Marantz 1820 Oscilloscope X-Y Mode Azimuth Adjustment
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- čas přidán 17. 07. 2024
- In the end, I changed the original pinch roller to no avail even though it looked good on closer inspection. This method seems to be really accurate to use and the slightest error can be seen.
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Cant believe I missed this video...came to your channel to double check my work, I figured you'd have to have a video on the subject! Thank you. I own that scope. ~Jack, VEG
Thanks for watching, VEG! I can't even remember making that video. But still, I hope it was helpful a little bit. Good scope.
Not only peak voltage but also phase, very interesting, thanks for the video.
Right, a recorded signal from one channel will be at its head gap a wee little bit earlier than the one from the other channel, which has its own head gap, if the head is tilted. There would exist a time error. Thanks for watching and commenting!
Nakamichi decks are aligned with a 15 kHz full track test tape. The higher you go with the frequency, the more precise the adjustment will be. But 10 kHz is more than adequate.
And that Lissajous looks good enough. There is no tape deck in existence that doesn't show slight instabilities in tape transportation which manifest themselves in high frequency phase and amplitude variance.
Thanks for that! 15 kHz tapes are hard to find and when you do find them they are expensive. I only have one tape, so I had to work with that
@@OldSchoolElectronics you can try Gennlab or A.N.T. Audio. Both produce full-track test tapes to different specifications at somewhat affordable rates. Just in case you might be working on more decks in the future.
Thanks for all of these infos! I will check that out. I am sure I will run across more decks in the future.
Great video! You are very good at cassette
Thank you, sir!
U R an electronic genius.
Thanks, I wish!
wait.. are you adjusting the azimuth of head, when aligning signals to phase?
Where did you acquire the rca plugs with the small wires coming out of the deck?
Randy, I would recommend getting something like this (depending upon your setup). www.ebay.com/itm/RCA-Audio-Jack-Cable-Y-Adapter-Splitter-1-Female-to-2-Male-Plug/312648406665?
www.ebay.com/itm/7-RCA-Audio-Jack-Cable-Y-Adapter-Splitter-1-Female-to-2-Male-Plug-OFC/202991821427?
Also, get a BNC to RCA male cable. www.ebay.com/itm/BNC-Male-to-RCA-Male-Pick-Your-Length-RG58-Coax-RF-Cable-High-Quality-50ohm-USA/164180912949?
Other adapters (like the ones in this video) are like this: www.ebay.com/itm/2x-Terminal-Block-to-RCA-Male-For-TV-Video-adapter-Cinch-connector-cctv/252471091470?
@@OldSchoolElectronics Ok thanks very much.
@@RandyWBrown I bought these very same plugs off Amazon a couple of weeks ago. They are pretty cheap, too.
@@svenschwingel8632 Indeed they are. I have a dumb question that you can answer or not for me. I bought an ancient heathkit av-2 Vtvm in like new condition. Ikr it's nearly 70yo but measures minute voltage and dB's. I have a Sony TC-WR635S and a Nakamichi rx-202. Both have been re-belted and play fine but their recordings lack treble. I was told to check the rec.bias and current bias levels on both decks.
I have SM but don't quite understand what 47kohm resistor in parallel with the meter leads of my ancient heathkit av-2 vtvm has to do with the measurements.
The Nak has more than I care to type here. But essentially it wants 400hz and 17KHZ to be within 1db of one another. And it's got like 6 pots per channel to adjust not to mention a couple of bias trap oscillators.
Thanks Randy Brown
Are there two settings possible? I mean can you adjust to the wrong direction or does the ellipse become wider the whole wrong way along?
The more the phase shift (the more you are off), the wider the ellipse. You just have to make sure your scope is set up right. That is, you will have a 45 degree line either going from bottom left to top right or from top left to bottom right (depending on your scope). If you feed (in the scope X-Y mode) a normal 1 KHz sine wave to both the X and Y input of the scope from an audio generator you will see which way the line goes. That initial slanted line is your reference. If your line (or slanted ellipse) direction is wrong when you play the alignment tape, then you are completely off (say if somebody turned the screw too far). Smartest would be to get an alignment tape that has a low frequency too (such as 1 KHz or 5KHz) so that you can do a coarse alignment first. Make sure you only turn the screw a little bit at a time. You might have to do some readings on the Internet too. Or watch other videos.
@11:20, your test tape shows you on the label the varience in dB for both channels. They do this to allow you to see the waveforms as individual traces instead of sitting on top of each other...I'd suspect your drive belt as that controls your capstan speed. Over times of non use, the belt develops areas that are weaker and allow for a small bit of RPM variance that you are seeing as a rhythmic oscillation. mark your belt and watch the oscillation compared to the belt position.
Hey Steve, thanks for these knowledgeable inputs! Thanks for pointing that out!