right off the top of my head I can't tell you...I will have to find my log, it seems like such a long time ago. I do remember 250mv was the last attempt(works out at 0.5 amps if memory serves) but I've noticed that after about 4 hours the temp on the trannie is worrying. The sinks are ok, its just the 300va transformer.
At 250mv it really does sing...under my normal philosophy I would leave it alone because it works, but for some reason I have the devil in me with this and I want to see if there is something beyond perfection.
Bearing in mind that it exposed the colour of your TVC, I think I understand exactly what a Li-Te DAC AH sounds like now as I've done the with and without test......Its not to be trifled with!
Last edited by ed on Mon Jan 14, 2008 7:57 pm, edited 1 time in total.
There's nowhere you can be that isn't where you're meant to be
I guess you mean 250mv across the R47 resistor? That would be 530ma. So that would be 3.2A from each rail, so 300va should be well within its limits. I think the piltron Ian used was 300va. Mind you, there will be some hefty spiked into the first cap.
Last edited by Nick on Mon Jan 14, 2008 7:59 pm, edited 1 time in total.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
yes thats exactly what I remember coming up with...which means 75watts per channel at idle....which gives 150 watts both channels....So I doubled that for the trannie spec(cos I'm accurate with things like this....DTB style) and came up with a safe 300va......
and what do you know......300 gets terrible hot...go figure
There's nowhere you can be that isn't where you're meant to be
Nick wrote: Mind you, there will be some hefty spiked into the first cap.
If you mean at switch on then I think the thermistor should cope. Its the same CL60 that is used in the big aleph psus and IIRC some of those milk bottle caps are way bigger than my puny 15000ufs(120000 in total).
There's nowhere you can be that isn't where you're meant to be
pre65 wrote:Hi-you cant have a transformer thats too big !
Within reason of course in case Darrens got one the size of a dustbin !!!!
Nah, the largest one I have is only 75Kg, nowhere near the size of a dustbin.
Chuffin 'eck is that a two 'man' lift?
The iron-ware for my current power amp was about 35kg, came in 3 separate boxes, and I thought that was more than enough....in fact I'm trying to ween myself off, so I don't have to strengthen the floor....
pre65 wrote:Hi-you cant have a transformer thats too big !
Within reason of course in case Darrens got one the size of a dustbin !!!!
Nah, the largest one I have is only 75Kg, nowhere near the size of a dustbin.
Chuffin 'eck is that a two 'man' lift?
The iron-ware for my current power amp was about 35kg, came in 3 separate boxes, and I thought that was more than enough....in fact I'm trying to ween myself off, so I don't have to strengthen the floor....
No I meant the charging current for the first cap. What I found was everything in the amp got hot, mainly becase it was surrounded by two heatsinks dissapating several hundred watts of heat.
One thing I did change, was replace the four parallel resistors between the caps, with TO220 resistors mounted on the case, that removed a small but extra source of heat. What I found was the heat was conducting into the caps and gatting them hotter than the needed to be.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
Darren wrote:
The iron-ware for my current power amp was about 35kg, came in 3 separate boxes, and I thought that was more than enough....in fact I'm trying to ween myself off, so I don't have to strengthen the floor....
It's on wheels, flippin needs to be.....
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Well mine isn't as big as Darren's but it's for sale if anyone is thinking of building one of these F4's.
btw did you source Ian's Plitrons and if so can you tell me where
Nope, Ian did, but I am sure he will tell you.
I think I should create a solid state area, to give this a place to live.
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I got the Plitrons through a group buy on diyaudio, and yes they are 300va. Because it was mainly americans who were participating in the group buy they were rated for 115v or 230v. I'm sure that 240v is within their tolerance range (my mate Nelson who always uses them says it is ) but I discovered later that they do another variant which is rated for 240v. I'm pretty sure you can buy direct from Plitron in Canada if you want.