Tube Buffers; Yaqin CD-1 & Musical Fidelity X-10v3

As above, I've determined that I like the way my systems sounds when using a turntable with the Yaqin CD-1 tube buffer in place better than without. The overall sound quality is better, the soundstage both deeper and wider, the focus of the phantom center channel and specific instruments much more "pinpointed" and the apparent channel separation greater.

I've now been listening for over 40 hour with and without the Yaqin between my NAD 5425 CD Player and preamp.

The 5425 was rated by Hi-Fi World and others as one of the "most musical" CD players available when was introduced in early 1992. It's Frequency Response curve is dead flat to 14,000Hz, and it tails off just a fraction of a db from 14,000Hz to 25,000Hz. Distortion is less than .03% in the audible range. It's a 4X oversampled, 18 bit DAC unit with a 100db dynamic range, a signal to noise ration of 110db, channel separation of 90+db and boasts "unmeasurable" wow and flutter.I paid $295 for my first one in January of 1992, and bought a second in 2008 on eBay for $11 (they generally go for $85) because the 18 Volt axial lamp that illuminmates the control panel had burned out and the owner thought it was dead. $3 and a couple of dots of solder later I had 2 perfectly functioning units. Both are close in serial number and sound identical.

The story is basically the same as with a turntable as a source. The size of the soundstage is magnified with the Yaqin in place, although not quite as large as noted in my turntable review above. The quality of the sound is also better and the pinpoint placement of voices and specific instruments within the soundstage was the same as with a turntable source.

Short and sweet (and again as with a turntable source) when the tube buffer was out of the loop, I wanted it back in!

What is most impressive to me is how the tube buffer opens up the soundstage. Even at low volume the soundstage is projects forward and beyond the outside edges of the speakers and the point from which vocals and individual instruments eminate is more tightly focused. As a quick story, I listen to a lot of Jethro Tull music. When performaing or recording, front man Ian Anderson alternately sings and plays a flute in front of a dual microphone setup. A standard mic is located straight up on the stand at about his Adams Apple level, and second a foot lower and to the right to capture his flute. He's quite animated when playing the flute and at times and marches in place, changing the location of his flute in relation to the 2 mics. With the Yaqin in place I can better discern that movement of the sound source.


Tull Fans: Ian Anderson solo tour - Fall '09; http://www.jethrotull.com/tourdates/index.html#iausa)

The Musical Fidelity buffer has a 3-pin female DIN connection to receive 24volt AC power from an external power source where the Yaquin has a 110V female IEC connector to power it's internal power supply. The Little Pinkie would not work with the Yaqin.

There is the opinion expressed in some forums that if you solder in a 33uF/400V electrolytic cap between the hot (+) and the ground wires within the CD-1, it will yield tighter bass and bottom end and accuracy and improve overall musicality. I will be experimenting with adding this cap to my Yaqin in the near future.

heiney9 wrote: »

I'm curious how you came to substituite a 6922 for 6N1? I have a Dared MP5 integrated hybrid amp that uses (2) 6N1's for the input buffer. I was told that anything in the 6DJ8 family (which the 6922 is) could most likely do damage to the tranny or internal parts so I've avoided using those. Russians make a superb 6N1P-EV and 6AQ8/ECC85 can be subbed as well. I have several early 60's era 6AQ8/ECC85 from Heerlen, Blackburn, West Germany (Siemens) as well as Telefunken's that are simply amazing sounding tubes.

In the future you may want to try and hunt one of these down and try them(6AQ8/ECC85). Did the manufacturer suggest the 6922? I'm half tempted to try a 6DJ8 variant for **** and grins.

H9

I'd done hours of research and read the JAN Phillips 6922 Green Label was really inexpensive for what you get (and in the 6DJ8/6922/ECC88 family) so I thought I'd give it a try. It's been great so far, and I did plug in the Chinese 6N1 provided for about 5 hours. This particular 6N1 really sounds inferior, although I guess I should give it a few days to be totally fair.

I sure hope this class of tube doesn't cause a catastrophic shower of sparks because I just ordered a NOS Bugle Boy Amperex Holland 6DJ8/6922/E88CC to try out next.

I've heard great things about Dared, but don't know enough about how power supplies and tubes relate to one another. It sure seems there are a lot of high-line 6DJ8/6922/ECC88 options out there to make it worth researching.

heiney9 wrote: »

. . . sounds ike you're having fun as well.

H9

It's true! (and it guys like you into tubing that did this to me )

This morning is a classic example. I'm self-employed and work from home so I can shift my schedule, but I got into my home office at 7:30 this morning to catch up on some paperwork.

That was more than 3 hours ago and all I have done is listen to music and **** around on the Internet and here at Club Polk.

Forgot to write it above; Welcome Aboard Jetmaker737!

Resetting the stage:

Here's the test platform for as near a perfect A/B test between the Yaqin CD-1 Tube Buffer and Musical Fideity X-10v3 Tube Buffer as I could design with the equipment I own.

Symmetrical 20' X 26' Finished basement with padded carpet over concrete floor and 8' height ceiling with 2'X4' insulated drop ceiling panels.

20' painted block wall behind speakers. Insulated stud wall with wood paneling on other 3 walls. Typical furnishings with mix of leather sofa/chairs and wood tables, entertainment center, shelving placed approximately equally from center-line of speakers.

Speaker backs are 7" from rear wall. Speaker sides are 3' from paneled side walls. Speakers are 21" wide leaving 10'-6" between inside edges of speakers. This puts speaker center-lines approximately 12'-6" apart.

Listening position is dead center and 12'-6" back from front plane of speakers.

--- All components powered by APC H10 Blk
--- 5' Groneberg Quatro Reference Power Cable from ABC to wall outlet. Wall standard duplex outlet is 10' run of Romex from dedicated 20A breaker in adjacent breaker box.

--- Modded Polk SDA SRS "2.1 TL's" with Cardas Binding Posts
--- 10' MIT Shotgun S2 Speaker Interface Cables (bananas all ends) to pre-amp
--- NAD 1700 Pre-amp (Rebuilt Caps, Power Section, Cardas Binding Posts)
--- 2M MIT Shotgun S2's with Adjustable Impedance Boxes with Locking RCA's from pre-amp to Power Amp
--- NAD 2600A Power Amp (Rebuilt Caps, Power Section and Cardas Binding Posts)

--- Pre-amp "CD" input from CDP1
--- Pre-amp "Aux" input from CDP2
--- CD Players both similar vintage 1992 and serial numbers within a couple thousand of one another.

CDP1 --- NAD 5425 --- standard 110V power cord to APC H10
--- 2M MIT Shotgun S2's with Adjustable Impedance Boxes with Locking RCA's from CDP1 to tube buffer
--- Musical Fidelity X-10v3 Tube Buffer with 2M MIT Shotgun S2's with Adjustable Impedance Boxes with Locking RCA's to pre-amp
--- Musical Fidelity female DIN power reseptacle connected to "Little Pinkie" 30VAC 2500mA custom power supply
--- Little Pinkie connected to APC H10 with 5' Shunyata Diamondback Platinum Power Cable

CDP2 --- NAD 5425 --- standard 110V power cord to APC H10
--- 2M MIT Shotgun S2's with Adjustable Impedance Boxes with Locking RCA's from CDP1 to tube buffer
--- Yaqin CD-1 Tube Buffer with 2M MIT Shotgun S2's with Adjustable Impedance Boxes with Locking RCA's to pre-amp
--- Yaqin CD-1 previously tested with NOS JAN Phillips 6922 Green Label and NOS Amperex (Holland) 6922 and Amperex won and will be used.
--- Yaqin CD-1 connected to APC H10 with 5' Shunyata Diamondback Platinum Power Cable

All components and connecting wires have been connected and energized long enough that I deem any synergies possible have been established.

I've found this to be an exceptionally good test bed where I can make component substitutions and immediately hear the results.

I have a few duplicate CD's that can be placed in the CD players.
The CD players are remote control, and both will work from a single remote
Pressing "Play" starts both CD players within a few milliseconds or one another, and remarkably, they are still with a fraction of a second at the end of the last tracks on the CD's
The NAD pre-amp is remote control and switch from "CD" input to "Aux" input is quiet and nearly instantaneous.
I have pre-listened to both CD players, swapping them to both pre-amp inputs, and to my ear their respective sound qualities are indistinguishable from one another.

Duplicate CD's I own in no specific order that I used for testing
Paul Simon; Graceland
Genesis; We Can't Dance
Pink Floyd; The Dark Side Of The Moon
Eric Clapton; Timepiece: The Best Of Eric Clapton
David Bowie; The Rise And Fall Of Ziggy Stardust And The Spiders From Mars

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RESULTS OF THE LISTENING TESTS USING CD Players

I conducted both long duration and short interval A/B testing (by pressing the "CD" or "Aux" buttons on the NAD remote).

I listened tube buffers OUT OF THE LOOP for 2 DAYS, and then IN THE LOOP FOR 3 DAYS.

Without the tube buffers, the sound is still very good as you would expect from a decently powered and cabled SDA system.

WITH the tube buffers in place and listening to EITHER tube buffer ...
1) The focus of the "phantom" center channel becomes "laser-like" and I literally felt the sense of sound pressure emanating from an 8" high by 20" deep X 24" wide cubbyhole in my entertainment center located at the center-line of the speakers.
2) As in the LP testing, I found the apparent location of the phantom center channel to be 3 to 4 (or even more) feet in front of the plane of the front plane of the speakers.
3) The width of the soundstage is essentially the entire 20' width and most of the 8' height of the back wall.
4) The depth of the soundstage extended from the plane of the speakers to an astonishing 12 feet out the side walls from that front plane of the speakers.
5) The overall sound quality remained very consistent, but voices, snares, instruments, are more extremely focused with what I term more "air around them"

Using an overall scale consisting of 100 points, if I were to assign the Musical Fidelity X-10v3 a "95", I would assign the Yaqin CD-1 an "88" to a "90".

Listening to all of the various types of music I had available, in each case the dimension of the soundstage thrown out by the Musical Fidelity X-10 was slightly larger. And I mean only slightly, but using the A/B ability of the remote control switch from "CD" to "Aux", it was possible to pinpoint even tiny apparent location shifts for any voice or instrument.

The size and focus of the soundstage, however, was so small that it did not account for my 5 out of 100 point difference call. The sound quality of the Musical Fidelity buffer was as best as I can describe it in words, "clearer"/"airier"/"less veiled" by a small margin, but I preferred it. This is one of those incredibly subjective calls, but at this point if I could choose only one, The Musical Fidelity X-10v3 Tube Buffer would stay.

One extremely important observation I made was that the power output LED's on the APC (which are incremented 20%, 40%, 60%, 80%, 100%, 120%) ALWAYS stayed on 20% with the Yaqin. On just a few of the most POWERFUL MUSIC PASSAGES, the Musical Fidelity would move the power usage to the 40% LED. I have to believe the Musical Fidelity was able to allow more current to pass to the drivers. The sound volume was not specifically louder, but there was an overall perceived enhanced sound quality.

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Now, as far as cost, this is an incredibly unfair test.

First, lets' be blunt, I'm using TWO $800 each (list price) Interconnect Cables & ONE $250 each (list price) power cable PER buffer to insure their top abilities (or deficiencies) are revealed.

Netting OUT the $1,850 (at retail) cable value, the delivered value of the brand new in box Yaqin ($118) plus the $100+ value Amperex vacuum tube I snagged for $20 off of eBay and the $20 value of a Herbies Ti-9 Tube Damper put the net delivered total value of the Yaqin CD-1 as tested at $158.00 USD.

Netting OUT the $1,850 (at retail) cable value, the delivered value of the vintage Musical Fidelity X-10v3 ($200) plus $219 delivered price of the brand new Little Pinkie Power Supply put the net delivered total value of the Musical Fidelity X-10v3 at $418 USD.

At least three good questions could be asked:

1) Can Greg's subjective ears be trusted to determine the two units are about 5% or so apart?
2) If the answer to Question #1 is "yes"; Would the units compare in the same way if "free" or "almost free" power cables and interconnects were used?
3) If all comparisons remain the same with lesser cabling, is it worth spending $260 more ($418 - $158) to get a 5%-7% increase in sound quality?

IMPORTANT NOTES:
-- The Musical Fidelity's wall wort power brick could probably be sold for $30 USD to reduce the price differential.
-- The Yaqin's ($158) sound quality was BETTER than the Musical Fidelity's at $200 before the upgraded Little Pinkie power supply was added.
-- There is supposedly a power supply improvement that can be made to the Yaqin by soldering a high grade 33uF ($60 for 3 X 11uf 200VDC Sonicap) electrolytic cap from the positve side of the power rail to ground. I will be performing this mod within the next 4-5 weeks and will POST AN UPDATE AS TO A/B SOUND QUALITY IMPRESSIONS.

hearingimpared wrote: »

Awesome work and very detailed write up Greg. I'm glad the tube buffers made such a dramatic difference in your rig. Much happy listening.

Joe, the day I snapped up your MF buffer turned out to be one of the best days of my audio related life. As you might have read, the power source is what unlocked its potential.

Now I'm afraid (well actually more like EXCITED ) that my future will be laden with days of shopping for, the buying of, excitedly waiting for (like Christmas morning), installation of, and tube rolling of many, many pieces of tube pre-amps and ultimately amps.