How important is the PSU in your amp?

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busb

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Nelly said:
Now this interest me because im going to get a tripath thats rated at 160w+160w but that is only if you can get a 36v 5amp power supply because it come with a 26v 4amp supply now is this rue for all amps if you up the power supply do you up the watts of the amp ?

I think of a power amp as being split into three sections per channel: input buffer, output section & PSU (Class D includes a little bit more). I'd speculate that the output & PSU's being the most important - in that their design is going impact the SQ the most. As for your question - it probably depends but upping the current capability will usually mean more headroom for transients without dropping the rail's voltage so much. I think the specification is called transient recovery time which was one of the more difficult DC PSU measurements I've had to do in the past. That 160W per channel will not be obtained from 36V 5A supply for starters - that implies 100% effeciency that not even class D can achieve. The true continuous ouput power maybe a lot lower but hell, even 80W is only 3dB lower.

Buying class D amp modules is going to be great fun for those into DIY audio more than those just trying to save money. The latter group would be better off buying 2nd hand IMO. So, if you are going for Tripath modules, go for decent PSUs! I don't know if Tripath shares class D's general attribute of dumping current back into the supply rails but designing PWM amps involves a little more than fitting OEM amp modules into a case. Get the PSU right & you'll get the SQ to challenge class A but with less heat for a lot more power.

I must take the case off my Primare A34.2 sometime - it's got SMPSs - my DAC generates more heat!
 

busb

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davedotco said:
Interesting, whilst I totally understand what you are saying, I would have thought that these variations would have been pretty small compared to the more obvious limitations of power supplies, output devices and the rest. You live and learn...... :?

There are other ways to look at the subject. Some people like low watt valve amps when partnered with easy to drive speakers. At the other end of the spectrum, amp manufacturers such as Naim & Cyrus sell accessory PSUs. Some will argue that the PSUs should be better to start with whilst the manufacturer's will surely point out that their products are built to price points but give their customers the option of spreading the costs of better SQ over time. I personally prefer the idea of buying a product without worrying over whether to improve it with yet another box unless the it's an internal module swap.
 

eagle123

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Psu and also other components like capacitors are critical to providing a sound that is neutral, i am talking of elna capacitors, torroidal transformers, the cheap budget amps used to have a frame type of psu, probably poorly shielded, this affected the amps dynamic range, its drive, and also colours the sound, reading old amp reviews will provide a classic example of a amp based on a budget, and therefore the sound is limited to a fixed budget.

marantz ken isshiwata used to take the budget amps like the pm series then add some exotic components like copper shielding a few choice capacitors and a upgrade to a better psu to torroidal amps.

the result is a amp that is tonally different than standard
 

Nelly

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Hi busb this is the amp im getting http://www.ebay.co.uk/itm/Class-D-Amp-2-Channel-2x-40W-Tripath-Audio-Power-Amplifier-For-Floor-Speaker-/190831252247?pt=UK_Sound_Vision_Other&hash=item2c6e6dd317

for the money it should run most speakers but if i upgraded the power supply i should get better sq and have more headroom for speaker selection ?
 

Nelly

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I was just thinking aswell are pc power supplies any good for powering amps and if so how would i go about connections as i can get the amp board without casing and power supply for peanuts
 

abacus

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Nelly said:
I was just thinking aswell are pc power supplies any good for powering amps and if so how would i go about connections as i can get the amp board without casing and power supply for peanuts

No you can’t.

Also you will not find any PC with a Power Amplifier built in, (Apart from a few watts for headphones) due to the power supplies not being up to the job.

A PC power supply also has fixed voltages which cannot be altered, (To maintain a standard) and it is unlikely that an external amplifier will require these exact voltages.

In addition quality PC power supplies are not cheap. (Unless you enjoy listening to a vacuum cleaner)

Hope this helps

Bill
 

andyjm

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Nelly said:
I was just thinking aswell are pc power supplies any good for powering amps and if so how would i go about connections as i can get the amp board without casing and power supply for peanuts

Of course you can use a PC power supply to power an amp, but it isn't ideal.

PC supplies are generally very high quality / high current - with excellent voltage regulation. The downside is that most have fans that can be noisy, and the usual output voltages (5v, 12v) are too low to run an amp that needs to supply a decent wattage into a 8ohm speaker load.

So, if you want to fiddle about as an experiment you could do it, but I wouldn't recommend it.
 

Electro

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Nelly said:
Hi busb this is the amp im getting http://www.ebay.co.uk/itm/Class-D-Amp-2-Channel-2x-40W-Tripath-Audio-Power-Amplifier-For-Floor-Speaker-/190831252247?pt=UK_Sound_Vision_Other&hash=item2c6e6dd317

for the money it should run most speakers but if i upgraded the power supply i should get better sq and have more headroom for speaker selection ?

I guess it might be too late but I have a slightly older version of one of these T amps that has a large and very good power supply built in

http://www.playstereo.com/product_info.php?products_id=1253&cPath=2&language=en

It works out at about £220 and weighs 4.5 kilo so that is an indication of the size of the power supply , there is also an internal picture in the link .

I have owned mine for about 3 years and it has driven several types and sizes of speaker with no problem at all and sounds fantastic especially for the money .
 

busb

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At that sort of money - suck it & see!

A couple of points - it has a cooling fan. They start off being quiet enough if you are lucky but can get loud. Looks like you need a case?
 

busb

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Sounds like a plan to me! At that price, you can't go too wrong. Probably uses a 12V fan so are easy to replace. As a general rule, the bigger the fan, the quieter.

I can remember building my own PC. The processor was cooled by a very large Zalman heatsink with 120mm fan running off a fan controller. Got the machine to run quieter than most laptops after lining the aluminium case with panel damping pads, sound absorbing foam, case fan gaskets. The 15dBA PSU wasn't cheap but when the thing woke up from standby at 3am to run backups without waking me - the effort was worth it. Electronics should be like children - seen & not heard! Unlike my plasma TV that buzzes |(
 

andyjm

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Nelly said:

That's a lot of electronics for £35. If a man in China can make that, ship it to the UK and make a profit for £35, then I don't hold out much hope for the domestic UK electronics construction biz (if there is any left).

It looks great value, and no reason to think the switcher PSU is a problem - after all the whole amp is one big switch mode supply.

Be a bit careful with the specs, it isn't unkown for Chinese firms to be a bit economical with the truth when it comes to performance numbers, but to be honest, for £35 you cant really go wrong.
 

andyjm

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CnoEvil said:
andyjm said:
......but to be honest, for £35 you cant really go wrong.

....unless it burns down your house. :twisted:

The majority of the components in your amp will have come from the area around Shenzhen, and it is quite possible that the amp itself was assembled there. Has your house caught fire yet?
 

CnoEvil

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andyjm said:
CnoEvil said:
andyjm said:
......but to be honest, for £35 you cant really go wrong.

....unless it burns down your house. :twisted:

The majority of the components in your amp will have come from the area around Shenzhen, and it is quite possible that the amp itself was assembled there. Has your house caught fire yet?

I was being a touch facetious....and FWIW my amp was assembled in good old Blighty.
 

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