Please teach me how to pick a suitable amplifier to drive my bookshelf speakers

[ztmj96]

Hi LTT forum,

 

Recently I'm trying to improve the audio setup on my PC, which previously only has a sound card (Xonar DX) , a pair of headphones (ATH-AD700X) and a cheap speaker setup.

I decided to upgrade my speakers and bought the Q Acoustics 2020i which has this set of specs: 

 

Enclosure type: 2-way reflex

Bass Unit: 125m

Treble Unit: 25mm

Frequency Response: 64Hz - 22kHz

Nominal Impedance: 6ohm

Minimum Impedance: 4.0ohm

Sensitivity: 88dB

Recommended Power: 25 - 75w

Crossover Frequency: 2.9kHz

Dimensions H/D/W mm:265 x 278 x 170

 

Unbeknown to be, I had no clue that passive speakers need to be powered by an amp. Now what I know is that I will have to power them with an amp/DAC that is of Class T or D? This is the part where it gets confusing.

 

Can the SMSL SA50 50Wx2 TDA7492 Class D Amplifier drive the speakers? From I see, the power output is sufficient and the rear I/O has the required ports.

 

My questions are:

 

1) What is the difference between the above mentioned amp and other Class T amps, like the SMSL Q5 PRO 2x50W? Is it just difference in sound quality?

 

2) The 2020i recommends power of 25 - 75W, so does that mean that the Topping TP22 30WPC Class T TK2050 T-AMP HiFi Digital Amplifier with an amplifier output of 30W@4Ω barely meets the requirement to drive the speakers? And something like the Topping VX1 24Bit / 96KHz TA2021B Class T Vertex Headphone Amplifier + USB DAC with output of 24.4W@4Ω would choke?

 

Can someone please kindly guide me through this?

[Volbet]

I see no reason why you would need a class T or D amp. Those are usually just the smallest and most affordable amps you can get. You could easily power the speakers with a class A/B or class A amp

1. The difference is that the Q5 Pro has a build in DAC and has a remote control.
2. Comparing the Wattage output of different amps can be a bit of a task. Most manufactures don't rate the output the same way. For example, SMSL rate their maximum wattage output with 10% distortion, which means they basically overdrive the amp. 

[ztmj96]

7 minutes ago, Volbet said:

I see no reason why you would need a class T or D amp. Those are usually just the smallest and most affordable amps you can get. You could easily power the speakers with a class A/B or class A amp.

Well, I do have limited desktop space and I'm on a budget of about US$100.

[Volbet]

4 minutes ago, ztmj96 said:

Well, I do have limited desktop space and I'm on a budget of about US$100.

The SMSL SA-50 should be perfect then.

[Rhodri1987]

Stick with a class D amp, they're generally pretty solid these days and quite cheap, not to mention light.If your speakers are rated at a minimum power output of 25 watts it means that it needs at least that much power to actually move the speakers properly. You can get a smaller amp and you will get sound out of your speakers, but the quality of sound will suffer. And getting a higher wattage amp than 5 watts for those speakers is also possible, though I probably wouldn't. The only real issue is that you wouldn't/or shouldn't drive the amp hard as you could ruin your speakers, bt if the volumes are generally low, then a larger amp wouldn't be that much of a problem and it woud leave room for upgrading your speakers in the future f wanted.

 

And finally, to answer your question regarding the amp yo're looking at; Yes, that amp can drive your speakers, very comfortably. Personally I would try to match p the maximum wattage of the amp to the speakers so I could get the most out of both units, but that' my personal preference and a sound tech/musician. 

 

And remember, anything that has the word passive in it's description, needs to be powered externally! ;-)

[ztmj96]

2 hours ago, Rhodri1987 said:

Stick with a class D amp, they're generally pretty solid these days and quite cheap, not to mention light.

Any other reason why I should stick with Class D instead of Class T? There are some Class T amps that seem to meet my needs.

 

I need another opinion. Would you recommend the SMSL A2 40WPC TDA7492 Class D or SMSL SA-98E 160WPC TDA7498E? The A2 has a subwoofer output and 3.5mm input but the SA-98E has a comparatively higher power output.

[Lutkeveld]

4 hours ago, Rhodri1987 said:

but that' my personal preference and a sound tech/musician. 

Sorry to say, but you're quite misinformed for a sound tech.

 

'a certain amount of power to move the speakers properly' doesn't exist.

Quality won't suffer with a smaller amp, only max output will

Matching output also isn't really a thing. It's not like a 50W amp is a perfect fit for a 50W speaker.

 

I'm of course open to corrections

[ztmj96]

38 minutes ago, Lutkeveld said:

Matching output also isn't really a thing. It's not like a 50W amp is a perfect fit for a 50W speaker.

So how do you tell if an amp is suitable for a speaker? 

[SSL]

1 hour ago, Lutkeveld said:

I'm of course open to corrections

Sounds right to me.

 

21 minutes ago, ztmj96 said:

So how do you tell if an amp is suitable for a speaker? 

Does it put out the minimum recommended power into the impedance of the speaker. e.g. Look at the rated output of the amp into 4 ohms. If it isn't high enough or isn't rated for that output, it may not be suitable.

 

It's usually advisable to meet or even exceed the maximum power handling in order to avoid driving the amp into clipping.

[Stagea]

12 hours ago, ztmj96 said:

Any other reason why I should stick with Class D instead of Class T? There are some Class T amps that seem to meet my needs.

 

"Class T" amps are Class D amps using chips from Tripath (part of Cirrus Logic). "Class T" is just a trademark, it is not a topology.

[Lutkeveld]

On 16-9-2016 at 4:57 PM, ztmj96 said:

So how do you tell if an amp is suitable for a speaker? 

There is not really a perfect match. Over- and underpowering both have their pro's and cons.

I usually recommend 'overpowering' to avoid clipping, but almost any amp will work adequately.

For your 50W speaker, anything between 10 and 250W will do, as long as they support the minimum 4 ohm impedance of your speakers