Opinions on Amp upgrade to incorporate a sub

[Robert94]

So I currently have a Cambridge Azur 340a driving B&W 685 S2 bookshelves but since reading how much everyone on here values a subwoofer I thought I might begin an upgrade if I can find a couple good second hand deals (Azur340a doesn't have any pre-outs/sub-outs).

Found a second hand Yamaha DSP-AX761 that is currently going cheap and was wondering if you guys think it's worth upgrading if I can get it for under £100. Here is a link to a site with specs on it. Although I only run 2 channel at the moment it would provide a long term investment to future additions of TV and surround etc. The 'scale of economy argument' is what made me look into AV amps and they're more readily available second hand.

I was thinking that I would keep an eye out for a deal on a sub for under £200 some time over the next month if I bought this amp. Do you think this is a reasonable upgrade and would it be noticeably better than the Azur before I get a sub or just have more functionality?

Thanks

 

[PENG]

So I currently have a Cambridge Azur 340a driving B&W 385 S2 bookshelves but since reading how much everyone on here values a subwoofer I thought I might begin an upgrade if I can find a couple good second hand deals (Azur340a doesn't have any pre-outs/sub-outs).

Found a second hand Yamaha DSP-AX761 that is currently going cheap and was wondering if you guys think it's worth upgrading if I can get it for under £100. Here is a link to a site with specs on it. Although I only run 2 channel at the moment it would provide a long term investment to future additions of TV and surround etc. The 'scale of economy argument' is what made me look into AV amps and they're more readily available second hand.

I was thinking that I would keep an eye out for a deal on a sub for under £200 some time over the next month if I bought this amp. Do you think this is a reasonable upgrade and would it be noticeably better than the Azur before I get a sub or just have more functionality?

Thanks

Going with an used AX761 is a potential downgrade. If you are happy with the output of the 340A now, you should just add a good sub such as the SVS SB1000 or PB1000. There is no need for subouts, those SVS will give you two options to hook up with the 340A, the preferred way is to use the RCA in/outs so the B&W will get the high passed signal. I can't find any 385 S2 from B&W's archive website, only 685 S2, what's the specs of the 385?

 

[Robert94]

I can't find any 385 S2 from B&W's archive website, only 685 S2, what's the specs of the 385?

Oh goodness I meant 685 S2 (typo) sorry to waste your time looking!

There is no need for subouts, those SVS will give you two options to hook up with the 340A, the preferred way is to use the RCA in/outs so the B&W will get the high passed signal.

I am happy with the Azur so if there is a way I can incorporate a sub without a new amp that would be awesome! The only RCA out is 'Rec-out' on the back, the rest are all inputs. I have my music going from my laptop into the Aux in. Just struggling to picture your suggested set-up.

Following on from that are you suggesting having the L/R speaker inputs going into the back of the sub and then having the B&W's wired from the back of the sub? If this is the case does the amp do any processing *EDIT - although I always use the direct input anyway* or will it all be done from the active sub? If this is the case then thanks for the great suggestion - this is exactly why I asked on here first!

 

[Robert94]

So I've had a look at the user manual for the SB-1000 and page 10 answers my above question but has created a couple more.

• Are there any disadvantages to this set-up - stress on amp signal mix up etc?
• I currently have Banana plugs with cable into my amp but I'd have to remove them for this (or have the two wires in the banana plug) so I'm assuming that it doesn't matter if the two wires touch i.e the two negative right channel wires that are tied into the same speaker output with one running to the high-pass input of the sub and the other to the right speaker.
• Why is the RCA in/outs more favourable - is it just to do with ease of setup?

Thanks.

**EDIT also just as a point of interest the best price for this particular sub in the UK is £410 which is ~£60 ($90) more that it would cost in the US

 

[PENG]

You are right, the 340 does not have pre outs so it cannot take advantage of the high pass filter offered in the SB or PB1000 subs. You can still run two pairs of speaker wires from the 340A's speaker output terminals, one pair will go to the sub's speaker level inputs. In that case the sub will just be extending the bass of your 685 S2 and your 685 S2 will still be fed full range.

There are other subwoofers, such as some Polk audio's do have two sets of speaker level terminals, one for inputs and the other for outputs. So with those ones, the 685 S2 should be connected to the speaker level output terminals on the sub to get the signals above the crossover setpoint.

http://www.polkaudio.com/dsw-pro-440-wi/d/1107C3255

My Cambridge audio 840W has pre outs, so I connect the pre outs to my Rythmik sub's RCA input and connect the sub's RCA filtered (fixed at 80 Hz in this case) output to my power amp so my L/R speakers are getting 80 Hz and above. I found no degradation in sound at all even though in theory the OP amp in the sub has become the weakest link.

 

[Robert94]

Okay so I believe there's less benefit to just extending the bass because one of the advantages of a sub is to remove some of the load that the speakers are required to handle so that they can focus on the frequencies they respond best at.

There are other subwoofers, such as some Polk audio's do have two sets of speaker level terminals, one for inputs and the other for outputs. So with those ones, the 685 S2 should be connected to the speaker level output terminals on the sub to get the signals above the crossover setpoint.

And getting a woofer with that capability would allow the benefit that I described above? Which means I need to do a bit of research to find a suitable sub available in the UK. Thank you for the advice.
Are there any inherent disadvantages to subs with speaker level input and outputs that I should be aware of, or is it time to do some research?

 

[PENG]

Okay so I believe there's less benefit to just extending the bass because one of the advantages of a sub is to remove some of the load that the speakers are required to handle so that they can focus on the frequencies they respond best at.

And getting a woofer with that capability would allow the benefit that I described above? Which means I need to do a bit of research to find a suitable sub available in the UK. Thank you for the advice.
Are there any inherent disadvantages to subs with speaker level input and outputs that I should be aware of, or is it time to do some research?

Even if you can't find one like that, as long as it has speaker level inputs you will still get the benefit. The one with filtered signal back to the L/R speakers will just be added (albeit small) benefits.

 

[PENG]

Okay so I believe there's less benefit to just extending the bass because one of the advantages of a sub is to remove some of the load that the speakers are required to handle so that they can focus on the frequencies they respond best at.

That could be the case for some speakers, but your 683 S2 is quite capable down to 50Hz. Some people actually prefer to run the subwoofer to just extend the bass.

And getting a woofer with that capability would allow the benefit that I described above? Which means I need to do a bit of research to find a suitable sub available in the UK.

You've got that right, and it may be tough to find one. In North America, I know Rythmik will custom make it for you as they did for me (I opted for the RCA line level one).

Are there any inherent disadvantages to subs with speaker level input and outputs that I should be aware of, or is it time to do some research?

It depends on the components and circuity used, but in practice I would say the answer is likely yes. In my case, that option is Op amp based, so in theory I have given up the theoretical advantage of my much more expensive Cambridge Audio preamp for that low cost feature, yet I do not perceive any sound quality degradation. It's like comparing a $1500 CA integrated amp to a $7000 Passlab amp, one has better quality components and workmanship but that most likely not result in audibly better sound quality if you can't seem them.

The fact that you already a well made integrated amp, there is no point in replacing it with an used and lower end unit just for the RCA sub out feature that may or may not come with any decent bass management capability. I would just buy the best quality sub that has speaker level inputs and is within your budget. When you are ready for a real amp upgrade, the sub will still be good.

 

[Robert94]

I do wonder if it is worth purchasing a sub when the 685 S2's are good down to 50Hz so I think I'll try and arrange a demonstration with a decent sealed box sub hooked up via speaker level input to get a general idea of the effect of adding a sub.

I don't think it'll really be possible to get a sub here with speaker level outputs and it would be quite restrictive with choice so I like your idea of getting a good sub with speaker level inputs that will still be good when I eventually get a new amp.

After you mentioned the SVS SB1000 I had a read around and found nothing but praise for it, particularly when used for music, but I won't be able to get a demonstration. It's also very hard to find subs around the SB1000's price range - and certainly to find one with a 12" driver! So if I decide having a sub will be beneficial and worth it for me at this particular moment I may see if I can get it with a trial period. In North America you guys seem to have a much greater choice of subs and speakers, I'm envious!

 

[PENG]

I do wonder if it is worth purchasing a sub when the 685 S2's are good down to 50Hz so I think I'll try and arrange a demonstration with a decent sealed box sub hooked up via speaker level input to get a general idea of the effect of adding a sub.

I don't think it'll really be possible to get a sub here with speaker level outputs and it would be quite restrictive with choice so I like your idea of getting a good sub with speaker level inputs that will still be good when I eventually get a new amp.

After you mentioned the SVS SB1000 I had a read around and found nothing but praise for it, particularly when used for music, but I won't be able to get a demonstration. It's also very hard to find subs around the SB1000's price range - and certainly to find one with a 12" driver! So if I decide having a sub will be beneficial and worth it for me at this particular moment I may see if I can get it with a trial period. In North America you guys seem to have a much greater choice of subs and speakers, I'm envious!

You can also look at this one:
http://www.rythmikaudio.com/L12.html

If you phone or email them about your issue, I am quick sure they can offer the speaker level option for a small charge. They may even put in the HF filter for your 685 S2, but that won't be free or cheap. I have the E15HP and am very happy with it because it does not sound like a subwoofer at all. I think the L12 will have the same characteristics but have less output.

What's your room dimensions? I assume it is small, since you are not complaining about the mere 50W of your 340A. For a smaller room, you already have a very nice sounding system for music, so I highly suggest you don't settle for less in picking out a sub. The SB1000 should probably the baseline, the L12 will be better. Of course if you can find something as good in the UK it will be the best.

 

[Robert94]

The room is about 14ft by 14ft but the speakers are located at one end about 4ft apart (on a large desk) and toed in slightly so the listening position is actually only in half of the room space. I'll be moving around a bit over the next couple of years and don't envisage having a larger room. The 50W can get the speakers to near deafening level at the listening position (8ft away from the speakers) at only 2/3 volume.

How does something like the Wharfedale Powercube SPC12 (£380) or the Wharfedale Diamond SW150 (£150 - just interested in the issues with cheap subs (I imagine it wouldn't do the B&W's justice)) compare to the SB1000 (£409). If I decide to spend around £400 I think I may hold fire for a while.

Also there are subs such as the REL T Zero (£299) that was recommended by a salesman but it only has a 6.5" driver, which is the same as the mid-base driver of my B&W's so how could this possibly be any good!? Sounds like that would be a complete waste of money to me.

 

[fmw]

So I currently have a Cambridge Azur 340a driving B&W 685 S2 bookshelves but since reading how much everyone on here values a subwoofer I thought I might begin an upgrade if I can find a couple good second hand deals (Azur340a doesn't have any pre-outs/sub-outs).

Before you spend any money it is important to understand that you can integrate a subwoofer into your system without bass management. You can manage the bass yourself with the level and filter controls on the subwoofer. I started with subwoofers well before preamp bass management entered the scene. It is convenient and quick but about 5 minutes of effort can get the job done manually. I've done it manually for so long I still don't use bass management even on the receivers I have that do include the feature. You only need to be sure that the sub you choose has speaker level connections. Most of them do.

Buy the sub you want and try to integrate it manually. If the results are satisfactory then you saved some money. If not you can then dive into changing amplifiers.

 

[KEW]

I am probably over-simplifying, but why couldn't he put a couple of these upstream of the speakers?

http://www.parts-express.com/80-hz-high-pass-8-ohm-crossover--266-458

Product Details
80 Hz High Pass 8 Ohm Crossover
Convenient crossovers that work great in any application requiring economical, flexible filtering. Also for use in car stereo installations with component speaker systems. Low pass, band pass, and high pass models complement woofers, midranges, and tweeters. Designed to be wired in-line between amp and speaker by using .205" disconnect terminals or soldering. The crossovers' compact size facilitates mounting virtually anywhere you desire.

Specifications: • Approximately 250 watts RMS • Type: High pass • Driver impedance: 8 ohm • Crossover frequency: 80 Hz • Roll off: 12 dB.

They also come in 4 ohm and 100Hz variants.

 

[PENG]

I am probably over-simplifying, but why couldn't he put a couple of these upstream of the speakers?

http://www.parts-express.com/80-hz-high-pass-8-ohm-crossover--266-458



They also come in 4 ohm and 100Hz variants.

Because those are passive, so they will interact with the speakers crossovers. I agree with fmw, he should just get a sub that has speaker level inputs, dial it in manually; and forget about the active high pass option that is not practically in his case.

 

[Robert94]

Thanks guys, based on everything that has been said I have decided that the next thing I'll get for my system is a sub. I don't know when yet, but hopefully not in the too distant future.