Frenzel Tube Amplifiers
www.frenzeltubeamps.com
© 2011 Copyright by Frenzel Tube Amplifiers. All rights reserved. All designs, technical data, pictures, and information are
copyrighted and may not be reproduced without the permission of Frenzel Tube Amplifiers.
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POWER SWITCH – turns power ON to filaments of tubes. Pilot lamp will light up when switch is turned to ON
(up) position.
STANDBY SWITCH – turns ON high voltage to tubes. Allow tubes to warm up 3- 5 minutes before turning to ON
(up) position. This protects tubes and lengthens tube life. Turn to OFF position(down) when amp temporarily not
in use.
REAR PANEL CONTROLS:
EFFECTS LOOP – is a passive insertion point between the preamp and the power amplifier. The SEND jack is the
output of the preamp. The RETURN jack is the input to the power amp. For normal operation these two jacks are
connected together by a push/pull switch on the SEND LEVEL. To use the EFFECTS LOOP, pull the switch out
on theSEND LEVEL control. This will open the loop and allows you to insert an effects unit into the jacks. The
SEND LEVEL controls the output level of the SEND jack and can be used to adjust the level to meet the
requirements of the input drive level your effect. Boost and distortion pedals can be used in the loop, but they
usually work better in the front of the amp before the preamp. This is what they were designed for. The loop
works best with studio digital effects that are designed to go after the preamp like Chorus, Delay, Reverb, Mixer,
Volume, etc.
The SEND jack can also be used without the EFFECTS LOOP function to drive a recorder, mixer, or another amp.
This function does not require the switch on the SEND LEVEL control to be pulled out.
EL34/6L6 BIAS SWITCH – Sets the bias for either using EL34 or 6L6 tubes in the output. WARNING: Failure to
set the switch in the proper position can cause damage to the tubes and amp.
POWER LEVEL SWITCH – Sets power output level to ¼ - ½- FULL power.
LINE OUT - is a post output transformer LINE OUT jack with LINE OUT LEVEL control for driving another amp,
mixer , recorder etc. It can be used without a speaker plugged into the amp. There is an internal load connected
by a switch on the speaker jack if a speaker is not plugged in. This internal load simulates the speaker and will
give you loaded clean and output distortion tones. Use a shielded cable to connect the LINE OUT to another
device. The LINE OUT also works with headphones.
LINE OUT LEVEL – controls the output level of the LINE OUT.
SPEAKER JACK – connects output of amp to speaker.
IMPEDANCE SELECTOR – selects the output impedance for the speaker to 4 – 8 -16 ohms. Set the switch to
match the impedance of the speaker.
FUSE - protects the power supply. Use a 3 amp SLO-BLO type fuse.
POWER CORD – connects amp to electrical outlet. The power cord is a three prong grounded cord. Always plug
into a grounded outlet to prevent electrical shock. The line voltage is shown over the power cord bushing. Be
sure that the voltage matches your line voltage.
TUBE LAYOUT CHART
6L6 V5
5AR4 V6
12AX7
V2
6L6 V4
12AX7
V3
12AX7
V1
FM-5E3 SD TUBE LAYOUT
V1 - F AND M PREAMPS
V2 - TONE STACK DRIVER
V3 - PHASE INVERTER
V4 - POWER OUTPUT
V5 - POWER OUPUT
V6 - RECTIFIER
