In order to understand the discussion below, I advice you to also read the pages about Electrical adjustments.
Everyone is not interested in investing a lot of money in instruments.
But, what do we need in order to check our recorder?
 

What hardware do we need?
Well, before we can measure or adjust, we need to know how it should be done.
For this, we need a service manual. Even if an original manual can be hard to find, copies are often sold
and do the job just as well.
 

1.
In my opinion, the first thing to invest in, is a test tape.
With a test tape (and the recorder´s VU-meters) a lot of checks and adjustments can be made.
The cost for such a tape is around 80-90$, money well spent.

If you have read my pages about adjustments, you know that a test tape is a "reference".
From that reference we can go on and make adjustments.
The test tape is necessary to adjust the "0" level on the VU-meters for example.
Frequency response can also be measured if you use a "multi frequency tape".
The VU-meter itself is the only instrument needed.

2.
My next choice is a multimeter. This is needed to adjust the electrical levels, for example adjusting the output
so that "0" on the VU-meter gives 0,315 V output (-10dBV).
Any multimeter cannot do the job however. There are two things that you should look for in the data sheets:
First, it must handle AC measurements up to 1000 Hz. This is the frequency used on many test tapes for adjusting input / output levels.
Such a multimeter should not be hard to find. Even my "budget" multimeter handles frequencies from 30 - 400 Hz.
More expensive ones can handle up to 20000 Hz.

Second, it must be able to measure low AC Voltages, for example 0,315 Volts. We don´t need to be that exact, but
it must be able to tell 0,31 from 0,32 V.
(So, a multimeter with a resolution that just can tell 0,3 from 0,4 V is not enough.)

The Wavetek Meterman 37XR can measure AC voltages up to 2000 Hz.

3.
A signal injector.
When it comes to adjusting input levels, and adjusting recording parameters on your favourite tape, you need som kind of signal source. Instead of buying an expensive signal or tone generator, one can very well use a battery operated "budget"
signal injector. Fostex has a model suited for recording purposes, which has the frequencies and levels needed for most adjustments.

4.
An oscilloscope. Who needs an oscilloscope?
For adjustments of tape recorders, I can only think of one adjustment that needs an oscilloscope: azimuth adjustments.
Otherwise, a multimeter is easier to use, and very accurate.

5.
Cables and adapters.

When you hook up your instruments, it is important that you use proper connectors and adapters.

It is a good idea to spend some money on good adapters and cables, so that you can connect RCA to BNC connectors for example. Then you can fully concentrate on the measurements.
You will also need some resistors, Usually 50 kiloOhm and 600 Ohm. They are used for measurements where
specifications say that the voltage "should be measured over a 50 k load".
 
 
 
 

TASCAM TSR-8

Next page Measurement setup

Back to  Recorders startpage