Record and playback calibration

[frpe12]

Hi al !

Now that my TS1000 is fully recap and new belts are installed, I'm working on calibration and I would need your support again.

I applied the folowing sequence :

- Feed a1KHz / 1.5V (2.12V peak 2 peak) sine wave signal to the Universal input (I used a lab waveform generator)
- Select "Automatic Recording" and press "Record".
- Set the L/R VU meters to 0dB using R61 and R62 on board D
- Record the signal at 19cm/s on a brand new tape. I recorded also a 10KHz signal with the same settings
- Playback the tape
- Adjust the playback VU meters level to 0dB using R53 and R54 on board G

In playback mode :
- On R channzl, I'm unable to reach 0dB with the trimmer with the 1KHz signal : minimum is +3dB. No issue on L charnel.
- I also have a difference between L and R VU meters levels with the 10KHz signal : need to adjust the filters with R13 and R14 on board G to get the same levels as with 1KHz signal.
- L VU meter level is less stable than R VU meter level : Head alignment issue ?

Questions :
- Why can't I reach the 0dB mark on the VU meters when playing back the tape ?  Is there another setting to do ?
- What are the rules of R88 and R99 (10K) on board D ?

Thanks for your support.

Kind regards.

François

[mampfi]

Hi,
your mistake was....
You have to calibrate the playback sequence with a test and calibration tape first.

Including...

• playback azimuth

• playback level***

• playback equalizer

• VU Meter adjusting

(if you want they show 514nWb @ 0dB) If you want they show 3% hiss (like Grundig wrote), you have to calibrate them in recording section.
*** = 675mV internal level @ 250nWb, or 1,35V @ 514nWb

If you do so successful, you can calibrate the recording section with recording azimuth, recording & bias level.

It make no sense to do anything with the automatic function.
Now you has decalibrated the TS 1000.....

Sorry...........

[frpe12]

Hi Mampfi,

Thanks for your answer.
Anyway, the TS1000 I get was already no more calibrated and I had to replace some trimmers during its restoration.
So, I'm starting from scratch !
Unfortunately, I have no pre-recorded calibration tape, and the cost of a new one is a bit dissuasive...
How can I proceed on my own ?
Is there a way to recover a calibration close to the original one ?
Kind regards.
François.

[mampfi]

Ebay 376076908796, if you are fast enough.....

[frpe12]

Hi !

Got it !
The tape is still available but it seems to be IEC2.
Is it compliant with the TS1000 ?
I thought IEC1 was mainly used in Europe.

Kind regards

François

[mampfi]

Yes, the Leveltape from Bluthardt, (Bluthardt was not far from my destination), is the right one.
The tape is, due to fulltrack recording, useable for 4 and 2 Track Recorders, and it is for 9,5cm.

The 1kHz Signal from the Testtape is in the neutral zone from the playback equalization.
So, no equalization is needed anyway. That's why it is a Level Testtape.

[frpe12]

Hi Mampfi,

I bought the tape.
I should receive it next week.

So if my understanding is correct, reading this tape at 9.5cm/s should provide a -3dB level on the VU meters, as it provides a 250nWb signal, right ?
To adjust, I have to tune R53 and R54 trimmers on board G but also R61 and R62 on board D.
What do you recommend ?

Thanks à lot.

Kind regards.

François

[mampfi]

Ok, if you playback the testtape, you have to adjust the internal level to 675mV (with this 250nWb tape) @9,5cm/sec
The internal level you can measure at the adpapter board

or on the input plug for the phones amplifier

Or the output from the monitor socket. If you do so, you have to put the output gain poti to maximum.

You have to adjust the internal level with gr53/gr54 on board G to 675mV.
After that adjust the VU Meters with GR61/GR62 on board D to -6dB, what corresponds to 514nWb@0dB

...that's it

[frpe12]

Very clear !
I'll use the adaptater board.
Nothing to do with other trimmers (R88 + R99 on board D and R13 + R14 on board G) ?
What are their role ?
Thanks

[mampfi]

R88 & R99 on board D are for the oprerating point from the automatic funktion.
R13 & R14 on board G are for playback equalization.
If you want to adjust the playback equalization you need another testtape with 1khz and 16 or 20kHz with the same level (-20dB)