Tube tuners, who likes them?
- Thread starter maxhifi
- Start date
Scott 310E or 4310
amptramp
Well-Known Member
Last year, I picked up a Fisher KM-60 for $22,50 and this year I really splurged - a Harman Kardon Citation III-X for $40. Both were from other members of the London Vintage Radio Club where all of us have way too much equipment for the space we live in, so it is a buyer's market. I have to re-do the dial cord on the Citation but the unit appears to be complete and in good shape otherwise.
mhardy6647
Lunatic Member
310E if you can find one & justify the cost.
Best sounding tuner I've heard with my own ears (and I've heard a number of the much-hyped models).
Thanks! I'll try the LT-10 for now...can't go wrong at $80 I don't think...in good condition and fully working. I love the sound of my HK, I can't imagine it can get even better! I love the tube tuner sound!
Saw a non-working 310E in eBay completed sales went over $500! Wow!
I'll have to do some research on the various models. As of right now I have no sense of what is good/better/best. You would think a 330 would be better than 310. And the letters...higher letter = newer "revision" of the same model?
Hawkeye,
Un-renovated LT-10s go on ebay for about $50 plus shipping. I'd pay slightly more for similar 311s or 314s. An early 311 will have the better 2-piece dial knob. Renovation including caps and alignment will cost at least $125.
330 denotes AM/FM. I wouldn't buy one unless I wanted a good AM tuner.
The 310 series is the best of the Scott tubed tuners because of the more extensive IF/limiter section. The LT-110 and 350 are stereo, but don't have the good IF.
This site has some good info: http://hhscott.com/site_map.htm
Sometimes one has to go through Wayback Machine to get there. Go down to the tuner section.
Un-renovated LT-10s go on ebay for about $50 plus shipping. I'd pay slightly more for similar 311s or 314s. An early 311 will have the better 2-piece dial knob. Renovation including caps and alignment will cost at least $125.
330 denotes AM/FM. I wouldn't buy one unless I wanted a good AM tuner.
The 310 series is the best of the Scott tubed tuners because of the more extensive IF/limiter section. The LT-110 and 350 are stereo, but don't have the good IF.
This site has some good info: http://hhscott.com/site_map.htm
Sometimes one has to go through Wayback Machine to get there. Go down to the tuner section.
mhardy6647
Lunatic Member
Yeah, $80 for an LT-10 seems a little steep; I believe mine was 40 or 50 at the NEARC semi-annual antique radio fleamarket.
great scott by Mark Hardy, on Flickr
FWIW, I like the Sherwood S-2000/S-3000 family (sonically) better than any of the HH Scotts I can afford (i.e., justify purchasing).
Also FWIW, I do like the (EDIT) MR-67 (not MR-74!) I got from Barncats a tad better sonically, though, than the Sherwoods.
A tad more expensive, though.
great scott by Mark Hardy, on FlickrFWIW, I like the Sherwood S-2000/S-3000 family (sonically) better than any of the HH Scotts I can afford (i.e., justify purchasing).
Also FWIW, I do like the (EDIT) MR-67 (not MR-74!) I got from Barncats a tad better sonically, though, than the Sherwoods.
A tad more expensive, though.
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Start with a properly restored Sherwood 3000 -- abundant and inexpensive. Be sure you get a stereo unit, there are many mono ones about. The Scott 4310 is very rare; the 310E got a rave writeup in The Absolute Sound which drove prices up. I've not heard either of those Scotts, but people who have love them.
mhardy6647
Lunatic Member
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.
DSC_8058 by Mark Hardy, on Flickr
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.
DSC_8058 by Mark Hardy, on Flickr
audiodummy
Well-Known Member
I've only got one "tabletop" AM-FM Monaural (1960s era) tube radio ... so it has a tuner and amplifier.
It sounds pretty decent but I'd have to compare with silicon radios of the same size to really compare, its ~ 5" speaker is big enough to reproduce some bass. Only 4W with a 50C5 output tube. There are definitely some transistor radios that I have that sound worse...
12DT8-FM RF amplifier, mixer and local oscillator
12BE6 - AM RF amplifier, local oscillator, mixer
12BA6 #1 - 1st AM/FM IF amp
12BA6 #2 - 2nd FM IF amp (Not used for AM)
14GT8 - FM Detector and 1st stage audio preamplifier
50C5 - audio power amplifier (gets quite hot!)
I have a few spare 12BE6, 12BA6, and one 50C5; but if the 12DT8 or 14GT8 bite it, the radio's done...
It sounds pretty decent but I'd have to compare with silicon radios of the same size to really compare, its ~ 5" speaker is big enough to reproduce some bass. Only 4W with a 50C5 output tube. There are definitely some transistor radios that I have that sound worse...
12DT8-FM RF amplifier, mixer and local oscillator
12BE6 - AM RF amplifier, local oscillator, mixer
12BA6 #1 - 1st AM/FM IF amp
12BA6 #2 - 2nd FM IF amp (Not used for AM)
14GT8 - FM Detector and 1st stage audio preamplifier
50C5 - audio power amplifier (gets quite hot!)
I have a few spare 12BE6, 12BA6, and one 50C5; but if the 12DT8 or 14GT8 bite it, the radio's done...
c.coyle
Fighting the Dunning-Kruger effect.
Would anyone here argue that tube tuners are superior to solid state anywhere other than in the audio stages?
c.coyle
Fighting the Dunning-Kruger effect.
I am pretty sure that I had a Sherwood mono tuner, with a gorgeous magic eye, very similar to the two in the picture, when I was in grad school in the late '70s. Unfortunately, I didn't realize what I had, and just left it when I moved out of the apartment.
amptramp
Well-Known Member
Quite a few early transistor tuners had poor RF intermodulation and spurious response characteristics due to the emitter - base junction of the bipolar RF stage acting as a mixer for incoming signals. I forget the manufacturer, but one English manufacturer made a tuner with all transistors except for a tube RF stage, just to avoid this. Modern JFET and MOSFET RF stages do not have the same problems and some designs used bipolar transistors with forward AGC to get the base - emitter junction so far into forward bias that the diode effect disappeared. With forward AGC, the stage is biased in the opposite direction of normal AGC with the extra current used to reduce the collector voltage and input impedance of the stage and therefore the gain.
Tube IF stages have a relatively small grid-to-plate capacitance that does not vary all that much with operating point meaning that regeneration is better controlled. Transistor stages often have to be neutralized.
Tube rectifiers do not have the reverse recovery problem of ordinary solid-state diodes that can only be fixed by going to Schottky or fast recovery diodes. This problem causes a pulse in the 27 to 35 MHz range and its third harmonic can be in the FM band.
audiodummy
Well-Known Member
Incidentally that 60s tube radio I have uses silicon diodes for:
1. AM demodulation.
2. Power supply.
3. It has a varactor diode for FM automatic frequency control... speaking of which, I suspect modern PLL frequency control will outperform any older forms of frequency control on tube sets, etc. - or does it?
1. AM demodulation.
2. Power supply.
3. It has a varactor diode for FM automatic frequency control... speaking of which, I suspect modern PLL frequency control will outperform any older forms of frequency control on tube sets, etc. - or does it?
One general superior technology for sound quality is that tube tuners use coil IF filters. Most solid state tuners use ceramic IF filters but those SS tuner that use coils generally have better sound quality.
Exceptions abound, of course, and other parts of the design also have affects.
But when I want the best sound quality from an FM tuner, I see coil IF coils as a clue.
Exceptions abound, of course, and other parts of the design also have affects.
But when I want the best sound quality from an FM tuner, I see coil IF coils as a clue.
I'd put my Si4735-C40 all digital tuner up against any tuner. Yes a cheap $10 chip will outperform ~95% of what has been designed previously. I do not have a tube tuner to compare against, but I do have Crown 1,2, Pioneer QX-9900, SX-1050, Sansui G-7500, Kenwood KT-8300 as a comparison.
The KT-8300 does sound nice in wide band mode if the adjacent/alternate carriers are not there or very weak. I do measure a very low THD, but it underperforms if there is a congested spectrum. It will need a IF filter mode to see if I can improve its IF rejection characteristics.
These old tuners have a hard time with adjacent channel interference, esp the ones with L/C tuned IF's where the bandwidth is too large to reject adjacent carriers.
audiodummy
Well-Known Member
That seems to be true that non PLL vs PLL (FM) tuners behave significantly different. My PLL tuners you have to be pretty spot on to tune to the right station and it's pretty accurate. The non PLL tuners have a bit of slop on both sides of the frequency, and you still have to tune carefully to get noise free operation.
All digital tuners are PLL tuners, though I suspect indeed the filtering and IF stages are different .
---
I just checked out FM on my tube radio as I've really only listened to AM with it. Tuning is a bit dicey with it, and selectivity between two adjacent stations (200KHz apart) is tricky, similar to my SS non-PLL FM tuner. Note that since this is a "cheap" tabletop unit, the tuner pointer string is pretty crappy (no large weighted knob, etc.); comparing it to my Heathkit (SS/AFC) and Hitachi (SS/PLL) tuners with their tuner pointer strings.
All in all, I think I prefer the frequency lock of PLL tuners, analog or digital.
All digital tuners are PLL tuners, though I suspect indeed the filtering and IF stages are different .
---
I just checked out FM on my tube radio as I've really only listened to AM with it. Tuning is a bit dicey with it, and selectivity between two adjacent stations (200KHz apart) is tricky, similar to my SS non-PLL FM tuner. Note that since this is a "cheap" tabletop unit, the tuner pointer string is pretty crappy (no large weighted knob, etc.); comparing it to my Heathkit (SS/AFC) and Hitachi (SS/PLL) tuners with their tuner pointer strings.
All in all, I think I prefer the frequency lock of PLL tuners, analog or digital.
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You seem to be confused about the application of a PLL. There are 3 possibilities areas in a FM tuner, to use a PLL type of ckt.
1. A PLL to generate the local oscillator( LO). They call this a voltage controlled oscillator (VCO). It uses a varactor diode to replace the mechanical variable cap.
2. A PLL to recover the audio from the IF.
3. A PLL to lock onto the 19kHz pilot tone in order to generate the 38kHz switching signal for the stereo multiplex decoder.
When I refer to an all digital tuner, such as a Si4735, it is a DSP based tuner, tuning, filtering, decoding is all done digitally with a dedicated processor such as a DSP. With a DSP you can make a filter with extremely steep response that is near impossible to accomplish with traditional analog techniques. the processor is smart enough to figure out that there is adjacent carriers and adjust the filter response in order to best reject the adj carriers.
Take some time and read up on the Si4735
http://www.silabs.com/documents/public/data-shorts/Si4734-35-short.pdf
1. A PLL to generate the local oscillator( LO). They call this a voltage controlled oscillator (VCO). It uses a varactor diode to replace the mechanical variable cap.
2. A PLL to recover the audio from the IF.
3. A PLL to lock onto the 19kHz pilot tone in order to generate the 38kHz switching signal for the stereo multiplex decoder.
When I refer to an all digital tuner, such as a Si4735, it is a DSP based tuner, tuning, filtering, decoding is all done digitally with a dedicated processor such as a DSP. With a DSP you can make a filter with extremely steep response that is near impossible to accomplish with traditional analog techniques. the processor is smart enough to figure out that there is adjacent carriers and adjust the filter response in order to best reject the adj carriers.
Take some time and read up on the Si4735
http://www.silabs.com/documents/public/data-shorts/Si4734-35-short.pdf
audiodummy
Well-Known Member
I specifically meant the use of the PLL for LO synthesis via VCO. The FM and multiplex detectors were something else I was ignoring. However even the Si4735 still uses the same techniques for synthesizing the LO via a VCO/PLL (the "sine wave" block), mixed with the incoming signal (the "X" blocks) to get the IF. The DSP works on the IF and indeed is another way to do detection.
The key point that was missed is that there's not enough tubes or even discrete transistors in a small receiver to make a PLL so they necessarily don't have them, and won't have as sharp frequency lock. An IC is required.
The key point that was missed is that there's not enough tubes or even discrete transistors in a small receiver to make a PLL so they necessarily don't have them, and won't have as sharp frequency lock. An IC is required.
