The BA-3 as preamp build guide

Jump to Latest
#2,722
Buongiorno everybody, how are things going your end? Here finally a cooler day after a straight 3 months of equatorial temperatures...

I am soon going to buy the transformers for the BA-3 as to find out which case size do I need (something among these), then RCAs, mains switch etc but now I need to know about the volume pot, as far as I understand from what I read the value can vary between 10 and 100 KOhm and seems the consensus aiming at 50KOhm, I don't need remote volume control and since I will be using the iSelect I would like to hear your advise for the best suitable pot considering I wanna maintain the budget for it within a reasonable 200$ at the most, the pot will be the single most expensive part of the preamp...
To achieve double output to one day drive two amps what does it take?

Grazie
 
#2,725
Last edited:
#2,727
You could go with a galaxy, as you are considering. The width could be tight, depending on what you want to populate it with (dual mono = 2 toroids, 2 psu, iSelect, amp, connectors, inlet, front-switch…)
I first had a smaller, 80 mm high chassis, was too small, now, with the same width/depth and it fits just tight and right (2 toroids, 2 Ubib, etc) … note that the ubibs are comparatively huge…

Otoh, the galaxy‘s side-panels aren’t what I would call „elegant“…
 
#2,728
myleftear said:
You could go with a galaxy, as you are considering. The width could be tight, depending on what you want to populate it with (dual mono = 2 toroids, 2 psu, iSelect, amp, connectors, inlet, front-switch…)
I first had a smaller, 80 mm high chassis, was too small, now, with the same width/depth and it fits just tight and right (2 toroids, 2 Ubib, etc) … note that the ubibs are comparatively huge…

Otoh, the galaxy‘s side-panels aren’t what I would call „elegant“…
Click to expand...
So you think the 2U is too tight in height? I don't have the boards here and too lazy to check the sizes now but I will arrange a CAD drawing to figure out the layout, the transformers aren't that big, if I recall correct less than 8cm diameter, maybe this one would better fit it all, the mini dissipante would be a waste as there is no need for cooling sides and a loss of internal space.
 
#2,735
I'll stick with standard width ( same as the deluxe 4u ) preamp cases going forward for a few reasons: much easier to fit everything in there, placement and stacking are easier too. Things can get weird when you start mixing widths and depths. Like many here, I'm also likely to repurpose a preamp case at some point for a different circuit...but dont know what that may be. Easier to just leave plenty of room.
 
#2,736
Hello,

I ordered the two transformers so one more thing done, I think it makes sense to stick with same width as not to end with weird stacks so there you go with next purchase being the Pesante 3U400N, no need for cooling so it should do fine.

Should I add the perforated bottom grill to make it easier to lay the boards? Aldo, full vented top would add to functionality/cooling?

Any suggestion for some nice wide and low feet for both the preamp and the already made F4 whose rubber feet I don't like at all?

Grazie

p.s. just noticed that even aluminum back is an option so at the end I will get the perforated base (as suggested below, I am editing this not to add another post) and the back as to make it easier to drill holes for the plugs
 
Last edited:
#2,739
I understand sitting low can limit air flow but the feet it came with are no Tour Eiffel either and they look plain ugly...
IMG_4733.jpeg
 
You must log in or register to reply here.
Top Bottom