Microwave oven amps. Spacemaker ii microwave
microwave oven amps – Pyramid PB717X
Pyramid prides itself on solid car audio without the huge price tag. The PB717X is no exception, featuring two MOSFET-powered channels of 50 watts RMS (75 watts at 2 ohms), bridgeable for subwoofers, and selectable high- and low-pass crossover modes for different applications.
Solid car audio without the huge price tag. Click to enlarge.
View output diagram.
View input diagram.
Delivers two channels or bridge mono for subwoofers. The PB171X cranks out 2 x 50 watts RMS at 4 ohms and is 2-ohm stereo stable for 75 watts x 2.
Selectable Crossover Modes
The built-in crossover can be set to full for normal full-range systems, or low-pass/high-pass for delivering specific frequencies to components or subwoofers. Low-pass and high-pass frequency controls are provided for setting the crossover frequencies.
The PB717X includes both high-level and low-level inputs, so you’re covered with the various types of car stereos. The high-level inputs take direct speaker wire leads, while the low-level use RCA plugs.
To further match the amplifier to your receiver/head unit, a variable input level control is provided to dial in the perfect setting without distortion.
Subwoofer fans rejoice: The PB717X features a bass boost of up to 18 dB, for added rumble.
The MOSFET pulse width modulated power supply helps provide excellent sound quality, minimal distortion, and efficient power handling.
High-performance audio requires a lot of power, and things can get hot quickly. Like any solid car amplifier, the PB717X features protective circuits. Overload and thermal indicators let you know they’ve activated and shut off the amp. In the event of a short circuit, power protection is provided in the form of easily replaceable fuses.
RMS power @ 4 ohms:50 watts x 2
RMS power @ 2 ohms:75 watts x 2
Maximum power output:500 watts x 2
Input impedance/sensitivity (low-level):10k ohms / 200 mV
Input impedance/sensitivity (high-level):100 ohms / 5V
Signal/Noise ratio:90 dB
THD:Less than 0.04%
Frequency response:15-30 kHz
Dimensions:9.84 x 10.03 x 1.96 inches (L x W x H)
Power supply voltage:14.4V DC negative ground
Maximum current draw:30A
What’s in the Box
Pyramid PB717X power amplifier and user’s manual.
Dick Bones and Ole : Volunteer Opportunity #1
"You’re late! We could have used you a bit ago for some unfortunate business." Ole told me.
They were looking for PVC cement for a leak that was innondating the kitchen of a sick mans trailer. We stayed outside searching for it but to no avail. Eventually they figured out a way to connect the PVC without the cement through rubber adaptors whose name escapes me. My first job was to find 1/2" PVC joints in a giant plastic container full of a random assortment of plumbing accessories. They were mostly PVC connectors with smaller clamps and other doo dads which I had no clue as to their use.
Ole first tipped the container a bit. A couple of pieces fell out at my feet. Then more came out and feeling that was unsatisfactory eventually he dumped the entire container out on the drive way and told me to help find the joints. After 30 seconds we found them.
"Your first mission, if you choose to accept it" he said "is to put all of this back into the container."
There was prolly 100-200 pieces lying there which I spent the next 3 minutes picking up and putting bthem back into the container. Then once we had all that we needed we went into the trailer.
I had no idea what exactly I was getting into but it was a shock to the system. The trailer was destitute. It reeked of stale cigarettes and very old and lived in dirt. An old man sat in a musty recliner watching the Ellen Degeneris show on TV. There was filth in every direction. Stains on the ceiling. A large square piece of some sort of cake sat on the table with a knife into a container of icing. Dishes piled in sink. Coffee of indeterminate age sat in a coffee pot that hadnt looked like it had been cleaned since hte clinton administration.
The oven had been pulled out in the kitchen to get the leak behind it. Black mud lay an inch thick on the floor while Ole got to his position on the ground. Apparently someone had used a radiator hose to replace a broken pipe for the hot water. The water, which apparently is hotter than the water used in your car, had slowly eaten away leading it to burst. It sat with the dirty dishes in the sink.
Richard and I stood around for a while. Richard held the light for Ole as I stood and watched. Ole was talking about how he keeps Richard around because "the man has every tool imaginable and always knows where it is. Even though he gives me hell from time to time."
The old man who owned the house mosied around a bit. He seemed unsettled. Apparently he was a dying man. His eyes, which looked seemingly bloodshot for years, had made big red circles around his eyes. A pack of Marlboro reds on the floor lay open. He was told by Ole that if he wanted them to help that he couldnt smoke while they were there.
Eventually I handed Ole a light. Then a saw to resize the PVC. I couldnt for the life of me find the little container of grease in his tool box which he immediately found when I brought it over to him. I was a little upset at myself for that. Eventually the old man got my attention.
"Here kid come with me I want to show you something."
He brought me down the hallway to the bathroom which was even worse than the rest of the house. A kitty litter container sat on the floor which hadnt been cleaned for days. Various bathroom ammenities were strewn about the counter and the floor was covered with dirt as well. Not just bathroom dirt but actual earth.
He pointed to his washer machine. " See this here. A need this here connected ’cause if I try to do it Ima break da fuckin thing off." He grumbled and sauntered with that sense of uneasiness that I couldnt get past. His communication skills were really subpar.
Once Ole had finished with the pipe I was told to check underneath the sink to see if all the joints were good and if there was any leaking. Seeing as I had no plumbing experience at all I was unsure but I shook each one and felt it to see if it was damp. Everything seemed to be in ship shape (or at least as good as it could be given the situation of the house) and I told Richard that things seemed ok.
From there we went back outside to take what we used for the pipe back to the van. I informed Ole about the washer situation.
"Ah, one of those ‘Theres also this’ situations. We get them all the time but we always help the people with whatever they need."
Though at that point we werent really sure what needed to be done. The man who owned the house I dont think was sure what needed to be done. So off we went back into the place where everyone wanted to get out of. There was a sense of duty and urgency about Ole though not Richard.
ring core from microwave oven EMI filter
this is a ring core from an EMI filter, one of the existing winding is used, worked instantly.
the regulator ICs can adapt to different inductivities, only at high loads they need to be adjusted more carefully according to the datasheet.
it is not uncommon for EMI filter cores to produce inductivity between 100 and 1000 uH. however, the material might saturate earlier than specially made cores.
normally a smaller core could be used, but this one is free from an old microwave oven.
magnetic cores do not have aging effects, so they can be re-used easily.
microwave oven amps