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Precision 8 Operation Manual
Precision 8i (international) Operation Manual
P2 Analog Operation Manual
Attenuator Diagram

1) What is the difference between the signals coming from the two different types of output connections (DB-25 and TRS)? Are they at different operating levels? Which one is higher quality?
There is no difference in the signal quality or operating level available at the TRS and DB-25 connections. They are electronically identical. Two different output connections are provided to facilitate easy connection to a variety of devices such as multitrack tape and disc recorders, mixer line inputs, patch bays, etc. Also, the Precision 8 can be used as an active mic splitter by routing, for instance, the eight-channel DB-25 cable to your tape/disc recorder and the TRS cables to your front-of-house mixing console.

2) How/where do I connect the microphones I want to use for M/S recording?
Connect the forward facing "Mid" mic (usually a cardioid pattern) to the MIC 1 input. Connect the figure 8 "Side" mic to MIC 2 input. Face the Side mic toward the right side of the sound field (perpendicular to the axis of the Mid mic). See pages 5 and 6 of the Operation Manual.

3) I want to make my own cable for the DB-25 output. How do I wire it?
The DB-25 output connector is wired according to the Tascam, wiring convention for 8-channel audio. See page 5 of the Operation Manual for a wiring diagram. (Note: the hold-down screws on the Precision 8 DB-25 connector are 4-40 thread.)

4) Can I plug a TRS balanced cable into the DI jacks on channels 7 and 8 so I can just use them for balanced line inputs?
No. The DI connectors on channels 7 and 8 are intended for unbalanced 1/4" plugs only. The DI will not operate if a TRS plug is used.

5) Are the preamps on channels 7 and 8 the same quality as the other six channels, or are they compromised in some way because of the additional DI function on those two channels?
Channels 7 and 8 are identical to the other preamp channels.

6) Does the Peak Reference selector switch change the gain range or operating level?
No. The Peak Reference selector only changes the level at which the LED indicators (PK, - 3, - 6) are activated. This is used as a visual aid to assist in matching levels between the Precision 8 and devices to which it is connected, but has no effect on output levels or gain.

7) How can I connect both the DI inputs and the channel 7 and 8 preamp inputs to my patch bay?
Sorry, this is not possible due to the dual-purpose connectors used on channels 7 and 8. You must choose either mic inputs or direct inputs to connect to your patch bay.

8) I'd like to try M/S recording for the first time - but I don't quite understand how to do it. How do you position the mics? How do you adjust the Precision 8?
We've included a basic discussion of the M/S technique on page 11 of the Operation Manual. But, for an excellent reference on M/S microphone techniques, as well as many other relevant topics, we recommend The New Stereo Soundbook, by Ron Streicher and F. Alton Everest. You can follow this link to the website: As for adjusting the Precision 8 in the M/S mode, please see the information starting on page 5 of the Operation Manual.

9) Can you recommend a good source of information on microphone placement techniques?
Check out The New Stereo Sound Book:

10) What could be causing some channels of my Precision 8 to have low level hum sometimes? It seems to depend on how I've got the patch bay set up.
Patch bays can be wired in many different ways. It frequently happens that, as the patch setup is changed, ground loops can be established between various pieces of equipment, or even internally within the patch bay itself. While there may be no problem routing line level signals through a patch bay with minor ground loops occurring, extra care should be taken when using a patch bay for mic inputs. It is a good idea to use separate patch bay strips for line level and mic level connections. Shields should not be commoned (connected together) inside the patch bay. Keep line level signal paths away from mic level signal paths. CAUTION: When using a standard TT or TRS patch bay for mic cables, be careful not to "hot-patch" the mic inputs. That is, do not change patch connections while phantom power is on and gain is up. This has the potential for damaging your precious equipment (and your ears!). The best approach is to use a separate XLR patch bay for mic cables.

11) I use the Precision 8 to record heavy rock drums. My favorite mics happen to be very high output and, while the Precision 8 does not overload, I sometimes peak out on my A/D converter (even though gain is set at minimum). What can I do to prevent overloading my A/D?
The maximum output level of the Precision 8 can reach +31dBu. This level exceeds the input capability of some mixers, signal processors, A/D converters, etc. (check manufacturer’s specifications). And, since we elected not to include an input pad (for reasons of sonic purity) it is possible for the Precision 8 to produce a signal level that overloads these devices. We offer two different Output Attenuators for use in these situations. As an alternative to purchasing one of our attenuators, you may wish to assemble your own using the circuit diagram available in our DOWNLOADS sections.

12) Where is the voltage selector for changing the input AC voltage from 120VAC to 230 VAC?

The current version of the Precision 8 is intended for operation at 120VAC, 60Hz only. If you plan to use the Precision 8 in a locale using other AC mains voltage, it will be necessary for you to acquire an appropriate power converter. Any power converter used with the Precision 8 must provide a means for earthing the chassis ground via the standard 3-wire power cable. NOTE: In the summer of 2002, TRUE Systems will be offering an international version of the Precision 8 that will operate on a variety of AC mains voltages.


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Tucson, AZ. 85710

Telephone: (520) 721-2735
Fax: (520) 722-4057