RSA SR71b, quad mono balanced. img. 1 & 17 Review pg 32, 34, 68, UPDATED 4/2013 for Improved sound.

[AnakChan]

I thought I'd give this thread a little bit of an update.
 
For those who may have read my impressions between the Rx Mk3 vs SR-71B may remember that I wasn't very impressed with the SR-71B. That test was with a single ended earphone but later I tested with balanced earphones and still felt the SR-71B lacked transparency and clarity.
 
Recently a new balanced DAC was released by CypherLabs known as the Algorhythm Solo -dB. Despite some balance issues, with guidance from relevant involved parties I've managed to implement a temporary fix as a test; and one of the tests involves trying different balanced amps with the CLAS -dB. The interim-fixed CLAS -dB works well with the SR-71B, and this is the first time I've actually been thoroughly pleased with my SR-71B. The clarity improved, the bass extension is clearly more apparent and so is the detail.
 
Where I previously mentioned the SR-71B mids and vocals felt rather muffled, that is all gone. Now with the backend balanced, the difference between the SR-71B and Rx Mk3 feels more to do with sonic preferences rather than superiority of competing products.
 
At least with the 3xIEMs I can switch back 'n forth between single ended and balancing, the balancing on these IEM/headphone side yielded minor improvements. Whereas (now I can test with the CLAS -dB) the backend balancing of the ICs appear to be a bigger improvement.
 
My thoughts are that the only way for me to enjoy the SR-71B is to have a complete balanced setup right through.

 

[ianmedium]

It is so funny how we hear things differently. For me the blackbird is excellent in transparency and clarity, especially through my Piano Forte's

 

[AnakChan]

Quote:

It is so funny how we hear things differently. For me the blackbird is excellent in transparency and clarity, especially through my Piano Forte's

 
Oh you're right . I don't actually like the Piano Forte's either . I wonder if it's any impedance mismatching that's causing me not to enjoy my SR-71B in SE. I haven't tried searching through this thread yet but anyone knows the output impedance of the SR-71B?

 

[ianmedium]

You know Anak, I had an interesting thing happen a few weeks ago with a fellow member here. He tried my Blackbird with the PF's and the LCD2 Rev2 and was scratching his head as when he heard a different blackbird previously he came to the same conclusions you do and yet when he heard mine he heard the clarity and transparency I mention even with the LCD's!

I can only put this down to either two things, one is I use pure silver with 1%gold interconnects or two simply the number of hours on my amp which is now well over a thousand. Other than that I can't explain and I must admit I thought it was my hearing that was different but if you saw the look of astonishment on the other members face when he heard what he did, well it made me feel that perhaps I was not the anomaly!


Having said all that as much as I love the sound of this amp something about the PF's keeps making me want to try tubes and low and behold a small maker called Analog Square Paper in Japan has brought out a portable tube amp running four tubes and I am now in the process of saving for it. Something tells me tubes and the horn like PF's will be a match made in heaven!

 

[zilch0md]

What do you guys make of (ALO) Ken Ball's statement in this 6 Moons interview:
 

To obtain a balanced working signal, a non-inverting amplifier buffers the input signal. The output of that amplifier is inverted with a unity-gain amp. The balanced signal is then taken from the outputs of both amps which are contained within the same IC. The worst-case mismatch between inverting and non-inverting outputs is 0.02dB. Going in single-ended [as input to the balanced Rx-Mk-3-B] is thus no worse than balanced. The real advantage of the RxMk3-b is its fully balanced amplification circuit and ability to drive all headphones in balanced mode.

 
Mike

 

[goodvibes]

Beside possible rejection form some noise coming in, there will also be advantages in noise and RF elimination of the amp circuit itself. The balanced output connector will also sound better than a standard jack. Besides that, there's no reason for it to be better other than it was likely optimized and voiced that way which is always part of the equation.

 

[AnakChan]

Quote:

You know Anak, I had an interesting thing happen a few weeks ago with a fellow member here. He tried my Blackbird with the PF's and the LCD2 Rev2 and was scratching his head as when he heard a different blackbird previously he came to the same conclusions you do and yet when he heard mine he heard the clarity and transparency I mention even with the LCD's!
I can only put this down to either two things, one is I use pure silver with 1%gold interconnects or two simply the number of hours on my amp which is now well over a thousand. Other than that I can't explain and I must admit I thought it was my hearing that was different but if you saw the look of astonishment on the other members face when he heard what he did, well it made me feel that perhaps I was not the anomaly!
Having said all that as much as I love the sound of this amp something about the PF's keeps making me want to try tubes and low and behold a small maker called Analog Square Paper in Japan has brought out a portable tube amp running four tubes and I am now in the process of saving for it. Something tells me tubes and the horn like PF's will be a match made in heaven!

 
Could I clarify your setup please? Going by your sig, so this is with the original CLAS, silver SE ICs to the SR-71b, then balanced out LCD2R1 or SE PF (Unless you balanced your PFs too ).
 
I have old Twag2 ICs with Neutrik minis but I also have some old ALO copper ICs too (to be honest, difference is slight - rather more transparent with the Twag2 and wamer with the ALO - but nothing that improves the sound of my 71b in backend SE mode). I may try different beefier ICs maybe. Would be an interesting debugging exercise.
 
Admittedly my 71b despite having it since last November (not first owner, don't know the history), hasn't really been used that much so burn-in is probably around the 200hr mark by me at least.

 

[zilch0md]

Hi goodvibes!
 
Quote:

Beside possible rejection form some noise coming in, there will also be advantages in noise and RF elimination of the amp circuit itself. The balanced output connector will also sound better than a standard jack. Besides that, there's no reason for it to be better other than it was likely optimized and voiced that way which is always part of the equation.

 
I have to tell you that I've posted that Ken Ball quote to perhaps five different threads across the past few months, but you are the very first person to actually respond.  And I love your response - I agree, completely.
 
It seems that people who own balanced output amps that offer either balanced or single-ended input have a natural, irresistible tendency to desire a fully balanced rig.  They want to hear reasons for pursuing a fully balanced setup.  They do NOT want to hear reasons for using a DAC with single-ended output.  All this despite the expense that can be associated with changing from a single-ended DAC to a balanced DAC.
 
Given what Ken Ball of ALO said during the 6moons interview I quoted, it amazes me that people just do not respond to his words at all - it's as if they would prefer to just stick their heads in the sand and pretend he doesn't know what he's talking about.
 
My only experience with testing single-ended output vs. balanced output from a DAC to a balanced-output amp was with a week of testing the iBasso DB2 dual Wolfson DAC (which I returned under their very generous no questions asked guarantee) and the iBasso PB2 balanced amp, which I still have.
 
Across several sessions, with many different tracks, using balanced out from the PB2 amp to my LCD-2 rev.1 via Toxic Cables' Silver Poison, switching back and forth between balanced output from the DAC vs. singled-ended output, I could hear NOTHING to distinguish the two, as long as they were volume matched.  I had used an iPhone app by JL Audio (called SPL Meter), with a lapel mic sandwiched between the LCD-2 ear pads, to determine the volume setting necessary on the PB2 to deliver 85.0 dB from a white noise WAV file - for both the single-ended and balanced-output DAC.  A friend assisted me with blind testing the difference between single-ended and balanced feed to the amp.  I could discern no differences and neither could he.  
 
I think the greatest benefit available for balanced connections between DAC and amp is the rejection of noise that can be an issue when you have particularly long cable runs between DAC and amp - where common mode interference can be troublesome.  Otherwise, I don't believe there's any real need for balanced output DACs, but if you've purchased a DAC that offers both single-ended and balanced output, by all means, you should use the balanced output, as the DAC is no doubt optimized for that - and, as is the case with the iBasso DB2, you're likely to get only half the Vrms out to your amp when using the single-ended output (1.0 Vrms, instead of 2.0 Vrms, for example).
 
Mike

 

[goodvibes]

You know, with a quiet input, I would think there'd be a subtle difference between them but not a better worse type of deal. If it truly sound virtually identical, it's a testament to the design and quality of the amp.

 

[zilch0md]

Good point.  I also think I would have heard a difference switching the iBasso DB2 DAC's output from single-ended to balanced ouput to the PB2 amp, had I been using a more power-hungry headphone, like the HE-6.  The difference between 1.0V rms into the balanced amp vs. 2.0V rms would become significant if the amp is having to drive something like the HE-6.  But we're just talking about a difference in in put voltage... 
 
My DACmini's DAC section, as well as my DACport LX, offer 2.0 Vrms output as single-ended DACs.  You don't have to get a balanced DAC to get 2.0 Vrms and thus, the 1.0 Vrms output of the iBasso DB2 when single-ended is just an unfortunate byproduct of its dual DAC design.

 

[ianmedium]

Could I clarify your setup please? Going by your sig, so this is with the original CLAS, silver SE ICs to the SR-71b, then balanced out LCD2R1 or SE PF (Unless you balanced your PFs too ).

I have old Twag2 ICs with Neutrik minis but I also have some old ALO copper ICs too (to be honest, difference is slight - rather more transparent with the Twag2 and wamer with the ALO - but nothing that improves the sound of my 71b in backend SE mode). I may try different beefier ICs maybe. Would be an interesting debugging exercise.

Admittedly my 71b despite having it since last November (not first owner, don't know the history), hasn't really been used that much so burn-in is probably around the 200hr mark by me at least.

Yep, you have it right, balanced LCD2 and single ended PF's, original CLAS. I had the TWag for a while in the balanced HP cable but much preferred the Toxic cables HP balanced cable. It's not the same manufacturer of cable as the IC's but of similar material. The IC's I had done by a DIY'er.

I feel the same as you, the IC's are a small part of the equation but I truly feel the biggest is the length of time used. Even though Ray quotes a lower time before full performance I noticed once the amp had sailed past the 500 hour mark and definite opening up of soundstage, greater transparency and resolution.

Not sure what your hearing is like, I had mine tested recently after doing an online one and the online test was so unbelievable that I thought I would have a professional check, it confirmed the online test which was that these almost 49 year old ears can hear up to 21Khz so perhaps thats a factor as well, though that would not explain the other members findings!

 

[wolfen68]

Please share your source for the online hearing test.  I get these at work, and am interesed if the online version even comes close to match the professional test results.

 

[ianmedium]

I cant remember it as it was on a thread somewhere here and I then searched for others and did a bunch. That was when I thought I would go for a proper check up and it got the same results.

 

[jamato8]

I have sent my 71b in for an update. The gain will be increased so it will be like the Intruder and there are some other updates that affect the sound. I am really looking forward to this, it will be like an all new 71b!!

 

[wolfen68]

Quote:

I have sent my 71b in for an update. The gain will be increased so it will be like the Intruder and there are some other updates that affect the sound. I am really looking forward to this, it will be like an all new 71b!!

 
Please provide more background on the "other updates".