The electron surgeon strikes again,very cool video and thank you for taking time to share your knowledge to help keep cool vintage gear in top drawer fashion,we shall all gather lupins to present to the stereo master TonyB :)
Many decent tuners had (horiz & vert) multi-path output so you could connect it to a scope and adjust antenna orientation using scope display. The idea is to get a horiz. line (no bends) on the scope. I have an old (re-capped) Kenwood scope with "multi-path" inputs. It really works.
An old H.H Scott LT-112B FM Tuner tuner ( available pre-built or in kit form) has V & H outputs on the back of it for a multipath connection to a scope, and they also have a good explanation of what it is, and how to use it, in the user manual which is available online to download. Some high end Marantz receivers had a scope with it built in as well, which is really sweet.
I always wondered what the switch on the tuner meter of my Sansui TU-7700 for signal/multiplex was for, now I understand it's function. There is another switch for multiplex filter, I assumed it was a stereo blending of the left and right, but not sure. Thanks Tony for sharing your knowledge and making these videos, always look forward to them.
The Sansui TU-7700 also has multipath RCA jacks on the rear for H and V for a scope XY input, and another single RCA jack for discriminator output. What is the discriminator output used for?
Tony, I don't think you have done a pioneer sx-1280 of which I just happen to own 😅. Jk. I do admire your attention to detail and the high standards you maintain 👍
The lissajous pattern should be symetrical, and it should in this case have 4 parts to the pattern because 19 x 4 =76 (X input is 19khz, and Y input is 76khz) . They are wanting you to precisely dial in the 76khz oscillator on the MPX chip. If the adjustment is off then the pattern will appear to rotate, you then adjust until the pattern stops rotating, it is then adjusted to exactly 76khz. They are assuming the 19hkz pilot is already precise. You have to do this with no modulation which I think you were doing. However, there was something not quite right there, if the X and Y inputs are the wrong way around then the pattern will appear to be on its side so that wasn't the issue, but it wont look like the pattern you had there, there was something else going on. I use the lissajous pattern method when called for (keeps my brain tuned into familiarity with my scope functions), mostly on Pioneer, as you probably do and know you can just use an accurate frequency counter, as long as its very high impedance, then set that osc to 76khz. Great Video though, always enjoy your uploads, thanks Tony!!
I'll have to check out how mine is set. I know I set the number of harmonics and weighting, but I can't remember what the sample filter (or whatever it's called) is set to. Thanks for the reminder :)
@@xraytonyb You can set the filter any time after the THD setup, during measurement of any AC signal. just press the filter button and it will walk you through it.
Thank you for the clarification on the MPX w/ SG80. Makes me feel less bad about just setting the control for center between the two points of signal loss. I may pick up one of those FETVM meters. I have had bad luck trying to find a decent working VTVM, (damaged movements, improper range, etc. ) that Japanese meter looks handy. I find that when doing the distortion adjustment using a Fluke 87V I can never get the voltage to stay at zero when the distortion is at minimum. When you make the distortion adjustment did you have to go back and forth a couple of times on the top and bottom cores?
@ 3:24 Do you have any explanation for why you are picking up any multipath signal from a output from a signal generator? Could it be some kind of impedance mismatch or reflected signal issue with how you are putting the signal into the unit? One would think that the amount of multipath distortion would be minimal with a locally connected signal.
I'm pretty sure it's because the tuner was put off alignment. If you go towards the end of the video, i do the same test with the signal generator and the signal goes flat line when i depressed the multipath button.
Thoroughly enjoy your instrument useage demonstration and alignment of Receiver. Excellent!!! Thank you for your ruminations.
Always enjoy the detailed tuner alignment class! Thanks for your time Tony!
I’ve enjoyed the series on this massive old receiver.
The electron surgeon strikes again,very cool video and thank you for taking time to share your knowledge to help keep cool vintage gear in top drawer fashion,we shall all gather lupins to present to the stereo master TonyB :)
Many decent tuners had (horiz & vert) multi-path output so you could connect it to a scope and adjust antenna orientation using scope display. The idea is to get a horiz. line (no bends) on the scope. I have an old (re-capped) Kenwood scope with "multi-path" inputs. It really works.
An old H.H Scott LT-112B FM Tuner tuner ( available pre-built or in kit form) has V & H outputs on the back of it for a multipath connection to a scope, and they also have a good explanation of what it is, and how to use it, in the user manual which is available online to download. Some high end Marantz receivers had a scope with it built in as well, which is really sweet.
I always wondered what the switch on the tuner meter of my Sansui TU-7700 for signal/multiplex was for, now I understand it's function. There is another switch for multiplex filter, I assumed it was a stereo blending of the left and right, but not sure. Thanks Tony for sharing your knowledge and making these videos, always look forward to them.
The Sansui TU-7700 also has multipath RCA jacks on the rear for H and V for a scope XY input, and another single RCA jack for discriminator output. What is the discriminator output used for?
Tony, I don't think you have done a pioneer sx-1280 of which I just happen to own 😅. Jk. I do admire your attention to detail and the high standards you maintain 👍
I have a sx 1250 Great stereo. I'm glad I bought it.
Ive been looking forward to this. Thanks from UK Mike.👍
Thank you Tony. 😃
My guess without watching the whole video is that there's a problem with the detector circuit.
The lissajous pattern should be symetrical, and it should in this case have 4 parts to the pattern because 19 x 4 =76 (X input is 19khz, and Y input is 76khz) . They are wanting you to precisely dial in the 76khz oscillator on the MPX chip. If the adjustment is off then the pattern will appear to rotate, you then adjust until the pattern stops rotating, it is then adjusted to exactly 76khz. They are assuming the 19hkz pilot is already precise.
You have to do this with no modulation which I think you were doing.
However, there was something not quite right there, if the X and Y inputs are the wrong way around then the pattern will appear to be on its side so that wasn't the issue, but it wont look like the pattern you had there, there was something else going on.
I use the lissajous pattern method when called for (keeps my brain tuned into familiarity with my scope functions), mostly on Pioneer, as you probably do and know you can just use an accurate frequency counter, as long as its very high impedance, then set that osc to 76khz.
Great Video though, always enjoy your uploads, thanks Tony!!
Tnx Tony !
The filter function of the 2015 really helps smoothing the readout while adjusting THD. I'll use 20 or 22 readings, moving average. Try it.
I'll have to check out how mine is set. I know I set the number of harmonics and weighting, but I can't remember what the sample filter (or whatever it's called) is set to. Thanks for the reminder :)
@@xraytonyb You can set the filter any time after the THD setup, during measurement of any AC signal. just press the filter button and it will walk you through it.
You can press the RF-IF tuning knob and it will change your tuning speed. 🙂
It's already set on the fast setting. The slow one moves it one decimal place to the right of it. Slower than pond water!!!
@@xraytonyb Okay, keep up the good work Bud.
Great video. You call 100dB a pretty strong signal. But what is a pretty strong signal at antenna level like you connected it.
Thank you for the clarification on the MPX w/ SG80. Makes me feel less bad about just setting the control for center between the two points of signal loss.
I may pick up one of those FETVM meters. I have had bad luck trying to find a decent working VTVM, (damaged movements, improper range, etc. ) that Japanese meter looks handy.
I find that when doing the distortion adjustment using a Fluke 87V I can never get the voltage to stay at zero when the distortion is at minimum. When you make the distortion adjustment did you have to go back and forth a couple of times on the top and bottom cores?
@ 3:24 Do you have any explanation for why you are picking up any multipath signal from a output from a signal generator? Could it be some kind of impedance mismatch or reflected signal issue with how you are putting the signal into the unit? One would think that the amount of multipath distortion would be minimal with a locally connected signal.
I'm pretty sure it's because the tuner was put off alignment. If you go towards the end of the video, i do the same test with the signal generator and the signal goes flat line when i depressed the multipath button.
@@xraytonyb That would hopefully explain it, thanks!