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
BEGINNER
BRIAN THANKS FOR THE INFO ON THE RESISTORS.I'LL PROBLLY SWITCH BACK TO ANOTHER BRAND.AS FOR THE SWITCH I'VE BEEN TO DIGIKEY AND MOUSER BUT ALL THERE ROCKER SWITCHS ARE RATED 15A. WHICH I CAN'T SEE HOW THE AMP COULD POSSILBILITY DRAW MORE THAN 15A.?
THANKS STEVE
BRIAN THANKS FOR THE INFO ON THE RESISTORS.I'LL PROBLLY SWITCH BACK TO ANOTHER BRAND.AS FOR THE SWITCH I'VE BEEN TO DIGIKEY AND MOUSER BUT ALL THERE ROCKER SWITCHS ARE RATED 15A. WHICH I CAN'T SEE HOW THE AMP COULD POSSILBILITY DRAW MORE THAN 15A.?
THANKS STEVE
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
THANK YOU FOR THE RESPONSES.CLAUS, GREAT WEB SITE. I PRINTED THAT INFO.NELSON SAID IN THE THREAD "ALEPH 4 PSU CAPACITORS" ADDING A INDUCTOR (CHOKE?) BETWEEN CAPS WOULD PROVIDE ADDITIONAL FILTERING. BUT IN SELECTING THIS CHOKE WHAT MA VALUE AND OHMS WOULD HAVE TO MAINTAIN.
220 0hm resistors
I'm assuming that you are talking about gate resistors. Don't even think about adding 1ohm in series with 220ohm to achieve 221ohm. The specific value of those resistors is not important at all. Anything around 200ohms is OK.
I'm assuming that you are talking about gate resistors. Don't even think about adding 1ohm in series with 220ohm to achieve 221ohm. The specific value of those resistors is not important at all. Anything around 200ohms is OK.
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
Steve,
Take off the caps lock...
The current rating on the switch is so that it can handle the turn-on surge.
Grey
Take off the caps lock...
The current rating on the switch is so that it can handle the turn-on surge.
Grey
SWITCH
Think about using a two-pole switch and wiring the two poles in parallel. For a big amp, the switch will fail if it isn't over-rated by a big margin.
Think about using a two-pole switch and wiring the two poles in parallel. For a big amp, the switch will fail if it isn't over-rated by a big margin.
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.
It is a good idea to put a capacitor (0.1uf 200v should do) across the switch contacts to prevent arcing and this should prolong the life of the switch.
Jam
Jam
What would be the effect of an Inrush-protection cirquit? Like a bank of resistors before the caps to limit the current, and bypass these resistors after the caps are charged?
Would that decrease the quality of sound?
Bouke
Would that decrease the quality of sound?
Bouke
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