Hi guys,
First of all I should mention that I’m not in the league of many of you , I’ve changed a few capacitors and upgraded cables on amps and speakers , I now have these huge power amps which I believe haven’t been switched on for about 10 years, I wish to power them up myself but can this only be done safely with a variac ? And if so how do I know how many amps the variac needs to be etc . They are 240v and I’m told are 1000w ( output) each .
Obviously I don’t want to simply plug them in and hope for the best so what’s the best plan of action please?
First of all I should mention that I’m not in the league of many of you , I’ve changed a few capacitors and upgraded cables on amps and speakers , I now have these huge power amps which I believe haven’t been switched on for about 10 years, I wish to power them up myself but can this only be done safely with a variac ? And if so how do I know how many amps the variac needs to be etc . They are 240v and I’m told are 1000w ( output) each .
Obviously I don’t want to simply plug them in and hope for the best so what’s the best plan of action please?
Thanks for your reply Naresh .
I’m just into my Hifi really.
I picked these up a few weeks ago, all I know is that they’re apparently 1000watts each , built by a medical doctor whose hobby was diy hifi .
They are rather intimidating to look at with those huge Drake transformers and then there are more transformers ( Sowter ) I can see quite a few mosfet transistors, they drove 4 sets of speakers, the fronts ( diy built) were around 6 ft tall and the rears were built with ATC drivers.
Inside the casing someone has painted on what I can only guess as a rubberised paint ( maybe bitumen) to aid with sound deadening, the son of the builder explained how they would rattle.
Will the dim bulb tester method work?
There was a mention that they’re of a Linsley hood design.
I’m just into my Hifi really.
I picked these up a few weeks ago, all I know is that they’re apparently 1000watts each , built by a medical doctor whose hobby was diy hifi .
They are rather intimidating to look at with those huge Drake transformers and then there are more transformers ( Sowter ) I can see quite a few mosfet transistors, they drove 4 sets of speakers, the fronts ( diy built) were around 6 ft tall and the rears were built with ATC drivers.
Inside the casing someone has painted on what I can only guess as a rubberised paint ( maybe bitumen) to aid with sound deadening, the son of the builder explained how they would rattle.
Will the dim bulb tester method work?
There was a mention that they’re of a Linsley hood design.
I think I read that when doing the dim bulb test that you must use a bulb that has the same amount of wattage as the item you are testing but I don’t know what the wattage of the amps are .
Don't loose your sleep over the dim bulb tester. Just use whatever bulb you can still find these days and give it a go. If your bulb is too "small" it will keep glowing a little bit even if the amp is working fine.
Before powering up the amp I'd make sure that mains earth is connected well to the chassis and that there are no loose wires or other things that came off from where they have been.
Just give it a go and see if the smoke stays inside. If things blow up, don't freak out but focus on the exact spot where the action is before turning things off. Otherwise you won't know where you need to fix tings.
Before powering up the amp I'd make sure that mains earth is connected well to the chassis and that there are no loose wires or other things that came off from where they have been.
Just give it a go and see if the smoke stays inside. If things blow up, don't freak out but focus on the exact spot where the action is before turning things off. Otherwise you won't know where you need to fix tings.
... and don't power them up on the plush carpet in the living room ;-)
Jan
Jan
If you are "just into hifi", I wouldn't power them up. I'd scrap them. Or give them to some seasoned DIY guru. By all means check insurance situation.
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I think you or someone else posted a similar query some time back.
Some close ups, enough to read numbers on the outputs, will be nice.
Some close ups, enough to read numbers on the outputs, will be nice.
😳😳😳😳
I'm the "do-it-yourselfer" type and always inclined to find solutions, but here I think we'll have to invest.
one solution would be to get you a big 240Vac to 120Vac transformer to wake them up gently and put a suitable fuse between the two (even undersized), all that only to wake them up gently by supplying them with 120Vac.
Also look at the service voltage of the capacitors of the "power" part to give you an idea of the supply voltage of the power boards.
Try to understand a little how the amp is made and what are the voltage / current in play here, it will give you an idea of the power, also look for the references of the power transistors.
I think very honestly that without a minimum of financial investment, you take a big risk of putting them under tension even with a DBT of generous size.
I'm the "do-it-yourselfer" type and always inclined to find solutions, but here I think we'll have to invest.
one solution would be to get you a big 240Vac to 120Vac transformer to wake them up gently and put a suitable fuse between the two (even undersized), all that only to wake them up gently by supplying them with 120Vac.
Also look at the service voltage of the capacitors of the "power" part to give you an idea of the supply voltage of the power boards.
Try to understand a little how the amp is made and what are the voltage / current in play here, it will give you an idea of the power, also look for the references of the power transistors.
I think very honestly that without a minimum of financial investment, you take a big risk of putting them under tension even with a DBT of generous size.
Response to #3 - idle thought:
I am not aware of all Linsley Hood designs - but the one that springs to mind is a class A amplifier.
However I doubt that even that massive amount of heatsinks visible on the pictures would be enough for 1000W (possibly with forced cooling, maybe).
But, if these are class A amplifiers - even "just" being a few 100W, that would make the lightbulb test close to unusable.
I am not aware of all Linsley Hood designs - but the one that springs to mind is a class A amplifier.
However I doubt that even that massive amount of heatsinks visible on the pictures would be enough for 1000W (possibly with forced cooling, maybe).
But, if these are class A amplifiers - even "just" being a few 100W, that would make the lightbulb test close to unusable.
Those transformers look like they came from valve era equipment, and some TO-3 as well.
Dangerous territory.
Bail out.
Outputs meant output transistors, not the supply transformers.
If you post transformer photos when asked for part numbers on outputs (output transistors, which is what I expected in this device), you are very new to this field.
You are putting your life at risk, as well as that of your family.
Not in your league, this is a mish-mash made by a dead person, who cannot guide you, unless you can find circuit diagrams.
I have no idea if this actually worked in the past.
Where are the speakers?
Most experienced technicians will hesitate at this , so it will be a long, lonely and expensive road to make this work.
This is unique, leave it alone.
Dangerous territory.
Bail out.
Outputs meant output transistors, not the supply transformers.
If you post transformer photos when asked for part numbers on outputs (output transistors, which is what I expected in this device), you are very new to this field.
You are putting your life at risk, as well as that of your family.
Not in your league, this is a mish-mash made by a dead person, who cannot guide you, unless you can find circuit diagrams.
I have no idea if this actually worked in the past.
Where are the speakers?
Most experienced technicians will hesitate at this , so it will be a long, lonely and expensive road to make this work.
This is unique, leave it alone.
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I can anly see a few power transistors, not enough to for a 1000W rating.
Try to take as many detailed photos of all the pcbs as possible.
These are devices that I could take months or even years to restart (a bit like I found a Formula 1 in a barn or a motorcycle gp), you have to take the time to do things in order and with extreme method.
Otherwise there remains the technique of the broomstick (to press the switch), in the garden, at the end of an electric extension with a fire extinguisher at hand. 🤪
These are devices that I could take months or even years to restart (a bit like I found a Formula 1 in a barn or a motorcycle gp), you have to take the time to do things in order and with extreme method.
Otherwise there remains the technique of the broomstick (to press the switch), in the garden, at the end of an electric extension with a fire extinguisher at hand. 🤪
I did doubt that the mentioned 1000w would be correct.
What good is 1000w anyway
on the other hand, 1000Va the power supply transformers seems plausible
These amps seem to be a relay trophy's in the particular neighbourhood. Rookies "picks them up" - one wonder if there is any money exchanged - presumably impressed by the size and power figure.
1000 WATTS - wow!
My toaster outputs 1200.
Let them rest. Take them apart and sell the trafos. Recycle the electronics in an environment friendly manner.
Let these amps RIP.
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1000 WATTS - wow!
My toaster outputs 1200.
Let them rest. Take them apart and sell the trafos. Recycle the electronics in an environment friendly manner.
Let these amps RIP.
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Guys, don't spoil the fun! Why do you guys assume this thing is bad/dangerous/evil/whatever?
I say plug those babies in in and see what happens!
I say plug those babies in in and see what happens!