Amp Camp Amp - ACA

[Alan4411]

Not sure I understand the questions, but here goes with a couple of answers...

comparison parallel mono and bridge, is it technically different?

Yes Parallel and Bridge mode are very different.

as our speaker have L and R , in bridge mode, there is still L and R

No in Bridge mode you get a mono amplifier. You need two Bridged amplifiers for stereo. (So 4 x ACA boards)

however in paralled its only have MONO which mean no difference from L AND R? no stereo ? affecting the imaging of the sound? is it true?

Yes in Parallel mode you get a mono amplifier. Again you need 2 Parallel amplifiers for stereo. (So 4 x ACA boards)

 

[6L6]

According to one of my experienced diyer of friend saying to be true parallels mono is 4 pcs of aca (2 for mono L) (2 for mono R)

How is this to be explained

That makes little to no sense.

And at the point of having 4 ACA, it would be much more logical (and a better amplifier all around) to build any of the FirstWatt amplifiers - Aleph J, F5, F6, BA-3, M2x, etc...

 

[tooppy]

Parallel is mono, bridge is mono. In both configurations you need 2 ACA amplifiers for stereo.

Yes, sound is different. I prefer bridged.

I don't understand the basic connexion of all this....

 

[6L6]

Amp Camp Amp V1.6 Build Guide - diyAudio Guides

Stereo, XLR bridge, and RCA bridge are steps 53, 54, 55.

 

[myleftear]

I don't understand the basic connexion of all this....

If you run the amp bridged or parallel, you are using 1 left & right channel (=1 ACA) for one channel, and a 2nd left & right channel for the other.

But 6l6 already showed the direction...

 

[planet10]

Yes, sound is different. I prefer bridged.

The ACA has an ouput impedance that can directly affect whether bridged or parallel is the best for you.

In bridged mode, you double the output impedance putting it into an area where the amp will start losing control of the woofer sin some speakers. Bridged also has each channel operating inopposite phase so at least some of the 2nd order products cancel. Bridged is going to suffer into lowe rimpedance loads.

In parallel mode, you halve the output impedance making it more sutabe for speakers that expect a low output impedance from the amp. Better into low impedance loads. The boards are in phase so the amp retains its SE character, but may suffer from some low level “blurring” of details which inevetibly happens unless the 2 board shave exactly the sam etransfer curve.

For instance, my big ML-TLs do not work well with bridged ACA, sterao (and i expect parallel) work better. With my Mar-Ken10pTT the bridged ACA sounds fantastic.

dave

 

[lifefordota]

Yes, I think it is about the phasing of the parallel and bridge is different. That's what I mean.

Is this the reason most of the people like bridge instead of parallel?

 

[aljordan]

I guess I am an outlier. I like parallel better than bridged into my Klipsch Forte II, which specification say are 8 ohm nominal and 99 dB efficient (but specifications may be lying). One should try both ways into their particular speaker.

 

[TonyTecson]

paralleled ACA = same voltage swing, twice output current, but need half the load to develop twice the power...into the same load, same power....

bridged ACA = twice voltage swing, same output current into the same load twice the power...

 

[planet10]

I like parallel better than bridged into my Klipsch Forte II, which specification say are 8 ohm nominal and 99 dB efficient

Given the wild impedance curve of these speakers that is not surprising.

Klipsch often seems to specify optimistic efficiency specs.

dave

 

[lifefordota]

The signature sound of mono always sound worse than stereo?

Is this statement make sense?

 

[Zen Mod]

no

 

[Alan4411]

Errr?
''The signature sound of mono always sound worse than stereo?
Is this statement make sense?''

No and No.

 

[lifefordota]

i don know why one of my diyer friend , saying that we all enjoy music in stereo mode as usual.

parallel mode is changing stereo to mono , therefore it is changing the way the music produced? which mean it is ruining the way the music produced?

 

[TonyTecson]

no and no.....

 

[Alan4411]

There is a lot of confusion here.

Bridge mode does not change stereo into mono.
If you have a stereo source (2 channels left and right) it will only amplify one of them, which ever you choose. It does not sound correct, because half of the stereo source signal is missing. You need another bridged amplifier to return both channels and have stereo.

Parallel mode also does not change stereo into mono if you use it as designed. In parallel mode both the input sockets are connected together. (As are the output sockets) You only use one socket for the signal input (either left or right) not both. So as above you only amplify half of the stereo signal. You need 2 parallel mode amplifiers for a stereo output...

If you have a mono source you only need one amplifier and it will sound just fine except there is no spacial information.

 

[TonyTecson]

ok, let us run this one more time, two channels of ACA bridged equals a single channel, you need 4 ACA boards to make a stereo amp.....

 

[Alan4411]

^^^
and the same for parallel mode.

 

[myleftear]

I think the OP meant that with one ACA In bridge or parallel mode, there‘s only one channel coming out.
Not „mono“ as in „left & right channels into 1 speaker“, but rather „1 plug in, one plug out“.
The root of this confusion could be the fact that 1 ACA has 2 amplifiers (left and right) although „ACA“ is considered an amp... [emoji848]

 

[tooppy]

What are the benefit of these Parallel & Bridge configurations over the simple stereo ?