HI GUYS,
I'M STEVE, AND HAVE BEEN FOLLOWING ALONG FOR AWHILE, BUT BEING A BEGINNER I DON'T HAVE MUCH TO ADD. I'M STARTING TO BUILD AN ALEPH 1.2 AND HAD SOME QUESTIONS.
L RESISTORS; THE "BRAND" I WOULD LIKE TO USE DOESN'T OFFER THE EXACT VALUE EXAMPLE:
221 THEY OFFER A 220
392 THEY OFFER A 390
IS THIS A PROBLEM?
2. CAPACITORS: I'M CORRECT IN ASSUMING THE VOLTAGE RATING ON THE POWER SUPPLY CAPS. SHOULD BE GREATER THAN 60V? 25000UF >60V? ALSO DOES THIS HOLD TRUE WITH C-5, C-6, C-7 ETC.
3. WAYNE WHERE DID YOU GET THAT NICE ROCKER SWITCH FOR S-1. RATED FOR 25A? DOES IT NEED TO BE?
THANKS, STEVE
I'M STEVE, AND HAVE BEEN FOLLOWING ALONG FOR AWHILE, BUT BEING A BEGINNER I DON'T HAVE MUCH TO ADD. I'M STARTING TO BUILD AN ALEPH 1.2 AND HAD SOME QUESTIONS.
L RESISTORS; THE "BRAND" I WOULD LIKE TO USE DOESN'T OFFER THE EXACT VALUE EXAMPLE:
221 THEY OFFER A 220
392 THEY OFFER A 390
IS THIS A PROBLEM?
2. CAPACITORS: I'M CORRECT IN ASSUMING THE VOLTAGE RATING ON THE POWER SUPPLY CAPS. SHOULD BE GREATER THAN 60V? 25000UF >60V? ALSO DOES THIS HOLD TRUE WITH C-5, C-6, C-7 ETC.
3. WAYNE WHERE DID YOU GET THAT NICE ROCKER SWITCH FOR S-1. RATED FOR 25A? DOES IT NEED TO BE?
THANKS, STEVE
For the resistors, it should not matter too much that they are a little off, as long as they are all of the ones that are 220 are 220. I would just buy ones that are 221. Read my page for the components that I bought:
Aleph PCBs
For the switch, Digikey has some nice switches.
--
Brian
gte619j@prism.gatech.edu
Aleph PCBs
For the switch, Digikey has some nice switches.
--
Brian
gte619j@prism.gatech.edu
Power Switch Rating
I'm not familiar with Aleph 1.2 .... but let me assume that 20A circuit breaker is sufficient for this amp ....... typically 15A is the maximum current allowed for No.12 conductors (Al or Cu-clad Al) .... from the house electrical panel to the receptacle ..... after any correction factors for ambient temperature and number of conductors have been applied.
I'm not familiar with Aleph 1.2 .... but let me assume that 20A circuit breaker is sufficient for this amp ....... typically 15A is the maximum current allowed for No.12 conductors (Al or Cu-clad Al) .... from the house electrical panel to the receptacle ..... after any correction factors for ambient temperature and number of conductors have been applied.
Hi Steve,
I am working on my Aleph 0 project, and I found this resistor-problem too... Perhaps the US uses a different system in Resistor grading? I noticed that in ALL Projects the resistor values are off about 1 ohm to what I'm used to.
All I know is the E220 resistor system, which steps through all values like this: 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, 82, 100.
Is this different than a supposed US system?
You could just as well add a 1 ohm resistor in series with 220 to get 221, but that's not what I prefer...
Bouke
I am working on my Aleph 0 project, and I found this resistor-problem too... Perhaps the US uses a different system in Resistor grading? I noticed that in ALL Projects the resistor values are off about 1 ohm to what I'm used to.
All I know is the E220 resistor system, which steps through all values like this: 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, 82, 100.
Is this different than a supposed US system?
You could just as well add a 1 ohm resistor in series with 220 to get 221, but that's not what I prefer...
Bouke
There are different E classes for component values. The most common is the E12 serie with 12 values per decade (1.0, 1.2, 1.5, 1.8, 2.2, 2.7, 3.3, 3.9, 4.7, 5.6, 6.8 and 8.2).
The value 221 is from E96 serie, meaning they have 96 values per decade.
Standard EIA Decade Resistor Values Table
Claus
The value 221 is from E96 serie, meaning they have 96 values per decade.
Standard EIA Decade Resistor Values Table
Claus
Hello,
The gate resistors are not critical, and if you want to use different value, then use it same for all gate resistors.
If you have problems to find 221 R, you can visit ;
www.rs-components.com
They have precision metal film resistors.
The stock no. for 221 R / 0,1% is: 165-135
Kristijan Kljucaric
The gate resistors are not critical, and if you want to use different value, then use it same for all gate resistors.
If you have problems to find 221 R, you can visit ;
www.rs-components.com
They have precision metal film resistors.
The stock no. for 221 R / 0,1% is: 165-135
Kristijan Kljucaric
Hmmmmm... don't know if I'm the wayne you want but here goes anyhow...
The switch in my amps are from Digikey, it's their part number 360-1488-ND.
As someone previously said you can wire the 2 poles in parallel to
hopefully help out a bit with the turn-on current surge - I didn't do this to mine. I hope they don't die an early death but they seem to have no trouble so far.
The switch in my amps are from Digikey, it's their part number 360-1488-ND.
As someone previously said you can wire the 2 poles in parallel to
hopefully help out a bit with the turn-on current surge - I didn't do this to mine. I hope they don't die an early death but they seem to have no trouble so far.
We're talking transformer ...not motors ...... so, I don't see why we need to use more than 15A switch. Example: Full load current for a 1000VA transformer is less than 10A. If we allow 75% more for in-rush current , 15A is still o.k. If it goes a lot higher than that, the circuit breaker at the electrical panel would trip before it even have a chance to destroy the switch.
inrush for a toroid during the 1st 1/2 cycle or so of the mains, is HUGE and when you also take into account the discharged capacitor bank which will initially act like a short circuit, the current surge will EASILY exceed 20A by a large margin if some kind of soft start circuit is not implemented.
Yes, there are the two factors listed above that produce huge inrush currents. I think Nelson talks about 50A and higher turn-on surges. My caps are short circuit - 88,000 uF worth. THe only
saving grace is the thermistor in the primary circuit which is about 9 ohms at turn-on. You need a big switch, the only question is whether my switch is big enough... time will tell.
BTW, the lights in my amp circuit go quite dark for a short time when I turn on the amps - the surge is quite pronounced.
saving grace is the thermistor in the primary circuit which is about 9 ohms at turn-on. You need a big switch, the only question is whether my switch is big enough... time will tell.
BTW, the lights in my amp circuit go quite dark for a short time when I turn on the amps - the surge is quite pronounced.
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