Frenzel Tube Amplifiers
www.frenzeltubeamps.com
2010 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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EDGE PULL SWITCH – when pulled out will turn off the negative feedback in the amp which produces a boost in
the volume and a more dynamic less compressed tone.
POWER STANDBY ON SWITCH – In the STANDBY position the power is turned on to filaments of tubes. Pilot
lamp will light up when switch is turned STANDBY position. Allow tubes to warm up 3- 5 minutes before turning
to ON position. This protects tubes and lengthens tube life. Turn to STANDBY position when amp is 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. ( Only on amps with the Effects Loop upgrade.)
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. ( Only on amps with the
Effects Loop upgrade.)
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 speakers. The jacks are wired in parallel.
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.
TUBES – The amp comes standard with the tubes shown below, but you canuse other tubes for different tones
and overdrive. For maximum clean and little or no preamp overdrive, you can use a 12AU7 in the V1 position. A
5AR4 will give less compression and a tighter sound in place of the V4 - 5U4 RECTIFIER. You can also substitute
5881's, KT66's, KT88's, 6550's in the output stage V5 and V6 for different saturation and overdrive tones
.
6L6 - V6 OUTPUT
6L6 – V5 OUTPUT
12AX7 12AX7 12AX7 5U4
V1 - PREAMP V2- PREAMP V3 – DRIVER V4 – RECTIFIER
TUBE LAYOUT CHART FM-5F6MB
