Ive got a questions regarding resistors ,caps
I go to the local store to purchase resistors and sometimes caps .
I noticed that the shop usually stocks NTE parts as far as transistors , resistors ect .
So the resistors I’m buying I’m guessing are made by NTE.
When I rebuild amps for myself or friends at least 2 out of 10 come back with issues say the power supply was blown I replace the fets and gate resistors and the amp comes back with blown fets again .
Wondering if I’m over thinking this or not but wondering could the resistors I’m buying from this store be causing issues or is it something I may have over looked ?
I know not to use NYE transistors in amps but could the resistors possibly be the cause of the amps being retuned even tho the resistors test good out of the package . It’s strange that if the fets were blown and I replaced them along with resistors and drivers I always get at least 2 amps back with the same issue after using the resistors I bought from the local shop .
Any thoughts ?
I go to the local store to purchase resistors and sometimes caps .
I noticed that the shop usually stocks NTE parts as far as transistors , resistors ect .
So the resistors I’m buying I’m guessing are made by NTE.
When I rebuild amps for myself or friends at least 2 out of 10 come back with issues say the power supply was blown I replace the fets and gate resistors and the amp comes back with blown fets again .
Wondering if I’m over thinking this or not but wondering could the resistors I’m buying from this store be causing issues or is it something I may have over looked ?
I know not to use NYE transistors in amps but could the resistors possibly be the cause of the amps being retuned even tho the resistors test good out of the package . It’s strange that if the fets were blown and I replaced them along with resistors and drivers I always get at least 2 amps back with the same issue after using the resistors I bought from the local shop .
Any thoughts ?
Do you test the amps at full power (with music) for extended periods of time before letting them go?
If so, the problem is likely that the problem in the vehicle that caused the amp to fail has not been resolved.
The resistors are likely fine but WAY overpriced.
If so, the problem is likely that the problem in the vehicle that caused the amp to fail has not been resolved.
The resistors are likely fine but WAY overpriced.
I test the amps with music for around an hour each not full power I test them at a moderate level and they seem fine for an hour of playing and I let them go .
Like I said maybe 2 out of 10 to 20 amps comes back with the same issues .
Like I said maybe 2 out of 10 to 20 amps comes back with the same issues .
Set up your bench so you can work on amps while testing others at high power.
I tested class D amps up to and into clipping with bass music for 3 hours (without exception). I used a dummy load that was double the lowest rated impedance. For class AB amps, I tested up to thermal shutdown, for most amps. To speed up the process for amps with better heatsinks, I put a towel over the sink to make them heat up faster.
This applies to amps that had blown outputs, PS FETs or blown caps, not to simple repairs like broken connections on terminals and such.
I tested class D amps up to and into clipping with bass music for 3 hours (without exception). I used a dummy load that was double the lowest rated impedance. For class AB amps, I tested up to thermal shutdown, for most amps. To speed up the process for amps with better heatsinks, I put a towel over the sink to make them heat up faster.
This applies to amps that had blown outputs, PS FETs or blown caps, not to simple repairs like broken connections on terminals and such.
Check out Arcol resistors like HS150,HS200,HS300 series depending on the power of your amps.
Heatsinked of course, they are ~20% of that rating without.
If you can't thrash it up to full power, you've not confirmed anything.
Heatsinked of course, they are ~20% of that rating without.
If you can't thrash it up to full power, you've not confirmed anything.
In my opinion, the cylindrical ceramic resistors are generally better (with forced air cooling from the end so air flows through the resistors). They are capable of withstanding 10x their rated power for intermittent peaks.
Yes. Wirewound but they don't need a heatsink and can take far more than their rated power, especially when fan cooled.
People can choose what they like. This is my preference. I used them for about 30 years and they worked beautifully.
People can choose what they like. This is my preference. I used them for about 30 years and they worked beautifully.
