T-amps (Off Topic)

by GC, Wednesday, March 14, 2007, 14:24 (3961 days ago)

Hi again Giovanni

I just read your post about this one: http://www.soundstage.com/revequip/audioresearch_1502.htm

before Bert deleted your version of the best T-amp ever.

Thanks for the input to my own search for the Golden Amp. :wink:

GC

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by PeterSt. ⌂ @, Netherlands, Wednesday, March 14, 2007, 15:45 (3961 days ago) @ GC

"I encountered one small glitch while using the 150.2. I use rabbit ears to grab the local CBS affiliate off the airwaves, and the 150.2’s digital circuitry interfered with signal reception on every TV in the house.... Audio Research says that the problem may have been eliminated due to CE testing for European sales, however."

... which I do not believe.
You can't get rid of this radiation by means of shielding or whatever; the design must be re-done instead ...
Also note that "CE testing" is a hoax. Nobody checks it.

Peter

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by GC, Wednesday, March 14, 2007, 15:57 (3961 days ago) @ PeterSt.

Hi Peter

Also note that "CE testing" is a hoax. Nobody checks it.


Not within consumer electronics. I wonder how much "GCX-Danger" people have on their shelfes.

But a lot of industries do comply with CE, even just stated by a declaration.

GC

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by PeterSt. ⌂ @, Netherlands, Wednesday, March 14, 2007, 16:13 (3961 days ago) @ GC

Anyway GC, don't forget it is just you who wants his TV swicthed on for controlling the audio ... :biglol:

Peter

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by GC, Wednesday, March 14, 2007, 16:39 (3961 days ago) @ PeterSt.

Anyway GC, don't forget it is just you who wants his TV swicthed on for controlling the audio ... :biglol:

And that's why we will not have such a RFI radiator in our house...:biglol: ehh...boats. :wink:

GC

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by Giovanni, Ravenna, Wednesday, March 14, 2007, 19:01 (3961 days ago) @ PeterSt.

I've read in some american forums about problems with EMI (electro-magnetic interferences), but never in Europe.

In USA not all houses have a safety ground like in Europe, maybe that is the problem.

Tripath chips are widely used in Panasonic car audio gears together with a tuner in the same box (don't ask me wich models, otherwise I have to start another thread) :blush:

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by Cappy @, Thursday, March 15, 2007, 04:32 (3961 days ago) @ Giovanni
edited by unknown, Thursday, March 15, 2007, 04:35

This link goes to a company that sells a well regarded PC controlled audio test system, the dScope.

Notice that a special box is required to test class-d amps to get rid of "shaped and switching noise":

http://www.prismsound.com/test_measure/products_subs/products_filter.html

If Prism has to go through a lot of trouble to get rid of the noise so they can test the things, I would think it could easily show up in our systems.

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by Giovanni, Ravenna, Thursday, March 15, 2007, 10:38 (3961 days ago) @ Cappy

All Class-D amps have a switching noise residual. The switching frequency goes from 400khz to more than 1 mhz. Output low pass filters recovers the audible range but the cut is not at 20khz but higher, not to affect audible frequencies. Tripath amps have usually a second order 100khz low pass output filter, so the range 20khz-100khz will still have switching noise.

This is not a problem because this is not audible, but is a problem for measuring instruments, so these need custom filters.

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by Cappy @, Thursday, March 15, 2007, 19:58 (3960 days ago) @ Giovanni

If only it were that simple.

Switching noise is known to cause problems in the audio spectrum. Even tube amp designs with solid state rectification have to consider the problem.

As I said in another sub-thread, I think battery power is a good idea for class-d to keep the switching noise from polluting the power line.

I'll try to post more thoughts when I have more time.

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by Giovanni, Ravenna, Thursday, March 15, 2007, 21:18 (3960 days ago) @ Cappy

Hy Cappy,

I was speaking of "in circuit" switching noise. Another problem are EMI and RF issues. When there is something in a box that switches as fast as radio frequencies waves, everything in the box can act as an antenna, the cables going out the chassis too. Doesn't matter if you have battery or ordinary power supply.

P.S. (off off topic)
maybe a delusion for battery fans, here are noise measurements of lead acid batteries compared to other regulated supplies:

http://www.tnt-audio.com/clinica/regulators_noise4_e.html

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by Cappy @, Thursday, March 15, 2007, 21:42 (3960 days ago) @ Giovanni

That is a good description you provided of EMI and RFI issues out of circuit.

Switching noise can effect in circuit performance too.

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by Cappy @, Wednesday, March 14, 2007, 16:45 (3961 days ago) @ PeterSt.

Thats why those battery operated T-amps are successful, IMO -- at least they aren't dumping tons of garbage back into the power line.

I've worked with EEs who had to spend a lot of time with CE testing, even if no one checked it.

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by GC, Wednesday, March 14, 2007, 16:50 (3961 days ago) @ Cappy

Thats why those battery operated T-amps are successful, IMO -- at least
they aren't dumping tons of garbage back into the power line.

Huhh....:dancing: :heat: Cappy, you saved my day. :grin:

Maybe my small investment in the SIG's is not wasted? :shame:


GC

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by Giovanni, Ravenna, Wednesday, March 14, 2007, 18:44 (3961 days ago) @ GC

Hi GC,

Ok new topic.

I never read reviews, always everything is fantastic...

Here is my contribution:

Audio Research 150.2
[image]

Signature 30
[image]

Looking at chip datasheets, components and PCB design is more instructive.

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by GC, Wednesday, March 14, 2007, 19:05 (3961 days ago) @ Giovanni

Hi Giovanni

Nice pic's.

Two different approaches.....ehh? Well at least regarding the PS..and as its looks, some other things too.

I understand you like the AR the most?

Did you have any TV's freaking out around your AR machine? :teasing:

GC

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by GC, Wednesday, March 14, 2007, 19:29 (3961 days ago) @ Giovanni

[image]

Giovanni

You're sure you didn't "sneak" in and copied this pic in 6moons' reveiw. It's not from the RWA site.

He he...dosn't matter anyhow. :grin:

GC

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by GC, Wednesday, March 14, 2007, 19:43 (3961 days ago) @ GC
edited by GC, Wednesday, March 14, 2007, 20:01

Oh my oohh.....:sorry:

Some reads homepages. Some reviews. Some Forums. It seems I'm most addicted to reviews, as I seldom study the homepages that much and that well as well. :attention:

But as allways, I'm the last one to check out the homepages thoroughly, I could have found all I wanted to know about the SIG's here

http://www.audiocircle.com/circles/index.php?board=78

A forum more or less like this one with plenty of questions and answers.

Mr. GC...once more :attention: auchh. Yes. Learn it :attention:

GC

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by Rudolf150 @, Wednesday, March 14, 2007, 20:11 (3961 days ago) @ GC

Hi Giovanni,

I didn't know that AR made this T-amps; interesting that they exist next to AR tube amplifier line.
There will be - I guess - some interesting discussions (soundwise and business wise) inside AR about the different product lines.

Have you heard this T-amp against a tube amplifier from AR?

Thanks,
Rudolf

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by PeterSt. ⌂ @, Netherlands, Wednesday, March 14, 2007, 21:26 (3961 days ago) @ Rudolf150

Giovanni knows much about T-Amps ... :yes:

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by Giovanni, Ravenna, Wednesday, March 14, 2007, 23:21 (3961 days ago) @ Rudolf150

Hi Rudolph,

Never heard ARC 150.2, too busy to build my own Tripath amps :grin: . But I own this too:

[img]images/uploaded/image231.jpg[/img]

It is an american car amp, but has the same chip as 150.2 (mine is TA0102A while 150.2 has TA0105A that only supports higher voltages). It has a well designed board, but I still have to get rid of all that output filtering used in car amps. Listening to it "as is" I can understand it has "something more".

My only good tube amp reference are my brother's Dr. Klimo' Merlin pre + Kent power amps. My Tripath amps hold the comparison. Better instruments timbers and cleaner sounds with valves, more details and surprising dynamics extension with Tripath (I don't bother you with other differences).

However I've the feeling that my speakers are not enough good for Tripath potential. Reading in this forum the enthusiast opinions about the small SI T-amp (nothing special by me), I understand that with your very efficient speakers you go further.

In other forums I always discover that many Tripath detractors have inefficient speakers, or listen to bum bum music. More often both. :wink:

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by fu_man @, Thursday, March 15, 2007, 04:23 (3961 days ago) @ Giovanni

hhhmmmm... those ARC amps look like they sound good :wink:

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by GC, Thursday, March 15, 2007, 05:18 (3961 days ago) @ Giovanni
edited by GC, Thursday, March 15, 2007, 06:02

Hi Giovanni

Never heard ARC 150.2, too busy to build my own Tripath amps :grin: . But
I own this too:

Ehh...didn't you say in this link http://www.bd-design.nl/forum/index.php?id=13328 that you will tell me what is the best commercial sounding T-amp in your opinion and in this link http://www.bd-design.nl/forum/index.php?id=13348 indicates that it is one of the two fellows shown on the pics?

How does that relate to that you never heard the 150.2?

Or am I reading things wrong here? You maybe only refer to the chip itself and not the complete amp as such?

Sorry for this clarifying question. :blush:

GC

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by Giovanni, Ravenna, Thursday, March 15, 2007, 11:17 (3961 days ago) @ GC

Even if I'd buy the ARC 150.2 I couldn't say how it sounds: I've not your speakers :wink:

Tripath chips are all the same (except smaller ones with simplified internal circuits), they all sound wonderful. What makes (a lot of) difference is board design, high grade external components choice and engineers tuning taste with good laboratory instruments.

The only high end engineered Tripath amps are Bel Canto Evo series (discontinued) and the Audio Research 150-M-150.2-300.2 (still avalaible). As you see the choice for the best is very easy.

All the rest is not for high end or are DIY products, made tweaking Tripath reference boards with datasheet components like mine at home (sorry, Signature is in the latter category).

Last thing, in one previous post you linked an article with a discussion of class-d amps with Bruno Putzeys (the creator of UCD) and others. You will see there that the Tripath reference amp considered is the ARC one.

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by GC, Thursday, March 15, 2007, 11:29 (3961 days ago) @ Giovanni

Hi Giovanni :grin:

Even if I'd buy the ARC 150.2 I couldn't say how it sounds: I've not your
speakers :wink:

Then listen to Rudolf...Go'n'get it he he....

Tripath chips are all the same (except smaller ones with simplified
internal circuits), they all sound wonderful. What makes (a lot of)
difference is board design, high grade external components choice and
engineers tuning taste with good laboratory instruments.

The only high end engineered Tripath amps are Bel Canto Evo series
(discontinued) and the Audio Research 150-M-150.2-300.2 (still avalaible).
As you see the choice for the best is very easy.

I am in the same situation as your are. (No Swings). Me (No amps). :wink:

All the rest is not for high end or are DIY products, made tweaking
Tripath reference boards with datasheet components like mine at home
(sorry, Signature is in the latter category).

Well at least you regarded that one of your choises, if I understood you correctly?

Last thing, in one previous post you linked an article with a discussion
of class-d amps with Bruno Putzeys (the creator of UCD) and others. You
will see there that the Tripath reference amp considered is the ARC one.

I did not exactly draw that conclusion, maybe I should read it again..:read:

GC

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by GC, Thursday, March 15, 2007, 11:50 (3961 days ago) @ GC

Hi Giovanni

Read it again. No conclusions here.

But here http://forums.avguide.com/viewforum.php?f=91
there is somthing indicating what you say.

However such discussions who's best leads of course to nowhere if you are up to trying, buying, one of the mentioned amps.

My curriosity were triggered by the NF's as you know.

I think by now I'm comming to the stage of saturation just reading all those opinions. Think my "fishing" for opinions came to an end.

And thank's a lot for your contribution Giovanni. :yes:

There's only one way to know: Go'n'get them. :wink:

GC

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by Bert @, Thursday, March 15, 2007, 13:08 (3961 days ago) @ GC

Hi GC,

http://forums.avguide.com/viewforum.php?f=91

Nice discussion about the NF's, probaly getting the same kind of discussion here after our personal shootout (if all T and D amps are here at the time).

Ciao,

Bert

--
BD-Design - Only the Best!

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by GC, Thursday, March 15, 2007, 13:13 (3961 days ago) @ Bert

Hi Bert

http://forums.avguide.com/viewforum.php?f=91


Nice discussion about the NF's, probaly getting the same kind of
discussion here after our personal shootout (if all amps are here at the
time).

I see no other outcome than: :drool: or :wacko: or :satisfied: or :biglol: or :drinks: or :scared: or :tomatos: or :attention:

GC

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