811a SET amp.
- pre65
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#1 811a SET amp.
Going on from the 10W SET amp thread in the "valves" section, this is the project.
First thing is to strip the old KT66 & PT15 (mk3) monoblock chassis of superfluous parts, I'm on the first one at the monent.
Next is to modify the octal adaptor (in a septar size hole) to take the UX-4 base. I already have a 4mm socket to take the flying anode lead.
It's a bit parky round the ears today, so the wooly hat has emerged from summer storage. Can't bear to put the heating on just yet.
First thing is to strip the old KT66 & PT15 (mk3) monoblock chassis of superfluous parts, I'm on the first one at the monent.
Next is to modify the octal adaptor (in a septar size hole) to take the UX-4 base. I already have a 4mm socket to take the flying anode lead.
It's a bit parky round the ears today, so the wooly hat has emerged from summer storage. Can't bear to put the heating on just yet.
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
- pre65
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#2
Here is a view of what it will look like. The 811a are not in my possession yet so a 300b is standing in.
The two 4mm sockets (red and black) on the side are for the 811a external filament supply. I will be using my 4A Tentlab modules, and I've just ordered two 100va 12v transformers to power them. 12v is too high really but 9v was just a gnats smidge too low, so I will resistor down to approx 10v.
The first cap has been increased from 2uf to 22uf as I need a few more volts HT. I would like 500v but may have to settle with less, perhaps 450-470v according to Duncan.
The two 4mm sockets (red and black) on the side are for the 811a external filament supply. I will be using my 4A Tentlab modules, and I've just ordered two 100va 12v transformers to power them. 12v is too high really but 9v was just a gnats smidge too low, so I will resistor down to approx 10v.
The first cap has been increased from 2uf to 22uf as I need a few more volts HT. I would like 500v but may have to settle with less, perhaps 450-470v according to Duncan.
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
- Dave the bass
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- pre65
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#4
It is if you look close up.Dave the bass wrote:Shoddy!
DTB
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
- pre65
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#6
Sure isMike H wrote:Ah the chassis with the wood end-cheeks
So far its been
829b PSE
826 SET
KT66 SET
PT15 SET
and one other I think, but can't remember.
Hopefull this will be the bestest.
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
- pre65
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#8
I was short of a few vital bits so I ordered them from HFC yesterday.
True to form the came in today's post.
Main items were the Clarity cap coupling caps. Only the 12v filament transformers and a couple of power resistors to come now.
Some bits have been soldered in already, but I'm having a day off today.
True to form the came in today's post.
Main items were the Clarity cap coupling caps. Only the 12v filament transformers and a couple of power resistors to come now.
Some bits have been soldered in already, but I'm having a day off today.
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
- pre65
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#9
Could not stop myself plugging the soldering iron in.
Everything that was here is now in place, just one cathode resistor and 12v transformer to do when they arrive.
Everything that was here is now in place, just one cathode resistor and 12v transformer to do when they arrive.
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
- pre65
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#11
Painfull.
The filament modules are now fixed to their bases, they are up high cos the air is cooler at altitudes.
Just a few wires to connect them up to the main amps and it's all done.
Can't get the 811a valves till next week now so there's no panic.
The filament modules are now fixed to their bases, they are up high cos the air is cooler at altitudes.
Just a few wires to connect them up to the main amps and it's all done.
Can't get the 811a valves till next week now so there's no panic.
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
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#12
pre65 wrote:The filament modules are now fixed to their bases, they are up high cos the air is cooler at altitudes.
Is that MDF or "proper wood" ?
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
- pre65
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#13
Just hordinery MDF from the scrap pile.
The weight of the 100va transformer gives it stability. The transformers came from a low voltage lighting specialist.
The weight of the 100va transformer gives it stability. The transformers came from a low voltage lighting specialist.
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
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#14
Which "filament modules" are you using?pre65 wrote:The filament modules are now fixed to their bases, they are up high cos the air is cooler at altitudes.
Ta
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#15
Hi Nick, they are the Tentlab 5 amp ones which I originally purchased for my 845 project, but have been used on 300b for quite a while.nickds1 wrote:Which "filament modules" are you using?pre65 wrote:The filament modules are now fixed to their bases, they are up high cos the air is cooler at altitudes.
Ta
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)