I had a magic moment where I was spot on for both of them (2 meters): 300mv/11.5v. I took a picture for posterity.
@e_fortier I will look for the videos -- I watched one very helpful video on the basics of how to use the 2 pots to set the bias. It's the "@Nelson Pass told me that the bias (VB) should be between 350 and 390 mV" line I quoted above that caught me by surprise.
There is a spot in heaven, close to where Mozart hangs out, for the person who knows all 130 pages of this thread and creates a post pinned to the top that points to the especially helpful ones. I started thinking about trying to do this, but clearly my judgement about what is accurate / helpful info is askew.
Re the spectacular, bespoke gold cages @e_fortier pointed to yesterday, I wrote to the creator of that amp, Bruce Heran, and he was kind enough to reply with the name of the boutique craftspeople who supplied them:
"they came from either Lowes or Home Depot in the home storage area. They were a little larger and had handles when new that I cut off. You can fasten thenm with "mirror" clips to the chassis."
I clearly need to set my sights lower than Ikea...
"they came from either Lowes or Home Depot in the home storage area. They were a little larger and had handles when new that I cut off. You can fasten thenm with "mirror" clips to the chassis."
I clearly need to set my sights lower than Ikea...
Another completed ACA Mini in the world tonight. I'm running it out of the headphone output of my CD player, since that has a volume knob on it. It's got enough ommph that if I gave it the direct output, I would suffer hearing loss.
First sounds to come through it:
1. Bach/Glen Gould "The Art of the Fugue"
2. Mary Lou Lord "Martian Saints"
3. Sarah Vaughn
4. Clash "From Here to Eternity"
@6L6's build guide was very useful to me. If the login on the "completed" button was the same as here, I would click that, but it appears to be different.
First sounds to come through it:
1. Bach/Glen Gould "The Art of the Fugue"
2. Mary Lou Lord "Martian Saints"
3. Sarah Vaughn
4. Clash "From Here to Eternity"
@6L6's build guide was very useful to me. If the login on the "completed" button was the same as here, I would click that, but it appears to be different.
Looking at the tweak using R11 and C6 doesn't that compensate for the diference
in RDS between the output devices. If so is there any chance that would also be useful
in the F5 ?
in RDS between the output devices. If so is there any chance that would also be useful
in the F5 ?
Sure, give it a try! It's a fairly simple bodge and if you preinstall insulating sleeves over any exposed leads, the risk is low that you will injure or destroy your F5 in the experiment.
The link to Ikea in post 2591 (https://www.diyaudio.com/community/threads/diy-aca-mini.379037/post-7553018) does not work for me.
The product referenced is "DRÖNJÖNS Wastepaper basket"
Kind regards,
Drew
The product referenced is "DRÖNJÖNS Wastepaper basket"
Kind regards,
Drew
Listening to some Stanley Jordan w/. 1 of my ACA Minis. Anyone who has been thinking about building 1 what are you waiting for? These punch so much above their weight class, are pretty easy to build and just make wonderful music!
Another ACA mini up and running. Had it up and running in about an hour. Waited until this morning to finish out the biasing. I can't quantify it but, yes, the jumpers on make it funner to listen to.
Winter bias setting day! 
Cold snap in the Mid Atlantic US calls for kicking it up a notch. I knew from taking ‘measurements’ that my Mini was running a bit cool in its spot.
Equilibrium in both channels now seeming to hover around 400mV for VB.
I know it’ll come down a bit in the place I use it where there is a little more air moving.
Cold snap in the Mid Atlantic US calls for kicking it up a notch. I knew from taking ‘measurements’ that my Mini was running a bit cool in its spot.
Equilibrium in both channels now seeming to hover around 400mV for VB.
I know it’ll come down a bit in the place I use it where there is a little more air moving.Attachments
I built an enclosure for the mini folks here coached me through, so I thought you might like to see it. Took a while to redo the wiring under the board, &c. &c. As when I first completed it, no joy: no LED, no nothing. Eventually I remembered that setting the bias might help. Hooray, it's alive and wonderful again. Thanks again for the help with this project: such a delightful sound and truly fun to build -- even when I was tearing out my last hair.
Attachments
When using a PC to drive ACA mini, would it be beneficial to add the Front End 2022 to the equation? Or better to drive it straight as is?
Also, if I wanted to put potentiometer in between the PC and ACA mini, what value would be recommended?
Thanks!
Also, if I wanted to put potentiometer in between the PC and ACA mini, what value would be recommended?
Thanks!
Are you getting enough volume? If not, use the FE. If yes, it's not needed, but you can always experiment.
25K or 50K will work well.
25K or 50K will work well.
I just acquired a blank PCB without the mosfets and JFETs. Anyone have these parts I can buy or is the best option just to buy a mini essentials?
Also, any opinions between the Harris and Fairchild mosfets? Anyone had a chance to compare?
Also, any opinions between the Harris and Fairchild mosfets? Anyone had a chance to compare?
IMO your best bet is to simply buy an essentials kit from the store. It comes with the Harris and LSK parts plus the board, all for $25, ordered from the comfort of your couch!
...which I might add, is a price that you could never beat trying to source parts individually.
That’s probably true.
I’m curious about this as well. I know there are a number of people who have installed them, myself included.
I'm using a mini for my desktop speakers (84db). Just a 25K pot between DAC and mini gets plenty loud.
Thanks guys!
It's going to my son, who doesn't live close, so testing with his speakers is a bit difficult. But I'll go with just a pot and we'll see how that works out.
But still one question... if I used the FE 2022, how much gain would it need to fully drive the ACA mini?
It's going to my son, who doesn't live close, so testing with his speakers is a bit difficult. But I'll go with just a pot and we'll see how that works out.
But still one question... if I used the FE 2022, how much gain would it need to fully drive the ACA mini?
Two brothers ... connected in parallel mode, one for left and one for the right side.
I have the feeling that they have now more pressure at the lower end.
I have the feeling that they have now more pressure at the lower end.