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DIY Class D power amp, who's build one?


mwhouston

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I have just ordered a $32 100W Class D stereo power module to build into a power amp. I usually build SE and UL tube power amps so a big change.

Just wondering if others have built a Class D amp and their comments.

 

I've built a couple (not modules, but a Silicon Chip design).

 

Ho-hum.

 

They were for a specific purpose (low power consumption) and sound quality was not the prime requisite. 

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Class D amps are more load sensitive than high current Class A/B solid state amps. This is due to the prescence of a large inductor on the output stage, which can cause a falling HF response when driving difficult loads, such as ESLs. Class D should be excellent in the LF area. Additionally and possibly more troublingly, almost all Class D amps present a significant amount of RF energy at the speaker terminals.

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Thats a splurge. I ordered a TPA3116 board last week. Cost $18.40 delivered. Going to build a small desk top amp for my daughter. Will see how it goes, If its any good I may get another.

 

How are you going to power it?

Edited by awty
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I have a pile of them. There is quite a difference between chipsets, and implementations of those chipsets so hard to lump them all together.

 

I have not built any of them "from scratch" but all pre-assembled PCBs built into cases with added power wiring, etc.

 

In the collection:

 

TPA3116

TPA3110

TK2050  (two different implementations)

TDA8920 (two different implementations)

IRS2092

TA3020 (fried one during a "learning experience", got another with better MOSFETS)

TA2020  (Lepai with some tweaks)

 

So far of the lot I like best the TK2050 (50W hifimediy T2 module) and TA3020 (approx 110W connexelectronics v3c)

 

My TPA3116 board I think sounds scratchy, but others in assorted forums seem to like them, mine has a measurable peak of 3HD @ 7Khz but there are now heaps of different implementations of these boards and maybe mine was one of the early ones before they started shaking the bugs out of the implementation.

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if you want to try a proper class D, Hypex is a must try :)

 

Yes the Hypex modules are supposed to be the best ones.

 

Agreed. Like linear amplifiers, home built products are unlikely to meet the highest standards of quality. 

 

But this is the DIY section.

 

Although nearly all of these (including the Hypex boards) are sold as premade modules just needing enclosures and power supplies so on the border of DIY .. most of these sub $40 boards can be powered with 19V 50W laptop SMPS to simplify things even further.

 

This image I'm reposting from the TPA3116 thread on DIYAUDIO forums, showing the variety of different  TPA3116 modules available...

 

post-113607-0-83820900-1405896676_thumb.

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Agreed. Like linear amplifiers, home built products are unlikely to meet the highest standards of quality.

The amp section is bought as a completed module, yes just add PS enclosure and knob. Stereophile reviewers are finding more and more Class D amps meeting audiophile standards. As I said 90% of my builds are tube related but I have built quite a few chip amps and tube\chip hybrids. I guess this is just another a avenue to investigate. I intend to use a linear PS which I will build from scratch.
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I have just ordered a $32 100W Class D stereo power module to build into a power amp. I usually build SE and UL tube power amps so a big change.

Just wondering if others have built a Class D amp and their comments.

I've had a couple, but haven't played with them for some years because I have too many other amps. The Hypex 180 modules made an excellent full range amp, the 41Hz and ICEpower were better left to LF amps because of too much Zout at HF and the LC Audio wiped out any AM radio in the house. Luckily, it was only 702.

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Like linear amplifiers, home built products are unlikely to meet the highest standards of quality. 

Sorry Trev, but in my experience, this is a load of cobblers.

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Sorry Trev, but in my experience, this is a load of cobblers.

 

When I see a Class D amp reach the performance of the Devialet, or a linear amp reach the performance of a top line Krell, ME or Gryphon, then I'll be convinced. Whilst I accept that a home built product COULD equal or exceed the performance of top of the line amp, the vast majority fall a very long way short. Valve amps can be even more difficult, given the availability of decent output transformers. 

 

FWIW: I am aware of at least one person who did build a copy of an ME preamp once, it ended up costing roughly three times the price of a brand new one (he had to buy 10,000 transistors, in order to find sufficient matched ones). This is hardly surprising. Even manufacturers at the expensive end of the scale work within economies of scale that home constructors cannot hope to match. Then there's the metal-work. This can be a very challenging area for anyone working outside the metal industry. 

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When I see a Class D amp reach the performance of the Devialet, or a linear amp reach the performance of a top line Krell, ME or Gryphon, then I'll be convinced.

The quote of yours was specifically talking about A/B amps and I replied to that. I'm not convinced of D yet, but have yet to see what items like the Devalier of the new Hypex units can do. For A/B, I think you can match or exceed almost all of the commercially available units for less than retail.

 

Valve amps can be even more difficult, given the availability of decent output transformers.
There are plenty of good transformers available out there, and many of the manufacturers will modify one of their designs if you need something slightly different. For the measured performance of some of the 'high end' items I've had across my bench I'm not of the mind that most of what's found inside a purchased piece of gear is better than outside suppliers, and in some cases much worse.

 

Then there's the metal-work. This can be a very challenging area for anyone working outside the metal industry.
There are numerous off the shelf cases for audio gear, even huge one's with heatsinks for a Krell like amp. That's if you care what it looks like. I don't particularly so I've repurposed a rack case for the control elements of my new system. It's going to get mounted with all the other amps in the rack so it's suitable and cost $20 and the cost of some dies for my hole punch. There are lots of other ways to do it too, and for the cost of some piece of hifi jewellery you could have it milled out of billet and still save. Valve amps are even easier if you use traditional construction methods.
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. Valve amps can be even more difficult, given the availability of decent output transformers.

It can be hard to find quality components and the $$$$$$$$$$$$ for one off case work

Cheers

Bloody auto correct

Edited by Malcolm
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OK, OK, OK, I got this form a audiophile mate with about $30K of new gear in his day-2-day listening room. Part of which is 60W pc 300B monoblocks amps and 400lb speakers. He made-up the module I have ordered to a completed amp with a SMPS and took it to another audiophile mate (Tommy) who has 10 pairs of very expensive speakers and high-end tube amps. He compared his DIY Class D to a $25k commercial Class D amp Tommy had on loan. There were a number of others there on the night. These people are audiophiles and know there stuff.

After many hours of A\Bing they could not pick the difference between the DIY Class D and the $25K Class D amp. That says a whole lot but I'll leave that to you lot.

So do all Class Ds sound the same? Or can a $30 Class D black signets module become a beautiful swan?

Edited by mwhouston
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OK, OK, OK, I got this form a audiophile mate with about $30K of new gear in his day-2-day listening room. Part of which is 60W pc 300B monoblocks amps and 400lb speakers. He made-up the module I have ordered to a completed amp with a SMPS and took it to another audiophile mate (Tommy) who has 10 pairs of very expensive speakers and high-end tube amps. He compared his DIY Class D to a $25k commercial Class D amp Tommy had on loan. There were a number of others there on the night. These people are audiophiles and know there stuff.

After many hours of A\Bing they could not pick the difference between the DIY Class D and the $25K Class D amp. That says a whole lot but I'll leave that to you lot.

So do all Class Ds sound the same? Or can a $30 Class D black signets module become a beautiful swan?

 

No. All Class D amps do not sound the same. Some are quite acceptable (the Devialet, for instance) and some are absolute crap (though they may still be quite expensive). 

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So do all Class Ds sound the same? Or can a $30 Class D black signets module become a beautiful swan?

 

Which module is it?

 

I can't say anything re: $$$ components and hard to drive exotic speakers, but a TA3020 module ($150) with a 500VA toroidal ($150) mounted in an old steel power supply chassis showed up pretty well against a $700 or so AB amp of similar specs, with fairly conventional 8 ohm speakers passive crossover waveguide speakers.

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It is the Banggood Techs 100W module with fan. $30.

Aha, this looks like the Sure Electronics STA508 (which I think appears to be another name for the TK2050 chipset ??)  - if so, so similar to the Hifimediy units, though less expensive parts.

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Aha, this looks like the Sure Electronics STA508 (which I think appears to be another name for the TK2050 chipset ??)  - if so, so similar to the Hifimediy units, though less expensive parts.

Would you expect good performance from this module. I'm told if you replace the input cap with a better one the performance is much improved.

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I bought one of these once but still haven't got around to testing it out. Has on-board power supply an speaker/relay protection. I believe it's a standard IRS2092 design from International Rectifier ;)

 

http://www.ebay.com.au/itm/IRS2092-class-D-power-amplifier-board-double-rectifier-with-high-power-/251531919856?pt=AU_Electronics_Audio_Amplifiers&hash=item3a907881f0

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