By feedback resistor do you mean R12, formerly 68.1K? That would seem to violate Nelson's 10dB feedback rule which causes higher order distortion products to be produced.
Yes. Now 39.2k.
Don't take what Papa says out of context.
I find degeneration does more to increase higher order distortion products than feedback.
Adding gain stages and degeneration are more evil in my book.
I will put it on the distortion analyzer and see what we get. I bet it still looks great.
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This seems like a better fit. The sink on each channel of my ACA is 8" wide, 3" length, and 1.25" fin height, 21 fins. Runs all day, every day in my office - temperature as about right, can leave my hand on it all day long.
Ok, thanks. I tried to find something close to the kit sink, but Heatsinks USA doesn't have an exact match. They had one with serrated fins that were longer but the base was too thin. I'm hoping the 10inch/254mm length will help.
All parts are ordered except the screws/washers/thread tap and power supplies.
I'm still debating going with 24V or stick with 19v to start. Especially when I'm not confident yet in how effective the sinks will be at 24V.
I have one Dell 19.5V 2.31amp that I can share for now with a laptop I only use for car diagnostics. But another one is around 25USD at Amazon. Kind of high for a 19v. I have to go through the thread again to see what the best options are.
I saw this but thought this was like the off brand eBay ones that others warned against for being noisy. I also saw that this is the place where DIYAudio got the supplies for the kit, so maybe this is a good one. I also saw a 24V on MPJA but it had a different connector that looked something like XLR (4 pin?).
The new amp is an additional model, and more expensive. Probably called the “Transformer” hint hint....M2ish
The ACA, now the ACA 1.1 with the couple of changes it’s accumulated over the years, will continue, because it’s just so great, and we’re looking for ways to reduce the cost without affecting the quality.
The ACA, now the ACA 1.1 with the couple of changes it’s accumulated over the years, will continue, because it’s just so great, and we’re looking for ways to reduce the cost without affecting the quality.
The graphs Nelson presented at BA showed better performance using 24V supplies.
I got the 19V because they were so cheap at MPJA. I'll give it a month or so and then try the 24V so I have something to look forward to. Also there are other options other than bricks at 24v that I'm still trying to understand.
I'm really psyched to start this build.
As of this evening all parts are in or scheduled to be delivered. Unfortunately all tools and hardware aren't. I've been procrastinating on the soldering station. I had a Hakko 88 that I liked but it's gone and I'm worried about choosing a cheaper iron until I can afford a proper soldering station.
I'm really psyched to start this build.
As of this evening all parts are in or scheduled to be delivered. Unfortunately all tools and hardware aren't. I've been procrastinating on the soldering station. I had a Hakko 88 that I liked but it's gone and I'm worried about choosing a cheaper iron until I can afford a proper soldering station.
I still haven't got around to building my ACA kits and now this. I actually like the single chassis design. I've been trying to find a complementary chassis to the mono locks that I can put a power supply in instead of using multiple bricks. With a single chassis that would no longer be an issue.
One of my original power supplies died after years of faithful service.
I replaced it with another 19v supply. It outputs about 19.3v and is rated to 1.5a. Now at turn on I get a short hi pitched whining/farting sound through the speaker for a couple of seconds. After that everything’s fine.
What gives?
I replaced it with another 19v supply. It outputs about 19.3v and is rated to 1.5a. Now at turn on I get a short hi pitched whining/farting sound through the speaker for a couple of seconds. After that everything’s fine.
What gives?
Noises from switching supplies is all over the map, and sometimes if you
add filter capacitance to the rail it will not start up at all, deciding that the
load is a short.
I make a point of actually testing a single piece before I buy any more. Some
supplies put out a lot of noise (even after startup), and some don't. Some
run quite hot, even under 1/2 load of spec.
That said, if it works in spite of startup noise, then there you are. The amp
circuit will be OK.
add filter capacitance to the rail it will not start up at all, deciding that the
load is a short.
I make a point of actually testing a single piece before I buy any more. Some
supplies put out a lot of noise (even after startup), and some don't. Some
run quite hot, even under 1/2 load of spec.
That said, if it works in spite of startup noise, then there you are. The amp
circuit will be OK.