Since you mentioned monoblock coversion a few posts back, how soon before you’ll have some photos and notes / cautions for the process? I know a couple of guys who’d be interested.
And since we’re at it, addition of B1 buffer and volume pot to formulate a sorta “integrated” amp?
I have been asked by management to make some comments on the
bridged arrangement and performance, which I will do in a couple days.
Also, there will be some comment about the 24V switching supply.
Hey 6L6!
I'm installing an xlr-4 point into the front of the chassis like so:
From my limited understanding you are inverting the phase by using the bare wire in this image:
I just want some more confirmation since this is my first build: if I follow your illustrated build guide and I use that bare wire to invert the phase then I should be able to configure the xlr-4 jack with the standard configuration, right?
I'm installing an xlr-4 point into the front of the chassis like so:
From my limited understanding you are inverting the phase by using the bare wire in this image:
I just want some more confirmation since this is my first build: if I follow your illustrated build guide and I use that bare wire to invert the phase then I should be able to configure the xlr-4 jack with the standard configuration, right?
If you re-read the build guide you'll see that the phase inversion is nothing more than inverting the speaker posts (hot -black / cold - red).
The bare wire is "only" tying the ground on the rear panel together and serves as the ground bus / bar / starground / whatever you name it for both channels.
Wire the XLR input as per convention, the phase inversion happens on the output when wiring as NP indicates.
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Ok so if that's the case then all I have to do is take the standard configuration for the xlr-4 jack and invert that. The configuration that I will be doing in this case is going to be:
1 - left channel -
2 - left channel +
3 - right channel -
4 - right channel +
Does that sound about right?
Flexmaster -
The phase inversion is merely for the speaker output, and the amplifier is merely hooked up 'backwards' to keep absolute phase intact. Inputs are still plus to plus and minus to minus.
I'm a bit confused what the 4-pin XLR is being used for, can you explain a bit? Are you going to feed stereo unbalanced through it?
SRMcGee (Scott) -
Ummmm... Kinda? This is a single-ended amp, not a Push-Pull, so daisy-chaining might get complicated. You could easily use 4 PCB and make a stereo bridge amp, that would be cool.
The phase inversion is merely for the speaker output, and the amplifier is merely hooked up 'backwards' to keep absolute phase intact. Inputs are still plus to plus and minus to minus.
I'm a bit confused what the 4-pin XLR is being used for, can you explain a bit? Are you going to feed stereo unbalanced through it?
SRMcGee (Scott) -
Ummmm... Kinda? This is a single-ended amp, not a Push-Pull, so daisy-chaining might get complicated. You could easily use 4 PCB and make a stereo bridge amp, that would be cool.
I'm going to use the 4-pin XLR as a balanced output for my headphones! I posted a reply to coolnoose before you replied, 6L6, so I might sound redundant when that message gets approved by moderators to be posted. I ask that you please ignore that message!
Without complicating things too much by being superfluous, my confusion lies because I'm going to be using the female 4-pin XLR as an output as well. Do I need to invert the configuration of the female 4-pin XLR port from the standard configuration of:
1 - left channel +
2 - left channel -
3 - right channel +
4 - right channel -
to
1 - left channel -
2 - left channel +
3 - right channel -
4 - right channel -+
or am I simply not understanding some basic concepts? Again, I apologize for my ineptitude, this is my first endeavor into DIY so please be understanding!
Flexmaster,
I might have added to your confusion I must admit - I did not read that the 4 pin XLR was referring to the output...though 4 pin should have rang the bell ...
That said your assumption to invert pin 1/2 and 3/4 is correct!
Simply invert +/- respectively for each channel.
Max
PS: Pls note I am not familiar with the 4 pin XLR Headphones output convention, that's your part
I might have added to your confusion I must admit - I did not read that the 4 pin XLR was referring to the output...though 4 pin should have rang the bell ...
That said your assumption to invert pin 1/2 and 3/4 is correct!
Simply invert +/- respectively for each channel.
Max
PS: Pls note I am not familiar with the 4 pin XLR Headphones output convention, that's your part
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Exw9 - Correct. Adjust pot in small movements and let things 'catch up' before moving more towards 10v
Flexmaster - Yes, you have it right; SEE EDIT
1 - left channel -
2 - left channel +
3 - right channel -
4 - right channel -+
That will keep absolute phase through the amplifier to your headphones.
EDIT - Wait a second, hang on...
You don't need to hook anything up backwards because the speaker jacks are already "backwards"
Look at this photo -
The red wire is from the (+) output of the PCB and connected to the red speaker post. The black is connected from the (-) output on the PCB to the black speaker post.
In this photo it shows the left channel.
So all you'd need to do is connect your headphone XLR properly to color, because in this amplifier it's the way we connect the speaker jacks to the PSU that flips the polarity of the amp, not the output wires from the PCB.
So -
Pin 1 L+, Pin 2 L-
Pin 3 R+, Pin 4 R-
Flexmaster - Yes, you have it right; SEE EDIT
1 - left channel -
2 - left channel +
3 - right channel -
4 - right channel -+
That will keep absolute phase through the amplifier to your headphones.
EDIT - Wait a second, hang on...
You don't need to hook anything up backwards because the speaker jacks are already "backwards"
Look at this photo -
The red wire is from the (+) output of the PCB and connected to the red speaker post. The black is connected from the (-) output on the PCB to the black speaker post.
In this photo it shows the left channel.
So all you'd need to do is connect your headphone XLR properly to color, because in this amplifier it's the way we connect the speaker jacks to the PSU that flips the polarity of the amp, not the output wires from the PCB.
So -
Pin 1 L+, Pin 2 L-
Pin 3 R+, Pin 4 R-
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Jim:
Sorry, I could have articulated my idea better. The basic ACA is 5 or 6 watts per channel. I'd like to build something a little bigger.
I was hoping to build a 10 or 12-watt version of the ACA and imagined a parallel configuration. Wouldn't a parallel amp design be better than a bridged design in this instance?
Either way, and assuming this is feasible and the heatsinks are large enough, it might be fun to use 3 pcbs per channel and shoot for a 15 to 18-watt amp. Is that possible? And if so, would it be advisable to match the MOSFETS?
Regards,
Scott
Sorry, I could have articulated my idea better. The basic ACA is 5 or 6 watts per channel. I'd like to build something a little bigger.
I was hoping to build a 10 or 12-watt version of the ACA and imagined a parallel configuration. Wouldn't a parallel amp design be better than a bridged design in this instance?
Either way, and assuming this is feasible and the heatsinks are large enough, it might be fun to use 3 pcbs per channel and shoot for a 15 to 18-watt amp. Is that possible? And if so, would it be advisable to match the MOSFETS?
Regards,
Scott
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