There won’t be much room in the mobile home to set up any “real” speakers so I‘m going to set up my first serious experiment with a “small” speaker system. I added a sub out to my 14 watt per channel 10EM7 amp. Another 12SL7 with degeneration to get the effective mu down to about 20, passive mix and 200 Hz low pass (to get rid of unneeded HF voltage swing). Speakers are the little brother to my 3 way 10” shop background system - 2” mid/tweet and 7” midbass. Powered sub is a sealed 10” GRS and 150W class H home brew. Linkwitz- transformed to be anechoic to 22.5 (In theory). Crossover is at 60, right where the mains cut off naturally (Dip switch adjustable). I don’t mind the sound of a little room gain - been living with and enjoying my 2x10 flat to 23 monkey coffins for almost 2 decades now.
Oh yeah, and “BOX 2” is coming with me out to the site tomorrow, while I work on decking in above the back room and getting the rest of the 2X10’s up. 60 watts per channel feeding a pair of BOFUs. The car stereo head is only the media player - I don’t believe any 50 watt x 4 power rating, since I only measured 6 volts peak to ground on each side of the BTL, as one would expect. I needed to use speaker out instead of line out because thats what comes up in factory default. No backup battery (yet). Forcing it into limited-output class A with resistor to ground, of course. I hate the high crossover distortion inherent to 12V chip amps.
Oh yeah, and “BOX 2” is coming with me out to the site tomorrow, while I work on decking in above the back room and getting the rest of the 2X10’s up. 60 watts per channel feeding a pair of BOFUs. The car stereo head is only the media player - I don’t believe any 50 watt x 4 power rating, since I only measured 6 volts peak to ground on each side of the BTL, as one would expect. I needed to use speaker out instead of line out because thats what comes up in factory default. No backup battery (yet). Forcing it into limited-output class A with resistor to ground, of course. I hate the high crossover distortion inherent to 12V chip amps.
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Very cool. A little more power than my office set up built around Mission 760 bookshelf speakers and a 6.5" Parts Express sub kit, driven by one of their little class D subwoofer amps. Mains are driven by a 5W per channel pure pentode high feedback design with 6V6 and 6J7 - somehow manages to sound good. Source is an RPI4 based Roon endpoint into a Topping DX-3 PRO dac driving my hybrid 6N6P hybrid parafeed pre. Sounds surprisingly good for a desk top system.
This little thing was originally designed to be 10 watts in class A push pull. Very high perveance triodes - it would be as efficient as pentodes if it weren’t for the 37 volts of cathode bias. High enough damping factor with zero global feedback thanks to the 900 ohm Ra. But there is enough gm compression near cutoff that it pushes a bit into class B and gives me 14W at clip. I’ll take the extra 4 watts. All cheap Antek iron. I’ve always wanted a little tube amp on my desk - and not just a 12AX7 driving a Tripath chip. The sub amp is an adaptation of a tiny class H (100W 8 ohm, 150W 4 ohm) “tweeter“ amp for my small format PA. Tailored for LF and adding the crossover, of course. I had the design, I had extra transformers so that determined what was built.
The source will end up being Virtual DJ and my little Hercules console. Same one I use in headphones late at night.
The source will end up being Virtual DJ and my little Hercules console. Same one I use in headphones late at night.
The 6J7 is very linear and the amplifier which was inspired by a nearly 80 year old design has survived the churn here for over a decade has multiple feedback loops and 12V (A123) batteries for grid bias in the output stage. I built it about 14 years ago IIRC.
Details here: https://www.diyaudio.com/community/...-fixed-bias-se-amp.173454/page-4#post-3707157
It's a long thread I started when I observed some odd behaviors in this design,
Details here: https://www.diyaudio.com/community/...-fixed-bias-se-amp.173454/page-4#post-3707157
It's a long thread I started when I observed some odd behaviors in this design,
Not much actual building the past couple weeks. Too much MOVING. The empty house is now packed to the rafters will most of our stuff. When the shop gets done it will all move there for the next year or so finishing the empty house. But now we are here full time. We have some tuckered out dogs from running in the pasture all day. And a couple of happy horses - happy that there is green grass and not being in a mud bog anymore.
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Finally back to work on this. Been a busy bee the past 3 weeks. Hung the staircase and landing, both catwalks, and took a big bite out of all the electrical. Ran through 3 250 fT rolls of 12/2, a 125 ft roll of 10/2, and more than 125 ft roll of 12/3 - and I haven’t even figured out which light fixtures I’m going to buy yet - so there goes at least another 250 ft of 12/2. Ready to pull the big stuff for the shop panel here, but I need to go frame the laundry room wall in the big house, so I can mount that panel and pull both runs on the same day. That requires an extra pair of hands to feed the cable and keep it from binding - and those days are few and far between.
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Only managed to get myself 60 Hertzed twice today, getting the feeds for both buildings tied in. Did the pulls earlier this week - on the hottest day of the year. No, I didn’t try to hook up the main lugs hot - killed the feed for that. But that only took like two minutes to do both hots. Did the ground and neutral live. Things only started getting difficult wrestling the 2/0’s into the 125A breaker. Finally ended up connecting to the breaker first, then wrestling it onto the bus. Was taking so long that i left it live so the AC’s would keep running. Wrestle with things, hot and sweaty, hands slip…. ZZAP!. At least no actual fireworks.
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Taking someone to the Train Station?
Watching the Yellowstone marathon now…… Done sweating for the day.
Watching the Yellowstone marathon now…… Done sweating for the day.
Both buildings are now on permanent underground power. Just had to re-set every GFCI in the shop, they come pre-tripped out of the box. Rained all day yesterday so I had to delay cutting over the shop. Arico’s in the house are at least plugged in inside now, with #10. Now I get to replace the cord on that distro - the one that’s been driven over for a year. Two hundred bucks for a 50 foot roll of 6/3 NM-B these days…..And I thought 100 was outrageous when I built that distro.
Maybe I’ll use the old piece for speaker wire. Got a bit over 200 feet of #2 Al that was used as lead wires for the pulling - no longer suitable for permanent install anywhere due to all the kinks where it hooked to the winch. Crossover inductor, perhaps?
Maybe I’ll use the old piece for speaker wire. Got a bit over 200 feet of #2 Al that was used as lead wires for the pulling - no longer suitable for permanent install anywhere due to all the kinks where it hooked to the winch. Crossover inductor, perhaps?
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Had a GFCI that wanted to nuisance trip occasionally. Finally it wouldn’t stay Re-set this morning. Black wire infinite ohms to ground, even on meg ohm setting. Pulled the white off the load side - and sure enough, short ground to neutral. At least the GFCI did what it was supposed to. Pulled the wire nut and separated the two feeds and one box downstream was the culprit. Pulled the cover off and the short clears. But damned if I can find any place where the insulation is worn through, scraped, or anything. I’m shortening up all the pigtails to the outlets it feeds to make room in the box, and I may as well replace the 7 foot section of incoming cable to tomorrow when I can see. I used the red plastic anti short bushings like youre supposed to (a 250 foot roll of Armorlite comes with a pack of 25 so there is no excuse) and I can’t get it to short moving the white wire around.
The light fixtures came yesterday afternoon but so far all I’ve done is unpack. I’m going to put cheater cords on the two 105W LED flat panel high bays that are going to light the 14’ high warehouse section and use them for work lights while doing insulation and Sheetrock.
The light fixtures came yesterday afternoon but so far all I’ve done is unpack. I’m going to put cheater cords on the two 105W LED flat panel high bays that are going to light the 14’ high warehouse section and use them for work lights while doing insulation and Sheetrock.
Electronics shop and mud room almost done putting up the rock. Just need to do the panel under the where air handler goes. Still need to mount it and run the refrigerant lines, but the upper panel needs to be primed and painted first. Need to get a tube of liquid nails to do the window casement - that part of the frame is steel. In the meantime moving on to the wood shop…
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Those things gotta be BRIGHT.
We have two 40W LED dual strips ( the kind that look like two 3 foot long fluorescent tubes ) in the garage and those things are really bright. But we got them on the lower trusses so they're just 8 feet from the floor. It helps to see into the tool chests and count the grains of dust on the floor. -!!-
Also, the color is much nicer than the old blueish fluorescent.
It always matters when lighting is being planned out, especially for shop use. Yes, the color of the light output, the intensity and actual coverage. It goes on seemingly forever, but we all remember those cases in the past, working in a poorly light environment, knowing that 'something was wrong' but never addressed it.
Those things were almost too bright in confined space. Just what the doctor ordered for the warehouse with a 15 foot ceiling, though. Ive got 14 4 foot LED strips going up in the finished areas - six in the electronics shop and 8 in the wood shop (which is larger). There’s 4 ceiling boxes in that room - the center one is a 20A twist lock receptacle to plug in the 2-sided work bench (from above), which goes in the center of the room. The mud room and closet just get fluorescent retrofits (which are only 1800 lumens per tube instead of the 2850 that the 32W are supposed to be). They are working fine in the upstairs loft.
When I start framing out the inside of the house, I may hang two of those 105W units from the rafters, to light the whole 2000 sq ft area - at least till the ceiling joists and decking go in.
When I start framing out the inside of the house, I may hang two of those 105W units from the rafters, to light the whole 2000 sq ft area - at least till the ceiling joists and decking go in.
Let there be LIGHT!
Got the ceilings painted, walls are ready for paint. Lights went up this weekend. Damn that’s bright. The photos don’t do it justice. I WILL be able to read the color bands on the resistors.
Got the ceilings painted, walls are ready for paint. Lights went up this weekend. Damn that’s bright. The photos don’t do it justice. I WILL be able to read the color bands on the resistors.
