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Topic: Webb amp pilot lights |
Brian Echenberg
From:
Quebec, Canada
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Posted 2 Jan 2009 4:21 pm |
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| hi Can anyone tell me , on the control panel, What makes the 2 pilot lights at each end, light up. mine is a 6-14E and the lights are on top of Sensitivity, and just after the name Webb steel guitar. My amp works great but nothing I do makes these red bulbs light up. thankyou |
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Ken Fox
From:
Nashville GA USA
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Posted 2 Jan 2009 6:39 pm
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They are driven off of a 60 volt DC or so tap off the power supply through a 5 watt current limiting resistor.
The older models use a screw in lens cap and the bulbs were replaceable. I have them in stock. The new ones are a lamp assembly, non replaceable bulb. Tom Bradshaw has that type in stock.
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David Higginbotham
From:
Lake Charles, Louisiana, USA
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Posted 2 Jan 2009 6:45 pm
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Brian, the older model Webb's use a standard #327 bulb 28v .040 ma that can be picked up at any industrial electronics store. I think I may have a few that I can give you if you can't find them.
If they are new bulbs and do not work Ken may have your fix.
Dave |
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Ken Fox
From:
Nashville GA USA
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Posted 2 Jan 2009 6:59 pm
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| I only carry the #327 bulb in stock. Tom Bradshaw would be the best source on the new bulb assembly. |
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Brian Echenberg
From:
Quebec, Canada
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Posted 2 Jan 2009 7:21 pm
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| thanks for the info, but what makes these bulbs light up.? |
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Ken Fox
From:
Nashville GA USA
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Posted 2 Jan 2009 7:28 pm
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Assuming you cannot read a schematic then simply put, electricity makes them light up
The circuit is shown above. When the amp is powered up the -60volt supply drives the bulbs through the 5 watt resistor. The resistor limits the current and voltage to the bulbs. The 5 watt resistor runs hotter than a match in these amps! I often see the circuit board well toasted by the heat from it. |
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Jerry Roller
From:
Van Buren, Arkansas USA
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Posted 2 Jan 2009 9:42 pm
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Ken, I think his question is what do the lights indicate? If I remember correctly they indicate that the amp is turned on. It just has two instead of one which is more common. Right?
Jerry |
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Ken Fox
From:
Nashville GA USA
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Posted 3 Jan 2009 7:10 am
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| Ah, yes that is correct Jerry. The other lights are LED's. One above the EQ switch to indicate if the EQ circuit is on. One of the three above the tone selector is on all the time and changes with the dial. The other LED is above the reverb knob and is on all the time, it serves no indicating purpose, just there to be pretty. |
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Brian Echenberg
From:
Quebec, Canada
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Posted 3 Jan 2009 8:02 am
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| tHANKS EVERYONE. i WOULD BE HAPPY TO BUY 2 0R 3 OF THE OLD #327'S From Ken. or anyone else who has them.keep on pickin' Brian fredechenberg@yahoo.ca |
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Jack Stoner
From:
Kansas City, MO
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Posted 3 Jan 2009 8:26 am
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| Use 387's instead of 327's they are a "ruggedized" and will last a lot longer. Some commercial communications patch panels that we had used 327's and they burned out fast, a guy from AT&T told us about the 387's and what AT&T used and they are a longer lasting lamps. I went to Graybar and got the 387's and as as the 327's went out we replaced them with 387's and they lasted a lot longer. |
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Ken Fox
From:
Nashville GA USA
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Posted 3 Jan 2009 1:07 pm
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| Both are rated 28 volts at .040 amps. The 387 has a life of 7,000 hours as opposed to 4000 hours on the 327 bulb. |
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