Alignment: is there a way to know when? Do I need one?

[lorne]

I know this a nebulous question, but perhaps some opinions in consideration of my particular case will help me to decide if I need to take my tuner to a local technician for an alignment. I did a search and could not find enough opinion.

BROADCAST SIGNALS
Here in Sendai, Japan, there are only two stations with any real power. NHK puts out 31 Kw at 82.5 Mhz. Another station — a J-pops broadcaster — puts out 23 Kw at 77.10 Mhz. A host of others put out less than 1Kw making them very localized. Over the years, no other tuner I've had ever tuned them in well enough to be very listenable. POINT: I don't need a not of discrimination. I only listen to NHK.

RECEPTION
The NHK station is very near me. I use a T-type (di-pole?) antenna that is pretty close to the optimum dimensions. The signal meter gets pegged right in the black zone, and the stereo indicator lamp is on while the dial pointer looks like 82.7 (for 82.5). I show lit lighted lamps for both Wide and Narrow bands / filters.

MAJOR CONCERN
So for me, I think the major thing is distortion and soundstage. RF'ing is not an issue. It sounds good to me, but could I be missing something?

THE TUNER
* Pioneer TX-8800 II (1977?), Japanese model in JPN bandwidth... apparently, more or less a TX-8500 II .
*I recapped it a few years ago.
* To my knowledge it has never been alighned.
*Some time ago the Stereo indicator lamp went off, but today I opened the unit up and pinch the lead wires and it came on again. (Hopefully it wasn't the the PPL thing refusing to lock.

There's not a lot of money around here at the moment ... so here I am wondering.

Thanks in advance. It's cool to know Karma members still like FM.

 

[KentTeffeteller]

In your area sensitivity is more critical than selectivity. Keep your tuner on Wide unless you have a nearby station for best Stereo performance, and least distortion. I've never seen a 1975 or later Pioneer tuner in poor alignment even now out of many which come in to the workshop, they're usually spot on. They hold their alignment very well. Your situation is interesting. Do bear in mind, FM is line of sight. A better antenna may help if available.

 

[musichal]

In your area sensitivity is more critical than selectivity. Keep your tuner on Wide unless you have a nearby station for best Stereo performance, and least distortion. I've never seen a 1975 or later Pioneer tuner in poor alignment even now out of many which come in to the workshop, they're usually spot on. They hold their alignment very well. Your situation is interesting. Do bear in mind, FM is line of sight. A better antenna may help if available.

A couple questions.

Does this tend to be also the case with Pioneer receivers' tuner sections, or is it strictly a separate tuner observation?

Do Kenwood tuners, or receivers, compare well in their stability over time?

 

[rcs16]

I think you can lump many of them together with similar issues or traits, since they use similar parts.
The tarnish in the var cap contacts may affect tuning more so than say the trimmers.
Usually you hear the tell tale signs of scratchy sound while tuning, turn muting off and have a good listen across the dial. certain areas where you do not use will show up more so.

 

[KentTeffeteller]

A couple questions.

Does this tend to be also the case with Pioneer receivers' tuner sections, or is it strictly a separate tuner observation?

Do Kenwood tuners, or receivers, compare well in their stability over time?

With Pioneers, my observations have been with receiver tuner sections and separate tuners alike. Kenwood, I have little experience with their tuners, the 3 I've deal with were separates. Switches were dirty on all 3, once cleaned, they worked very well, good Stereo separation and sensitive and good selectivity. Kenwood for me in that era is the best performing of the Japanese tuners, but they specialize in two way commercial and amateur radio gear.

 

[Blue Shadow]

. Kenwood for me in that era is the best performing of the Japanese tuners, but they specialize in two way commercial and amateur radio gear.

All that radio frequency experience made the production of simple FM and AM gear an easy project for Kenwood/Trio and they did a great job.

It is nice to see that many of the units we are throwing caps into might not need an alignment. I've had good luck with the Pioneer units I have had as far as tuners/tuner sections are concerned. Not much experience these days with the Kenwoods but I know they history.

 

[RxDx]

...
* Pioneer TX-8800 II (1977?), Japanese model in JPN bandwidth.

Description at fmtunerinfo.com makes it sound more like a 9500II- five gang tuning,
primarily. Anyway, worth asking about basics- cleaned connectors, switches, relays,
and/or bearings lately?

 

[amptramp]

Tune above and below the station of interest and if the level dies out and distortion begins at the same amount of detuning, chances are it is set up correctly. I have had some receivers where the station will peak off-frequency or have a peak that doesn't fall off when tuning above but falls off rapidly when tuning below or vice versa. The response to detuning should be symmetrical. Since there are five tuning gangs, it is possible for the RF to be off. Most of the IF selectivity comes from ceramic filters so if these are mismatched, you can only correct it by replacement.

 

[lorne]

Thanks forum mates for these answers. I am reassured in a number of ways, particularly by KentTeffeteller's comment about Pioneers being so alignment- stable.

> Your situation is interesting. Do bear in mind, FM is line of sight. A better antenna may help if available.

Japan has strictly controlled the number of licences issued for FM transmission. Years ago I read that the average is about two per prefecture. Exceptions are the mega cities such as Tokyo-to (metro Tokyo), Kanagawa (Yokohama) and Kansai (Osaka). So, yesterday I was surprised to see a Japanese web-site that listed many more broadcasters with very limited transmitting power.

> A better antenna may help if available.

Most Japanese get their TV broadcast reception via roof antennae and satellite dishes — not cable. Part of every array is an FM antenna. Years ago, I used this for my tuners. Currently our house has three rooms with a wall consent carrying signal. My room and listening space is not one of those rooms. Still, the NHK FM signal-strength meters at max. I've made 1/4 wave dipole antennas corresponding exactly to NHK's 82.5 Mhz, and I've used the ubiquitous types that generally come with a tuner, or available in the shops. I've not been impressed by a difference. There is a HAM guy up the street. Sometimes, (fortunately rarely) I think he is riding on my reception. (He has a huge antenna rig.)

> Description at fmtunerinfo.com makes it sound more like a 9500II- five gang tuning, primarily. Anyway, worth asking about basics- cleaned connectors, switches, relays,
and/or bearings lately?

Here is says 4 gangs: https://audio-database.com/PIONEER-EXCLUSIVE/tuner/tx-8800ii-e.html (For Japanese gear this beautifully presented database is an icon.)

I'd forgotten that I wrote about the 8800II back in 2014. Ironically, some of the information you got at the FM Info Centre was my contribution. And ... I made a mistake about the gang compliment. :0 As I said above, 4 not 5.

http://audiokarma.org/forums/index.php?threads/pioneer-tx-8800ii-a-japanese-domestic-tuner.616456/

I believe I did clean switches and connectors, but I hope I left everything under the V-cap shielding alone. It was a clean unit and it tunes silently. All the electrolytic caps were changed out.

Finally:
> Tune above and below the station of interest and if the level dies out and distortion begins at the same amount of detuning, chances are it is set up correctly.

Thanks! That's reassuring, I checked this out before I started the thread.

 

[Bob@FM]

Based on what you've done already, last thing to try is a cheap attenuator perhaps on the antenna input. Sometimes the older models can grossly overload the RF front end and cause distortion, especially if you are very close to a 31kW transmitter. This is especially true on models with 2 RF amps before the mixer. Most modern tuners now only use 1 RF amp, and have provisions internal to attenuate strong local signals.

Also try changing the indoor antenna location. You can remote it with 75 ohm cable. If horizontal, try vertical, then another wall, corner, ceiling, window, etc. Multipath occurs easily with indoor antenna situations and strong signals, and can also cause distortion. If there are H and V outputs, you can use those to minimize the location for multipath (google it). Many early Pioneer user manuals had this info in it as well.
Make sure you tack it up and step away when trying a different position.

The other thing I normally would suggest is to compare it to another tuner, if possible. It could be the station itself with the problem, unless that can be ruled out by others (audio guys with good tuners) local reviews.

Not sure I agree all Pioneer tuners after 1975 are "good" for alignment. And I've seen many as well.

 

[lorne]

Bob@FM wrote:

... SNIP ...If there are H and V outputs, you can use those to minimize the location for multipath (google it). Many early Pioneer user manuals had this info in it as well. ... SNIP....

Thanks Bob: after reading your reply, I consulted the TX 8500 II user manual that I found on HiFi Engine. I had always assumed that because I do not own an oscillosope that the HORIZ / VERT pins were, for me, redundant. Well, the manual says that a stereo amplifier can be used to determine optimum antenna position ... moving it around wile monitoring the sound on the right channel (VERT). Brilliant! All these years, and I never knew!