Tuner Experts, Your Thoughts, Do Analog Tuners sound better than Digitally Synthesized?

lojyo610

lojyo610

Active Member
Hello Tuner Fans:

I was recently gifted a Luxman T-450 analog tuner from 1982.
I know this is a mid-level tuner form the Alpine-era of Luxman, but holy poop, does it sound good. I did hook it up using slightly upgraded interconnects and a decent amplified indoor antenna.
Having recently owned a few okay digitally synthesized tuners, i was surprised at how much better this tuner sounded, to me. Could it be the the nostalgia factor or the sleek Euro inspired esthetics?
Can anyone out there provide any info as to why an analog tuner would sound better than a digitally synthesized one?
 
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I did a Techie no-no and just hooked it up without pre-testing or inspection. Can a non-tech-type like me determine if it's aligned, other than comparing where the indicator falls, relative to the known frequency of the station?
 
Lots of factors to consider when it comes to sound. I personally prefer analog tuners and those with LC IF filters over those with ceramic filters. There are digital tuners out there that sound fantastic, others not so much. Even those digital tuners that sound good. I don't like using them. I like the tactile feel of analog tuning verse press and up down button. Most look pretty boring also.
 
One difference might be the oscillator phase noise which can manifest itself as noise in an otherwise strong signal that should result in full FM quieting. A L/C (analog) oscillator generally has less phase noise than a synthesized oscillator. Depends largely on the design of the synthesizer; the ones I've seen in consumer-grade tuners do not pay close attention to minimization of phase noise.

There are also analog tuners that use a variable resistor with a varicap diode for tuning, and they can be susceptible to phase noise. The McIntosh MR80 is one example of this design, although the example I have doesn't seem to have a noticeable phase noise issue.

I have a Watkins-Johnson WJ8618 professional-grade 2-1200 MHz receiver that doesn't exhibit any noise on strong FM signals. Of course the synthesizer was very carefully designed to minimize LO phase noise - and was priced accordingly.
 
Without instruction and the other Stuff you need, you're akin to riding blind on pot hole infested road... good luck. pc
 
FYI they are not all alike.
Inabout 1985 Yamaha engineers must have had the same thoughts about pll noise and worked with Sanyo to design the lc7220 part that Yamaha taughted as their afc servo tuning system (csl) to solve that problem.
When I listen too a station and compare the difference between pll and afc tuning mode, I can’t hear any difference :)
Also in that same timeframe yamaha figured out that you could combine L/C and ceramic filters to create a low group delay IF filter with the best of both worlds.
Very few designs used balanced mixers. The cheaper units used bjts, more expensive used dual gate mosfets.
Some never even bothered with any rf agc. So much for mixer overload.
Now we have issues with iboc noise using switching type stereo decoders. well aren’t we lucky that Yamaha figured out a sine wave product detector type of decoder that solves that problem too. Imagine that they solved a problem before they even knew one existed :)
That’s why I like the T-85 design, try one out and let me know what you think. I do not think the bean counters had much say in that design:) Some might think of its packaging as the bpc era but it’s only the skin. Turn the lights out, listen to the tunes, the deep red LEDs aren’t too hard on the eyes.
 
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rcs16 said:
That’s why I like the T-85 design, try one out and let me know what you think. I do not think the bean counters had much say in that design:) Some might think of its packaging as the bpc era but it’s only the skin. Turn the lights out, listen to the tunes, the deep red LEDs aren’t too hard on the eyes.
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TX-1000/2000 share much of same design as the T-85. With some updated electronics and bit of cost saving from the bean counters. Still great tuner. Worth seeking out if you admire the T-85.
 
I took a peek at the T85 service manual, and it doesn't have the schematic for the front end which would include the FM LO. While the dual mode straight synth/AFT capability is innovative and effective,I don't see the IC7219 per se as having a great positive impact on the LO phase noise. LO phase noise depends greatly on the power filtering of the tuning voltage going to the VCO and the PLL design. More importantly, if the phase noise of the reference oscillator is poor, the phase noise of the entire system will suffer. In this case we have an on-board 32KHz crystal oscillator. A more robust design would have a separate reference oscillator having well-filtered power, and at a much higher frequency which is then divided down. Simply, as the ref frequency is divided down, its phase noise decreases.

Since the T85 service manual on hifiengine doesn't have the front end schematic, I took a look at the T-80 service manual, and I'll presume that the front end designs are similar. Here too I don't see great care in reducing oscillator phase noise. THe board isn't even shielded, the tuning voltage shares a ribbon cable with a bunch of other signals, and it appears the loop bandwidth is reduced when in AFT mode by switching in a few capacitors off the tuning voltage via a transistor. Any noise on that transistor will be transferred to the VCO. Also, the power filtering of the VCO is a bit indifferent - a more robust design would have L/C filtering of the power and tuning voltage.

All that said, it's likely considerably better than most consumer grade tuners, but I wouldn't hold it up as an exemplar of superb synthesizer design. All of the things I noted above would cost money and likely price this already expensive and feature-laden tuner into the McIntosh price range
 
I'll post the schematic of the T-85 front-end RF section for your reference. They use a cap multiplier, Q108, for extra supply filtering.
The T-85 has an outstanding mono S/N of -98dB and in stereo its -90dB, pretty damn good for something suspected of having a high phase noise VCO.
A correction the Sanyo custom part is a LC7210. I just need to decode the Japanese spec I finally found.
As you say the bottom line is that 'All that said, it's likely considerably better than most consumer grade tuners"
I recall one time having to measure phase noise on a HP 8640B RF SG, a fun exercise as a green tech.

Looking at the TX-1000/2000 design, I see where the Yamaha's bean counters might have had their say, they scaled back the RF FE, the balanced mixer was removed, no bypass of the first RF gain stage, I assume to fund the dual antenna.
The active filters on the O/P must have been a cheaper option than the L/C filters used in the T-85. I am fine with the T-85, see no need for a TX-1000/2000, the remote control is a nice addition however. I am not a fan of VFD displays, they tend to dim out with time.

Enjoy your FM

Rick
 

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THe LO seems to be almost identical to the T80. I didn't say that it certainly had high phase noise, I've never measured it, but looking at the design I stand by my statement that it is most certainly not an example of superb synthesizer design. Generally though, I would say in terms of consumer grade audio equipment, *most* L/C LOs will have better phase noise than *most* synthesized LOs. THat's certainly not a hard and fast rule.

One way to find out if the synth contributes to listenability is to shoot a signal from a 8640B or similar low-phase noise sig gen at 10.7 directly into the IF, then do the same at 100 Mhz into the front end and compare.

In any event, all of this is kind of a moot point since OTA sound quality from many FM stations is sorely lacking. No more on-site engineers keeping an eye on things, general managers wanting to sound "loud", poor source quality, poor STL links, IBOC, and that damn annoying Arbitron or Neilson data stream that makes everything sound metallic result in ever-decreasing listenership. Or so it seems to me.
 
Are we answering the original ? sufficiently :)
I guess I am debating the merits of a high quality digitally tuned radio vs the ole mechanical marvel that just oxidizes away before your eyes :)
40+ years are tough on mechanical tuners, I do not really trust them.
yamaha did practice a lot of design reuse, compared to Pioneer per se.
... If I had a 8640B but I ain't getting one. repairing a few of them once upon a time is enough of that model for a lifetime :)
back in the day they used a 8642? to replace the older 8640B
soory not going to chase that phase noise measurement. I have a 8901A and a 11715A however
Would have thought that the -98dB S/N spec would infer a very low phase noise VCO, well at least the audio frequency spectrum of that noise, where it really matters.
We're lucky in that I normally listen to a very small station, CFGI that does their own thing. They purposely under-modulate for what I think is pretty good fidelity.
usually have to contend more with interfering stations 50+ miles away, that and the atmosphere that does weird thing
I fix the transmitter for CFGI, I was surprised to learn that it was built and designed in Canada, its a Nautel VS1, well designed unit, the SMPS died, easy fix.
They forgot to clean the filter was the root cause.

Good discussion hoping its entertaining to the tuner crowd
cheers
 

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Kind of skeptical of the 90 dB S/N spec after seeing that the claimed distortion spec for the T-85 is 0.03%, yet the service manual calls for 0.2% in the alignment. No S/N spec called for in the alignment procedure. Possible that their claim of 90 dB S/N occurs in the narrow IF bandwidth position, where stereo distortion increases to 3%. I dunno.... manufacturer specs are often pretty dubious.

Anyhow, all of this is conjecture and may or may not be a factor in the sound of a synthesized tuner vs a L/C tuner.

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I guess I need to do some tests. A member here and on fmtuner forum has recently performed some of these thd measurements on the t-85, confirming the specs. I think the table in the adj procedure you highlight is in error.
Sony made some good performers as well but I have never tried any of them out.
 
lojyo610 said:
Can anyone out there provide any info as to why an analog tuner would sound better than a digitally synthesized one?
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Do you like the sound? That's all that really matters and everyone's opinion is going to be just that: opinion. Have you done a side-by-side comparison? That's the only way you're going to tell if it sounds as "good" as a digitally synthesized one. Sound is science, but listening is purely subjective.
 
How ironic I’m about to leave to go pick up an analog tuner to replace my digital one.

An analog dial is infinitely adjustable where as a digital momentary switch is not. That switch says nothing about the tuner frequency “locking” system but I do believe some analog tuners can outperform most digital ones.
 
PioneerFreq said:
How ironic I’m about to leave to go pick up an analog tuner to replace my digital one.
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I'll take an analog tuner over digital most of the time. In fact, I can't think of an instance where I'd take digital over an analog tuner unless the analog tuner is utter garbage.
 
w3jn said:
yet the service manual calls for 0.2% in the alignment
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While in the same manual listed spec for super wide mono 1Khz is .02%. Which is technically less than .2%. The alignment say < .2%. I will confirm personally have measured .02% on the T-85.

Alignments procedures rarely mention actually measurement values. You use the listed specs as a guideline.
 
My good AM/FM, portable, C.Crane EP-Pro is digitally tuned but has a "fake" linear display like the old radios. While you can "dial-in" the pointer, it has to be precisely placed to properly lock-in the station, unlike real analog which allows some off-center slop.

Although I like the radio for its good sound and other features, this seems to be the worst of both worlds as the "analog" display lacks enough detail for repeatable tuning. A rotary dial with digital read-out seems to offer quicker tuning with an accurate frequency display.
 
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