I want to share a very interesting experience I've had with 'Dottore Walkman', probably the best walkman technician in the world, if not the best one. I knew about him in Stereo2Go forums more than a year ago and I contacted him for doing some adjustments on my best units: SONY D6C and DD9.

The SONY D6C is widely known for being the most precise and high performance walkman ever made. It's playing and -specially- recording quality is simply outstanding, and not similar to other walkmans, but to HIFI equipment. In fact, some magazines state after reviewing it that its performance is much better than many HIFI decks.

I wanted to send him my D6C for doing a complete test, manteinance and calibration for my tapes (Maxell XLII-S), so I wanted to do good quality recordings. I knew that I can buy a top-quality tape deck (like a Nakamichi) but I prefer to have a small unit like a D6C, knowing that it offers a quality that rivals with the best decks.

My SONY D6C, one year ago.

Dottore told me that very high quality can be obtained from the D6C by adjusting bias for calibrating for my tapes. I had to decide whether I choose to calibrate to metal or chrome tapes. I choosed chrome ones, because Metal are so rare to find and expensive, and chrome ones are more widely available, and the prices are better. Dr Walkman told me that the quality achieved with a good chrome tape can be very close to metal tapes, so I prefer to keep with chrome.

I read about the quality of the Maxell XLII-S and Dr. Walkman told that there were another tapes that have similar quality and bias, like the TDK SA or the SONY UX-Pro. Finally we decided that he will calibrate it to the best one: the SONY UX-Pro, knowing that it will work perfectly also on the other ones.

Maxell XLII-S, avery good chrome tape.	TDK SA60	SONY UX-Pro, one of the best chrome tapes.

But a bit later he told me he can do a much better job: he can perform a special upgrade and build a 'super D6C' by selecting parts that he can pick up from other D6C units, do change some components for better ones and calibrate for my tapes. He explained that I have to buy another unit with a serial number carefully selected so he can extract some parts. And I did. In fact, I bought two units more, so I finally sent him my three D6C, so he could pick up the best parts of everyone to build a super-D6C.

When I bought the first one and tested it I was suprised about how good it sounds for me, much better than any other unit I have in my collection. In fact, I was really impressed by its quality, much better than any other I ever listened to (I have to confess that I never had a top-quality tape deck at home, except my ONKYO hifi system which has Dolby B-C-HX Pro, but lacks manual record level or bias.When I was younger I use to record tapes with my boombox, my loved AIWA CSD-SR6, which has a good head, feather-touch buttons, CD and Dolby B. But the quality of the recordings were not so good, and I alreay knew since many years...

My loved AIWA CSD-SR6, that accompanied me for so many years.
It sounds great, but the recording quality was not so good.

so it's time to discover what a good tape inside and excellent deck can offer.

What did Dr. Walkman perform?

So what he did was:

With all that he built a top-level unit, indeed, but he needed to take a lot of time for that (because of some personal reasons). This artisan of the walkmans has really done and impressive work. I can not recommend enough him for repairing walkmans. He is a truly precise artisan of walkmans!

Here there are my three D6C units being dissasembled.

Finally, after a long wait, I received on march 2012 my 'Super D6C' and started to record and do listening tests. Be in mind that I didn't listened to an excellent recording or a top-level tape deck before, so I don't know which level of quality and fidelity can be achieved with tape.
But I have some excellent headphones (Sennheiser HD280 Pro reference studio, Grado SR325i, SONY CD3000) and I normally listen to (high quality digital) music in my computer, using an excellent sound card, the Creative X-Fi Elite Pro, (which features an 'advanced multi-bit Delta-sigma DAC' and has about 120dB of dynamic range and -110dB total distortion+noise, so it's a very high quality circuitry). Thanks to it I have to say that I know how does it sound a high quality music, but I don't know how a good tape compares to it.

My Grado SR325 headphones, that I bought following recommendations by Dr. Walkman.
And I'm not disappointed at all; they sound like being in heaven. However, this cans are very sensitive and
every small imperfection in the sound is clearly perceived. So they are better suited for digital sound.
But my 'Super-D6C' can handle them pretty well. I don't believe there so many decks that can do this actually.

The first thing I noticed was that the speed stability (wow&flutter) is absolutely excellent, and there are inexistent small duration problems while playing tapes. I mean: normally when I played tapes on good walkmans, I always found that randomly appear small (very short duration) problems that seems like it there were a small dust on the tape or on the head when recording (I know that this is probably not true, but it's my way to explain it). Probably has more related to non uniform tape transport or small irregularities on the capstan and roller.

With the super D6C they are simply inexistent. But they were present in it before I sent the unit to Dottore Walkman.

My latest jewel: the 'super D6C' by Doctor Walkman.

I asked him to send me his signature on a paper and I managed to scan it and stamp in the image, with his permission ;-)

The second thing I noticed is the excellent response to the whole spectrum. For doing that, I recorded (without dolby at all) in a clean Maxell XLII-S 'Come rain or come shine' from 'riding with the king' album, by Eric Clapton and BB King, which has a powerful bass, good voice and precise guitars. I was simply blowed out when I listened to it. the most impressive thing was the clear and powerful bass and the open sound (remember that the D6C hasn't any eq adjust or preset). It's clearly way ahead the response that it had before I sent him. I'm pretty sure that sounds clearly ahead than an iPod, in terms of equalization. The sound is open, very well balanced, stable and clean.

Another thing I noticed and surprised me a lot is that if you play with Dolby C a record that wasn't recorded with it, the sound is horrible: strongly cut highs and very poor performance.

But (here comes the magic) if I record WITH Dolby C ON and then play with it ON, the result is simply AWESOME! The sound clarity is almost identical (or even better) than playing without dolby and the highs aren't cut at all. More on, the backgound noise is really low (I measured 14dB of difference).

Then I played this record made with Dolby C on other units of my collection, and I realized that on the AIWA PX410 (which has Dolby C too and is known for being a high quallity C circuitry) the result was awesome too. I switched ON the DSL to position 1 and I was blowed out!

But I was really surprised to discover that playing this tape on my AIWA PX505 (which has a 'standard' dolby C and normally cut the highs) does NOT cut them as I normally expected. So this superb D6C really has a Dolby C circuitry that outperforms all that I ever tested and allows to play a record on small players equipped with dolby C, even those that normally cuts the highs a lot.

With the help of Doctor Walkman and my computer equipment I could start to do some measurements and learn a lot about the real quality difference between recording and playing on many walkmans. This also can show me which quality can be achieved with a good tape and deck, so I can have a good reference point to compare with many units.

My intention is to use it to make reference recordings, so I can test the playing and recording quality with my walkmans and compare with this extraordinary unit. This will help me incorporate better measures of the sound quality of them when revieweing a model.