ACA Upgrade Information
Audible upgrades for all versions prior to V1.6
To use the new 24V PSU and also bring your ACA up to 1.6 specification:
- If you have a PCB labelled revision 1.0, add bias resistor R15 (increases power to 6W)
- If you have PCB 1.0 or 1.0b, adjust R12 from 68k to 39.2k
- If you have PCB 1.0, 1.0b or 1.1, simply plug in the 24V PSU (no DC jack change required) and adjust the DC value on the output to 12V
Aesthetic / mechanical upgrades
V1.6 to V1.8
Please see the list of differences between the two here at the top of the V1.8 build guide. List of all differences between V1.6 and V1.8:
- Rear switch is a 3 position DPDT instead of 2 position, necessitating a change in wiring
- Rear panel is printed with a connection diagram
- Chassis rails are improved using weld nuts and secured by bolts
- Blade terminals are included for the front power switch
- Longer wire
- LED resistors have been changed from 10k to 33.2k to reduce LED brightness
Please note that the PCB did not change whatsoever between 1.6 and 1.8, and so the PCB included in all 1.8 kits says "V1.6". That's the correct version of the PCB.
V1.5 to V1.6
If you want to build matching monoblocks, you can order a whole new complete kit and choose the "silver faceplate with no power switch hole" option (we added this option just for you!). It will perfectly match your existing chassis.
Then to upgrade your V1.5 to be the same as your pre-ordered V1.6:
From the store pre-order:
- Pre-order 1 of the new Meanwell 24V power supplies
From Parts Express:
- Buy 1 Neutrik NC3FPP (we added the XLR jack as standard), or indeed any Neutrik "D Series" XLR jack (FYI the large XLR jack hole on the back panel is 24mm diameter)
- Buy 1 DPDT mini toggle switch (beefier)
- Buy 1 pack of blue LEDs (only if you want blue LEDs)
- Buy 1 imperial step drill bit (for enlarging the back panel holes)
From Digikey:
- Buy 1 Tensility 54-00064 DC jack (beefier)
Chassis modification:
- Using a low speed battery operated drill and the above step drill bit, perform the following operations on the rear panel:
- Enlarge the 8mm DC input cutout to 7/16" (11mm)
- Enlarge the 6mm toggle switch cutout to 1/4" (6.4mm) (this step may not be required)
- Make sure the panel is secure and you are going slow enough not to hurt yourself! A Panavise 350 is a great all rounder that did this trick for me nicely (you might want to look at this too for soldering).
PCB
The only difference between the Parts Kit V1.5 PCB (labelled V1.1) and the new Parts Kit V1.6 PCB (labelled V1.6), is that V1.6 has some extra mounting holes so it can be mounted to a 4U or 5U UMS heatsink. There are no changes to the design or sound.
If you also want an exactly matching V1.6 PCB for a perfect OCD zen state as well, I do understand. We'll have V1.6 PCBs available for separate purchase in July 2018 (they are not currently available for order). However, if that's the case, it might be better to finish your current ACA and enjoy it for the next 3 months, pre-order 2 more and build them in August, and then (a) give away your V1.5 to a worthy friend, or (b) use it as a center channel :)
If you have already built the ACA V1.0, 1b (or 1.1 that was given away at BAF 17 (not the one in the March 2018 ACA!)) and want to use the new chassis
Ok, so you've built an ACA before but want to use the fancy new chassis? Yes, you can do it, but there are some caveats as the PCB mounting has changed so you'll need to DIY...
- Please see this post for how you'll need to wire it
Then:
From Parts Express:
- Buy 1 Neutrik NC3FPP, or indeed any Neutrik "D Series" XLR jack (FYI the large XLR jack hole on the back panel is 24mm diameter)
- Buy 1 DPDT mini toggle switch
- Buy 1 pack of blue LEDs
- Buy 1 set of 4 mini binding posts
- Buy 1 pair of RCA jacks
From Digikey:
- Buy 1 Tensility 54-00064 DC jack
- Buy 1 Front Power Switch
You will need to find some small nuts and bolts to mount the XLR jack, depending on your mounting preference (inside or out).