7
The CUT KHZ and the BOOST KHZ controls may be used together to achieve the effect desired.
For example, roll off could be at a higher frequency while brightening up a lower frequency.
Deficiencies in the program material can very often be eliminated by judicial use of both peaking
and frequency cut.
CONNECTIONS
The Input and Output connections should be made in accordance to the wiring convention shown
in Table 1 of this manual. The Input and Output configurations can be switched to allow the use
of mixed Input and Output impedances. See Figure 1 of this manual for details.
INPUT LEVELS
It is best to operate the PEQ-1 with input levels between 0 and +10dBm when in the Balanced
mode. This will insure adequate headroom when using program requiring large amounts of boost.
The “soft” overload characteristics of a tube system is often less objectionable than the harsh
overload sound of typical solid state designs, but for good program quality it is best to avoid
overload. Most audio devices having Unbalanced ( Hi Z) outputs will have output voltages
between 0.5 and 2 volts rms. A 2 volt signal into the Hi Z input will result in an output of
approximately +8 dBm at the Balanced output. This is a good operating level and it can be
trimmed with the gain adjust, if desired.
SERVICE NOTES
Other than the eventual replacement of vacuum tubes V1 (12AX7) and V2 (6146), there should be
no need for routine service of the PEQ-1. The front panel can be cleaned with a soft cloth. No
harsh solvents or abrasives should be used
The PEQ-1 contains hazardous voltages as is common in vacuum tube equipment. Any
required service is best left to qualified service personnel.
TUBE REMOVAL AND REPLACEMENT
Both tubes are easily removed via the tube access port at the rear of the unit. Remove the tube
shield by pressing in and rotating slightly counter clockwise to clear the shield J retaining slot,
then pull out to remove shield. In units equipped with wire clip retainer, slip the retainer spring
away from the tube so that it is off to the side. Carefully pull tube to remove from socket. Do not
rock to side as this can damage tube socket.
CAUTION: ALWAYS ALLOW TUBES TO COOL FOR AT LEAST 5 MINUTES AFTER
REMOVING POWER TO AVOID BURNS. TUBES CAN REACH TEMPERATURES
HIGH ENOUGH TO INFLICT PAINFUL BURNS UPON CONTACT WITH
UNPROTECTED SKIN.
Replace tubes with the proper type as shown in the Specification section of this manual. It is well
known that all tubes are not created equal and some will perform better than others. Experience
has shown that quality brands of tubes will offer better performance and service then cheap off
brands. The exception to this rule may be guided by the users experience and practice. Some older
NOS (new old stock) tubes from the 1950’s and 60’s will very often perform and sound better
than current manufactured tubes. If in doubt, replacement tubes can be ordered from Psidex.
Insert tube into socket with tube pins in proper alignment with socket. Press tube into socket using
only nominal force. Be sure tube is fully seated in socket. Replace shield by placing shield to
receive the J slot socket “bumps”. Press in and rotate slightly clockwise to engage J slot bayonet.
