DIY ACA mini

If you want a good laugh...here's a video of me biasing the amp with one meter. I didn't want the video to be an hour long so I was moving too quickly. The key to doing this well would be to make "small increments". It's definitely possible with one meter and if you're new to this give yourself a good hour...it's not a race.

ONE METER BIASING ACA MINI
Yup. That's how I did it. I have but one meter. :-( It's dobale. It just takes a bit more time.
 
If you want a good laugh...here's a video of me biasing the amp with one meter. I didn't want the video to be an hour long so I was moving too quickly. The key to doing this well would be to make "small increments". It's definitely possible with one meter and if you're new to this give yourself a good hour...it's not a race.

ONE METER BIASING ACA MINI
if I had 4 voltmeters I would use all four of them and bias both channels on one go
 
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I hooked the Mini up to the main rig, and tweaked VO & VB until I convinced myself to put away the meters and just listen. And great googly moogly, am I impressed.

I find that with the jumper in place, it is much closer in character to my direct-coupled 417A/45 SET with regulated heaters and filiaments - and only marginally louder - whereas without the jumper it leans more toward my triode-strapped, cap-coupled Tubelab SSE. My overall preference, as it is with the amps themselves, is the former.

With my Aleph J nearly completed, save tapping 8 holes, assembly and testing, this amp has lit a proverbial fire to get that amp finished - and yet I’m fine leaving the Mini in place until I do.
 
@6L6
Hi, 6L6 Lovely, explicit ACA mini assembly pics. One thing though ... in post #29 we find IMG_3065.jpg showing the board and the barrel of a soldering iron. Would you be so good as to share with us the brand name of the iron and the tip? Thanks in advance -Edward
It's a Weller TC-202 base with T-201 handpiece, bought surplus in the 80's and given to me by my Uncle when I was racing R/C cars when I was probably 14 or so. Has worked without complaint or any fuss since then.

The tip is a medium conical. Solder is the absolutely outstanding Fire-Metall Pb/Sn/Ag/Cu eutectic that member Einric sells. https://diyaudiostore.com/collections/consumables/products/fire-metall-solder It's the best solder I've ever used, beating out Multi-core and Cardas quad in my opinion.
 
Thank you Ben for your reply. I almost added it to my cart but wasn’t sure. What is the difference with 10 percent vs 5 percent? Thank you again and have enjoyed reading about your creations and contributions even though I don’t post much🙂
 
Hi everyone,

It seems like mouser and most places out of c1 part 505-mks21/100/5 in the BOM. What would be a good equivalent part or if anybody had any spares I would gladly pay. I’m in the USA thank you !
Hi EADFan,

I just did a search for it by part's specs and I found what I think it's the right one. Here is the link.

I once was looking for a part by part number and I couldn't find it but when I searched by specs I found the part so I called Mouser to find out the difference and they told me that it was just the packaging and that's it. so since then, when I can't find the part by the part number then I search by it's specs.

You might want to double-check with more experienced people on the thread just to make sure one of them is the correct part.

Best
Daniel
 
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