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The peculiarities of a high value, low cost, amp

Bought the acclaimed STA200, last year. 

Was surprised to find it can drive my Tekton Moabs with fully developed, detailed, musical sound. I've practically passed out in front of my Moabs, time after time, late at night, for the past six weeks, starting when they first entered my home.

When I push the volume into dynamics that persist into the 85db and up range, for the better part of an hour, the amp yields a fair amount of heat to the top of the chassis and the rear heat fins. This is concerning. Things start getting hot and I draw the volume down. I imagine I'm not the only one facing unseasonable heat with their amps... I keep my tuning mostly to jazz and acoustic sections. Occasionally, I get an itch for rock and roll or something that pushes the bass down and deep. A week ago, I played Lorde's "Royals" and could hear the amp struggle to push the bass notes out, full and clear. There just wasn't enough juice. This, of course, nudges me away from bass rich electronic content, somewhat regrettably, as I do love to embrace as much variety as comes my way.

Another piece, is that the STA is stated to NOT work (well?) with 4ohm speakers, and that is probably what is happening in my description of the limits of the higher volume and bass (electronic) heavy content. Now, I mostly keep my listening in the 85db and under range, and the music is gorgeous. I can hardly believe I'm riding on Moabs, a $500 amp, and a few other inexpensive pieces that collectively deliver sound that I never though I would be able to afford.

Still, the amp is running at its limit on the "bigger" bass pieces. I keep specifying electronic bass, but I'm sure there is more that would push the amp into heat mode. To be more precise, it is probably when deep bass notes are pulling 90+db that the amp fails to keep up, and what is a deep electronic bass note if you can't feel it, thick and full.

So, I'm curious as to your thoughts on what I'm running into... is the heat a problem? I hear it's damaging... If this amp is one of the "steals," but I'm running, on occasion, to its limits, what other "steals" are out there?

When I say steal, I think of things like what I'm reading about class D audio amps. For all of $600 or $700 I can bring an amp into my home that provides 400-600 watts per channel, accommodating the 4ohm load of the speakers... 

The Schiit aegir looks very attractive, but I don't think I will have more than 40 watts a channel and then the problem with Royals.

The Vidar looks interesting, could surely push the drivers more effectively than the STA, but I hear the highs are a bit forward and I want my highs right where they are - clear, pure, authentic, not at all harsh.

There may be some other interesting options, but keep in mind - I want very high value for my dollar. Used might be an option... 
listening99
teo_audio
2,197 posts
 
good amp, if it is built akin to the job225.

If you like that, then the suggestion is to stay away from class d amps, and try to find a traditional design with more power than the job simile called nuforce optoma.

If you get class d, it will be more of the same. as in, your current life is like ’otto at the airport’ as I like to say. Where you get one, but not the other. Never both.

Meaning, the Nuforce is giving you the finesse you want but not the power ...and if you get the class D, the class D will give you the power - with no finesse.

You will get some of the relief you want but probably lose the qualities you desired and liked in the Nuforce.

Thus, stick to traditional old school class a/b amps with traditional power supplies and go for more power. To get past your situation, I’d suggest 150 w/pc into 8 ohms and up, as a good area to find what you want. That’s a good 3db more than the optoma at 150 w/pc, on paper that is.. as all things are not equal, so millage may vary.

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islandmandan
1,260 posts
 
I bought, and built, Class D Audio amps, mainly to use for HT. The amp for the main speakers is an a CDA 254 with an upgraded power supply, and two CDA 254 modules, for 500 Wpc into 8 ohms, The sound is ridiculously good, especially at the price.

I mostly listen to my two tube amps (SET 300B and SET 845) for music, but once in while, I listen to music through the Class D amp, and I am again surprised at just how good music sounds. They are a bargain, and an easy build, if that is something you like doing.

Regards,
Dan
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condosound
128 posts
 
I had a STA200 for a while and enjoyed it, although there are many better choices, even for the price. I especially liked that it was a pure dual-mono design. If you like your STA200 that much I'd encourage you to chase down other dual-mono designs. Akitika GT-102 amps are better, and just as cheap--about $400 for the kit and $500 complete.

As I remember the STA200 wasn't bad on heat--nothing like a PASS XA25, for example. The XA25 is superb, and as a bonus you can fry up some bacon and eggs on it while you listen.
dwmaggie
222 posts
 
On the one hand a big beefy class A/B with lots of power like a BGW 750 or studio 620, take mine they are space takers.  Or....you could try a class D.  Not all class D will give you everything, however a Digital Amplifier Company class D might just leave you breathless.  Why?  The smoothness of a tube, the detail of a transistor and the immediacy of a class A without the trade offs.  I have a closet with class A/B monster amps gathering dust.

The DAC class D amps are like none I have ever heard.  They get out of the way and let the music come through, whether soft and polite or large and loud.  Small company, zero advertising, not a great big price.  You can buy a BGW or Acurus for about 400 dollars in a lot of places-why, because they sound like a class A/B in the mid range and up.  Great for a subwoofer, not so subtle as you work up the frequency range.
elangley01
93 posts
 
The Crown 1502 sounded like garbage in my setup. I am VERY happy with my Emotiva PA-1s.
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