Wednesday, January 31, 2007

Gain calculations, two different amps

I noticed an interesting topic in Audio Asylum concerning bi-amping and input sensitivity. I copy here part of the answer, full text here. Topic issue is bi-amping with Art Audio Carissa and Cary Audio SLM200, input sensitivity 0.6V and 0.7V, respectively.

"You want the gains of the two amps to be the same into the same load. To convert sensitivity to gain, you have to calculate the output voltage into the load at the rated power of the amp.

P=I*E and I=E/R so P=E^2/R.

Solving for E gives you E=Sqrt(P*R). Gain equals 20*log(Eout/Ein). For the Carissa rated at 16 watts (I assume into 8 ohms) with a sensitivity of 0.6 the gain can be calculated as follows.

E= sqrt(16*8)=11.3v and the gain is 20*log(11.3/0.6)=25.5.

Similarly for the Cary rated a 130 watts into 8 ohms

V=sqrt(130*8)=32.2 so the gain is 20*log(32.2/0.7)=33.2. Thus your amps have a 8db difference in gain which is not so good. "

Tuesday, January 30, 2007

V-Caps and Ancient Audio's Lektor Prime

I've both the V-Cap OIMP & Tef caps installed in my Great Northern Sound modified Audio Research LS25 Mk2 pre-amplifier, see pictures of original unit vs. modified (sorry, over 2MB).

Whatever positive is said about V-Caps (see their Web-site or e.g. Audio Asulym for reviews), I concur. They have taken ARC LS25 to new sonic heights, way exceeding what I anticipated. These caps let through phenomenal amount of information and nuances. But burn-in period is as painful as documented in Six Moon's review of Ancient Audio Lektor Prime CD-player. Let me quote from Six Moon's review:

"Bill Baker of Response Audio who was on the beta-testing panel for the V-Caps and uses these parts extensively in his modifications, had this to say: "The first 50 hours can be unbearable at times. During the initial 150 hours, these capacitors have a unique routine of one step forward, two steps back. After you get through the initial 150 hours, the capacitors will start to improve on a consistent basis without the back-stepping. I would say that you are at about 60% at this point. They really do not start to open up until you reach the 400-hour mark. At 400 hours, you are at about 90-95%. Teflon is known to continue changing even up to 1200 hours. Obviously these changes become much more subtle but this is the characteristic of Teflon-based capacitors. I used several hundreds of these throughout 2006 and can honestly say that if there is not at least 300-400 hours on the unit, the evaluation is premature and you are not experiencing its full potential."

BTW, read whole review of that Polish CD-player, it's interesting stuff. Ancient Audio evidently has attitude, look into Lector Grand 3-chassis design: transport with two separate mono DACs.


For audiophiles EMM Labs is well-known for its CDSD Signature Edition transport and DCC2 SE DSD converter, the combo Harry Pearson commented in February/March 2005 TAS as "You simply don't get this kind of improvement in part of the component chain of anything in audio more than once in a decade or so and now that day has come."

EMM Labs has since introduced a single-box solution, the CDSA SE CD/SACD Player. This dual format player "... doesn’t merely upsample CD audio to SACD, it upsamples to double the SACD standard sampling rate. Pop a CD into the CDSA SE, in other words, and the player takes the 44.1kHz signal and upsamples it to 5.6448MHz. Making CDs, not surprisingly, sound remarkably like SACDs."

European prices seems to be 9.900 euros, available in early 2007.

Thursday, January 25, 2007

Hificritic - new British hifi magazine

Some renowned British hifi journalists (Martin Colloms, Paul Messenger) have turned their back to commercialism and founded ad-free, bimonthly hifi magazine Hificritic. Magazine is purely subscription-only.

Somebody might conclude that Hificritic fills the hole in the UK market left by HiFi+. I personally felt that in the beginning HiFi+ was very well editored grass-root hifi magazine, but unfortunately it closed the gap with mainstream magazines within 2 years of existence. It was acquired in 2006 by Absolute Multimedia, owners of longstanding United States hifi magazine The Absolute Sound.

The Absolute Sound is also a partnered magazine with Enjoy the, one of the Web's leading sites with a immense variety of both audiophile equipment and music reviews.

Interesting audio related links

If you have missed these four links, you have missed a great deal of audio reviews.

Stereomojo has for vinyl lovers good snapshot of CES2007 analog gear.

Toneaudio has published TONE Audio as fabulous PDFs.

Dagogo offers "A Unique Audiophile Experience", read for example their review of $79.350 Audio Note Ongaku SET amplifier.

And last, see Audiophile Audition, and their component reviews.

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Tuesday, January 23, 2007

New Mark Levinson & Revel products

Harman International has announced updates to its Mark Levinson family of amplifiers and Revel speakers.

In Stereophile's CES2007 blog you can see replacement for Marki Levinson top-of-the-line 33H mono amps, new model No.53.

Revel has announced replacement for its Ultima series speakers, entitled Ultima2. As their Web-site puts it: " Ultima Salon2, Studio2, Gem2 and Voice2 are the much anticipated successors to the world-renowned Ultima Series loudspeakers, offering dramatically improved sound quality and aesthetics." I heartily remember a pair of first-generation Studios I owned for 4 years, and replaced by a pair of JM Lab Micro Be a year ago. Personally I found previous futuristic design much better looking than "normal" looking Studio2. Judge yourself.

Ray Samuels Audio Hornet

Ray Samuels' miniature headphone amplifier Hornet has created buzz of excitement. Stereophile's gang Wes Phillips & Sam Tellig gave all positive reviews and editor, uber-measurement guy John Atkinson found Hornet to be particularly well executed in terms of measurements.

See also Positive Feedback's review of Hornet. When you visit Ray Samuals' Web-site, don't miss super presentation of their Emmeline II, “B-52” fully balanced Headphone amplifier and full functioning preamplifier.

Aqvox Phono 2Ci Mk II phonostage

If you need an affordable phostage with balanced connections, your choices are pretty limited. Ayre P-5x comes first in mind. German hifi-magazines have some time touted Aqvox Phono 2Ci Mk II phonostage, the latest positive review was published by Positive Feedback. See also TNT-audio's review, which in Part2 has some measurements.

Sunday, January 21, 2007

ModWright LS-36.5 line stage

I've appreciated Dan Wright since I purchased Perpetual Technologies P-3A external DAC, modified by ModWright up to their Signature level. Still today a killer DAC.

In CES 2007 ModWright announced an extension to their pre-amp family. The LS 36.5 employs 6H30 tubes (2) with a 5AR4 tube rectifier, has balanced inputs and outputs and phase inversion switch. In addition, line stage utilizes MdWright's own, custom-made oil-impregnated poly and teflon film-foil capacitors.

iPod for audiophiles - MSB

iPod has reached its 5th generation and still it has no digital-out. As MSB puts in their Web-site "The digital format of its audio files are converted within the iPod, which negates any attempt to create true-to-CD audio." Companies like Sonos apply different approach, i.e. they let you access your iTunes music collections wirelessly and control unit connect via true digital-out to your main rig.

As for iPod's digital out, MSB has announced iLink, a modified 80GB iPod and external iLink base station, which has full set of digi-outs: Toslink, Optical RCA and AES/EBU. What makes this system ingenious is usage of RF. According to MSB "The iLink is supplied with an RF transmitter. It looks like a small connector and plugs into the base of the iPod. It is powered by the iPod and transmits the digital audio to the base station while the iPod is played." All you have to do is match the iLink with an external DAC.

Blog is active once again

Over a year between posts, scaring to think how I've immersed myself into work. Anyway, 2007 should be a tad easier and less busy year and I'll contribute quite frequently to this blog.

In the last post I mentioned that my new system consists of JMLab Micro Be speakers and Velodyne DD12 sub. Amplifiers are still the same, Audio Research LS25mk2 and Mark Levinson 334 power amp. Source remains same, i.e. Mark Levinson 390S.

Some developments, though. I contribute on the freelance basis to Finnish on-line hifi publication and in that context have reviewed various gear. Some time ago I reviewed Musical Fidelity kW250S, MF's high-end, all-in-one solution. Although I found 250S' sound quite involving but somewhat less resolving that my own gear, I started to wonder whether my mainly 5 years old (design-wise) set-up represents high-end in today's standard. Cutting a long story short, I received 5 weeks ago my trusted ARC LS25mk2 pre-amp back from upgrade. The mod was performed by Great Northern Sound, and entails a re-built power section and replacing all coupling caps by V-Cap Teflon® Film Tin Foil caps. The indicated 400 hours burn-in is not yet completed, so I'll post listening report later on. But let me give you a teaser - I seriously doubt whether a brand-new ARC LS26, direct replacement for LS25, could even remotely be as transparent and resolving as my mod unit.

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