Search found 5449 matches

by mediatechnology
Sun Feb 22, 2015 2:02 pm
Forum: The Peabody Lounge
Topic: Heat loss and insulation
Replies: 14
Views: 17427

Re: Heat loss and insulation

So guys - What would you recommend for an absolute maximum power device temperature? The rule of thumb I've always heard is that if it's too hot to touch it's too hot. I'm reading 80 deg C at the heatsink. 80 deg C is not something you want to grab. The devices have a 150 degree C maximum junction t...
by mediatechnology
Sun Feb 22, 2015 1:42 pm
Forum: Pro Audio Design
Topic: Limiters with optocouplers
Replies: 48
Views: 125111

Re: Limiters with optocouplers

I believe it was the Cadmium. Silonex is now Advance Photonics http://advancedphotonix.com/optosolutions/products/optocouplers/ Available from Digi-Key: http://www.digikey.com/product-search/en?site=us&lang=en&v=209&c=57&WT.z_supplier_id=209&WT.z_page_type=SP&WT.z_page_sub_ty...
by mediatechnology
Sun Feb 22, 2015 9:40 am
Forum: Pro Audio Design
Topic: Designing the pcb
Replies: 12
Views: 22177

Re: Designing the pcb

The supply bypass on every chip would go to the supply ground. Is this still a single-supply design? If so, the supply bypass for op amps should be from Vcc to Vee. (e.g. pins 8 and 4 of a dual op amp) Although Vee connects to DC supply ground it is better practice to have the bypass capacitors - a...
by mediatechnology
Sun Feb 22, 2015 9:29 am
Forum: The Peabody Lounge
Topic: Heat loss and insulation
Replies: 14
Views: 17427

Re: Heat loss and insulation

I saw a YouTube demo of a Fluke IR camera the other day that was really cool.
by mediatechnology
Sun Feb 22, 2015 8:02 am
Forum: Pro Audio Design
Topic: A Simple 10W Direct-Coupled Class-A Power Amplifier
Replies: 98
Views: 189824

Re: A Simple 10W Direct-Coupled Class-A Power Amplifier

You need a couple of LEDs on the PCB so it looks more testicle if the punter opens up the case :)

Even better if the case has a transparent window so these can be seen from the outside. Or a tube with just the filament powered up.
Good points.
by mediatechnology
Sat Feb 21, 2015 5:50 pm
Forum: The Peabody Lounge
Topic: Heat loss and insulation
Replies: 14
Views: 17427

Re: Heat loss and insulation

I backed away about 2 feet with the laser spot on the HS and it's more like 175 degrees F. I checked it with the junction-based probe and it also reads about 175 F. I've thought all along I wanted to sandwich a third heatsink into the middle of the stack. I looked into temp sensors before and don't...
by mediatechnology
Sat Feb 21, 2015 4:07 pm
Forum: The Peabody Lounge
Topic: Heat loss and insulation
Replies: 14
Views: 17427

Re: Heat loss and insulation

I think the laser-pointer-assisted IR thermometer I have is inaccurate at close range. (inches)

I backed away about 2 feet with the laser spot on the HS and it's more like 175 degrees F.
I need to use the contact temp probe.
Still, I'm hopeful about the egg cooker...
by mediatechnology
Sat Feb 21, 2015 1:19 pm
Forum: The Peabody Lounge
Topic: Heat loss and insulation
Replies: 14
Views: 17427

Re: Heat loss and insulation

An egg needs a temperature of 158°F to become firm. In order to cook, proteins in the egg must denature (modify), then coagulate, and that won’t happen until the temperature rises enough to start and maintain the process. Source: http://www.loc.gov/rr/scitech/mysteries/friedegg.html OK. The heatsin...
by mediatechnology
Sat Feb 21, 2015 9:26 am
Forum: The Peabody Lounge
Topic: USB Typewriter Conversion Kit -- Easy Install Version
Replies: 1
Views: 5471

USB Typewriter Conversion Kit -- Easy Install Version

OK, now I've seen it all... If I had posted this on April Fools everyone would have thougth this was a joke. https://img0.etsystatic.com/010/1/5903781/il_570xN.419763490_ps46.jpg https://www.etsy.com/listing/110949979/usb-typewriter-conversion-kit-easy? Should I have posted this in "Build?"
by mediatechnology
Thu Feb 19, 2015 6:06 pm
Forum: Pro Audio Design
Topic: A Simple 10W Direct-Coupled Class-A Power Amplifier
Replies: 98
Views: 189824

Re: A Simple 10W Direct-Coupled Class-A Power Amplifier

Thought I would post a photo of the "Simple Dual 10W Direct-Coupled Class-A Power Amplifier" powered by Meanwell 18V, 60W switchers. This is the whole enchilada: https://proaudiodesignforum.com/images/jpg/DCAO-10W_Class-A_Amp_With_Switching_Power_Supplies_small.jpg Dual 10W Direct-Coupled...