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I just want to get clarfication on the wattage of the 120ohm cathode resistor in the Lightning. My first build was from a Ceri@tone kit, which comes with a 10watt resistor, however I'm currently building another "three" Lightnings (one with an extra ef86 channel) and the only 120ohm resistors I could source easily were 7watt. I figured they'd be ok (the Marshall 18watters only use 5watt cathode resistors) but thought I'd seek the advice of the experts here. Any takers??

Thanks

Barry M

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Barry M

You'll probably be fine with a 7 watt resistor (as you say, the 18watt has a 5 watter) but I'll wait for the experts to chime in before saying so with any level of conviction...

-F

Thanks for the reply .. it's just one of those things you'd rather be sure about
A friend of mine has a "real" Lightning in his Music Store (current production) - it has a 10watt cathode resistor, however all the resistors seem to be over rated (2watt carbon comp resistors throughout).
The signal/coupling/tone capacitors are interesting - they look similar to Sozo's but are physically larger; they've even used these caps for the 51pf and 180pf values.
The electrolytics, on the other hand, appear of the type that you can buy in any electronics store - Xicon (I think) for the 33uf values and Sanhwa for the 22uf values.

REGARDS

Barry M

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Barry M

Hey Barry, I have had the same problem getting values from the BOM of a number of amps. I have resorted to using the nearest value I can get from RS components and just testing voltages to see if they fall within 20% of what is required. I get the same issue with caps, I use 10uF instead of 8uF etc. I have not run into any major problems yet
Nigel

Thanks for the feedback Nigel. For some reason, the 120ohm 10w resistors seem hard to find. I ended up getting the 7 watt values from Farnell. They also have lots of silver mica caps, metal oxide resistors (3w) and Vishay Roederstein MKT1813 Ero caps (in lots of values including .0015uf, 0.01uf and .022uf and more). The Vishay's are nice caps - along the somewhere in between a Mallory 150 and Sozo.

Regards

Barry M

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Barry M