[analog97]

Hi,

I am building a phono-pre by combining the Bugle and Bugle PS which are now built and work.  I am having trouble with 3 items:

1.  I need a fuseholder that will accept a 1/16 amp slow-blow and have gotten confused going thru that massive catalog.  Can someone who has done this specify the part # for a fuseholder that is very simple, screws down to a wood chassis that will accept one of those small 5x20 mm fuses?  Hopefully, this is simple and someone has done this.

2.  I want to get a Blue LED for the PS that will operate on the 15V Bugle PS.  Again, a part # is appreciated.

3.  A simple on/off switch for the 120 V supply.  Again, a part # is appreciated.

Any help is appreciated from those of you who have gone through this process.  I know how to wire all this together, but I guess I must be "Digi-dyslectic"  when it comes to that massive catalog.  Thanks for taking the time to help!!   

[Bill Epstein]

I didn't have much luck at Digikey either but Parts
Express has http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=071-500

They also have a great switch http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=060-370

Can't help with the LED, I don't know enough to recommend a voltage/amperage but once again, PE has plenty.

[Bill Baker]

 I don't have a digikey catalog here but do have the www.mouser.com catalog in front of me.

 Fuse holder - # 441-R345A

 Power switch - # 633-M201101-RO (SPST 6A Toggle) one of dozens of options

 LED - what kind of current?
 

[analog97]

The LED looks like it runs on 15V DC.  The Bugle PS uses 120 V AC input to a transformer which converts to 15V DC.  Pretty sure I'm reading that right.     

Thanks for the help gents.  Greatly appreciated!!

[Bill Baker]

 Hello analog,
A transformer does not convert AC to DC. You need rectification for this.  I am sure there are some diodes in there somewhere.

 15VDC is quite high for most LED's as they usually run in the 3-10V range. There are some that can run on much higher voltages but you would have to look through a catalog to find just the right one. Blue LEDs are much more sensitive (and more expensive) and have to be choosen carefully. You can also easily reduce the voltage going to the LED if you cannot find one that is happy at 15V.

[analog97]

You are obviously correct!!  On second look, it appears there are 2 1K ohm resistors  (one per leg) between the transformer and the LED.  So, the LED does see less than 15V DC.

[BradJudy]

It's a 30V power supply (+/-15V), but there are LED resistors in place, so it should handle most LEDs without problems.  You might have to change the LED resistor values to adjust for brightness depending on the LED.  With blue ones, I'd recommend getting a lower output rated LED - they always seem bright.  Just make sure you do the polarity correctly, or it will be a short-lived LED. 

[mgalusha]

For future use you can download a nifty little electronics calculator from here: http://www.electronics2000.co.uk

One of the calculators is specifically to calculate the dropping resistors needed for and LED based on the source voltage.

[Bill Epstein]

Great Link! Thanks!

I saved it to my 'tools' folder.

[analog97]

Gents,

Thanks for your kind replies and helpful links.  It seems that getting the DC value into the LED is a tad tricky as apparently these LED devices change color depending on input voltage.  I'd rather not burn up a few trying to get a blue light output, so if someone knows the part # for an LED that will be blue in the already stock-built Hagerman Bugle PS, that would be of tremendous help to me.   Thanks again for all the helpful information.     

[BradJudy]

LED's don't change color with voltage or current (by definition they emit one very specific color).  The main issue is the resistors that limit the current that goes through the resistor.  Too much current and an LED will burn out immediately or just have a shortened life.  Too little current and they will be dim or won't light up at all.  Within the usable range, adjusting the current can affect the brightness. 

Most typical blue LED's should work fine in the stock circuit.  For a power indicator I'd recommend something not too bright and with a wide viewing angle.  Blue ones tend to be bright and narrow, but there are exceptions. 

Something like Mouser part 604-WP7113MBC might work well (I haven't tried them myself). 

[analog97]

LED's don't change color with voltage or current (by definition they emit one very specific color).

I thought LED's changed color based on voltage because of my Coronet and Clarinet LED's which change color in a few seconds.  Anyway, thanks Brad very much for taking the time to identify a part for me.  Best regards.

[BradJudy]

Looking at the Clarinet manual, it uses a two-color LED, which is essentially two LEDs crammed into one.  It has three leads, letting you turn on each color separately (or both at the same time).  Reading further in the manual, it appears that Jim wired this two color LED to indicate the stages of power-up on the device (heater power and high voltage power).  It's easy to see how this statement is confusing, but the two colors are triggered by two different circuits rather than two different voltage levels. 

Probably more than you wanted to know. 

[hagtech]

Indeed, LEDs are driven by current, not voltage.  In fact, the light output is very proportional to current.  2mA is twice as bright as 1mA.  The CLARINET circuit steers a current to one or the other LED.  For a short time, there is some overlap and both LEDs are on at same time.

Typically, the BUGLE POWER SUPPLY runs at a high LED current, probably 13mA to 14mA with the 1k resistors.  Maybe better to use 2.2k to 4.7k resistors to tame the output optical power a bit.

jh