Hybrid tube/ss amps?

ok , convince me, mains talk, I have never really believed in it, what can I buy that is not pricy that will really improve my mains...isolation tx? transreactance toroid?

Lee, I am really not convinced that people can make hifi sound a certain way TBH, when Mr Ken Ishi did the cd 63ki, then the 6000ki, they both have the same dacs, opamps, transformers, copper plating, some capactitors( largely he favours silmics and cerafines, the odd polystyrene), yet are totally different( the 6000 is more laid back, even and coherent, the 63 is more forward and lively), if KI's tastes are the same, how come his tuning yields such different results, ditto with the cd17ki (different dac, but same copper, tx's caps to tune and is extremely dull and boring) ,the ki 66 amp and the ki 6000 amp, too. they are nearly identical, yet sound totally different.

If there is a way to 'set' a sound I would love to know about it.
 
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Originally posted by Lt Cdr Data
ok , convince me, mains talk, I have never really believed in it, what can I buy that is not pricy that will really improve my mains...isolation tx? transreactance toroid?
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That depends on:

a) what you mean by pricy?

b) how big an improvement you're expecting?

There are several places to start. You could start with cables that reject interference by dissipating it in magnetic material. The Eupens give an improvement in many systems and are relatively affordable. http://www.audusa.com/

They are not the only option. There are other relatively affordable cables using various combinations of braiding and shielding that can improve things.

Then we move on to components that remove interference. A starting point here could be the Olson Sounds Fantastic mains block. http://www.soundfantastic.co.uk/

This is relatively affordable and makes some difference but not in the same league as an isolation transformer. Sorry I've lost the link for Trichord.

Or you could try the Isotek Cleanline for about £300. Looks nice and has a BLUE LED :eek: http://www.isotektechnologies.com/clean.asp

And then there is WM's new toy, the foo-foo box, which looks set to become an Omiga Audio product and shows considerable promise. Don't know what it will cost. Penance bought one but he is probably sworn to secrecy :) I would have bought one if I didn't already have the Trichord 1000.

Going back to the cables, it would be interesting to compare one of the expensive mains cables (around £250 for a metre) with something like an Isotek Cleanline. I think the results could be very interesting. One thing we didn't try on Monday was to use the expensive mains cables without any sort of 'box' in the circuit. We always used either the Trichord or the Foo-foo box.

The difference between the expensive mains cables and the Eupen is like night and day. The difference it made in my system is the sort of difference you might expect if doubling the price of each component. So even though expensive, for what you get out of it they are good value IMHO.

All of which has nothing whatsoever to do with hybrid amplification. Sorry sanj :shame:
 
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All I will say is his name is Terry. And he says it is mainly down to the distortion introduced into the amp and where it is introduced, either in the pre stage or the power.
 
Originally posted by merlin
Hmm indeed

WM owned a 500, tweaked the sh-t out of it, and roundly critisized mine as being the cause of (no groove).

Didnt know that. He reccomended mine to me without reservation.

I took the Audio Research round to Robbo (I was unaware that WM had mentioned it to Robbo, although I had tipped off WM on the subject)

I know he speaks highly of it. Hadnt realised it was you that took it round.

I bought a lot of Shunyata kit. I believe I took my cables over to WM to let him hear them. He remains convinced the OA product is better (or should I say more to his taste)

He thinks OA cables are better than EVERYTHING... but what would be his second or third choice? Shunyata?

Give WM the choice of Meridian or Teac and guess what he'll choose

We'll have to ask him!. Id be suprised if he reccomends basic Teacs over the Meridian 500... WM over to you?

Give WM the choice of Audio Research or Bel Canto and guess what he'll choose

Again, name ANY ampifier he would reccomend before Bel Canto?

Give WM the choice of Shunyata or Omiga Audio and guess what he will choose.

Again, name ANY cable he would pick before OA?

Nothing at all wrong with that,, there are many ways to find happiness. But the term naturalness is generally used to describe the products WM would discard in the interests of speed and Thwack.

Id agree that he prefers a thwacky speedy sound, but all the above is true IMHO
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Ive edited the above with responses..

Im going to let WM fight his own corner now!! hehehe

:)
 
Originally posted by Tenson
Could you name a few class T amps? I'm quite interested to hear what they sound like, as well as the pure digital ones.

I presume the class T works the same way, i.e. they use the digital signal as a direct control for the power-switching transistor?

Thats if I understand how the digital amps work!

I suppose they are all very very expensive still?
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First of all, there's no such thing as class T. Class T is simply Tripath's version of Class D and with the general confusion that surrounds "digital" amps they've managed to make it stick :rolleyes:

Tripath and BelCanto (who use the Tripath chipsets) will tell you all kinds of stories about why Class T is actually different to Class D (pulse density modulation as opposed to pulse width modulation, intelligent feedback etc, etc.) but it's all marketing bull - they are the same thing and it's rather depressing that so many people have fallen for it :(

Class D (aka switching or PWM - pulse width modulation) amps all work by switching the output devices very rapidly in pulses with the pulse width (or density) varying according to the analog waveform they are trying to reproduce. A low pass filter in the output stage removes the switching frequency so you're left with the analog waveform going to the speakers. Do a search on the net and you'll get a better explanation with diagrams.

The benefits of Class D amps is that the output devices are either on or off so linearity isn't an issue and neither is crossover distortion. Also, since there's no continuous bias current they are extremely efficient and generate very little heat. A secondary benefit is that they require less meaty transformers and PSUs (generally half of what would be required for an equivalent Class AB amp).

Now, there are two types of Class D amp. Ones that take a digital input and ones that take an analog input. The output stage is the same. The ones that take a digital (PCM) input are in theory pretty straightforward. A simple delta-sigma conversion gets you from PCM to PWM and Bob's your uncle. With an analog input you need an integrator circuit that converts the analog input to PWM. One problem with the digital input is that it's impossible to do any kind of feedback from the output stage because feedback in the digital domain is extremely tricky.

TacT, the new Panasonic digital AV amps, Sony S-Master and others are all based on digital inputs.

Tripath, as used by BelCanto, Eslab, Sonneteer and others use analog inputs. Other analog input Class-D solutions exist. Jeff Rowland have a new series of Class-D amps and LC Audio make their own proprietary design Class-D modules which I used in my DIY amp and have been used in some commercial amps. SolarHifi also use the LC Audio modules and make some very well received and nice looking amps.

This month's (July 2004) has reviews of the BelCanto eVo2i integrated and the ESLab Class-D pre/power combo. They are all pretty expensive (comparatively) as are other commercial Class D offerings which is a pity since the cost of making a Class-D amp is dramatically less than that of a convential Class A,AB or B amp. When Sony et.al. start making Class-D amps that are every bit as good as BelCanto's for a 3rd of the price (and they will) we will hopefully see an "adjustment" in the rather exorbitant prices charged ;)

Michael.
 
Originally posted by michaelab
SolarHifi also use the LC Audio modules and make some very well received and nice looking amps...
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...along with some of the worst marketting bullshit I have ever seen. For example:
500 watts of power production, with only 40 watts of power consumption - less power consumption than most light bulbs.
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Utter b*llocks! :mad:
 
Come one Chris, you know what they mean and it's not bullshit. They're referring to the efficiency of the amps. Obviously they aren't getting 500W from 40W otherwise they would have solved the world's energy problems :D . They mean that they have an amp rated at 500W (rms) with an average power consumption of 40W. Anyone who knows anything about amps would know what they meant :rolleyes: . Anyone who doesn't know is unlikelyl to be looking at their site.

Michael.
 
They are all pretty expensive (comparatively) as are other commercial Class D offerings which is a pity since the cost of making a Class-D amp is dramatically less than that of a convential Class A,AB or B amp. When Sony et.al. start making Class-D amps that are every bit as good as BelCanto's for a 3rd of the price (and they will) we will hopefully see an "adjustment" in the rather exorbitant prices charged
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This was one of the appealing aspects of the Sonneteer. £800, which seems to me a very reasonable price for a nice bit of kit. Bel Canto seems overpriced to me.

-- Ian
 
Originally posted by michaelab
TacT, the new Panasonic digital AV amps, Sony S-Master and others are all based on digital inputs.
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Apart from the Tact S2150, which of course uses Toccata Equilog technology as opposed to Equibit. Equilog is also used under licence by Dynaudio and Tannoy via their association with TC Electronics.

One problem with the digital input is that it's impossible to do any kind of feedback from the output stage because feedback in the digital domain is extremely tricky.
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But it is easy to apply DSP for adding even order distortion or subtley EQ'ing the response;)
 
Gee I'm getting a bit of a slating here :D (still nothing new)

WM had a 500 meridian, it was just fitted with an output board nothing more.
I did recomend the 500 to Chris, as I felt for him personaly it would suit his tastes (which I think it does) even if I dont like the equipment, I still see its strengths and advise accordingly.
I do like the AR sound, the Amp Choice was either the B/C or the 200 AR, very close. just the price was the deciding factor.
If It was a fight between Meridian & Teac, I'd would personally chose neither. Both need help.
Given the choice between Shunyata & O/A , as I have both available (and the Hydra 8) its a simple choice, a personal one, their gear does good things, some people prefer them to ours/others.
WM doesn't have to disgard any thing in favour of thwack, the balance I have in the system is correct. Tonaly & texturiously.
Mikes Fave the Class 'T' :D I do agree, I'm sure the mass boys will soon be on the bandwagon, and they are over priced especially with the £$ thats rude.
Off all the digital amps I've sampled, only the Spectral has a serious challenge on the B/C.
Anyone wishing to try the Tripath design, can try an 250w per side evo board for £180+vat.
However, Implementation is the key here.
Not all amps are created equal.
Ian, seems a fair price, Henry imported an Evo 2i inc taxes for £1480, voltage conversion was a very simple operation.
Any more for any more, I'm on a email spree so please do give Generously. cheers Wm
 
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Originally posted by michaelab
Not an issue for PWM switching amps either ;) . No IMD or crossover distortion - actually, very little distortion at all :MILD:
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Properly designed amps have virtually no IMD anyway: 0.003%being quoted by one manufacturer for all the amps they make.
If you *can* hear 0.003% IMD, I pity you, I really do.
BTW what's the switching frequency on the output of the Tripath etc boards?
 
Originally posted by joel
BTW what's the switching frequency on the output of the Tripath etc boards?
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The LC Audio boards in my amp switch at roughly 490kHz if left to oscillate naturally but they can be driven by an external clock at anything upto 1Mhz.

The Tripath boards vary their switching frequency (according to the signal amplitude apparently) from 200kHz to about 1.2Mhz if I remember correctly. This continuous variation of the switching frequency is another reason why Tripath say that their "Class T" is not the same as Class D but IMO it's not a difference fundamental enough to merit it's own class. It's just an implementation detail - a variation on the same theme.

Michael.
 

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