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Amp Camp Amp


JohnA

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For those that are familiar with quality Class D amps, how does the ACA amp stand up? Is it a significant improvement or just marginal? I am really happy with my Lepai 2020A+ but this kit looks interesting. 

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Just now, twk123 said:

For those that are familiar with quality Class D amps, how does the ACA amp stand up? Is it a significant improvement or just marginal? I am really happy with my Lepai 2020A+ but this kit looks interesting. 

 

I have had and currently have both. Had nCore's and currently have Wyred4Sound mAmps ICE module and also have a 3875 chip amp. And two Nelson Pass Class A amps.  I have always favored the more transparent sound of Class A amps. For me Class D is more opaque, thicker, not as clean and crisp. It may have to do with the huge amounts of negative feedback necessary with Class D and how that cuts off the timbre and sustain of a piano string being struck or cymbal sizzle slowly fading. Maybe I'm biased as I've listened to Class A amps for a while now. With that being said Class D sounds damn good, there is little to complain about, they run Waaay cooler than A,  use much less power,  are much smaller, can be cheaper although the better ones ain't cheap.

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--- we talked earlier about heat sinks and associated heat produced with Class A amps. This morning I moved the Pass Labs Class A XA25 and replaced with the First Watt Class A F3 JFET amp. The XA has the more elaborate heat sink thus more square inches. All FW used the same chassis and simpler sinks although quite large. The JFET F3 runs Waaay warmer than the XA, actually more to the Hot side of warm. I'm sure I can keep my hand on the XA for more than the several seconds the F3 allows. Of course different circuits, much different  power transistors etc. but what a difference. 

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4 minutes ago, CECAA850 said:

This ^^^^^^^

 

Between the class A ACA's and the linear power supply, things can get pretty toasty.

 

 ---- as you see in my description of the F3 maybe the boys with deep pockets can start sending F3's instead of toasters ??! I'm certain one can put a crisp on a piece of wheat bread ---

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33 minutes ago, twk123 said:

For those that are familiar with quality Class D amps, how does the ACA amp stand up? Is it a significant improvement or just marginal? I am really happy with my Lepai 2020A+ but this kit looks interesting. 

 

---- and to add - I see the Lepai sells for less than a hundred bucks. Without being condescending in any way the amps I mentioned are dozens of times more expensive and should should perform better, way much better. But I'd bet a dollar to a donut they don't sound dozens of times better. For the money the Lepai seems a no-brainier. A friend of mine has a first generation Red Wine amp using the Tripath chip still keeps it after buying/selling literally dozens of amps that are far more expensive. So much synergy is involved that one never knows what fills the bill and works to satisfaction. And some never learn -- (yes a finger is pointed back at me) ?!!

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7 minutes ago, richieb said:

 

---- and to add - I see the Lepai sells for less than a hundred bucks. Without being condescending in any way the amps I mentioned are dozens of times more expensive and should should perform better, way much better. But I'd bet a dollar to a donut they don't sound dozens of times better. For the money the Lepai seems a no-brainier. A friend of mine has a first generation Red Wine amp using the Tripath chip still keeps it after buying/selling literally dozens of amps that are far more expensive. So much synergy is involved that one never knows what fills the bill and works to satisfaction. And some never learn -- (yes a finger is pointed back at me) ?!!

Thank you for the input, the Lepai 202A+ was about $25 when I bought it so definitely not the same league as $600 amps. It is actually becoming a rarity too since Tripath stopped making the chips. I had one just die on my in my office setup which was a bummer. In any case my birthday is coming up and its a tossup between this amp build or a Cinema F-20 to go with my LaScalas and maybe even a Qtr-Pie bass horn setup. I think I am going to go with the speaker upgrades and keep my amp as it is for now.

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Guest wdecho
1 hour ago, twk123 said:

For those that are familiar with quality Class D amps, how does the ACA amp stand up? Is it a significant improvement or just marginal? I am really happy with my Lepai 2020A+ but this kit looks interesting. 

Class A is class A and depending on your hearing you should hear a big difference in quality of sound. You may want to catch up on this thread for better D amplifiers. The TPA3255 boards are far above the little tripath chips. I built a much larger amplifier using the 2050 chip in the Hifimediy boards. Really good, comparable to the TPA3255 but I would give the edge to the TPA3255. 

 

https://community.klipsch.com/index.php?/topic/172028-class-d/

 

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6 minutes ago, wdecho said:

Class A is class A and depending on your hearing you should hear a big difference in quality of sound. You may want to catch up on this thread for better D amplifiers. The TPA3255 boards are far above the little tripath chips. I built a much larger amplifier using the 2050 chip in the Hifimediy boards. Really good, comparable to the TPA3255 but I would give the edge to the TPA3255. 

 

https://community.klipsch.com/index.php?/topic/172028-class-d/

 

This looks intriguing. Is this is board you are talking about?

 

https://www.amazon.com/Nobsound-TPA3255-Digital-Amplifier-Assembled/dp/B07544FJYC

 

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Guest wdecho

I just received that board this week and you can read about it on the D section of this forum. I bought mine on Ebay for $56. Looks the same. 

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Guest wdecho
44 minutes ago, wdecho said:

Class A is class A and depending on your hearing you should hear a big difference in quality of sound. You may want to catch up on this thread for better D amplifiers. The TPA3255 boards are far above the little tripath chips. I built a much larger amplifier using the 2050 chip in the Hifimediy boards. Really good, comparable to the TPA3255 but I would give the edge to the TPA3255. 

 

https://community.klipsch.com/index.php?/topic/172028-class-d/

 

I failed to mention specifically about the TDA3116 boards used in the Parts Express old ones they sold. I have tried a number of the different boards using the 3116. A lot of sound vs cost but all seemed somewhat thin sounding compared to the newer designs, chips, available now in D amplification or when compared directly to better amplifiers. RichieB can explain more details than myself because he has one of ultimate 3116 board builds. 

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17 hours ago, DizRotus said:

 

Have you received an answer to this?  If I understand your question, IMO, the answer is no.  With my class D amps (Wiener TPA3118 and TI TPA3255EVM) the hot and cold signals are distinct from ground.  The cable shielding is grounded, but neither the cold nor hot signals are grounded.  For me it’s somewhat counterintuitive.  

 

Gary Marsh, the designer/builder of the Wiener, drew me the attached hookup diagram that I found instructive.  The hot and cold signals for each channel are at the RCA pins, i.e., there need to be four connections, two for each stereo channel in balanced/differential mode.  The four RCA collars are connected to the cables’ shields and to ground.

 

gmarsh_schematic_balanced.thumb.JPG.9552ac133e249fe1adc7fac7492299e8.JPG.

So far a couple of vague comments that's all. I know what a balanced input is, I know what a differential signal is and I know what a bridged output is. So I think I am going to have to figure it out for myself and determine whether it is worth purchasing.

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Guest wdecho

This was posted on the other forum and considering it refers to Klipsch speakers I decided to post this guys results here. The guy possibly could be a member here. 

 

Just finished up an ACA v1.5 - relatively easy build (good thing, since I haven't dusted off the soldering iron in a while) - everything worked fine on power up & bias adjusted nicely (although it took a while).

Did a little listening - replaced a crown pro amp between a Bottlehead Smash preamp & a pair of Klipsch Cornwalls. Very, very nice!! Lots of clarity & good bass response. I think this amp will stay in play.

I think this is clearly a case where simplicity in design can yield great results (if done carefully).

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On 5/11/2018 at 4:05 PM, wdecho said:

I failed to mention specifically about the TDA3116 boards used in the Parts Express old ones they sold. I have tried a number of the different boards using the 3116. A lot of sound vs cost but all seemed somewhat thin sounding compared to the newer designs, chips, available now in D amplification or when compared directly to better amplifiers. RichieB can explain more details than myself because he has one of ultimate 3116 board builds. 

 

Rich, @rhing, first put me on to the $5 TDA7297 amp, which led to the Wiener TPA 3118 board designed and built by Gary Marsh, which led to TPA3255EVM.  He feels, as do I, the Wiener gives the 3255 a run for its money.  While I too give the nod the the 3255, I have been enjoying the Wiener exclusively while I complete the process of putting the 3255 and Mean Well power supply in a case.

 

When showing off to friends, the 7297 gets the best reaction.  People are amazed at the quality sound produced by that tiny $5 chip amp from a pair of Heresy.

 

 

 

 

 

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1 hour ago, wdecho said:

This was posted on the other forum and considering it refers to Klipsch speakers I decided to post this guys results here. The guy possibly could be a member here. 

 

Just finished up an ACA v1.5 - relatively easy build (good thing, since I haven't dusted off the soldering iron in a while) - everything worked fine on power up & bias adjusted nicely (although it took a while).

Did a little listening - replaced a crown pro amp between a Bottlehead Smash preamp & a pair of Klipsch Cornwalls. Very, very nice!! Lots of clarity & good bass response. I think this amp will stay in play.

I think this is clearly a case where simplicity in design can yield great results (if done carefully).

Yup - a member, but I mostly read.  So far, the ACA seems to be a nice match to the Cornwalls.

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Guest wdecho
5 hours ago, mpeg2 said:

Yup - a member, but I mostly read.  

I also did the same for years before doing any posting. I only started being active upon retiring.

The Amp Camp's are a good example of a single ended well designed low cost class A amplifier. Many here have had doubts about the cheap little lap top charges with the old kits sold at diyaudio and rightfully so, but the reason was keeping the cost down for beginners and being safer than building a linear supply for a beginner. The newer kit has a much better switching power supply with the kit and also 24V.  Someone on the other forum asked Nelson about why he has not used a switcher on his Firstwatt amplifiers and Passlabs. Below is a short answer,

 

 

In the case of First Watt, I initially bought 2,000 sets of power supply
parts, and I am not quite done with them.

In general, noise, availability, and reliability of switchers are a problem.

The kind of switching supplies I would want for PL and FW are really quite
expensive, and would generally have to be custom made.

With regards to ACA and some other projects, a decent switcher has
the tremendous advantage of being simple and SAFE. The Amp Camp
event would not have been possible without them. Also the cost was
very cheap, as there was (and still is) a glut in the market on 19V
switchers used for laptops.

 

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Guest wdecho
6 hours ago, DizRotus said:

 

Rich, @rhing, first put me on to the $5 TDA7297 amp, which led to the Wiener TPA 3118 board designed and built by Gary Marsh, which led to TPA3255EVM.  He feels, as do I, the Wiener gives the 3255 a run for its money.  While I too give the nod the the 3255, I have been enjoying the Wiener exclusively while I complete the process of putting the 3255 and Mean Well power supply in a case.

 

When showing off to friends, the 7297 gets the best reaction.  People are amazed at the quality sound produced by that tiny $5 chip amp from a pair of Heresy.

I also have some of the 7297 Chinese boards and prefer them over the Chinese 3116 boards. Supposedly the 3118 is the same as the 3116 with the heatsinking reversed but maybe because a better Chinese design the cheap little Chinese 3118 boards sound better than the 3116 ones I have tried. The Wiener is taking the TPA3118 to it's peak potential from all accounts of those that have built one that I have read about.  

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