Sound Technology ST1000A - Aligning a Pioneer SX-780 FM Section

[@markanderson350]

Very specialized equipment for the most common application of radio technology, the FM radio. It always amazes me that something invented over 60 years ago is still so well loved and used. Much talk of digital but analogue still lives on.

[@johnsalas8155]

Thank you so much for taking the time . I also have a ST1000a. Watching this helps more than reading endlessly about this model.

[@dtvdave1]

Something to keep in mind about receiver distortion measurements: back when the FCC required testing and documentation of station audio performance, the maximum distortion allowed (between 100Hz and 7500 Hz) was 2.5%. We always shot for no more than 2% across all audio frequencies. The performance of receivers of this era was an order of magnitude better than transmission systems of the time.

[@harveyparent4822]

Excellent video Tony. I just recently bought a 1000A and learned a lot from your video demonstration. My job for the past 40 years has been maintaining high power FM transmitters, up to 100Kw but did not get involved in the receiving end. I"m looking forward to using my 1000A soon. Thanks for the video!

[@thornev]

Excellent training video, Sir. I've been restoring tube amps for 2 years now and the 1000A was daunting with the complicated Fisher 500-C instructions. I wrote out all the steps you demonstrate and I'm confident I can do this to get my 500-C sounding its FM best. Thank you !

[@buffdriver62]

Thanks, Tony. I really enjoyed the video. I have a ST-1000A and appreciated your experience and perspective as you applied it to the task at hand. Like you, I prefer to use an HP digital signal generator, and I inject a multiplexed signal from the ST1000A into the HP just as you described. The thing that I like about the dual sweep method is how easily it attaches compared with trying to couple a traditional signal generator to a point inside the receiver. At any rate, thanks for taking the time to document some of the techniques used with the ST-1000A.

[@dell177]

Thanks for the hands on walk through! I picked up a 1000a a while back (it was not cheap but is in good shape and was just serviced and aligned) I'm impressed at how well this works for FM alignment. All I had before was an ancient EICO 368 that was pretty much by guess and by golly, The newer digital equivalents are more accurate but they are also more expensive and good luck fixing one if it needs service.

[@bostonaudi]

I’ve got one of these myself, it’s a great tool for quick analysis and alignment of vintage tuners. Thankfully I’ve also got the Model 100. On the note of using it with newer synthesized tuners, you can use a newer tuner to get an idea how close the RF output frequency dial really is, and mine is pretty much spot on. Thanks for the video on this vintage gear!

[@barryg41]

Thanks Tony! Learned quite a few new things doing alignments.

[@FreqBand]

I bought an unworking 1000a. Needed fresh psu caps, and a cal (as best I could). Added the low-distortion mod, and added option M1. Aligned my Luxman tuner...Yay. However, I could not get the "dual sweep" pattern on any of my scopes.

[@rrangana11]

Thanks for this excellent Tutorial video on using ST1000A.

[@GeorgeEI7KO]

Great video Tony. Thank you for that.

[@xray111xxx]

Excellent I have been wanting to see how you do this Tony. Love your videos Tony.

[@1941lynnslb]

Excellent video. We used ST instruments when we worked at a high end audio store. One note on adjusting for maximum separation use the vtvm to monitor the channel that is off, and lower the meter scale, to get a reading and adjust for minimum deflection. Use same method for the other channel. Would you believe we have seen 40db of separation at 10khz on some excellent tuners. If a multiplex circuit isn't aligned properly they obviously won't be as clean sounding. BTW the distortion will be a lot less. Thanks for reading.

[@geirendre]

I really envy you all the great test equipment you have. I'm trying to build up a hobby lab on a budget, but it's not easy. Some of the units I want aren't exactly budget friendly. A decent AM/FM test generator for instance to align old radios.

[@gearheadted9210]

done a lot of car alignments,not a radio alignment lol but learning,thanks man!

[@mdzacharias]

I know this is over a year late, but for future reference, you can set the filter on the Keithley 2015 to slow down the reading and smooth it out so that when adjusting the distortion you can really find the bottom reading easily.

[@RapperBC]

I actually have one of these, and haven't seen any videos on it. Thank you for making this one. if you'd care to make a video of it, I'd love to see the modification for lower THD, as well as see a calibration of the ST1000A. My frequency scale is definitely a bit off.

[@mdzacharias]

I know I'm a year late, but I use the filter function on my Keithley 2015 to reduce the digits jumping around. Helps get an easier to read THD.

[@johnsellers8555]

Hey Tony. In dual sweep the scope should be in XY mode. The note at time 8:55 isn't correct. If you use the ST1000a horizontal out just to trigger the scope (non XY) then you can get weird displays and repeating sweeps that bleed into one another - play with the scope's time domain and receiver tuning to see this. The scope can't be used to properly tune the receiver to the ST1000a signal. Also, the ST1000a phase control can't be correctly adjusted. When you use XY, then only 1 sweep will appear, you can tune the receiver by watching the scope and centering the potato between the goalposts (technical terms), and the phase control can be dialed in. The manual could be written better to make this clear.

[@xraytonyb]

Thanks for the info! I'll be sure to look into it more, the next time I use it. I had a really hard time with X-Y mode when using dual-sweep mode. Thanks again for the advice and thanks for watching!

[@califunkin]

Thank you so much, been waiting for someone to do a video like this. You just got a new subscriber, Cheers from California.

[@robertcalkjr.8325]

Thanks Tony. Because of the copywrite crap I don't even listen to the radio anymore or buy any CD's or anything.

[@walterramjet]

Great info and presentation. I am just now admiring your B&K Precision 177 analog meter. How do you get it to read micro-volts? does it have something to do with the probe?

[@DAVIDGREGORYKERR]

I suspect that a lot of new radios will use DSP chips and high school Maths to do the signal processing E.G. AM uses sqrt((i^2)+(q^2)); FM will use the atan(x) in conjunction with some pre-processing to recover the audio from the FM signal.

[@kathnrich1]

Great tutorial,, you know your shit brother!!

[@user-xc9ck5gr5i]

Low power FM transmitter using EXT audio, too ;)

[@williamsquires3070]

Hi! I have a few questions. 1) is that unit tube, hybrid, or solid-state? Can you do a quick video showing the insides (electronic porn)? 2) when you hooked up the scope and the VTVM to the “record out” jack, didn’t that put their impedance in parallel? Or did you have a splitter and impedance-matching transformers for each? 3) If it’s only for FM, why does it have a setting for CW (Continuous-Wave) and SCA (some sort of sub-carrier; closed-captioning, maybe)? 4) can you do a video on diagnosing problems with FM stereo receivers that have some sort of problem in the FM section (shorted FM discriminator diode, maybe, or picks up signal well (you can hear the station), but the stereo light doesn’t come on but it should.)? Anyway, nifty unit there - hope it - and you - are still going strong for a good while yet! 🤠

[@sincerelyyours7538]

Interesting demo, but for me, devices like this represent what is most intimidating about FM alignments. I barely understand and have collected enough equipment to do AM alignments. FM Stereo is a whole 'nuther animal. If you could please show us how to do FM alignments without the exotic equipment that would be most welcome.

[@jdmccorful]

Good stuff, heiped me make a decision. Thanks.

[@jamesbender9083]

Hey Tony what's out there today to match this st model T- 100 matching transformer 50-300 ohms for my 1000a? thanks ...and always learning with your videos ..keep it up

[@spikester]

As a kid I always thought FM stereo multiplexing was magic, until I realized it reduced the volume and dynamic range of the signal by like half when I became an adult, there really is no such thing as a free lunch.

[@plyzo]

Do you know where one can find a 50 to 300 ohm matching transformer that works with this unit?

[@jaghifi]

Id love to find some test equipment like this. I have a scope and a good dmm. im limitied and not able to work on tuners cause of this. Do you know of any places to get good used test equipment? I have about 10 to 15 vintage receivers/tuners id like to align.

[@pdppanelman5889]

Are those BNC's 50 Ohm or 75 Ohm? . A note of caution. 75 Ohm pins are smaller than 50 Ohm pins. Put a 50 Ohm plug in a 75 Ohm socket and you spread the socket connector. 75 in a 50 = poor contact and so on

[@russellhltn1396]

Gotta wonder how much of this can be replaced by some software and a "HackRF One" "transceiver". About $300 for the SDR.

[@caspianwendell]

If the music is broadcast over the air for everyone to capture, how is it a copyright infringement when your demonstrating a tuner? Complete and total B.S

[@budandbean1]

Man, I think almost every single person on KZbin agrees with you! The only people that don’t agree are the KZbin folks and the bums getting rich filing copyright infringement issues. Sadly, they are the ones that seem to make the rules. Pisses me off too!

[@davesanders4381]

Tony have you had any experience with the Leader LSG-231?

[@xraytonyb]

I have one. Great piece of test equipment.

[@mnoxman]

Is it me or does this look a bit like a CRM114 from Dr. Strangelove?

[@mr1enrollment]

it is 10khz + 60hz in sweep mode not 1khz

[@kathnrich1]

What do you charge for such an alignment?

[@xraytonyb]

I don't really do this for a living, it's just a hobby.