minermark Posted February 16, 2016 Share Posted February 16, 2016 Parts sourcing for the last week I come across some interesting finds. I thought this was just a cute LiL headphone amp till I saw the back side! http://www.ebay.com/itm/191501803016?ru=http%3A%2F%2Fwww.ebay.com%2Fsch%2Fi.html%3F_from%3DR40%26_sacat%3D0%26_nkw%3D191501803016%26_rdc%3D1 1 Quote Link to comment Share on other sites More sharing options...
CindyJarvis Posted February 16, 2016 Share Posted February 16, 2016 Looks so cute! I am certain it us using a smps. It is an interesting subject to me at this time. I am currently recycling a laptop power supply good for 20vdc at 3.3A. I plan to run two 12au7 with the heaters in series. The switching noise 66.6kHz is evident on a scope, roughly 100mV so some additional filtering will be still necessary. It is above our hearing but still.. -Cindy Quote Link to comment Share on other sites More sharing options...
mustang guy Posted February 16, 2016 Share Posted February 16, 2016 Looks so cute! I am certain it us using a smps. It is an interesting subject to me at this time. I am currently recycling a laptop power supply good for 20vdc at 3.3A. I plan to run two 12au7 with the heaters in series. The switching noise 66.6kHz is evident on a scope, roughly 100mV so some additional filtering will be still necessary. It is above our hearing but still.. -Cindy You make me feel like an ape with a stick. Just how smart are you? Quote Link to comment Share on other sites More sharing options...
richieb Posted February 16, 2016 Share Posted February 16, 2016 That looks like an early 4 tube version of the little Miniwatt integrated. The newest version uses 2x EL84 and 1x 12au7 for about 2-3 watts I believe. What Cindy said the Miniwatt also uses a switching power supply. Heard one with my Belles a few years back and they sound remarkably good for a tube amp you can hold in your hand. 1 Quote Link to comment Share on other sites More sharing options...
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