Monoblock ACA bridged mono <=> parallel mono at the flick of a switch

[starcat]

What is "parallel" mono, first time seeing this. You mean plain, standard stereo maybe?
Bridged mono is a term; used to increase power (each amp amplifying one half of the sine wave).

So, basically either stereo or bridged (and not balanced).

 

[Extreme_Boky]

Two AMP PCBs, connected in parallel.

 

[starcat]

Two AMP PCBs, connected in parallel.

Care to describe how exactly you do drive them?
Do you have one amplifying the positive signal and the other one amplifying the phase inverted signal of the same input?

In bridged mono, both channels amplify the positive and negative half of the sine wave of the same input, in order to increase power

What the heck is "parallel mono", maybe
Both single ended and both working in "parallel" so you can do bi-amping, for instance?

 

[6sX7]

Parallel mono is just that, one RCA single-ended split to the two signal boards then summed.

Here's the wiring diagram for the ACA:

https://cdn.shopify.com/s/files/1/1006/5046/files/ACA_wiring_-_All_Together_-_V18.pdf?v=1593415056

and the back panel to show the switch and speaker hookup positions.

https://cdn.shopify.com/s/files/1/1006/5046/files/ACA_V1.8_Rear_Panel.jpg?v=1593489546

 

[6sX7]

Steps 15, 16 and 17 in the build guide, show the various hookups for the different modes:

https://guides.diyaudio.com/Guide/Amp+Camp+Amp+V1.8+Change+Information/10?lang=en

 

[Extreme_Boky]

What the heck is "parallel mono"

Bridged mono utilises one (single) input and usually a little phase rotation OP AMP to create two identical signals with opposite phases. Good for voltage increase at the output, but with the same current and pretty bad damping factor. ACA uses the output of one AMP PCB to feed the input of the other AMP PCB - that's a bridged operation, but only mono (out of an ACA single chassis)

Parallel mono is when one (single) input is fed to both AMP PCB's in... what for it... in.... in parallel (inside a single ACA amplifier chassis). You get the same output voltage, but (approximately) double the output current and half the damping factor. Good for low impedance speakers. Downside: the input impedance goes down to 5Kohms.... with stock-standard PCB's.

 

[starcat]

Bridged mono utilises one (single) input and usually a little phase rotation OP AMP to create two identical signals with opposite phases. Good for voltage increase at the output, but with the same current and pretty bad damping factor.

What are you describing here is balanced (mono) - voltage swing and the slew rate increase at the output.
This is not bridging though.

ACA uses the output of one AMP PCB to feed the input of the other AMP PCB - that's a bridged operation, but only mono (out of an ACA single chassis)

Ok, kind of bridging, to increase power at output.
Thx.

In both cases you get mono out of two channels.

 

[Variac]

Or one can use the XLR input from a balanced source.

These different approaches have different sound signatures due to second order distortion cancellation in the
“balanced” configs and since in “bridged”, half the signal has been run through the amp to invert it. As mentioned configs may work better for some situations, more power in some configs such as “bridged” and “parallel” for low impedance speakers.

 

[ItsAllInMyHead]

Starcat - Here are some fairly basic diagrams showing various configurations for the ACA. These use the terms within the amplifier build guide to avoid potential confusion.

 

[Variac]

The diagrams from IAIMH have lines on the DPDT switch to show how the circuit flows through it in different positions, But builders should be aware that one doesn't necessarily connect the switch pins with wire even though there is a colored line between them.