Here are some pics of the unpainted
chassis that I have ready to be filled
with
parts for future amplifiers.
I have enough chassis to build
4 of 100 watt monobloc amps with 4 x 6550/KT90/KT88/EL34/6L6GC.
2 of 100 watt monobloc amps amps with 1 x 13E1.
4 of 50 watt monobloc amps with 2 x 6550/KT90KT88/EL34/6L6GC/300B.
2 of 25watt monobloc amps with 2 x 13E1.
All dimensions are overall sizes given in millimetres. To convert to
inches divide mm by 25.4.
The chassis are 1.6mm thick steel plate partially zinc plated,
transfromer cases are 1.2mm steel plate
for potting the transfromers solidly, cages are 1.2mm steel plate.
All external corners are welded and ground smooth to give an
excellent finish for any chosen colour
of powder coating. The default colour is plain satin finish black
but other colours are available upon request
pending availablity.
1 x 13EI.
This one is for 1 x 13EI or other single tube which may fit. Driver and
inout tube = 2 x octal.
space for Size of chassis = 360L x 210W x 55H
Size of transformer box
= 125L x 125W x 140H, allows up to 70 stack of 44 tongue E&I core.
Size of cage = 204L x 96W x 140H
2 x Octal.
This one is for 2 x Octal output tubes or other such as 300B. Driver
tube and input = 2 x mini nine pin.
Size of chassis = 360L x 210W x 55H.
Size of transformer box
= 125L x 125W x 140H, allows up to 70 stack of 44 tongue E&I core.
Size of cage = 204L x 96W x 140H.
2 x 13EI.
This one is for 2 x 13EI output tubes or other such as 300B etc. Driver
tube and input = 3 x mini nine pin.
Size of chassis = 400L x 230W x 55H.
Size of transformer box
= 125L x 125W x 140H, allows up to 70 stack of 44 tongue E&I core.
Size of cage = 224L x 136W x 140H.
4 x Octal
This one is for 4 x Octal output tubes. Driver tube and input = 3 x
mini nine pin.
Size of chassis = 400L x 230W x 55H.
Size of transformer box
= 125L x 125W x 140H, allows up to 70 stack of 44 tongue E&I core.
Size of cage = 224L x 136W x 140H.
2 and 4 octal chasssis :-
The large slots where transformers are mounted allow for the primary
and secondary terminals mounted in
phenolic boards to project into the sub-chassis area for easy winding
and selection of winding arrangements.
The E&I laminations are vertically mounted and the clamp yokes bolt
to the chassis through each hole
near each end of the the chassis slots. The laminations are kept
slightly clear of the steel sheet chassis material.
Slots around the octal socket holes allow for rising streams of air
around each tube without allowing objects
with a dimension larger than 3mm to fall through the slots.
Not shown are the 2mm steel plate transformer yokes, steel bottom
plates with a large area perforated for ventilation.
1 and 2 x 13EI chassis :-
The large slots where transformers are mounted allow for the primary
and secondary terminals mounted in
phenolic boards to project into the sub-chassis area for easy winding
and selection of winding arrangements.
The E&I laminations are vertically mounted and the clamp yokes bolt
to the chassis through each hole
near each end of the the chassis slots. The laminations are kept
slightly clear of the steel sheet chassis material.
The large holes for output tubes allow for a gap of about 12mm between
the edge of the hole
and the glass of the 13E1 or other large output tube ( 6C33c? ). The
socket for the 13EI is mounted about
30mm below the chassis top level so a good ventilation flow up around
the output tube is possible.
Not shown are the 2mm steel plate transformer yokes, steel bottom
plates with a large area perforated for ventilation
and sub-chassis plates for mounting 13E1 sockets.
Chassis for preamps.
The preamp chassis are without holes which are determined when details
for the preamp are established.
I have Q-max punches to place chassis holes for any tubes or other
large holes.
2 x 845/211.
This project was a totally custom project for 2006 and will use 2 x 845
in parallel SET for 45 watts with
KR Audio 845 made in Prague. The chassis has 2mm steel sheet and is
larger than any shown above and with larger transformer boxes.
I do not supply amplifier kits with all drilled chassis and ready wound OPTs.
The chassis sets are not for sale separately unless you make an
offer which will allow me to order
replacements from CanFab at Fyshwick in the ACT. The purchase price for
small quantities of
chassis, say just two is expensive since CanFab charge a hefty set up
fee for their precision
computer controlled stamping machines. I purchased the above large
number of chassis and parts for several thousand dollars
to get the rate per chassis down to a reasonable level.
I have inspected their best powder coated samples and the gloss version
be the best finish anyone could wish for.
The price from CanFab for just two chassis for 100 watts with 4 x
KT88 with chassis, cages, 4 x transformer boxes,
bottom plate, transformer yokes and with exposed parts all powder
coated to the top finish
would be approximately aud $800. The problem with diy chassis building
with powder coated finishing is that
any mistakes for hole positions/sizes or blemishes cannot be fixed and
painted over. Changes to design as you progress
cannot be accomodated.
I will not be getting the powder coating done on the above chassis
until I have pre-fitted all items in the chassis, so I know
I will not have to change anything or drill/cut anything after the
powder coating is baked on.
it is expensive for me to get the chassis powder coated at a pair at a
time but at least the customer
can have a choice of colours. I am not sure if the zinc plated steel
sheeting can be chrome plated but at present
I will not offer that option as a finish because samples of old
amplifiers I have seen with chrome plating lead me to believe
it is an unreliable finish prone to peeling and cracks and blemishes
unless attempted on a mass scale.
I do know a gentleman who can fabricate the chassis shown above in stainless steel, and you pay for what you get.
Australia is full of excellent metal workers who can do just about
anything but they do need more than a bowl of rice
each day to keep 'em working.