Express power supply board, question...
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Express power supply board, question...
I have a question regarding the resistors used in this power supply, I can't seem to find metal oxide resistors of the 9.1k or 18.2k values where I live, I'm inclined to use wirewound 10K+8.2k in series for the 18.2k and 8.2K+1k in series for the 9.1k, any thoughts on this?
Also I'm haven't been able to get the 25w 1k resistor, would a 17W workout?
thanks
Also I'm haven't been able to get the 25w 1k resistor, would a 17W workout?
thanks
Re: Express power supply board, question...
No prob, you may do so!
Larry
Larry
Larry's Website now with included Pix's Gallery
Re: Express power supply board, question...
The actual values aren't critical. You may use slightly different value R's, 2w or preferably 3w-rated.any thoughts on this?
It will. the original 25w is vastly oversized : a 3 or 5w model is more than adequate!Also I'm haven't been able to get the 25w 1k resistor, would a 17W workout?
Re: Express power supply board, question...
For the current through it, yes it is oversized. However, it is entirely possible that there is some inductance from that resistor that helps shape the tone. According to "legend," EVERYTHING on the Wreck was chosen carefully and specifically.
Wife: How many amps do you need?
Me: Just one more...
Me: Just one more...
Re: Express power supply board, question...
Riscado, Those resistor combos are fine. You could probably use 10K throughout. The larger watt 1K resistors will run cooler. That resistor does heat up once you start spanking. The 25W stays cool but, the 10W heats up quite a bit if I remember correctly.
Allynmey
Allynmey
Re: Express power supply board, question...
thanks allyn
by the way I also noticed the express uses two 100k 3w resistors, I can't find those unless I use 1W because I haven't found wiredwounds as high as 100k...
by the way I also noticed the express uses two 100k 3w resistors, I can't find those unless I use 1W because I haven't found wiredwounds as high as 100k...
Re: Express power supply board, question...
1W types are on the border!
They'd withstand, because each of the 100K is dissipating only 0.4W @ a voltage of 400VDC across both in series - but due to their small body size/surface they'd become fairly hot and the steady radiation due to the heat will be sucking dust and dirt to it over the time.
Larry
They'd withstand, because each of the 100K is dissipating only 0.4W @ a voltage of 400VDC across both in series - but due to their small body size/surface they'd become fairly hot and the steady radiation due to the heat will be sucking dust and dirt to it over the time.
Larry
Larry's Website now with included Pix's Gallery
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Re: Express power supply board, question...
Re: 100K 3 W Resistors.
I've wondered why he used Carbon Comps here (Francesca). I found a couple of 2 Watters in my stash that I'm using for my build.
I have to think that Ken used what he would have around in some cases.
Cheers, Mike
I've wondered why he used Carbon Comps here (Francesca). I found a couple of 2 Watters in my stash that I'm using for my build.
I have to think that Ken used what he would have around in some cases.
Cheers, Mike
The Jammy Dodger
Re: Express power supply board, question...
It physically can't. Wirewounds such as the ones used on Wrecks show very little inductance and have totally negligible effect in a power supply RC network.However, it is entirely possible that there is some inductance from that resistor that helps shape the tone.
Yeah, this is the legend. Ken F. did an outstanding job with the Wreck architecture, which is basically medium/high gain with balanced disto from stage to stage and overall an amp always on the verge of instability.According to "legend," EVERYTHING on the Wreck was chosen carefully and specifically.
He used whatever components were available to him, fine tuning/voicing each and every amp to his liking.
He knew his stuff.
That's why he was one of the true greats, not because he sprinkled his perf boards with vintage mojo powder or used polyester caps potted in the Outer Hebrides by blind zen monks.
Re: Express power supply board, question...
I understand mouser has pretty much anything necessary, however I'm in europe and it would be overkill to order 5 or 7 resistors from the states.
However thanks for pointing it out.
However thanks for pointing it out.