What to look for in specifications

[Vivek Batra]

Hi FMs

I was thinking from sometime to post this thread as I didn't find any dedicated thread on this forum just about how to or what to read in specifications. I am not a very experienced guy in to hifi but just about an year old and still not have much knowledge. I am starting again from scratch to build my system hence again looking at the specs for the equipment. There must be many more people out there who reply on the forums to pick a direction before going forward and making a purchase. I had a very bad experience when I bought my first system just out of ignorance and eventually had to sell all of that. I just do not want the same to happen with any one else.

I would request all of you to pitch in and share your knowledge with all the people around here

So when are looking to buy an Integrated amplifier or a Pre Amplifiers and Power amplifier there is a lot of information in the specs. Sometime the most important information is either not mentioned or deliberately hidden. For instance many companies would give the RMS rating at 6 Ohms while mostly people use 8 Ohms speakers and the actual rating at 8 Ohms would be even less than whats advertised. or not even close to whats claimed. Most of the stuff is just a marketing gimmick only.

My intent to post this thread is to know what exactly is to look for in the specs at what is more important before you buy a product or even decide to demo the product based on the specs alone.

I have come across many terms while looking at the specs and would love to see you guys explaining those for the people like me. Here goes the list

Integrated/Pre Amlifiers
1. Frequency Response
2. Bandwidth
3. THD at 8 Ohms 1KHz and at 8 Ohms 20 hz -20 KHz
4. Damping factor
5. Hum and Hiss
6. Signal to Noise Ratio
7. RMS output 4/6/8 Ohms
8. Classes (A, A/B , D etc)
9. Output Impedance
10 .Speaker Terminals
11. Feedback (Negative Feedback)
12. Synergy with other equipment

Power Amplifier
1. Cross talk
2. RMS output at 4/6/8 Ohms
3. Continuous output
4. Peak output
5.Speaker Terminals
6. Input Impedance


There must be many more terms mentioned in the various brands specs. You are welcome to add more to the list.

Thanks.

Regards
Vivek

 

[flat_listener]

Absolutely! One of the big problems with measurement in hi-fi, is that we focus on optimizing the things we can measure and ignore and sacrifice the things we cannot quantify... If only we could measure the warmth of vinyl or the musicality of a great DAC...

It's often that way with specifications: Many give a misleading picture and, as a result, many reputable audio manufacturers - especially at the very High-End - either no longer publish them or have reduced those that they do release to the barest minimum.

Use your ears. They're the best test instrument the world has ever known... your system is for your own enjoyment; why look to others for information about how good it is... when you can simply let your ears do the measurement?

 

[Vivek Batra]

Absolutely! One of the big problems with measurement in hi-fi, is that we focus on optimizing the things we can measure and ignore and sacrifice the things we cannot quantify... If only we could measure the warmth of vinyl or the musicality of a great DAC...

It's often that way with specifications: Many give a misleading picture and, as a result, many reputable audio manufacturers - especially at the very High-End - either no longer publish them or have reduced those that they do release to the barest minimum.

Use your ears. They're the best test instrument the world has ever known... your system is for your own enjoyment; why look to others for information about how good it is... when you can simply let your ears do the measurement?

I agree to that what ever sounds best to ears go for that. But at least just to short list few brands models etc one should reply on the specs to some extent.

 

[Hiten]

You have coverd most of the specifications Vivek. Instead of explaining; the information from net will be precise and comprehensive. Specifications are important part. For example it tells us about how well the product is made. For example not all amplifiers can deliver current at low impedance speakers (Multiway speakers have variable impedanec). So if an amplifier outputs 100 watts at 8 ohms it should theoratically deliver double power at 4 ohms. But due to losses (I am not expert to explain that) the good amplifier will deliver at least 50% more. i.e. 150 watts. So if amplifiers published specifications tells that it delivers (lets say) 130 watts in 4 ohms that means transformer and powersupply caps specifications (Or may be circuit topology) are compromised.
Practical example from net is Lets take marantz PM7005 and Pioneer A-40ae. Marantz gives 60/80watts at 8 ohms and 4 ohms load (30% more). Pioneer gives 30/60watts (50% more) at 8 and 4 ohms. So even with (at) lower power the pioneer can handle varying speaker load well.
This doesnt mean that one would like one amplifier over other or choose one over other. This just tells how the amplifier designer/company has designed the amplifier. There is no harm in learning this as this hobby is expensive and it is good to know where one is putting money in. One can always decide subjectively after narrowing down few products. In short if anyone is buying an amplifier why not choose an amplifier that is spec'd well and sounds good.
Regards.

 

[Hiten]

In short if anyone is buying an amplifier why not choose an amplifier that is spec'd well and sounds good.

...unless ofcourse one likes low power single ended tube amps

 

[pks.k]

...unless ofcourse one likes low power single ended tube amps

May I have suggestion in some of entry level SET amplifiers (if any available) sir?

 

[Vivek Batra]

May I have suggestion in some of entry level SET amplifiers (if any available) sir?

Please go ahead.

 

[Hiten]

May I have suggestion in some of entry level SET amplifiers (if any available) sir?

Hi pks.k,
Dont have any experience with entry level SET amplifiers. I did tried to diy tube amp but importing well made transformer and original tubes cost are high. 'Mullard 3-3' or 'RH84' tube amp looks interesting. I have friends in US and am trying to see if costs can be reduced. Mind you low power SET amps have limitations so do get informed about it.

..Also please dont call me sir. It makes me feel old
regards

 

[pks.k]

Hi pks.k,
Dont have any experience with entry level SET amplifiers. I did tried to diy tube amp but importing well made transformer and original tubes cost are high. 'Mullard 3-3' or 'RH84' tube amp looks interesting. I have friends in US and am trying to see if costs can be reduced. Mind you low power SET amps have limitations so do get informed about it.

..Also please dont call me sir. It makes me feel old
regards

Hi Hiten!
Thanks for your valuable information.