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Old 18th Mar 2023, 11:01 am   #1
SteveCG
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Default Technics Tuner ST-Z11L

Does anybody have the set-up (ie alignment) frequency information for the LW section of this tuner please?
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Old 18th Mar 2023, 4:07 pm   #2
Edward Huggins
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Default Re: Technics Tuner ST-Z11L

I regret I cannot advise the alignment detalls that you will need, but have just checked online for you and it is readily available.
However, I would like to offer the following.
I have usually found the LW circuitry on this generation of Receivers nothing more than a token gesture, offering very poor sound. Also because of the unit's siting, it is not always possible to "rotate" the receiver for the best signal pick up. The average LW bandwith is very poor and nowhere near as good as you might get from, say, a Grundig"Yacht Boy".
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Old 20th Mar 2023, 8:34 pm   #3
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Default Re: Technics Tuner ST-Z11L

Service Manual here.........

https://www.hifiengine.com/manual_li...s/st-z11.shtml
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Old 20th Mar 2023, 8:46 pm   #4
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Default Re: Technics Tuner ST-Z11L

Quote:
Originally Posted by Edward Huggins View Post
I regret I cannot advise the alignment detalls that you will need, but have just checked online for you and it is readily available.
However, I would like to offer the following.
I have usually found the LW circuitry on this generation of Receivers nothing more than a token gesture, offering very poor sound. Also because of the unit's siting, it is not always possible to "rotate" the receiver for the best signal pick up. The average LW bandwith is very poor and nowhere near as good as you might get from, say, a Grundig"Yacht Boy".
Agreed. Get yourself a Hacker or similar if you want LW.
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Old 22nd Mar 2023, 3:48 pm   #5
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Default Re: Technics Tuner ST-Z11L

Actually I already have the hifiengine service manual - unfortunately it only covers the ST-Z11 model which is MW/FM model only.

I've tried looking on the web for the LW alignment details information without success. Where did you find them Edward?
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Old 22nd Mar 2023, 9:21 pm   #6
Edward Huggins
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Default Re: Technics Tuner ST-Z11L

Ahh, so sorry. It was the Technics User Manual that I found. Now on now reading through it, there are no alignment details.
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Old 23rd Mar 2023, 12:38 pm   #7
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Default Re: Technics Tuner ST-Z11L

Hi Steve,

You probably do not need service data to align the LW-band.
Alignment is similar e.g. to aligning the MW-band on a capacitvely tuned receiver.
First you need to locate the LW antenna coil, it is probably on the same ferrite bar as the MW antenna coil.
You need to locate the LW oscillator coil, you also need to locate the trimmer capacitors of the LW oscillator and and antenna circuits that are switched in with the LW-band.
Hopefully you have those controls too, but there is a possibility that those trimmers do not exists for the LW band.
You need to trace out those components from your actual receiver.

Assuming the AM IF is aligned correctly first you set the local oscillator to follow the LW band.
You start at the low end of the band as you radio is tuned by a variable capacitor.
Set your signal generator to the low end of the band, tune your radio to the low end, then align the oscillator coil for maximum output. (use AM modulated signal from you signal gen and monitor the audio output at your speaker.)
Then set your signal gen to the high end of the band, the radio too, and with the oscillator trimmer cap find the max audio output. Repeat these steps a few times.
Next you align the tracking, the antenna circuits.
Alignment is similar, except you use frequencies about 10% higher and lower from the ends of the LW-band, this gives better tracking.
Set you signal generator 10% higher than the low end of the band, find the signal by tuning your radio, then max the output by aligning the antenna coil.
Next do the same thing towards the end of the LW-band, this time adjusting the trimmer capacitor of the antenna circuit. Again repeat this a couple of times.

There is also a chance that your radio does not have the trimmer capacitors for the LW-band. In this case you can just "center" the receiving band by adjusting first the oscillator coil, then maximizing the reception with adjusting the antenna coil.
The LW-band spread will be whatever the components give, probably not totally accurate. Similarly the tracking will also be "sub-optimal" by centering it. You would have to play with it to find the optimal adjustments.

Hope it helps, Peter
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Old 24th Mar 2023, 11:52 am   #8
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Default Re: Technics Tuner ST-Z11L

Thank you orbanp1 for your tips. As it happens I have the service information for the ST-8011 (a similar model) as well as the ST-Z11 (These are the AM only versions, with the service info provided by a USA contributor to HiFiengine). I also have the circuit diagram information for the ST-Z11L and also the ST-8011L. From these I have pieced together what I need to do - the only thing I am missing is what the low-end and high-end alignment frequencies are for the LW. I'm guessing that 160 Kc/s and 310 Kc/s respectively will be good enough in the absence of manufacturer's figures.

Incidentally, the service information for both the ST-8011 and the ST-Z11 gives the IF frequency to be 450 Kc/s whereas I've established that it is 470 Kc/s in these 'L' models. Also the MW alignment needs to be done before the LW alignment as the LW is only a 'correction' to the MW set-up.
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Old 25th Mar 2023, 10:59 am   #9
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Default Re: Technics Tuner ST-Z11L

Thinking on orbanp1's tip of a frequency choice of 10% from the end of the band, I eventually opted for 160 Kc/s and 330 Kc/s. Not that there is much there at the top end of the band - although I was getting a weak repeated Morse message - presumably an aeronautical beacon - at about 331 Kc/s?
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Old 1st Apr 2023, 10:40 am   #10
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Default Re: Technics Tuner ST-Z11L

Quote:
Originally Posted by SteveCG View Post
although I was getting a weak repeated Morse message - presumably an aeronautical beacon - at about 331 Kc/s?
The morse characters are CAM. Cambridge?
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Old 4th Apr 2023, 10:50 am   #11
SteveCG
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Default Re: Technics Tuner ST-Z11L

Ah, I'm no good with Morse. However from checking the direction I wonder if this is coming from the Gloucestershire part of the world?
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Old 18th Apr 2023, 11:13 am   #12
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Default Re: Technics Tuner ST-Z11L

As part of a general alignment performance check I've been using this tuner on all of its bands.

Given its 'simple' AM circuitry it seems to perform well on both MW and LW. For instance I can receive Polish Radio on 225 Kc/s without Droitwich 198 getting in the way (this is unlike some of my other radios that use LC IF stages). And for MW both Punjab Radio on 558 and Radio Caroline on 648 are useable (in the day-time).

On FM the narrow band IF option works a treat for me - I can resolve Tacolneston (91.9) between a decidedly stronger Oxford (91.7) and Wenvoe (92.1) which I cannot do with the normal wide IF setting.

Although the tuner is not a 'special' high performance one - like the NAD 4300 - or even the NAD 414 with its FM narrow IF option., I wonder how well it stacks up against the decidedly more expensive rivals? Perhaps some of the Tuner Gurus on this site can opine please.
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