I remembered that I had these tiny heatsinks left over from another project, so I thought
I'd try them on this build. I got them from Amazon. They're stick on.
I'd try them on this build. I got them from Amazon. They're stick on.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
This is great for adding a LiPo and DC step up, Bluetooth module, and a graphic LED FFT spectrum display!
you should get your hands on some and see what you can do with it
something else I was thinking of was how to include in circuit charging for the 9V batteries
some more knobs arrived today. These are the high quality finish ones that X mentioned, but this is from eBay
5 Pcs Adjustable Turn Rotary Knob for 6mm D Shaft Potentiometer | eBay
5 Pcs Adjustable Turn Rotary Knob for 6mm D Shaft Potentiometer | eBay
In those big tins, a simple but cool mod would be to just wire in a couple LEDs to illuminate the circuit inside. Maybe soft orange to give a tubey vibe?
Had to put my second board on hold...a quick-turnaround work project popped up. To top it off, my wife kicked my little DIY audio station out of the house. I guess she is sick of looking at parts and tools... Now I have to set up a workspace in my shop down the hill...but maybe I'll use the opportunity to rig up a proper vent hood for myself.
Had to put my second board on hold...a quick-turnaround work project popped up. To top it off, my wife kicked my little DIY audio station out of the house. I guess she is sick of looking at parts and tools...
Now I have to set up a workspace in my shop down the hill...but maybe I'll use the opportunity to rig up a proper vent hood for myself.
StellarElephant,
It's easy to add an LED in parallel with existing one but facing up on SMT side. Sorry to hear SWMBO kicked your operation out of the house. You have a shop down the hill? You must live on a large property. I have a basement "Man Lab" so can make my mess and not be bothered too much.
It's easy to add an LED in parallel with existing one but facing up on SMT side. Sorry to hear SWMBO kicked your operation out of the house. You have a shop down the hill? You must live on a large property. I have a basement "Man Lab" so can make my mess and not be bothered too much.
Power Supply
Would there be any issues in using a DC block psu for this? Something like T1810-21J | Access Comms Plug In Power Supply 18V dc, 1A 1 Output, 2.1 x 5.5 x 11 mm Centre Positive Switched Mode Power Supply | Access Comms ?
Would there be any issues in using a DC block psu for this? Something like T1810-21J | Access Comms Plug In Power Supply 18V dc, 1A 1 Output, 2.1 x 5.5 x 11 mm Centre Positive Switched Mode Power Supply | Access Comms ?
just quickly assembled a frankly ridiculous amp (gonna be cap testing bed). 1000uF KZ + 220uF silmic on output, with 2700uF FR on rails. I wanted to put 2x1000uF KZ per channel but couldn't fit it through one of the holes - must've gotten a speck of solder in.
Running at 64mA bias. Quick (10mins lol) impressions with Audio Technica MSR7 is that I enjoy both amps - initial one with KA as well as this one with oversized caps. My original maybe sounds a bit congested - but I'm thinking it may be due to the lower bias (58mA) rather than the caps?
More listening & pictures to follow....
Running at 64mA bias. Quick (10mins lol) impressions with Audio Technica MSR7 is that I enjoy both amps - initial one with KA as well as this one with oversized caps. My original maybe sounds a bit congested - but I'm thinking it may be due to the lower bias (58mA) rather than the caps?
More listening & pictures to follow....
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OT but I cannot resist: I don't have a man cave, so I do it on the dining room table and often get kicked out. Wish one could sometimes add a resistor, or measure with a multimeter, or add capacitance, or slap on a heat sink to cool things down - to SWMBO!
It might work but depends on how much line AC ripple gets through. It is switched so that is good for cutting out mains 50Hz ripple, but what is switching frequency? I use a 1.2MHz DC step up after a 12v 3a SMPS PSU.
Hi X,
I just completed my attempt 2 build using all stock components and got following measurements using a 70W medical grade switching DC 15V power supply:
Channel B measurements:
R3: 6.94 V
MOSFET GDS: 8.15, 15.03, 5.28 V
JFET GDS: 1.85, 8.1, 2.1 V
R7: 5.26 V
Channel A measurements:
R3: 7.2 V
MOSFET GDS: 7.86, 15.03, 5.09 V
JFET GDS: 1.93, 2.18, 7.84 V
R7: 5.06 V
I get sounds on both channels, so that's the good part, but the measurements are a little off from what you stated, how should I trouble shoot this?
thanks!
M
Congrats BabySupra. Nothing to debug. Your particular JFET and MOSFETs happen to be in this state which is fine. 5.26v on S of MOSFET means you have 45mA bias. A bit low but perfectly usable. You can increase R4 a tad maybe try 51R. Aim for 55mA bias is you can. You can also increase R3 to 1.1k if making R4 bigger doesn't work. But if I were you - just leave it alone and enjoy it. It soudsns perfectly good here unless you are driving impedance cans.
Congrats BabySupra. Nothing to debug. Your particular JFET and MOSFETs happen to be in this state which is fine. 5.26v on S of MOSFET means you have 45mA bias. A bit low but perfectly usable. You can increase R4 a tad maybe try 51R. Aim for 55mA bias is you can. You can also increase R3 to 1.1k if making R4 bigger doesn't work. But if I were you - just leave it alone and enjoy it. It soudsns perfectly good here unless you are driving impedance cans.
Thank you for the confirmation! And yes my goal is to give my M1060 planar a little bit more oomph at 50ohm (it's optimal power range is 200mW to 2W at 50ohm)
What happens if I switch to a 18v power supply?
And also what happens if I replace R7 SMD bank to two 33ohm resistors in parallel per your desktop variant idea?
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Using 18v is fine but you can't just change R7. It may draw too too much current for the SMT mosfet to dissipate. Remember that the PCB is the heatsink and it size for about 500mW ea. If you want the desktop amp follow all the changes to the resistors and have an IRF610 with external heatsink.
