Hot Rod Deluxe occasional pop

[woodyc]

It was R57. I went back to the shop after dinner and didn't find it until 12:20am.

So the purpose of this post is to publicly humiliate this resistor:



Anybody know what type/brand it is?

[Enzo]

Brand??? Could be a hundred brands.

The dumbell shape tells you it is a film resistor. Note #3 on the factory schematic tells us "all resistors 1/4w 5% carbon film."

[soundguruman]

The brand does not matter.
Use metal film audio resistors. Replace all the resistors in the audio path.
There are also mechanical relays and FETs that cause occasional POPs.

[Gtr_tech]

Hmm....yes. The common phase inverter plate load failure. I'd use nothing less than 1/2w here. 1w ain't a bad idea for *all* plate loads.

[soundguruman]

I think 1W plate resistors are a good idea. Good suggestion I think.

[woodyc]

...The dumbell shape tells you it is a film resistor. Note #3 on the factory schematic tells us "all resistors 1/4w 5% carbon film."

Thanks Enzo, I probably looked at that schematic for a fifteen minutes yesterday and didn't notice.

The film resistors I use the most are the torpedo shaped Dales on the right:


Gtr_tech yeah I did use a half watt -- Good idea.

soundguruman, changing all the resistors in the signal path would be kind of silly, you know, in my humble opinion.

[J M Fahey]

Replace all the resistors in the audio path.

You know, thereīs people who read such blanket statements and follow them to the letter .
They donīt really know why .... but .... "it was on the respected Music Electronics Forum , so .... "
I mean, fully agree in *certain* cases, such as in noise sensitive input stages, or some PI plate load resistors, but ... *all* resistors?
Specially considering that a beginner (no disrespect intended, quite the contrary) maybe does not have Nasa-approved soldering skills (Iīm really worried about de-soldering and pulling parts) and probably will do more damage to the PCB than any potential sound improvement he might get.
And yes, I have had to repair amps where solder iron happy people had been trying to "improve sound" by following every and all "Guru" suggestions posted all over the Net.
jm2c