subwoofer. Or is made for two subwoofers?

Because if it’s made for two subwoofers at the same time, I don’t I don’t know...

I know the amplifier supports pre out, one extra set off speaker terminals. So I can of course use those options.

But I really want to try the subwoofer outputs.

Conclusion. Well one RCA cable, not two from the mono subwoofer outputs convert the sound to stereo?

Thanks!

 

[Helix Hifi]

I understand pre out needs two RCA cables, then you get sound from the subwoofer. Then you run 2.1 system.

But does mono subwoofer work the same. I mean two RCA cables just like pre out?

My understanding is an amplifier with mono subwoofer out, pre out subwoofers (many names) allows the amplifier to filter out the high frequency’s. The amplifier only sends the low frequency’s.

Whereas pre out runs the entire frequency range.

Hence subwoofer out is better, even if you need to adjust the crossover settings on the subwoofer.

Ps, Rotel does not have bass management. But apparently many run one, two subwoofers with it l, and are very happy.

 

[Helix Hifi]

Well i figured it out. Rotel tells me I need to use pre out for one subwoofer or two, so they are configured in stereo.

The other option is to use the speaker terminals because then subwoofer (subwoofers) are getting full range signal as the speaker. Then it’s also stereo.

Most likely am going to see if two small 10 inch subwoofers run directly in both mono sub outputs is better. I’ll check out subwoofer which can play as low as 30Hz.

It could be I don’t need subwoofer at all. Rotel is very powerful. Still it’s nice to have this options.

 

[Khazul]

Well i figured it out. Rotel tells me I need to use pre out for one subwoofer or two, so they are configured in stereo.

See https://www.rotel.com/sites/default/files/product/manuals/ra1572mkii_om_en.pdf and look at back panel - it explicitly says 'mono sub out' and backs this up somewhere in the manual.

It seems you have 2 subs outs and they are both mono, not left+right.

 

[Helix Hifi]

120 watts in 8 ohm-200 watts in 4 ohm. Do I need so much power? Well it’s fun. The amplifier controls the speakers with an iron gripe.

Test track is Tears In Heaven (unplugged) version. Many amplifiers starts distorting on the guitar on very loud volume, but the Rotel just strolls down the road “am no in no rush”. The volume begins on 0 to 95. On volume 70 it sounds remarkable. I haven’t dared played any louder then this. I probably only use 20 watts but this 20 watts is no joke.

The back ground is totally silent, so cymbals pops from the mix white out listing fatigue. Bass is not fat, slow. It’s precise, punchy sounding. Bass intro on Scream by MJ which suddenly stops, then starts again. It’s torture test on loud volume, still the amplifier has totally control. The bass is controlled, deep on low volume too.

Take The Power, the guitar is frightening to listen to. The knock on the door on Black and white by MJ, particular shows the amplifier imaging strength. The knock on the door on the right speaker is so realistic.

Midrange tracks like The Moon Is Harsh Mistress. An excellent test to see if the amplifier handles female voices. You hear the pain, the longing in her voice. Be My Baby. You hear the back vocals far, far away. While the lead vocalist is the center of the speakers.

Neil Young voice is rusty, yet romantic. So the midrange is excellent.

Treble is not bright. It just hides in back ground, then suddenly it’s not. An excellent track is Time. The clocks is not bright, neither it is flat sounding.

Volume control is easy to control. Even if it’s digital volume control it does not need much gain to rock the house.

Remote, meh. Plastic. In this price class it should be aluminum. The front plate with all the buttons looks overwhelming in the beginning. It is perhaps too much buttons, still there’s charm to them. Back there are tons of connection. Balanced inputs too.

After listing to Bluetooth. I’ve changed my mind. It sounds acceptable compared to cd, Spotify. Also handy for other people to play their favorite music without using my iPad. I believe it’s the highest BT resolution you can find.

It has pre out for adding power amplifier. Two mono subwoofers outputs. So I can run two subwoofers in stereo by using pre out, or two in mono.

I have soft spot for Marantz, but sorry it can’t compete. It sounds slow, and not so realistic as Rotel.

An excellent match for my speakers. Warm, yet not too much. Neutral sounding in my opinion.
You can also adjust fixed gain, treble etc from the remote. Nice bonus.

I just don’t know why I haven’t though of owning Rotel before. No speaker hiss from the speakers also, only on max volume. Then it is only audible 15 cm from the speakers! The noice floor is excellent. if you look inside the transformer is huge. Then there are caps which rapidly gives the speakers power when they need it.

Break in, yes it gets better after 24 hours. It’s not bad sounding in the start, but it sounds bit thin then. I also like display on the front of the amplifier. You can dim the blue light too.

I would’ve have given it 10 out of 10. Still there are better amplifiers out here. The remote mentioned is plastic. Bluetooth is an odd feature. I’ll have to say BT doesn’t sound bad. So for all you BT users, this amplifier may suit you. So my score is 9.5 of 10.Thinking off getting two SVS subwoofers too.. Still as mentioned this amplifier has tuneful, deep bass.

This amplifier should be on your list if you want some warmth to the sound without falling a sleep. It gets my foot tapping. I don’t know how much power this amplifier can give on max. As mentioned it is measured 120 watts, then 200 watts. I believe it easily can give 20-30 watts more then the published measurements. It’s monster, but beautiful too.

 

[Helix Hifi]

Has anyone else listened to this amplifier? It seems Rotel falls in the background when it comes to other famous brands. I well admit I was in this category before.

It’s a brand which didn’t appeal to me before. I though it was all about power. An amplifier symbolized with Cervin Vega. Not true hifi like Marantz, Rega, Yamaha, Arcam, Naim and Hegel. Take Hegel as an example. Hegel in short time sky rocketed to fame. I know of course why. Power, finesse.

 

[Helix Hifi]

Rotel suits MA perfectly. You get an amplifier with pretty neutral sound with tad forward midrange which suits MA laidback midrange.

This gives the listener an exiting sound when the recording demands it, while being gentle with jazz, acoustic recordings.