Lightning Boy Audio 1401 Gravitone 30 User manual

Lightning Boy Audio
1401$Gravitone$30$Rev.%A$
$
%
Users%Guide%2014%
%
Congratulations%on%an%excellent%purchase!%%This%guide%was%put%together%to%help%you%get%
the%most%out%of%your%investment.%
%
The%1401%Gravitone%30%was%designed%to%serve%as%the%driver%amplifier%for%the%LBA%1401%
Analog%Plate%Reverb.%%Though%it’s%features%are%specifically%designed%with%the%1401%Plate%
Reverb%in%mind,%the%Gravitone%30%also%works%exceptionally%well%as%an%electric%guitar%
amplifier.%%%%%%
%
Getting$Started:$$
Carefully%unpack%the%Gravitone%30.%%Be%aware%that%there%is%glass%in%the%package,%so%
proceed%with%caution.%%You%will%find%a%metal%tube%shield,%a%box%containing%the%vacuum%
tubes,%and%a%box%containing%a%3u%vented%rack%panel.%%Carefully%remove%the%vacuum%tubes%
from%their%boxes.%%Align%the%pins%of%the%vacuum%tubes%with%their%respective%sockets%on%
the%top%of%the%Gravitone%30%and%insert%it%into%their%sockets.%%Next,%the%tube%shield%will%
need%to%be%attached.%%Slide%it%over%the%preamp%tube%and%rotate%into%its%locked%position.%%
There%are%little%nubs%on%the%tube%socket%to%lock%the%shield%in%place.%%You%can%then%plug%in%
the%power%cable%and%rack%mount%the%Gravitone%30.%%%
%
Powering$Up:$
The%power%switch%is%located%on%the%front%panel.%%Once%engaged,%it%will%take%about%30%
seconds%for%the%tubes%to%warm%up%sufficiently%to%take%the%amp%off%standby.%%15%seconds%is%
the%minimum%wait%to%prevent%damage%to%the%power%tube,%but%longer%is%recommended.%%
Flip%the%standby%switch%to%the%upward%position%to%engage%the%amp.%%%
%
Controls:$
The%Front%panel%offers%controls%for%Gain%(tube%saturation),%Bass,%Mid,%Mid%frequency%
selector,%Treble,%volume,%standby,%on/off.%%The%top%panel%has%a%control%for%the%bias%
adjustment.%%The%amp%will%arrive%to%you%biased%for%the%tubes%it%arrives%with.%%The%rear%
panel%offers%a%ground%lift%switch%for%the%balanced%line%input.%
%
Connections:$$$$$
The%rear%panel%offers%a%pair%of%4%ohm%speaker%outputs%via%Neutrik%¼”%locking%jacks.%%Use%
one%jack%to%connect%a%single%4%ohm%speaker%cabinet%or%use%both%jacks%to%connect%a%pair%of%
8%ohm%speaker%cabinets.%%Below%these%jacks%are%the%¼”%instrument%input%jack%and%the%
balanced%XLR%line%input.%%The%line%input%is%always%active%unless%and%instrument%is%plugged%

into%the%¼”%instrument%input%jack.%%Also%on%the%rear%panel%are%Bias%test%points%and%the%IEC%
power%inlet.%%
%
Features:$
Noted%here%are%the%less%conventional%features.%%The%Line%input%is%intended%for%use%as%the%
input%when%using%the%Gravitone%30%as%the%Plate%Driver%for%the%1401%Analog%Plate%Reverb.%%
However,%it%also%works%perfectly%as%a%built%in%re-amping%box%when%using%the%Gravitone%30%
as%a%guitar%amp%in%the%recording%studio.%%A%ground%lift%switch%is%provided%next%to%the%line%
input%jack.%%The%ground%lift%switch%only%affects%the%line%input%and%not%the%instrument%
input.%%By%inserting%a%¼”%cable%into%the%instrument%input%jack,%the%line%input%is%
automatically%bypassed.%
%
The%Bias%control%is%set%for%the%tubes%that%shipped%with%your%amp.%%If%in%the%future%you%
wish%to%change%tubes,%a%bias%adjustment%pot%and%bias%test%points%have%been%provided.%%
The%amp%should%be%re-biased%by%a%qualified%amp%tech.%%%
%
Technical$Information:$
•Inputs:%%%
o¼”%unbalanced%instrument%input%%
oXLR%transformer%balanced%+4dBu%line%input%%
•Output%Impedance:%%4%ohms%
•Vacuum%tube%compliment:%
oPlate%Driver%–%6V6,%12BH7,%5AR4%
oGuitar%Amp%–%KT88,%12AX7,%5U4%%%
•2A%slow%blow%fuse%
%
Warnings:$
DO%NOT%TAKE%THE%COVER%OFF%WITH%THE%UNIT%POWERED%UP.%%RISK%OF%SEVERE%AND%
PERMANENT%DEATH.%%Servicing%should%only%be%conducted%by%a%qualified%repair%tech.%
%
Servicing/Questions:%
If%you%have%any%questions%or%comments%or%if%your%unit%needs%servicing,%please%email%
[email protected]%%