The Two Channel Advice Thread

It's been a long time coming, but I'll be picking up a pair of JBL L112's soon, which I'm super excited about but now I need to amp the beasts properly, and for not a lot of money.

Given my budget and the power requirements of them I'm going to have to go solid-state; any recommendations for a good, beefy (100+wpc into 8ohms) power amp that can be found for $500 or less? Given that the JBL's are more on the neutral side I want something with warmer sound signature... I've considered the GFA-555 but am concerned it might be too neutral. Thanks in advance.

 

Maybe Yamaha? I think the S501 is in your price range.

 

What are you using for a preamp?

 

I'm currently using a passive volume controller (Mackie Big Knob Passive) between my Gungnir Multibit and Adam 2.1 setup that I'm happy with, so I'd prefer to put all my money into a power amp as opposed to an integrated solution (thanks for the suggestion though, @Riotvan). Thus far I've been looking at vintage hifi/pro power amps as they seem to offer the best value (the Yamaha M4 is another I've been considering). I just have zero experience with power amps.

I suppose if a Vidar popped up at the right price I'd be tempted to try that as well...

 

Missed the "power" part

 

Vidar is an excellent power amp for the money and I would recommend it for almost anyone within 2x its price. However it has a very neutral sound sig. You won't find much in the way of "warmth" there if your upstream preamp/source are not adding it.

 

I vote for used Bryston, even 25 years old.
I recently bought two 2B Pro amps, probably 25 years old and bridged them - that gets you around 200W per channel.
I sold 5 years old Emotiva XPA2 to buy those and never looked back.
Bryston was and still is making some remarkable stuff. I have never had a decent power amp so can only compare with XPA-2. Better extended bass, very crisp without any bloom but still punchy. Instrument separation and sound stage way better than Emotiva. They may be a touch bright but it may be because of Bryston BDA-2 DAC which is very in your face.
I listen to classical music mostly, details and layering is very important to me and here 2B is better as well.
The sound still may be not the best I can get from this setup because my speakers are 6Ohm, in bridged configuration it means the amp sees 3Ohm. 8Ohm speakers would be better I think.

 

You can find used B&K amps from the late 80's-late 90's fairly easily for under $500 to well under $500. They were always noted for a "warm" sound (Mosfets) and simple solid reliability. Easy to upgrade/refurb also.
Ive had an 200wpc EX442 for the last 10 years, its my end game amp. I see some ST-140's out there for $250 or so; 70-100wpc channel,depending on the version, the 70wpc is highest recommended as it was designed by Van Alstine even if B&K didn't credit him for it. (what, you thought Massdrop invented that?)

 

This wasn't really obvious to me but after something ''clicking' I bet 80/90s Bryston is similar to Vidar in terms of sonics. That'd be a really interesting comparison actually.

 

Thanks for the recommendation @Pogo, did some research and got a slightly scuffed-up B&K ST-2140 (the ST-140's successor) on eBay for very little; sounds like it should be a good amp with just the sound signature I was after. Once I have the L112's in and hooked up I'll report back.

 

Naive doubt, but can't really understand this one.
I'm planning to get a custom two way speaker, something small for desktop use, and searching for cabinet types, I've found the isobaric ones.
With a cone to magnet configuration, wired in parallel and a sealed box, like this one:


If you start with an 8 ohm, 90db driver, it will already loose 3db because of the sealed box, and also loose another 3 db because of the isobaric configuration, so now it is an 84 db driver. Also, impedance halves, so it's a 4 ohm driver. For wiring in parallel, will it gain 3 db or 6 db, I mean, would it be 4 ohm 87 db or 4 ohm 90 db in the end?

It seems to be an interesting configuration for a small 2 way desktop speaker (small size, no port noise), but I can't fully understand it yet, I'm dumber than usual today

 

@9suns
Here's a decent explanation on isobaric desing: http://audiojudgement.com/isobaric-subwoofer-box-design/

The overly simplified breakdown is this:
- if I have two separate speakers, I get more sound
- or I can shove two drivers into a single cabinet, but then the cabinet needs to be kinda double sized because each speaker needs a certain volume to behave properly
- two drivers in isobaric configuration behaves like a single beefier driver, and thus you only need a regular sized box.
- pros: more oomph for the (roughly) same size
- cons: more complex to build (more $), you need a second driver (more $)

The most popular application is for compact subwoofers, or sometimes even big ones when you simply need more volume. There are also quad-isobaric designs out there; check out the monstrosity about 2/3 of the way down this page: http://www.vueaudio.com/isobaric-subwoofer-design/

Neat Acoustics is one of the few companies I can think of that has isobaric designs in non-subwoofer configurations.

 

That's how I understand it too, it's simply 2 times the moving mass and 2 times the motor power for same radiating area.

I don't see too many performance advantages with it.
(there would be some real gains in performance with opposing driver for spider and BL curve nonlinearity compensation)
You get more extended bass in same size enclosure due to halving of Vas. Voltage sensitivity in parallel wiring stays the same.

I have noticed from listening tests and read about impressions in correlation to Vas,
that too low Vas will likely limit the transducer of performing well in microdynamics.

Driver selection is so diverse you can probably find single driver that can do the same.
The trend in personal audio woofer design seems to be to lower Vas and heavier cone accompanied with stronger motor anyways.

 

Sometimes yes, but then finding that one perfect driver might actually be more expensive than a wonky isobaric design.

There's been a trend in the last few decades towards smaller lower sensitivity speakers because, well, power is cheap (and space is expensive). It's generally easier to build an "ok" but very robust driver and crank a kilowatt of power through it to get the volumes you want. Slap it on a ported box to bump up the last octave, add a tweeter with a minimal high pass filter, and there you go that's 85% of all your cheap speaker designs out there.

Of course, then you're cheating the low end. Bass energy needs to move a certain volume of air, and with a smaller surface area that means you're usually cranking the excursion. No matter how many other tricks you have up your sleeve, that's simple physics right there, and that trickery is going to trade output for accuracy. Granted, I'm all for the trickery if I'm looking for something that needs to fit into a literal bookshelf.

 

I'm looking to finally get a nice-ish 2 channel system. I've been more of a portable audio guy and know very little about 2 channel setups. Assume a medium sized room.

My preferences:

• Balanced with a some warmth
• I have wide ranging tastes so should be versatile
• But absolutely must do timbre for acoustic instruments right
• Smaller better than bigger (all else equal - and I know it's not)
• I don't listen that loudly - more important to play well at modest volumes then to shake the walls.

I'd prefer active speakers because a) I've heard they're better for the dollar, b) they're more portable and c) I don't feel I need to get on the upgrade-itis cycle. But most actives seem to be studio oriented and I'm sure how well that will work for casual, non exhausting home listening.

Looking for a record player too within that budget.

All suggestions appreciated!

 

I can't help you with active recommendations, but when I first read your post I thought of the classic B&W 80x series speakers. The stuff from the late 80's to early 90's so they'd be used. Put a used Bryston 3bST amp and BP5 preamp on it and you should have plenty left over for a decent vinyl rig. The phono section in the preamp is decent, but you might want to consider a Mani anyway.

I had this system back in the 90's for a while with B&W 802s and even tried 805s with great results. Timbre was great and it had that slightly warm sound but not excessive. The newer 8 series went to a different tweeter to increase detail but IMHO lost the warmth.

 

I think you should go out and listen to different setup and see what you like, make notes etc. Throwing an arbitrary budget at this without actually having much experience is a recipe for disappointment. Don't disregard studio speakers because of the label, speakers are speakers and you either like them in your situation or not.

 

No I have nothing except Flac files on my laptop and ZX300. I'll start buying my favorite albums on vinyl it turns out I dig the sound a lot more than digital.

Edit: No to DIY. I don't feel confident in my skills there.

 

Thanks. I had some BW602s with a Yamaha receiver/amp a long time ago and was disappointed. They were overly warm and not at all dynamic. I assumed that was the BW house sound so have steered clear of BW. The 80x series is different?