New to this -- recommend a good ~50Wpc board?

rongon · 18th August 2010, 05:16 PM

I'm looking for a way to make an inexpensive stereo amp out of kit boards. 50 watts per channel should suffice. The intended use is as a gift to someone who plays classical music and opera CDs and FM radio into a pair of floorstanding speakers of moderate efficiency.

I'm a tube hobbyist person, so am not adept enough at solid state to build from scratch. Figured I'd get my feet wet with a kit. I'd buy the enclosures separately, along with the jacks, binding posts, etc.

I was thinking I'd put an input selector switch and volume control in there and call it an 'integrated' amp. There's no need for a tape monitor loop.

What is the typical input sensitivity of these amp kits? Would the output from an FM tuner be capable of driving one to near full power? (I figure about 250 to 500mV from the tuner, but I don't know for sure.)

How do these Class D amps sound? Are they comparable to store-bought receivers in the $500 USD range? Or (hopefully) a noticeable step up from that?

So, what are the best kits available these days? Chinese stuff from Ebay? If so, are there really good ones to get? Others in particular to avoid? Or does Parts Express have a good kit that will fill the bill?

I'm basically looking for a pleasant (non-aggravating) sounding amp for cheap.

Thanks.

Tekko · 18th August 2010, 05:40 PM

Maybe an AMP5 or AMP6 from 41hz would suffice, alittle tricky to assamble tho.

Perhaps a preassambled one from ebay like that 2x100w from connexelectronics or something.

Do some looking around and see if you find something you like.

keantoken · 18th August 2010, 05:44 PM

Try this.

Based on Hugh Dean's AKSA 55

Ask in the thread, I believe Greg has PCB's he can offer. The AKSA is legendary as well as super simple, I think it is what you are looking for.

Or if you want to go whole hog you can purchase the original from aksaonline.com.

- keantoken

rongon · 18th August 2010, 06:37 PM

Have done some looking around -- Is the Sure Electronics TA2050 board decent?
2*100w TK2050 TP2050 Tripath Class-T AMP Board Upgraded - eBay (item 250681462338 end time Aug-18-10 21:15:06 PDT)

I was looking at AMP4 from 41hz. Tried to log on to 41hz site, but it won't come up. Network problems maybe. I'll try later.

It looks like the AKSA boards are out of my price range. But I'll ask Greg about PCBs.

How sensitive are these things to loading from input switching and volume pots?

--

keantoken · 18th August 2010, 08:20 PM

Class D amps are designed for efficiency, not sonics. An analog solution would probably be more fitting. Many people in fact try to avoid chips... But that is the purist approach.

I usually see a 50k input pot being used in amps. Usually there is a high-value resistor right at the input, to precharge the input cap which prevents loud pops when switching. Apart from this I've never heard complaints about volume controls. However for purists there are "constant impedance" stepped volume controls...

- keantoken

theAnonymous1 · 18th August 2010, 08:58 PM

Quote:

Originally Posted by keantoken

Class D amps are designed for efficiency, not sonics.

Ouch.... that was unnecessary.

keantoken · 18th August 2010, 09:24 PM

Okay, I'll rewrite that a bit. Yes they are designed to sound good, they must to sell. But from what I hear, they still don't compete with the analog alternatives. So if you don't need the efficiency, why would you even consider one? This was my line of logic.

Opinions are scary, yes they are,
- keantoken

gaetan8888 · 09:43 PM

Hello

I agree with keantoken, a very well designed analog amp will have more musicality, a better sound stage and a more engaging sound compared to a class D. For sure you need to use an excellent cd player and well recorded music cd to ear the differences.

Class D are still a young design compared to analog amp, so we will see how they will develop in the future.

Bye

Gaetan

TheDealer · 18th August 2010, 09:41 PM

Quote:

Originally Posted by gaetan8888

p, so we will see how they will develop in the future.

Bye

Gaetan

good morning Sir ! My greetings to the midle-ages ....

gaetan8888 · 10:06 PM

Quote:

Originally Posted by TheDealer

good morning Sir ! My greetings to the midle-ages ....

Hello

Do some serious blind tests listenings of some the best high-end analogs amps compared to the best class D amps, you will ear the differences, class D sound much less musical compared to the best high-end analogs amps.

No need to tell more, since the thread are not about that.

Bye

Gaetan

18th August 2010, 05:16 PM	#1
rongon diyAudio Member Join Date: Jul 2009 Location: Across the river from Rip's big old tree...	New to this -- recommend a good ~50Wpc board? I'm looking for a way to make an inexpensive stereo amp out of kit boards. 50 watts per channel should suffice. The intended use is as a gift to someone who plays classical music and opera CDs and FM radio into a pair of floorstanding speakers of moderate efficiency. I'm a tube hobbyist person, so am not adept enough at solid state to build from scratch. Figured I'd get my feet wet with a kit. I'd buy the enclosures separately, along with the jacks, binding posts, etc. I was thinking I'd put an input selector switch and volume control in there and call it an 'integrated' amp. There's no need for a tape monitor loop. What is the typical input sensitivity of these amp kits? Would the output from an FM tuner be capable of driving one to near full power? (I figure about 250 to 500mV from the tuner, but I don't know for sure.) How do these Class D amps sound? Are they comparable to store-bought receivers in the $500 USD range? Or (hopefully) a noticeable step up from that? So, what are the best kits available these days? Chinese stuff from Ebay? If so, are there really good ones to get? Others in particular to avoid? Or does Parts Express have a good kit that will fill the bill? I'm basically looking for a pleasant (non-aggravating) sounding amp for cheap. Thanks.

18th August 2010, 05:44 PM	#3
keantoken diyAudio Member Join Date: Aug 2006 Location: Texas Blog Entries: 1	Try this. Based on Hugh Dean's AKSA 55 Ask in the thread, I believe Greg has PCB's he can offer. The AKSA is legendary as well as super simple, I think it is what you are looking for. Or if you want to go whole hog you can purchase the original from aksaonline.com. - keantoken __________________ The Kmultiplier rail filter! LTSpice wiki with special attention to new users' troubles

18th August 2010, 08:20 PM	#5
keantoken diyAudio Member Join Date: Aug 2006 Location: Texas Blog Entries: 1	Class D amps are designed for efficiency, not sonics. An analog solution would probably be more fitting. Many people in fact try to avoid chips... But that is the purist approach. I usually see a 50k input pot being used in amps. Usually there is a high-value resistor right at the input, to precharge the input cap which prevents loud pops when switching. Apart from this I've never heard complaints about volume controls. However for purists there are "constant impedance" stepped volume controls... - keantoken __________________ The Kmultiplier rail filter! LTSpice wiki with special attention to new users' troubles

18th August 2010, 09:24 PM	#7
keantoken diyAudio Member Join Date: Aug 2006 Location: Texas Blog Entries: 1	Okay, I'll rewrite that a bit. Yes they are designed to sound good, they must to sell. But from what I hear, they still don't compete with the analog alternatives. So if you don't need the efficiency, why would you even consider one? This was my line of logic. Opinions are scary, yes they are, - keantoken __________________ The Kmultiplier rail filter! LTSpice wiki with special attention to new users' troubles

18th August 2010, 09:33 PM	#8
gaetan8888 diyAudio Member Join Date: Apr 2007	Hello I agree with keantoken, a very well designed analog amp will have more musicality, a better sound stage and a more engaging sound compared to a class D. For sure you need to use an excellent cd player and well recorded music cd to ear the differences. Class D are still a young design compared to analog amp, so we will see how they will develop in the future. Bye Gaetan Last edited by gaetan8888; 18th August 2010 at 09:43 PM.


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18th August 2010, 05:40 PM	#2
Tekko diyAudio Member Join Date: Jan 2005	Maybe an AMP5 or AMP6 from 41hz would suffice, alittle tricky to assamble tho. Perhaps a preassambled one from ebay like that 2x100w from connexelectronics or something. Do some looking around and see if you find something you like.

18th August 2010, 06:37 PM	#4
rongon diyAudio Member Join Date: Jul 2009 Location: Across the river from Rip's big old tree...	Have done some looking around -- Is the Sure Electronics TA2050 board decent? 2*100w TK2050 TP2050 Tripath Class-T AMP Board Upgraded - eBay (item 250681462338 end time Aug-18-10 21:15:06 PDT) I was looking at AMP4 from 41hz. Tried to log on to 41hz site, but it won't come up. Network problems maybe. I'll try later. It looks like the AKSA boards are out of my price range. But I'll ask Greg about PCBs. How sensitive are these things to loading from input switching and volume pots? --

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