Tube tuners, who likes them?

[KiM3Ce]

FWIW:
There is absolutely nothing wrong with listening to the mono Sherwoods -- they sound excellent.
And the price is usually very, very right.
Excellent mono, to my way of thinking, beats mediocre stereo any time.

I see original S3000 and S3000-II mono units under $100 on Ebay. The S3000-III can be confusing to buyers because they may say "stereo" on the front but lack the decoder in the back. The 3000-III underwent many model changes under that name; just be sure you understand what you are getting. All the 3000-IV and 3000-V models are stereo.

 

[rcs16]

All in all, I think I prefer the frequency lock of PLL tuners, analog or digital.

There is one disadvantage of precise tuning when it comes to a digital tuner with a PLL/VCO. If there is a strong adjacent interferer, it is sometimes advantageous to detune slightly away from centre and still have the IF within the pass band. having very narrow band IF response (selectable prefered) can also be an advantage to reject strong adj carriers and over modulators.

If you are going to have a PLL for LO synthesis via a VCO, you also need a means for the RF front end to tune to the desired signal in ?, thus varactor diodes are required in these tuned stages (instead of a manual var cap) and be connected to the DCV tuning signal from the phase comparator/LPF ckt.

 

[audiodummy]

I haven't seen adjustable IF bandwidth tuners out there, which would be even more tricky for those that have "AFC" type (or just plain LC without frequency locking) LO's. I'd think these receivers would have wider band IF pass to help out the drifting - narrow IF bandpass would just make the drift more apparent. Were there any receivers out there that had on-the-fly adjustable bandpass IF stages? That would be interesting, and it would help reject the strong nearby carrier issue at the acceptable cost of having to tweak the tuning as the temperature changes.

 

[rcs16]

Only the very high end tuners have selectable IF bandwidths. Usually fixed not sliding, only wide and narrow. Kenwood has some. I have a KT-8300 that has wide and narrow. Even the narrow setting using ceramic filters, is not narrow enough for strong adj carriers. 600T had 3 BW settings.
As for drift, that depends on how well the LO is designed against temperature related drift. Assuming the LO has no feedback to correct for drift.
Wide IF filter bandwidths are meant for stereo reception. if you use mono, you can tighten up IF BW considerably as you do not need to pass through the sideband info used for stereo decoding.

Were there any receivers out there that had on-the-fly adjustable bandpass IF stages?

The Si4735 radio I built has selectable IF bandwidths, all done in the DSP filter algorithms. You can leave it figure it out in auto mode or you can program a register to set it, from 150KHz on up. It has a digital PLL for VCO, locked to a crystal, there is no drift unless the crystal drifts.
The Si4735 also has programmable or auto stereo blending to reduce stereo noise/hiss when receiving weaker signals. Sansui had this feature in some higher end analog tuners. They took the detected signal level and used that to control a LDR which was in series with a cap across the L/R signals. It was crude and the filter slope was fixed. In the SI4735 the blend amount/filter slope are adjustable, can be set manually or auto, determined by the S/N ratio and/or Rx sig level. very sophisticated by comparison.

 

[amptramp]

There was a tube tuner with a unique form of variable bandwidth. The Knight-Kit 83 YX 732 had a circuit called DSR (Dynamic Sideband Regulation) that took an AC-coupled output from the detector and fed it back into the AFC tube. The feedback is linear with capacitance vs. voltage so it is not linear with frequency, but it reduced the measured distortion to 0.35% harmonic and 0.29% intermodulation, close to the best of its contemporaries. I like circuit designs where intelligent outside-the-box thinking and a few passive parts gives an impressive improvement in performance. This tuner could switch DSR and AFC separately. The effect of DSR was to give the effect of a wider IF stage when it was on.

 

[markkb]

Lavane, that custom Dynaco FM3 faceplate looks cool!
Here's my MR67, run through a Citation 1. The MR67 opened my ears to tube tuners, it's the best sounding tuner I have.

 

[Patrice B]

Lavane, my Dynaco FM-3 has the same black faceplate ... and also black knobs. Classy! And even if I often read that FM-3 was so-so, my poor ears are really satisfied. Quite the contrary with a (now sitting on a shelf) Sherwood S7700-III receiver. I know mhardy6647 praises for Sherwood but this one has too much problems and serious rework needed to be able to compete...

 

[macgolf]

Philco RT-400 Stereo Simulcast Tuner - don't have an MPX module

Pilot 500 Pre/tuner I do have the optional MPX

Wells-Gardner WG-2820A Receiver - Don't have an MPX


Still working on getting the Philco to pick up more than local AM. Yes I like my tube tuners.

Mark

 

[radioactive]

Tube tuners,S.S tuners old tube type communication i.e shortwave receivers i love them all and my basement shows it.Amplifiers, preamplifiers,etc.. come and go but i hardly ever sell a tuner.ive always liked to have matching gear but unlike many people i started with buying a tuner first and if i liked it id go afer the maching amp and preamp or integrated.

 

[Drummerboy2]

I'm a big fan of tube tuners. The best sound quality was the Scott 310E but I sold it for my daughter's college tuition. After that the McIntosh MR71 and Sherlock S3000v. The Fisher KM60 was Ok but has me wanting the FM200b. My new apartment is much smaller than my garage in California so I'll have to be more judicious in my purchasing.

For a well-engineered FM station with a strong signal, a tube tuner brings a lot of listening satisfaction.

I have a Fisher KM-60 that I had Mike Zuccaro aligned and it was very nice sounding in stock form. I then upgraded the output caps, resistors, and put in a new Tung-Sol 12ax7 output tube. This is awesome sounding now with scary soundstage and depth. As of right now, it's the best sounding tuner out of all my tuners. My SUMO Charlie is a close second. The McIntosh MR-80 needs to go to Mike Z. for alignment and to find out why it stopped playing in stereo intermittently. Most likely due to the needing alignment. The MR-80 was upgraded already when I bought it. The guy I bought it from got it in as part of a big Mac purchase and didn't even know it had been upgraded with all Audio Grade Nichicon KZ, FA, FG, and high quality Low ESR caps so I made out in that part. I also need my Mitsubishi DA-F20 to be aligned, I also have upgraded it with Elna Cerafines in the power supply and Elna Silmic II for everything else.

I also Have a Fisher 200B, its a little more refined in the sound but the KM-60 is a overall better sounding. It's supposed to have been aligned but I will have to check it out since I get a smell from the tranny area which could be due to overheating or drawing too much current. My KM-60 doesn't do this. I will most like redo the power supply with new caps. The 200b does pull in distant stations a little be better than the KM-60. once I get the heat issue solved I will do the upgrades to this 200b as I did to the KM-60 and then I can compare which one is better.

 

[Patrice B]

@Drummerboy2 : I never had the opportunity to listen to the KM-60 but a good aligned and working 200B should be at least equal. But, maybe like me, you prefer a "no frills" tube tuner. I really enjoy my FM-3 as we speak right now.

 

[tonyg88]

I think both of my tuners in my magnavox console and fisher 800c sound great.

 

[Spe@kerBox]

Fisher 400 Receiver FM tuner sounds fantastic!