recommendations for a tube amp for small speakers?
Nov 17, 2008 at 9:08 AM Post #16 of 26
Wow, just put together a preliminary BOM for the midget and the price looks good! However, I am having trouble trying to source the parts for the following labels on the schematic:
2H 70mA inductor
100V diode


I couldn't find the 2H 70mA inductor on mouser or digikey (value seems huge?), and I'm not sure what part would be appropriate for a "100v diode". Any help?
Thanks again for the great suggestions.

For reference:
Pete's website (Mighty Midget)
Audio Xpress Article (Mighty Midget)
 
Nov 18, 2008 at 4:29 AM Post #18 of 26
What was the final damage for the Mighty Midget, and would you mind sharing the BOM? Just for some sleepy time reading... :wink:
 
Nov 24, 2008 at 9:40 PM Post #21 of 26
Ok, as promised here is the BOM. There are two blanks tho. I wasn't sure what an appropriate LED (3x per channel) would be, and the 61.9k 1W resistor is a vishay-dale part that is non-stocked at the major vendors. This is the first BOM I've put together from scratch, so please feel free to critique.

MightyMidgetBOM.jpg
 
Nov 24, 2008 at 11:41 PM Post #22 of 26
If you have trouble finding the Vishay Dale resistor in the RN military specification, just use the CMF ones, they are the exact same part, just with commercial labeling and spec's. For example the RN60 is rated at 1/4 watt. The exact same CMF60 can be rated up to 1 watt, depending on the ambient temp. Just check the data sheets before buying.

Note: I always check to make sure the part is "in stock" also. I can't tell you how many times I have placed an order with Mouser only to get an e-mail the next day stating that the back ordered parts will be shipped later. Shipping can add up real fast.
 
Nov 25, 2008 at 2:21 AM Post #24 of 26
Give Nebraska Surplus a try - mayhaps they will have some pieces you need. Oh, and you might add tube sockets to the BOM.
 
Nov 25, 2008 at 3:08 AM Post #25 of 26
Right you are, I'll add it once I find a well priced pair. And thanks for the link, they do appear to have the 61.9k RN70 in stock.

So for the LED's...since they drop 1.8v per, would a 1.8V 20mA LED do the job? or would I want something beefier like 3.6v 20 mA. If I overdo the LED's voltage rating it wont light up right?
 

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