Ive read that it is essential to use a variac and slowly up the voltage the first time you run the amp and measure some points some where?
I understand the measuring part but is a variac absolutly necessary. As they are rather pricey (AU$199) i would not be willing to buy one. Is there another safe avenue i could take?
I was unshore wether this belogns here or in the electroncis forum. Moderators move at will
Thanks,
Joel
I understand the measuring part but is a variac absolutly necessary. As they are rather pricey (AU$199) i would not be willing to buy one. Is there another safe avenue i could take?
I was unshore wether this belogns here or in the electroncis forum. Moderators move at will
Thanks,
Joel
Put a light bulb in series with your transformer primary. Check www.sound.au.com or in the forum logs for more info about this.
I was close. . .
I have the cutters, iron, multi-meter, scope and decided to build a +/-25V adjustable lab supply (Rod Elliot project). Guess I should have gone with the variac. . .
A quick question, though: I can use the adjustable supply to re-form older caps? It seems that if I were to throw in a 10k resistor and connect my PS caps one at a time to the supply, I could bring the voltage up from 1-25V and drain back down with a resistor. Is that the proper technique?
Considering the above, I plan on being quite cautious with the caps, as is always recommended.
Any other suggestions for re-forming or testing surplus caps?
S.
I have the cutters, iron, multi-meter, scope and decided to build a +/-25V adjustable lab supply (Rod Elliot project). Guess I should have gone with the variac. . .
A quick question, though: I can use the adjustable supply to re-form older caps? It seems that if I were to throw in a 10k resistor and connect my PS caps one at a time to the supply, I could bring the voltage up from 1-25V and drain back down with a resistor. Is that the proper technique?
Considering the above, I plan on being quite cautious with the caps, as is always recommended.
Any other suggestions for re-forming or testing surplus caps?
S.
Testing 1-2-3..phuttttt
Frazz is right.................on the last project I did...it took me ages to check things out........only to be caught out with a tiny solder...... track....(about width of a human hair).......this gave me a real fright..........when a mini cloud of smoke rapidly appeared.
Fortunately no damage ensued......but this was a low power preamp.........I think the china syndrome is far more likely with a powerfull poweramp........and big powersupplies......any body fancy a bacon sandwich....
So .... I've invested in a variac........you just can't be too carefull.
D3 Bolton uk
Frazz is right.................on the last project I did...it took me ages to check things out........only to be caught out with a tiny solder...... track....(about width of a human hair).......this gave me a real fright..........when a mini cloud of smoke rapidly appeared.
Fortunately no damage ensued......but this was a low power preamp.........I think the china syndrome is far more likely with a powerfull poweramp........and big powersupplies......any body fancy a bacon sandwich....
So .... I've invested in a variac........you just can't be too carefull.
D3 Bolton uk
Find a couple of multi-tapped mains transformers and connect them back-to-back with provision for switching between windings.
Doesn't matter what the secondary voltages actually are as long as they are similar ranges, and the overall rating of the txs is adequate for what you want to power plus a bit for losses.
eg - HT in > 6V sec >12V sec > approx 0.5 HT out:
HT 6V 12V 0.5HT
---II------.------II---
---II------.------II---
Doesn't matter what the secondary voltages actually are as long as they are similar ranges, and the overall rating of the txs is adequate for what you want to power plus a bit for losses.
eg - HT in > 6V sec >12V sec > approx 0.5 HT out:
HT 6V 12V 0.5HT
---II------.------II---
---II------.------II---
Variacs are very good things. They are clever in design, and come in a multitude of forms and shapes. They had been around a long time so there are vintage models too. One should start a collection immedietly. I have one as a doorstop and one to dim my tracklights, and a couple for makin' amps... You can adjust the output of your Son o Zen to just a cople of watts when you just need background music...Plus the name is super-cool
As they say about oil wells in Texas: "If you ain't got one-get one"
As they say about oil wells in Texas: "If you ain't got one-get one"
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