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What specs do actually matter in amps?

AMPaul

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I believe this is a topic that gets a lot of coverage but i would like to address it still in this post.

Long story short i am on the lookout to "upgrade" my NAD C320BEE. Ofc i'm not made of money so about£600-700 or up to 1000USD is the budget. I am am talking solid state here and not tube amps.
In principle an integrated amp shouldn't affect the sound, it should simply amplify the signal and just provide an exact copy of the input but magnified x-times.

the amp, in my opinion, should do the following:
1) provide enough power to drive 4 to 8 ohm loads. in a reliable manner - most of them do that
2) provide enough power to handle low frequency transients ( like thumps, fast bass lines etc).
3) have a good design for handling high freq transients in an as close possible to a natural sounding manner.
4) have a really low floor noise with a good THD and signal to noise ratio (i understand anything over 70dbA is perfectly fine).

I believe that any deviation from ideality on these 3 points that i have outlined leads to amp "sounding" in a certain way. i am talking about un-intended consequence from circuit design and not manufacturers intentionally designing the circuitry and use of components that do "color" the sound to their liking.

Now back to my story- i was looking at several amps (Rega IO, Rega Brio, Audiolab 6000A).. I usually look for pictures of the inside circuitry and like many of us here i look at the toroidal transformer and electrolytic capacitor "capacity" first. As i understand it the capacity defines how much power one amp can deliver per channel in a reliable manner. Also them being part of the power delivery stage, a bigger capacity would allow- in principle- bigger transients with a bit of power overhead left over for instantaneous high power delivery. Now, for example : the Io has 2x6800uF capacitors (for 30W max power), while the 6000A has 4x15000uF (for 50W per channel). For sake of comparison my NAD C320BEE has 2x15000uF (for 50W). They obviously all can drive a lot of speakers but i was wondering what actually does matter in this case: is it the total capacitance or how well these capacitors charge and discharge to handle transients ( especially low freq ones). To word it differently, does the amount (ofc down to some reasonable extent) matter more than the make and quality of the component (in this case electrolytic capacitor).

I believe the same argument would hold for micro transients but there there are several ways of addressing them by circuit designing and component matching.

I am not talking here about the preamp stage which may also play a role.

Perhaps some of you connoisseurs can enlighten me and hlep me make an even more informed decision when buying future amps.

Thanks!
 

escksu

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Hmm....For those power capacitors, brand/model isn't that critical, Nichicon, Rubycon, United Chemicon, Cornell etc... all will be fine. For quality, its more of specs like 85C vs 105C rated ones, long life ones etc....Some are rated 3000hrs, long life ones oculd be over 10,000hrs.

However, capacitors are only part of the story. There is still your power transistors. There is no point have a massive reserve if your transistors could not deliver the power required. There is also your transformer, it has to deliver enough current too.

I am not sure how old is your C320BEE, if its very old, you can replace the capacitors since they would have degraded already. Btw, you can replace them with a slightly higher value but not too much. This is because it will cause a surge in current when you turn on the amp. Its going to either blow your fuse or trip the breaker. You can include a soft-start circuit to prevent this but I dont think its worth the time and effort.
 

escksu

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Btw, regarding the 6000A, Its not exactly suitable for 4ohm loads. It can run but you will face limitations. ITs 50W at 8ohms but only 75W at 4ohms. If the amp is well engineered, it should be double the power. Eg. 50W 8ohms, 100W 4ohms , 200W 2ohms.

Lastly, if you like tinkering with old amps, the Krell KAV300I and even the 300IL/400XI are extremely powerful amps. I restored an old 300IL bought online that cost less than USD1K. The amp had distortion but its due to worn out caps. Replaced them and its awesome.
 

sergeauckland

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The first question I would address is:- What about your current amplifier are you dissatisfied with?
In other words, what would constitute an 'upgrade' as opposed to just a change?

The amplifiers you mention, Rega Brio and Audiolab, are similar in output to your NAD, the io rather less, so at least as output goes, they wouldn't represent an upgrade. NAD have a justified reputation for conservative ratings, so I wouldn't see any of them as upgrades.

I accept that power output isn't the only criterion, so if your NAD lacks some facility, then perhaps an alternative is justified.

As to power supply capacitance, I wouldn't use that as a way of judging amplifier competence. In an amplifier with a conventional sagging supply, i.e. not stabilised, the reservoir capacitors affect dynamic headroom, meaning how much power the amplifier can provide for short-term peaks over and above its continuous rating, and I would look at those figures rather than just the amount of capacitance. There is also a secondary benefit to higher capacitance in terms of residual hum, but that depends largely on the power supply rejection ratio of the amplifier's circuits rather than the amount of capacitance.

When choosing an amplifier, I first start with what facilities I need in terms of number of inputs, tape or processor loops, number of loudspeaker outputs, type of tone controls, remote controls and of course power output, then find what products meet those requirements, and choose amongst those.

S.
 
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AMPaul

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The first question I would address is:- What about your current amplifier are you dissatisfied with?
In other words, what would constitute an 'upgrade' as opposed to just a change?


S.
Well my amp is about 18-19 years old and like many here i was hoping getting a newer one with good specs/reviews would future proof my system. What i'm looking at is improvement in low frequency handling ( call it bass tightness if you want), and flat overall frequency response over 20Hz-20kHz (or as flat as possible). thing is, i don't wanna spend £600 for a lateral "upgrade". I believe the NADC320BEE is low frequency "emphasised" which in my head would make a sort of less tight bass and "warm" coloration.. For example, form what i gathered, the Muscial Fidelity amps are described a bit "bright", which i don't like either. Also i don't mind a pure analogue amp such as the Regas. Perhaps what i would like doesn't exist within this budget...
 
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AMPaul

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"...I believe the NADC320BEE is low frequency "emphasised" which in my head would make a sort of less tight bass and "warm" coloration.."

Sry but your believe is just wrong. Its ruler flat with a littel lose of ca .5db at the very low end.
https://www.audiosciencereview.com/...surements-of-nad-c-320bee-pwr-amplifier.8504/

Maybe the speakers or the way they are positioned?
Yes i have seen the review but that doesn't reflect on the "tightness" of the bass. so perceptually (even though frequency response says otherwise), a less tight bass leads to me thinking "hmmm this is a bit bassy"- the amp seems "warm sounding".
 

tomtoo

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Yes i have seen the review but that doesn't reflect on the "tightness" of the bass. so perceptually (even though frequency response says otherwise), a less tight bass leads to me thinking "hmmm this is a bit bassy"- the amp seems "warm sounding".

Is this always or only if you listen loud?
 
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AMPaul

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Is this always or only if you listen loud?
to be honest, i'm not sure whether listening level becomes relevant after certain point (in terms of power delivery) with regards to low frequency dynamics , meaning whether there is a certain power handling efficiency intrinsic to the circuit that reflects on bass tightness. one would say yes, and would think that at high listening levels, the amount of power that can be managed over a certain time decreases as power output increases. i think amir measures already at a high output level (5W) but i must check his graphs again to look for low frequency distortion.
 

tomtoo

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Another question, did you tested it with another amp?

To be honest from your descriped proplems, i would first look at speakers and positioning. If you not outpower the amp, i see no reason why it should come from the amp?
 
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AMPaul

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Another question, did you tested it with another amp?

To be honest from your descriped proplems, i would first look at speakers and positioning. If you not outpower the amp, i see no reason why it should come from the amp?
thanks for the reply. My whole point is to evaluate what specs can be identified before changing the amp, what controls the low frequency management (mostly) in terms of available capacitance and other aspects that matter in the efficiency of power handling by the amp overall. Is replacing an old amp from 2000ish with a more "modern one" in the price bracket i mentioned, a move that provides "better sound". I know "better" is subjective. Amir cant measure EVERY amp so that i can have objective measurements helping me decide.

Perhaps a better question is "what do i pay for" when i acquire a >$1000 or >$2000 amp? as per my initial post, 2 amps offer same power at same price (Brio vs audiolab), but vastly different capacitance on the circuit board. Does that matter? seems not? but then i must pay for power delivery circuitry design? right? but then if a manufacturer induces a certain sound on the amp, do i see it as a perk or not?

Has the power amp design evolved enough over the last 20 years to justify (besides wear and tear that is inherent to time passing) spending on a newer amp - when considering only sound delivery - and not extra connections , BT, streaming, integrated DAC, etc.?
 

tomtoo

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Has the power amp design evolved enough over the last 20 years to justify? No

But i still not get why you are so fixated that this is a amp proplem?

For me and i say it again this is a typical speaker,room,positioning problem and not a amp problem.
 
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AMPaul

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Has the power amp design evolved enough over the last 20 years to justify? No

But i still not get why you are so fixated that this is a amp proplem?
im not saying it has a problem. i'm just thinking of changing it and not breaking the bank while evaluating and hoping that within budget i get some objective sound improvements.
 

tomtoo

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im not saying it has a problem. i'm just thinking of changing it and not breaking the bank while evaluating and hoping that within budget i get some objective sound improvements.

Did you checked the possible speaker,room, positioning problems before thinking to change the amp?

Couse if the amp is not the couse, you can change as often you like.
 

Frank Dernie

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im not saying it has a problem. i'm just thinking of changing it and not breaking the bank while evaluating and hoping that within budget i get some objective sound improvements.
I wouldn't expect any objective SQ improvements by changing your amp unless it is underpowered for the speakers and listening level you use.
 

Roland

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Power is the only relevant measure because all amps “sound” the same, or rather don’t “sound” at all. Apparently.
 

Mart68

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I have a 320BEE amongst my collection. I don't think any of the amps you suggested would be worth changing to.

It's a good amplifier, it doesn't like low impedance loads though, gets a bit 'loose' in the bass. So it depends what your loudspeakers are doing in that respect

The pre-amp section could be better, I bypassed it and just used it as a power amp with a Philips pre-amp.
 

Koeitje

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Unless you are lacking in power or need to drive low impedance loads I don't think you will gain anything.
 
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