Mini Hi-Fi advice

tigerstyle · 9 Jun 2017 at 19:18

We currently have a Sony TA-FE370 Amplifier and similar spec Sony+Denon CD and Radio units as the sources, powering Eltax Liberty 5+ speakers. Happy with the sound, quality etc, just not the size of the unit. We would like to replace it all (but keeping the speakers) with a smaller unit. It's not used for anything fancy, just background music, bit of radio, and having DAB would be nice.

Denon and Onkyo seem to do decent range of mini H-Fi systems, but in basic terms, how well will the amps in those compare to the Sony? Sony should be 70WPC @ 4Ohms.

The Denon DM-40 is 30WPC @ 6 Ohms. ???

We don't need max volume all the time, but noob here; the numbers look a lot lower, will it struggle? I'm pretty sure not as although these are floorstanding speakers they shouldn't need more power than the bookshelf speakers they basically are anyway, but occasionally we will want it pretty loud.

signs · 10 Jun 2017 at 08:54

keep the amp , keep the speakers , buy a google chromecast audio £30 job done

tigerstyle · 10 Jun 2017 at 11:03

Thank you but no. We need a smaller unit, and want something that'll be easy to play CDs from, my dad isn't that digital enough yet to stream everything.

tom_nieto · 12 Jun 2017 at 22:30

What's the budget?

hornetstinger · 12 Jun 2017 at 22:41

That Sony power output 70W, but it's at 1khz, which means 1khz test tone. And at 4ohm, which the amp brands use to inflate figures, rather than giving both 8 and 4 ohm output figures. 87dB isn't massively high, for example the ones I use are 90db, so in effect you need twice as much power as me, to get the same dB level (if exact same room, distance etc)

It's always good to have more power than is required, than not enough. Lack of power & distortion fries tweeters

tigerstyle · 13 Jun 2017 at 12:03

ahhhhhh ok, marketing waffle has clouded what I thought were real numbers there! I see that a more sensitive speaker needs less watts to drive it, we like the size/shape of the speakers so will keep those, and at 87db they aren't that sensitive so will need a bit of power to drive them, but it sounds like what I thought was a pretty powerful amp (the existing Sony) actually isn't, so it might be comparable with the 'lower' output Denon anyway?

DENON DM40 DAB is £170 online, so budget is around that, low I know. But it is just a basic system that we require. Even looking out for second hand stuff but the value of those seems high for what they are.

Would like something with a lot of power to know it has some in reserve, but doesn't seem anything around? Could for an amp sat in the cupboard with just the inputs out and on display, but can't find anything like that either.

EdButler · 13 Jun 2017 at 13:08

I can recommend the Cambridge Audio One. I have one driving some CA SL30's in my Kitchen/Diner and it had plenty of punch but the speakers are definitely holding it back. I managed to get a perfect condition 'refurb' on the bay for ~170.

The whole thing feels well thought out and it handily has a USB out to power a Chromecast. DAB is quick to navigate and sounds great.

hornetstinger · 13 Jun 2017 at 13:12

Typically small amplifiers are low in power, as class A/B do radiate heat and need heatsinks. For example I use these (200W into 8ohm, per channel)

http://www.ati-amp.com/images/productimages/AT2000_lg.jpg

If you want something small with decent amount of power you'll be looking at class D amplifiers (such those used on subwoofer plate amps) Some pro amps are low profile but they are power amplifiers not integrated or avr's.

tigerstyle · 13 Jun 2017 at 13:22

EdButler said:
I can recommend the Cambridge Audio One. I have one driving some CA SL30's in my Kitchen/Diner and it had plenty of punch but the speakers are definitely holding it back. I managed to get a perfect condition 'refurb' on the bay for ~170.

The whole thing feels well thought out and it handily has a USB out to power a Chromecast. DAB is quick to navigate and sounds great.

Oh wow, there are some on eBay for 175 currently.

Am I right in saying 70 Watts at 4 Ohms is the same as 35 Watts at 8 Ohms?

hornetstinger · 13 Jun 2017 at 13:24

tigerstyle said:
Oh wow, there are some on eBay for 175 currently.

Am I right in saying 70 Watts at 4 Ohms is the same as 35 Watts at 8 Ohms?

If a amplifier outputs 100W into 8ohm load, full range, with 0.05% THD, ideally it should output 200W into a 4ohm load, full range, 0.05% THD.

Power should double from 8 to 4 ohm load. That's if it's a good amplifier, but if it increases by 50W then that's ok. Just if it's lower then really shows amplifier design isn't that great.

Psycho Sonny · 13 Jun 2017 at 13:28

tigerstyle said:
Oh wow, there are some on eBay for 175 currently.

Am I right in saying 70 Watts at 4 Ohms is the same as 35 Watts at 8 Ohms?

i don't think it's safe to just change ohms like that. there should be a setting in the amplifier. also lower ohms are harder to drive i believe which causes amps to overheat.

hornetstinger · 13 Jun 2017 at 13:32

Psycho Sonny said:
i don't think it's safe to just change ohms like that. there should be a setting in the amplifier. also lower ohms are harder to drive i believe which causes amps to overheat.

Good amplfiiers shouldn't have a switch, they will be designed to drive any load, and good amplifiers won't overheat. Typically though budget AVR's are not designed to drive 4ohm and lower speakers. They have reduced amount of heatsinks, smaller power supply, not as many power transistors etc.

Saying that I'm using 4 ohm speakers with a AVR but that's for PC use but for 1m listening distance that's ok.

tigerstyle · 13 Jun 2017 at 13:38

Psycho Sonny said:
i don't think it's safe to just change ohms like that. there should be a setting in the amplifier. also lower ohms are harder to drive i believe which causes amps to overheat.

I've never seen any options like that? I thought it was kind of auto-selected? So the speakers just have as much resistance as they 'have' are built with naturally. And the amp drove as hard as it could naturally, almost like a car driving flat out into a headwind, it'll just do what it does?

Thanks for the explanation Hornet, I can see that ideally that is how things work, but electrically it's not a perfect conversion each time, circuits have inefficiencies etc.

Edit, just seen this in the eBay ad: 30 watts rms (into 8 Ohms) or 40 watts rms (into 6 Ohms)

Edit 2, This is really confusing me, the speakers say 4-8Ohms, the amp gives power ratings for 6-8Ohms, so erm, what will it 'do' when connected?

hornetstinger · 13 Jun 2017 at 13:48

tigerstyle said:
I've never seen any options like that? I thought it was kind of auto-selected? So the speakers just have as much resistance as they 'have' are built with naturally. And the amp drove as hard as it could naturally, almost like a car driving flat out into a headwind, it'll just do what it does?

Thanks for the explanation Hornet, I can see that ideally that is how things work, but electrically it's not a perfect conversion each time, circuits have inefficiencies etc.

One amp looking at PDF now 300W into 8ohm, 450W into 4ohm. Both FTC rating.

It's a very expensive amplifier.

tom_nieto · 13 Jun 2017 at 14:47

If you're using domestic speakers with a domestic amp and sticking to normal listening volumes you are very unlikely to do any damage to your gear. I can't recall seeing a domestic amplifier with an impedance switch recently!

If you're mixing PA speakers with a domestic amp, hiding everything away in a poorly ventilated cupboard and throwing a massive rave you'll have trouble.

Modern audio equipment is very resilient and straightforward. If you were buying vintage stuff then perhaps more care would be needed. A lot of modern amps have a thermal cutout anyway.

For £200 you'll do just fine with the little Denon or CA system. They're not fancy and won't set your ears alight but they'll do exactly what you want.

Psycho Sonny · 13 Jun 2017 at 15:07

my AVR has a setting to switch from 8ohms to 4ohms it's hidden away in a special secret service menu. you can't get into it without doing certain combos and on the actual AVR itself not the remote. and it's the type of thing that you do once and leave it, it's not something you would play about with.

also has a secret bit within that menu for 4K HDR10. before sky q would only send an 8 bit signal. after i changed a setting in the hidden menu it accepted 10 bit signals.

hornetstinger · 13 Jun 2017 at 15:13

I believe the ohm setting limits power or something like that, when put into 4ohm mode.

tom_nieto · 13 Jun 2017 at 15:36

Psycho Sonny said:
my AVR has a setting to switch from 8ohms to 4ohms it's hidden away in a special secret service menu. you can't get into it without doing certain combos and on the actual AVR itself not the remote. and it's the type of thing that you do once and leave it, it's not something you would play about with.

also has a secret bit within that menu for 4K HDR10. before sky q would only send an 8 bit signal. after i changed a setting in the hidden menu it accepted 10 bit signals.

You're on to quite advanced settings there for the home market! I presume your amp is pretty high end and could be used with THX reference style cinema speakers rather than simple hi-fi speakers if desired...

Psycho Sonny · 13 Jun 2017 at 15:45

tom_nieto said:
You're on to quite advanced settings there for the home market! I presume your amp is pretty high end and could be used with THX reference style cinema speakers rather than simple hi-fi speakers if desired...

it was £500 nothing fancy but not total crap either

https://europe.yamaha.com/en/products/audio_visual/av_receivers_amps/rx-v781/index.html

it's the top of the range yamaha without going into the aventage high end models. so i would say higher mid range style avr.

tom_nieto · 13 Jun 2017 at 15:49

Fair enough! I guess I haven't delved into the advanced settings as deeply as you have! The majority of people wouldn't ever need to touch the impedance setting I wouldn't think.