Why does the Marantz 10B Tuner sound so amazing ???

There was a really good article on the 10B several years ago in Vacuum Tube Valley. Or was it Sound practices? Higly recommended reading. Dig it up.

Aside from the exceptional tuning front-end and all-tube circuits, I think the big difference may have been the six IF stages. Yeah, six. Far more than anything else you can buy. And I believe the filters might have been phase-linear, resulting is the cleanest and most selective IF bandpass possible. Another plus was that I think they used a discriminator circuit instead of the usual FM demodulator.

So it probably isn't the front-end or the audio back-end that makes the sound so clean. I'd wager the sonics are due to the linearity and bandwidth of the IF strip and demodulator circuits.

jh

YES! Great tuner!! Magic !! I picked mine up directly in Long Island City when it was new!! I think they moved to California soon after that.

I have owned two of them in my audio lifetime and now make do with a Luxman T110. If you don't live in NYC, what good is it to have the world's finest tube tuner? Here in Washington, DC, there is one good FM station with decent quality FM music broadcasts, but that is IT for FM. This is what keeps me from buying another 10B.

The 10B, Mr 71 and Mr 67 are all wonderful and a pleasure to listen to for long periods.

If you have a few good stations in your area, any one of these
classics would fill the need quite nicely.

With the iconic 10B, however, you have an amazing midrange with a large
soundstage and layering that is hard to duplicate. The magic could be in its hand made point to point wiring, custom built power supply and dream team design it.

With a good antenna, it does things digital struggles to achieve if ever.

If you change out the optocouplers, which are available on e-bay, replace the sweet and lush 6jk6 tubes as needed they can be reliable. The alignment is very solid and rarely needs work
if they have not been absused.

Let's hope for a few more good stations.

I found this link on goggle from Pro Audio Group that summarizies why the 10B is so unique.

"The Model 10B came out in 1963. It was a no rules-money is no object project. It has an onboard CRT tube for tuning in multipath stations. There are 22 tubes total. About 5000 were built. It weighs 38 pounds and sold for about $650 back in 63. It took 3 and 1/2 years to develop and nearly bankrupted the company. The engineers, Syd Smith, Dick Sequerra (who built another killer reciever) and others worked 18 hour days and weekends.

The tuning capacitor was a Hammarlund 8 gang, silver plated, push pull design. It balances out circulating currents and minimizes cross coupling between stages. It also cuts down on common mode feedback. It is calibrated at ten different points. It is also designed to make the radio dial linear. It is the most expensive part in the tuner and you couldn't afford it today.

The IF section used 3 pole filters in six stages which were heated in an oven prior to aligning in a special jig. Torroid cores were used until they discovered that the soldering irons were magnatizing them, which changed the bandpass. They switched to pot-gapped cores later. The screws are hidden to prevent people from trying to allign the reciever themselves.

The multiplex section featured a new concept called a quasivestigal sideband system. It uses more of the lower sideband than the upper sideband by unbalancing the mix between the two over the frequency range.
and Neon lamps were used on the grids of the direct coupled vacuum tubes to prevent excess voltgae from damaging the tubes before the heaters warmed up. They also used the neon lamps to optically control swithces in the tuner, such as the Stereo/Mono switch, which gave noisless operation.

The Tuner has 108db/octave cutoff slope, making it the most selective tuner in existance."