[MRC001]

Audeze's power recommendations are ridiculously high. If anyone listened to an LCD at even 1/2 that amount of power he'd have hearing damage. A few years ago, I posted the simple math that proves this point in another thread here.

If you already have a good DAC, you can't go wrong with the Jazz. IMO there's no better amp in your price range.

 

[zimbao2339]

Thank you, that is very reassuring.

I'm not very knowledgeable about headphone amps/dacs and wanted to be sure about my purchase.

 

[wantan]

What exactly is the difference between the ff and non-ff versions of the Jazz?

The FF Version has more microdetail, it has more room around the instruments and everything sounds slightly more "real". It also has a wider soundstage and the treble region is very slightly more pronounced (it's not bright or glarey).
The non FF version has slightly better macrodynamics and slams slightly harder. It's slightly warmer and darker. There's no hardness in the sound of both amps.

It depends on the transparency of your whole setup how audible these differences are.

I like the JAZZ a lot and would easily recommend it. Even compared to my Phonitor e it doesn't fall back as much as other amps in this pricerange do.

 

[Richter Di]

The FF Version has more microdetail, it has more room around the instruments and everything sounds slightly more "real". It also has a wider soundstage and the treble region is very slightly more pronounced (it's not bright or glarey).

Fully agree with this. And as I am a fan of details and realism this was clearly the to go.

 

[jaco61]

... mesurements in the review of the corda jazz on ASR Site https://www.audiosciencereview.com
quite shocking ..

 

[MRC001]

The reason it's shocking is because the fellow who measured it didn't know the output was balanced, so the ground channel wasn't connected. Thus, it measured half the voltage, 1/4 the power, and 6 dB worse distortion and noise than it actually has. This is discussed at length if you follow that thread.

Correction edit: after initially questioning whether it was measured correctly, they determined that it was. So the measurements stand! There is no 6 dB difference.

 

[jaco61]

ok..thanks. So, at the end not that bad.

 

[MRC001]

The Jazz does have a problem when the volume is turned past the 2:00 position, distortion goes crazy high. But that's very loud. No need to turn it up that high, in high gain mode it will put out > 1 watt before reaching that point. Other than this design bug, it measures decent if not spectacular, and the stepped attenuator volume gives perfect channel balance at all settings.

 

[a-LeXx]

No need to turn it up that high, in high gain mode it will put out > 1 watt before reaching that point...

Not entirely true. Yes, with low impedance headphones it would be able to reach very high power levels, because it can drive lots of current.

However, this amplifier is very limited in undestorted max. level swing. With a 300Ohm Sennheiser it will be only providing around 30mW undestorted, with a 600Ohm Beyer T1 only around 15mW. This is WAY below 1W. Also designer himself stated this and also stated that the specs he provides for Jazz on his home page are wrong...

 

[MRC001]

You meant to say watts, not amps, right?

Because the AP analyzer wasn't differencing the ground channel, the output levels measured at AudioScienceReview were low by 6 dB. If so, that means actual power output is 4x higher than measured. That makes 120 mW into 300 Ohm and 1.2 W into 33 Ohm.

Amir may re-test and find out.

Edit - correction: the measurement was correct; see above.

 

[a-LeXx]

You meant to say watts, not amps, right?

Because the AP analyzer wasn't differencing the ground channel, the output levels measured at AudioScienceReview were low by 6 dB. If so, that means actual power output is 4x higher than measured. That makes 120 mW into 300 Ohm and 1.2 W into 33 Ohm.

Amir may re-test and find out.

Amir already replied that he was doing a floating measurement and his results are correct. Also Jan himself replied and stated that his design can provide 3.5Vrms max because of the clipping in the first amplification stage. Ok, Amir measured 3V max before clipping.

Your calculation is wrong, it would be right for a true differential (balanced) setup, while this is not a real balanced design. Have you actually even check the explanations Jan gave to his design, how it works, with formulas? Check that, it‘s available on Jan‘s homepage, then you will see that you are wrong with your assumption that you need to double the voltage like in a true balanced calculation...

Even if we take the theoretical max values that Jan gave (3.5Vrms), instead of the actually measured, the amp still can only drive 400mW into 30Ohm, 40mW into 300Ohm or 20mW into 600Ohm...

While it‘s delivering absolutely enough power for low impedance cans, there is not much headroom for the higher impedance cans. Jan himself told in that thread that his amp will start to distort above 112dB SPL with HD800. And while 112dB SPL are way too high for normal listening, when you listen to dynamically uncompressed rock or classical albums at pretty high average volume, peaks can go beyond 112dB, which means they will be distorted...

Edit: just noticed your comment reg. mW vs mA... Good catch, corrected that... this is what happens when you are trying to type on an ipad and watch after two running, jumping and screaming kids at the same time...

 

[MRC001]

You may be right. It all depends on how Amir's AP analyzer works. Amir said he used floating ground, but the question remains whether the AP differences the Jazz + output against Earth ground, or the floating ground. If the former, it will measure only 1/2 the output. If the latter, it will measure the full output.

 

[a-LeXx]

You may be right. It all depends on how Amir's AP analyzer works. Amir said he used floating ground, but the question remains whether the AP differences the Jazz + output against Earth ground, or the floating ground. If the former, it will measure only 1/2 the output. If the latter, it will measure the full output.

No, even if he‘d do this wrong way around, he will not measure half the amplitude. As I said, that would be a case for a true differential design. This one is not differential! It‘s an active ground setup, just have a look at the formulas at Jan‘s page, he is not shy explaining this in a very detailed way...

 

[MRC001]

Yes, and if you follow Meier's formulas and do a little algebra, you see that in the special case when the input signal is the same in both L and R, the output looks like differential: + and - are mirror images of each other. Amir measured this and showed in post # 56 of that thread.

 

[a-LeXx]

Yes, and if you follow Meier's formulas and do a little algebra, you see that in the special case when the input signal is the same in both L and R, the output looks like differential: + and - are mirror images of each other. Amir measured this and showed in post # 56 of that thread.

Sure, in this special case, it‘s true (measurement at post #56). But this is not how he‘s done his original measurement, that‘s the point! But you keep saying he is missing 6dB... He is not And Jan wouldn‘t make his own design worse than it actually is, he said it will distort starting at 3.5 Vrms himself...