Competition Closed...but what is in the Retro – Stereo 50?
Mar 10, 2015 at 10:35 AM Post #181 of 516

Mach3

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From the 4th to 2nd prizes, the winners are...





4th prize - Music Direct $200 voucher AND 2 free Native DSD Music album downloads



Goes to...Mach3


3rd prize* - micro iTUBE with micro iCAN with 3 free Native DSD Music album downloads (worth over US$550)



Goes to...GearMe


2nd prize* - micro iDSD with Alclair Curves iems with 4 free Native DSD Music album downloads (worth over US$700)



Goes to...brooko


Nope, we have not forgotten the 1st prize!

and the 1st prize* - micro iDAC2 (launch in early April) + micro iTUBE + micro iCAN + iRACK with 5 free Native DSD Music album downloads (worth over US$1000)



Goes to...evanft


* The 1st, 2nd and 3rd prizes will all be signed by one of the Skunkworks team. We'll personalise it for you. Doesn't get much better than that!


A huge congratulations to you all!!!



What to do next:


1) Please drop our Laura a PM on Head-Fi or email press@ifi-audio.com

In this PM/email please outline:

i. Your actual name and H-F name

ii. Your preferred contact - email or phone

iii. If you are 1st, 2nd or 3rd winner, your delivery address (as we need to get the iFi units to you!).


Last and not least we would like to say a big THANK YOU to all who have participated. And if you enjoyed this competition, we may host another in the not too distant future.
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Omg first time in my entire life I won something. Thank you, thank you x10000000 to the power of infinity and congrats on all the other well deserve winners. Special mention Brooko who write some of the best reviews. Hopefully he can review the iDSD Micro as I'm keen to purchase one.
 
Mar 10, 2015 at 10:53 AM Post #183 of 516

EVOLVIST

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Awesome, you guys! Enjoy the gear and enjoy the music!
 
Needless to say, the honor goes to iFi for not only committing to such a great competition, but also for posting here almost daily: answering a near endless stream of questions, and for expounding upon their gear and how it all works together.
 
Kwanza!
 
Bring on the iDSD Pro, yo!
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Mar 10, 2015 at 11:07 AM Post #184 of 516
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Omg first time in my entire life I won something. Thank you, thank you x10000000 to the power of infinity and congrats on all the other well deserve winners. Special mention Brooko who write some of the best reviews. Hopefully he can review the iDSD Micro as I'm keen to purchase one.

 
Just thank the iCLUB team as they took it in turns to pull the names out!
 
 
 

 
iFi audio Stay updated on iFi audio at their sponsor profile on Head-Fi.
 
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Mar 10, 2015 at 3:12 PM Post #185 of 516
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Wow - thank you iFi and iClub team!  Did not expect that.
 
Definitely a review coming from me once I've had time to get to know the iDSD and Alclair Curves.
 
And congrats to the other winners!
 
Mar 10, 2015 at 3:31 PM Post #186 of 516
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[size=17.0300006866455px]2nd prize* - micro iDSD with Alclair Curves iems with 4 free Native DSD Music album downloads (worth over US$700)[/size]

Goes to...brooko
 
What to do next:
 
 
1) Please drop our Laura a PM on Head-Fi or email press@ifi-audio.com
 
In this PM/email please outline:
 
i. Your actual name and H-F name
 
ii. Your preferred contact - email or phone
 
iii. If you are 1st, 2nd or 3rd winner, your delivery address (as we need to get the iFi units to you!).

 
Sorry - "thick" question - can you please advise Laura's Head-Fi name - so I can drop her a PM.  Thanks 
 
Mar 10, 2015 at 7:13 PM Post #188 of 516

EVOLVIST

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"...the best in men's clothing. Call Paul's Boutique and ask for Janice and the number is (718) 498-1043. That's Paul;s Boutiue and they're in Brooklyn.*"

Yeah, guys; just PM iFi and you'll reach Laura.
 
Mar 11, 2015 at 8:58 AM Post #189 of 516
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Power is everything (Part 3)

 

But in the end the output transformer is what makes or breaks a tube amplifier. And the one we use is as good as any of the Golden Age and of the modern times. If used in straight line in configuration (tone control in bypass) the only further element in the signal circuit is a motorised 16mm Alps Black Volume control. That is it!
 

 
If the tone control is engaged, the passive, James type network optimised by us, is put into the circuit before the Volume control and a preamplifier circuit derived from the Class A TubeState circuitry found in the iCAN micro. Again, MELF resistors and C0G capacitors are used for all signal critical parts.
 
Yet there is an old saying - any amplifier is only as good as its power supply. Here is where we break with tradition big time. We use what is called a resonant power converter, it is somewhat similar to the much (and often justly) maligned switched mode power supply (SMPS) in operation, but it avoids the hard, high current switching of classic SMPS, thus avoiding many of the SMPS's sonic problems.
 
This power converter operates at very high frequencies, making it much faster than the common AC supplies and it is regulated. This means no matter what the mains voltage from below 85V to over 265V the voltages remain rock steady on nominal. Equally, common tube power supplies tend to "sag" as more power is drawn, this is often claimed as the reason for the "woolly bass" of some tube amplifiers. With a regulated supply the power remains steady from no signal to maximum output and bass is solid and taut.
 
This has an added benefit. As we have a reliably regulated voltages for heater and high tension there is no need to leave any headroom or over-voltage margin to accommodate varying mains voltages. Instead we can use the design maximum specifications producing more power than common. As we have no drop in power supply voltage with increased power output again, more power is produced by the Amplifier than a classic design using the same output tubes.
 
And of course regulated power supplies have very low noise. The Retro Stereo 50 manages > 95dB(A) Signal/Noise ratio at 2.83V output.

Source: AMR/iFi measured on AP2
 
 
This compares to the around 70dB (A) of many classic designs and even today many traditional design tube amps struggle to offer better than 80dB (A) SNR.
 

 
Note: these two graphs have the exact same x and y values, so you can make a proper side-by-side comparison.
 
 
More crucially, all the noise in the Retro Stereo 50 is tube noise (often called tube rush) there are no significant hum components that can be ascribed to the mains frequency. What this means in practice is that if a 90dB/W/m Speaker (e.g. the matching LS3.5) is connected to the Retro Stereo 50, any noise at 1m distance is around 5dB lower than the hearing threshold.
 
So for the Retro Stereo 50 beauty is more skin deep, combining the latest modern technology with classic tube design gives the best of all worlds, the classic tube, but without the noise, limited bandwidth, limited power and woolly bass that many have come to negatively associate with tubes.
 
In fact, like a good sports car, the more you rev it, the better it gets. Wanna play Nirvana? the Stereo 50 just says "stop tickling me at such a low volume and let's crank it up".
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Mar 11, 2015 at 12:42 PM Post #190 of 516

XjunkieNL

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Nice info on the Stereo50. Knowing how much knowledge has gone into the design makes it even more special to own one.

One remark you mention 90 dB/W/m for the speakers. I think it must be 87 dB/W/m or 90 dB/2.83v/1m as the speaker are 4 Ohm.

/Paul
 
Mar 11, 2015 at 12:57 PM Post #191 of 516
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Nice info on the Stereo50. Knowing how much knowledge has gone into the design makes it even more special to own one.

One remark you mention 90 dB/W/m for the speakers. I think it must be 87 dB/W/m or 90 dB/2.83v/1m as the speaker are 4 Ohm.

/Paul

 
Hi,
 
No flies on you!
 
Sorry for this boo boo.
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90dB/2.83V/1m instead of dB/W/m.
 
iFi audio Stay updated on iFi audio at their sponsor profile on Head-Fi.
 
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Mar 11, 2015 at 8:36 PM Post #192 of 516

Mach3

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Power is everything (Part 3)

The Retro Stereo 50 manages > 95dB(A) Signal/Noise ratio at 2.83V output.

This compares to the around 70dB (A) of many classic designs and even today many traditional design tube amps struggle to offer better than 80dB (A) SNR.
 

 
15dB difference doesn't sound much but it actually a lot. I remember for every 3dB it 2x the difference. So does that mean the Retro Stereo 50 produce 2^5 (32x) less noise than the typical tube amp design? Correct me if I'm wrong on this iFi.
 
Mar 11, 2015 at 8:48 PM Post #193 of 516

kapanak

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15dB difference doesn't sound much but it actually a lot. I remember for every 3dB it 2x the difference. So does that mean the Retro Stereo 50 produce 2^5 (32x) less noise than the typical tube amp design? Correct me if I'm wrong on this iFi.


15dB difference means just a hair over 31x different in intensity.
 
Mar 11, 2015 at 11:02 PM Post #194 of 516

deskmate

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15dB difference means just a hair over 31x different in intensity.

Thank you for the explanation, save me a trip to Google a dB calculator.   Why can't people wrote something layman can understand? Stop being dB this, dB that ...  Do we really need an engineering degree to enjoy audio?
 
Some others (e.g. LH Labs) are better at explaining stuff to the general public, please try to use XXX times instead of dBs, even it means a big number, so be it. For example, it is a lot easy for me to understand "it is about 30,000 times better" than "it is 45dB better".
 
Mar 11, 2015 at 11:45 PM Post #195 of 516

kapanak

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  Thank you for the explanation, save me a trip to Google a dB calculator.   Why can't people wrote something layman can understand? Stop being dB this, dB that ...  Do we really need an engineering degree to enjoy audio?
 
Some others (e.g. LH Labs) are better at explaining stuff to the general public, please try to use XXX times instead of dBs, even it means a big number, so be it. For example, it is a lot easy for me to understand "it is about 30,000 times better" than "it is 45dB better".


While I understand your point, quantifying volume and sound intensity in dB is a standard that's been used for a century. Also, for most people, 10x is really big, but they won't be able to feel that "10x more intensity" when going from, say 60dB to 70dB.
 

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