Dialing in the deck properly (the modern way)

[docs]

This is how I do it in the 21st Century with excellent results.

Tools needed:
A laptop
A PicoScope 2204A (PicoScope 2204A) This is a modern day oscilloscope with a lot of powerful features. We use the basic features here but this can be used for full troubelshootign and daignostics including signal generator etc.
PicoScope software installed on laptop
2x BNC to RCA adapters to connect the RCA cable to the PicoScope
1x RCA to 3.5mm jack cable
1x 3.5mm jack to 6.35mm adapter
A recorded 3Khz tape
Screwdriver
15 mins of your time

1. Firstly get your software installed and test with the PicoScope so you can see something.

2. Connect the BNC adapters to the PicoScope and the RCA cable to the adapters and use the jack adapter to plug into the headphones socket if necessary.



3. Get your boombox ready to test with the 3Khz tape.



4. Make all your connections, RCA cable to PicoSCope, plugged into headphone socket, PicoScope connected to laptop and fire up the PicoScope software.

5. Play the tape, make sure you have all settings on the boombox set and function to tape. If all successfully connected, you will see your sine wave. Observe your sine waves, Red and Blue represent Left and Right channels. Here we can see they are slightly out of alignment which tells us that the azimuth on the head is off.



6. On this screen, in the lower left, we can also see our average speed the tape is being played at. Remember we are using a 3Khz tape so if the speed of the deck is correct we should be seeing close to 3Khz average. This tells us the deck is running slightly slow.



7. So let's sort out our sine waves first by aligning the head. Remove the cassette door or front panel if necessary to reveal the hole where the azimuth screw can be adjusted.



8. Adjusting this screw slightly while observing the sine waves on the PicoScope software you can align them like this to ensure the heads are aligned.



9. For the speed adjustment, some boxes have access to the motor from the rear of the unit, check if you are lucky. I had to remove the front cover for this unit and remember to reconnect the PicoScope cable to the headphone jack.



10. Luckily this motor is forward facing so access to that screw for adjusting the speed is easier than having to remove the deck.



11. While playing our 3Khz tape and observing the average speed on the PicoScope software, you can adjust to get the speed close to 3Khz.

BEFORE:


AFTER:


And there we have it, a beautifully dialed in deck with the correct clarity from the head and the correct speed being played.

If you need a 3Khz tape, you can purchase them or if you are confident you have a correctly dialed in deck, you can record one of your own using a tone generator app on your phone connected to your amp setup.

Hopefully this will help others for a little outlay, the benefit of having your decks dialed in perfectly is rewarding.

 

[Northerner]

That’s some hi tech schenanigans for sure! If you’re gonna do something, do it properly. Nice work and a helpful guide

 

[fyj2972]

Doc， Your configuration is too complicate, Lets make it simple. A 3000HZ tape plus a multi meter with frequency counter function.

 

[fyj2972]

How do you know your 3000hz is accurate or not?

 

[docs]

Doc， Your configuration is too complicate, Lets make it simple. A 3000HZ tape plus a multi meter with frequency counter function.

The beauty of my setup is its simplicity and ability to use the tool for many other diagnostics. In addition to a multimeter not helping to adjust azimuth correctly. This is as simple as it gets.

 

[docs]

How do you know your 3000hz is accurate or not?

Test tape original or using a nad/quartz timed deck.

 

[Superduper]

The problem with adjusting azimuth using this method is that the L/R could be off by a whole cycle yet appear to be in-phase. The preferred method if your scope has X-Y capability is observing a Lissajous waveform.

 

[docs]

This is true Norm but a quick listen establishes accuracy. Also I’m pretty sure the software has the ability to add markers to display on the waves to see the same points.

Each to their own, this is a modern take on a method with numerous solutions, i’ve done 100 plus decks like this in, quickly, and have huge success so it works for me.

 

[hopey]

This is awesome great to see a visualisation on the as azimuth. I do mine by ear and I can hear the balance change L to R as you turn the screw. I make sure I use my own recording and a prerecorded tape so as to get the best compromise.

 

[docs]

This is awesome great to see a visualisation on the as azimuth. I do mine by ear and I can hear the balance change L to R as you turn the screw. I make sure I use my own recording and a prerecorded tape so as to get the best compromise.

Thanks hopey. I realise this method isn't for everyone but it works for me with excellent results. I think most of us adjust the azimuth by ear but I like the accuracy of this and the tool is so powerful for other uses that I sold my old oscilloscope and covered the cost of doing it this way.

 

[docs]

The problem with adjusting azimuth using this method is that the L/R could be off by a whole cycle yet appear to be in-phase. The preferred method if your scope has X-Y capability is observing a Lissajous waveform.

Norm, I added the XY view which helps thank you.
Would you agree with the following?

Slightly out of phase but in cycle:



In Phase and cycle:

 

[fyj2972]

Great！

Doc， If you may add W/F measurement . It will be super.
A.N.T

 

[Superduper]

Looks good to me. Try to use a true azimuth test tape though, probably 6.3khz or 10khz. Speed tapes and 1khz signals probably aren't the best choice.

 

[T-STER]

This is fantastic work Docs and good of you to share a step by step, thanks!