That's just the model. The actual traced curves are not so pretty, so the model is not totally accurate. See trace #2 in preceding post #34.
I finalized my case design and picked up my aluminum order today.
Coincidentally, my power transformer from Antek also arrived in the mail today. It took the long way from the east coast of the United States to central Canada, and then criss-crossed, back and forth to the west coast three times before it found its way to my mailbox. Total travel time was over two weeks.
On the other hand, I ordered two heatsinks from Modushop, and they arrived from Italy via Fedex in about a week. One thing I have to mention: Gianluca and Modushop are serious about serving their customers. One heatsink arrived with a small gouge in one of its fins. I emailed Modushop about it in the evening and went to bed. In my email the next morning was a response from Gianluca saying a new heatsink was on its way to me. I did not expect this, but I was sure impressed.
My PCB order at JLCPCB is somewhere over the Pacific Ocean, I assume, but it's not on the critical path of the timeline (yet), so meanwhile I will work on building the case. That should take a week or so.
Coincidentally, my power transformer from Antek also arrived in the mail today. It took the long way from the east coast of the United States to central Canada, and then criss-crossed, back and forth to the west coast three times before it found its way to my mailbox. Total travel time was over two weeks.
On the other hand, I ordered two heatsinks from Modushop, and they arrived from Italy via Fedex in about a week. One thing I have to mention: Gianluca and Modushop are serious about serving their customers. One heatsink arrived with a small gouge in one of its fins. I emailed Modushop about it in the evening and went to bed. In my email the next morning was a response from Gianluca saying a new heatsink was on its way to me. I did not expect this, but I was sure impressed.
My PCB order at JLCPCB is somewhere over the Pacific Ocean, I assume, but it's not on the critical path of the timeline (yet), so meanwhile I will work on building the case. That should take a week or so.
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This amp will be stunning.
When building my F3 I also used bare aluminum but with some elbow grease and some trick from a friend I got a nice result that looks like brushed aluminum, see before and after.
Looking forward to see your progress.
Eric
When building my F3 I also used bare aluminum but with some elbow grease and some trick from a friend I got a nice result that looks like brushed aluminum, see before and after.
Looking forward to see your progress.
Eric
Yep but make sure your aluminum piece is being held tight and then always scratch going the same direction, don’t go back and forth. A few coats of clear varnish will bring out the depth.
I finished fabricating the case today. Everything came together without any cursing, and I made the blind taps in the front panel without punching through. It's illogical, but I always think I'm going to drill through the front panel.
Speaking of taps, I couldn't find my piece of aluminum angle which I usually use as a guide to keep the tap perpendicular to the drill hole. I decided that I should buy a tap/drill guide. I went online to check to see what was available, and I wasn't pleased with the selection or price of the ones in the local stores. Then it occurred to me that I can make one. After all, it's just a piece of metal with holes in it. So, I found a piece of 1/2" aluminum and used my drill press to make a nice selection of holes in it. Works like a charm, and saved me a trip to the store and $15.
Speaking of taps, I couldn't find my piece of aluminum angle which I usually use as a guide to keep the tap perpendicular to the drill hole. I decided that I should buy a tap/drill guide. I went online to check to see what was available, and I wasn't pleased with the selection or price of the ones in the local stores. Then it occurred to me that I can make one. After all, it's just a piece of metal with holes in it. So, I found a piece of 1/2" aluminum and used my drill press to make a nice selection of holes in it. Works like a charm, and saved me a trip to the store and $15.
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Nice work! Very similar to the LuFo but with one N channel MOSFET for the cascode.
https://www.diyaudio.com/community/threads/lufo-amp-39w-se-class-a-from-28v-rail.372679/
https://www.diyaudio.com/community/threads/lufo-amp-39w-se-class-a-from-28v-rail.372679/
Thank you.
Yes, it's very similar to the LuFo. Just lower power and smaller choke. The lower power dissipation was my goal to beat the summer heat.
Yes, it's very similar to the LuFo. Just lower power and smaller choke. The lower power dissipation was my goal to beat the summer heat.
My PCBs from China arrived today and just in time as I'm nearing completion of my case work. Next up is to drill mounting holes in the bottom plate and heatsinks. Then, I'll build up the amp PCBs and see if all the electrons go as planned.
I think I have all the pieces now and hopefully I haven't forgotten to order a part.
I think I have all the pieces now and hopefully I haven't forgotten to order a part.
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The amplifier PCBs for both channels have been populated and they have been mounted on the heatsinks along with the transistors.
This morning, I took the big leap and powered them up for the first time. I have a regulated power supply with current limiting, so that made things a bit less stressful. Anyways, the bottom line is both channels powered up without problems and amplified the input signal. I ran each channel for about 15 minutes and everything remained stable.
I didn't make any measurements, but the meters on my power supply indicate 18 volts and 1.4 amps for each channel. This falls in the range of what I expected.
This morning, I took the big leap and powered them up for the first time. I have a regulated power supply with current limiting, so that made things a bit less stressful. Anyways, the bottom line is both channels powered up without problems and amplified the input signal. I ran each channel for about 15 minutes and everything remained stable.
I didn't make any measurements, but the meters on my power supply indicate 18 volts and 1.4 amps for each channel. This falls in the range of what I expected.
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Ideal for 19 volt computer smps. Any plans to try it? May need filter from diystore, but should be cheap option.
Those mounted PCBs remind me of the ACA. Power rail voltage and bias current are very similar as well. Lots of good options for a PSU and chassis from the store.
I finished the power supply today. It's a dual mono system fed by an Antek AS-2215 200VA transformer with 2 x 15VAC windings. The snubber resistors are 14 ohms as determined by Quasimodo.
Filtering is CLC with 44 mF, Hammond 159ZJ (10mH, 0.16 ohm), followed by another 44mF of capacitance. The ripple should be in the millivolt range.
I load tested each side with 16 ohms of resistance and the resulting voltage was 17.8 volts (1.1 amps). I expect the final voltage will be around 17.5 or so when connected to the amplifier stage.
Filtering is CLC with 44 mF, Hammond 159ZJ (10mH, 0.16 ohm), followed by another 44mF of capacitance. The ripple should be in the millivolt range.
I load tested each side with 16 ohms of resistance and the resulting voltage was 17.8 volts (1.1 amps). I expect the final voltage will be around 17.5 or so when connected to the amplifier stage.
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