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  #21  
Old 11-20-2015, 09:53 PM
Harris4crna Harris4crna is offline
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I considered purchasing another accuphase cd transport to connect with my DC-37. I am coming to the conclusion it would not be cost affective. I visited Accuphase yesterday and spoke with Mr. Tozuka, international rep. I asked him if I could purchase a old cd transport like the dp-77 and connect to the DC-37. He advised against it because the newer components don't match well with the older components. In other words it would degrade the potential of the system. After reading the tests between the ultra expensive components and the modest expensive components, I am thinking a cost-effective oppo will be the best match for the DC-37.
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  #22  
Old 11-21-2015, 12:01 AM
nvp nvp is offline
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OK, I have found an explanation! I have found online a service manual for the A-65 amp and therein it was mentioned that the uncertainty of the meters when indicating values of 0.020W is +/-50%.
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  #23  
Old 11-21-2015, 02:04 AM
Barsur Barsur is offline
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Quote:
Originally Posted by nvp View Post
Barsur (also Mattia), I have repeated my experiment and this time with some very unexpected results (at least for me). Basically, I was not able to reproduced the result I have obtained yesterday. In fact, I have repeated the experiment several times and each time I have obtained (slightly) different values!

To pinpoint the problem I have changed the setting of the A-65 meters from infinite to the “1 second” setting. I have recorded repeatedly the indications of the A-65 meters during a 10 second long music passage that exhibits rather large dynamic variation without changing any settings in system. To my dismay the A-65 showed each time slightly different values. For example, if I was back-forwarding 30 seconds before the beginning of my reference passage the meters indicated power variations from 0.005 to 0.063 watts (during the reference passage), whereas if I was back-forwarding 20 seconds the meters indicated power variations from 0.005 to 0.048 (during the same reference passage).

The funny thing is that this type of results have convinced me a long time ago, while still a student, to pursue a theoretical/computational (as opposed to experimental) path as a physicist. Already then it was clear to me that it is much easier (at least for me) to reproduce computational results than experimental results. Even funnier, is the fact that about 6 months ago I have decided that maybe I should try my hand again in the lab and, as such, I have spent €200k of my research money on a spectrometer that should arrive next week. Hopefully my PhD student will be better than me at this.

Nonetheless, do you guys have any reasonable explanations (e.g. caps recharging time) for these strange results?

I look forward to hear your thoughts!

Paul
Dear Paul,

in my humble opinion you are relying to much on the power meters from the Accuphase A65. I own A60 and A 70 and I know that these power meters reading are the best in the whole hifi industriy but I am not sure if these power meters show the exact amount for low power. My suggestion, do it the way, I explained in one of my quotes. You have two choices:

1. You measure the output voltage, but you have to take care with your extrem sensetive speakers, that you have the exact amount of voltage from both equipments.

2. Take a 1khz test tone, measure the SPL from both equipments and equal the SPL (Maximum difference 0,1 dB). Of course you need an exellent microphone and good software to do this.

In my humble opinion and please don´t be upset, something went wrong so far in your experiment, because it is absolut impossible that one equipment sounds 10dB louder than the other as you explained when you leveled them on the same SPL before.

I asked also a good friend of mine, who gave me years ago the idea and the right procedure for the blind test (He worked in the past for the Frauenhofer Institut and was part of the MP3 blind test. But better I don´t tell you, which results they achieved...). He told me again that in a "correct" blind test it is absolut impossible the results and differences in SPL which you achieved.

Good luck and best regards

Martin

Last edited by Barsur; 11-21-2015 at 02:11 AM.
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  #24  
Old 11-21-2015, 02:10 AM
Barsur Barsur is offline
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Quote:
Originally Posted by nvp View Post
OK, I have found an explanation! I have found online a service manual for the A-65 amp and therein it was mentioned that the uncertainty of the meters when indicating values of 0.020W is +/-50%.
Oh sorry Paul, I saw to late your newest quote. This could be an explanation as I described before.

Best regards

Martin
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  #25  
Old 11-21-2015, 08:33 AM
meltemi meltemi is offline
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Every engineer knows:

"Who measures a lot, measuers a lot of sh..."

It means;
The individual setup of a measurement/test environment will influence the results. (Similar to: I only believe into statistics I have falsified myself).
This is why a large number of measurement procedures are fixed in international, national or industry standards (i.e. IEC, IEEE, EIA, DIN, IHF, AES/EBU and more).

A plausibility check is necessary to help to determine, whether the measurement results are relyable or whether you need to apply changes to your measurement/test setup.

In addition, all measuring equipment has tolerances. The measured value has therefore to be understood as value +/- tolerance.

These are essential basics for everyone who measures/tests.

Martin
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  #26  
Old 11-21-2015, 01:55 PM
nvp nvp is offline
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Quote:
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I only believe into statistics I have falsified myself.
I like this quote very much and I often mention it to my students. Most often they understand its meaning only after a whole year of hard work.
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  #27  
Old 11-21-2015, 02:14 PM
nvp nvp is offline
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Quote:
Originally Posted by meltemi View Post
I only believe into statistics I have falsified myself.
I like this quote very much. It's funny and true. I often tell it to my students, and usually they need to work on real world research projects for more than a year to appreciate it.
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  #28  
Old 01-22-2016, 09:56 AM
Mattia Mattia is offline
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I reopen this topic because I'm waiting for a DC-300 to arrive so I can finally try it out by myself and compare it to the C-2420. If for me there are no perceivable differences in noise and general audio quality, I'll have the added benefit to be able to use the DG-58 in a digital loop, and to connect many more digital sources to the DC-300, all equalised, compared to go digital to the DG-58 (with fewer inputs) and then use the C-2420 preamp basically just as an expensive volume control (since I only use 1 source).

I've chosen the 300 and not the newer 330 because I ideally like the multibit approach (16x PCM 1702 as the DP-75), I think it has a better, no compromise, construction regarding PSU (digital+ analogue-R + analogue-L separated PSU) and beefier filter section, it has more inputs without having to acquire extra option boards and I like the simpler style.
It is overall simply more interesting to me.

What is also interesting, is that on the used market a DC-300 is valued 1/3 or max 1/2 the price of a C-290V, even if his price in Japan, at the time, was exactly the same (980'000¥).

This fact alone maybe can partially answer my original question on the first post: the "DC-3xx" line of preamplifiers was probably never updated (also) for lack of clients interest and then sales.

The subsequent 2xxx line, with AAVA, seems in fact to try very hard to push the fact that the AAVA is analogue. It is repeated a thousand times everywhere in the promotional material. Evidently, many Accuphase customers perceived the digital volume of the DC-3xx as something obviously and surely inferior to Good Old Analogue (maybe, as often is sadly the case, without having the possibility to properly test out and compare).

Last edited by Mattia; 01-22-2016 at 11:51 AM.
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  #29  
Old 01-23-2016, 10:31 AM
Mattia Mattia is offline
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Barsur,
just a quick question.

In the light blind test you performed and mentioned before, how was the DP-510 connected to the DC-300?

It was connected to the analogue inputs or digital? Because if connected in analogue (so with another AD/DA passage in the signal path) the DC-300 was as transparent as the others, that would I think be an ulterior testament of his quality.

And to further abuse of your patience: do you find any difference (regarding CD material obviously) in going digitally from the DP-510 to the DC-300 versus going analog?
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  #30  
Old 01-23-2016, 01:38 PM
Barsur Barsur is offline
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Quote:
Originally Posted by Mattia View Post
Barsur,
just a quick question.

In the light blind test you performed and mentioned before, how was the DP-510 connected to the DC-300?

It was connected to the analogue inputs or digital? Because if connected in analogue (so with another AD/DA passage in the signal path) the DC-300 was as transparent as the others, that would I think be an ulterior testament of his quality.

And to further abuse of your patience: do you find any difference (regarding CD material obviously) in going digitally from the DP-510 to the DC-300 versus going analog?
My DC-300 is normally in the following sysem: Accuphase DP 90 digital into DC 300 in Accuphase A100 and than to Harbeth P3ESR. This is one of my beloved aystem which I own. Absolut wonderful.

For the light blind test, I had following configuration: Accuphase DP 510 analog in DC 300 in Accuphase A 70 and than to Magico S1. I used the analog input for comparison reason, because C290 and C2420 doesn´t have digital inputs.

I compared (no blind test) the digital input against the analog input of the D-300 and the digital input seemed a little bit more transparent. But ofcourse without blind test this statement has no value at all.

If you know what is playing than comes normally a psychologic effect. Typically for example, if people know that they are listening to tubes. In one of our last blind test, I compared a Mcintosh tube amplifer against a solid state Mcintosh amp. People thougt they would here to the Mcintosh MC 275 because I told them so, but instead they were listing again to MC 452. But everybody told me how much "warmer" the music is now with the tube amp. But I didn´t switch the amps, they were listing in reality again to the solid state amp. They were shocked how big the psychologic effect is in audio.
Best regards
Martin

Last edited by Barsur; 01-23-2016 at 01:43 PM.
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