Class D is a power amplifier type. It is the class for amplifiers that employ PWM. On a preamplifier, amplification is linear, hence not class D.
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Hypex DIY Preamplifier Kit Review
- Thread starter amirm
- Start date
That makes sense, I was going to add that I am far from convinced that PWM could have a real use for a simple line stage. Or if it had an actual real meaning. Hypex own input buffers are not class D and it's not fundamentally different. Now I don't know all complexities of class D design, I do know how it generally work tough. When you say on a preamplifier amplification is linear, do you mean generally? Or you mean that it can't be otherwise? I know full well that we don't find class D designs on the market, as I mentioned I think it serves no purpose, but are you saying it's impossible? That's two different things. There is always one first. In the end, you can produce a voltage gain with class D designs, and some headphone amps chips operate in class D and don't output more voltage than this preamp. but I also think this is not Class D.
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All low level amplifiers are linear as there is no benefit, which is efficiency, for class D when no power is output. In fact the efficiency will drop dramatically.
Yes, I already said that, but at 10W this is not a particularly efficient preamp. I mean I know you are right but it's still to me an assumption. Theoretically they could still have chosen that route despite no benefits. I still think it could be a question to ask when you brand your preamp diyclassD. Keep in mind that there is also an headphone amp in the box, and it's not rare that they have the same gain stage as the preamp. But OK.
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Where do you see that power value?
In the specs under power consumption.
DIYClassD DIY PreAmplifier
Build yourself a state-of-the-art high-end preamplifier with this DIY kit by DIYclassD. Easy to follow instructions will make the built a breeze.
www.diyclassd.com
That is power from mains. It includes PSU losses, HP amplifier and control circuitry consumption. The actual pre amplifier section will consume a tenth of that.In the specs under power consumption.
DIYClassD DIY PreAmplifier
Build yourself a state-of-the-art high-end preamplifier with this DIY kit by DIYclassD. Easy to follow instructions will make the built a breeze.
Have a look at the picture of a class D amplifier. That is effectively a single op-amp. Imagine many of them as a preamplifier needs it. Imagine the chokes on the output, etc. you may visualise how impossible to use class-D in a preamplifier.
Again, I think you are right that it's not, I am just not as categorical as you. I do not agree with this last thing tough, a preamp don't have a gain stage for each inputs! its not a space constraint, how much real estate do you think this chip would use in a big box like that?
If you control the volume with an IC you need buffer on input. Look at the PCB photograph and count the ICs…
That is a power amplifier, not a preamplifier.
Not sure what is has to do with the discussion, the attenuation comes before the gain stage I was not talking about that
It's meant to drive headphones, I know, but a gain stage is a gain stage, there is a headphone amp in the box my disagreement with your comment is just "It's impossible". I do not agree that it's impossible, I agree that it's not beneficial.
You said no need to use amplifier in the inputs. I explained that you need to buffer the input stage (use an amplifier) so that you can feed signal to a volume control IC which is before the gain and output stages.
A HP amplifier is not a gain stage but a power stage. The levels fed to a HP is not dissimilar to the levels used in a preamplifier. The difference is the power delivery.
A class-D amplifier use a high frequency clock, which means the physical circuit layout is constrained by RF emissions. When you use a large number of those amplifiers the circuit layout becomes unmanageable. That is what I mean by impossible.
Dimitri
Senior Member
Portofolio offering expansion. It's for their benefit, not yours
OK... I think this is running in circle, I understand all that, but an unloaded "power" stage still gives you voltage gain. You keep moving the goal post it makes it difficult to follow the discussion sorry. First it was space constraints that makes it impossible, now RF Emission constraints. I did not say no use for amplifier in the inputs, I was not talking about the buffers I have been talking about the preamplifier gain and the headphone amplifier gain the whole time, which is often derived from the same circuitry.
I mean congratulation if you can tell from this picture what the class of operation is. Me I can't, and I am sorry you did not demonstrated to me clearly that voltage gain in a preamp cannot be achieved in class D. We are at least both in agreement that it would be a poor choice, I'll leave it at that.
rvsixer
Addicted to Fun and Learning
And your point?
You said there are no miniDSP SHD or Flex devices with digital only output. I gave you the two specific models that have digital only outputs. And your comeback is that there is an analogue ouput version (which has already been pointed out BTW)
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Nice "MOLA MOLA" measurements. However, this DIY preamp kit is simply not modular enough to be remotely interesting.
Feature set as-is is very weak due to the limited selection of inputs/outputs. Future feature set still seems weak due to the probability that we are dealing with limited expandability.
Feature set as-is is very weak due to the limited selection of inputs/outputs. Future feature set still seems weak due to the probability that we are dealing with limited expandability.
JRS
Major Contributor
Taking into acct price/performance ratio I rated as not terrible. At this price I would expect an amp capable of several watts and indifferent to load. Certainly someone there can design such an item.
Great noise numbers can had be for a fraction of the cost. Except for the case and XLR's, a topping DX3 pro+ walks all over this as an amp and is quite close enough as a preamp. I dare say being a Hypex may have mattered. Add a DAC and a full array of digital inputs it might even prove useful at this price. I guess I just dont know what this does beyond being an analog volume control.
Great noise numbers can had be for a fraction of the cost. Except for the case and XLR's, a topping DX3 pro+ walks all over this as an amp and is quite close enough as a preamp. I dare say being a Hypex may have mattered. Add a DAC and a full array of digital inputs it might even prove useful at this price. I guess I just dont know what this does beyond being an analog volume control.
At least the Makua has tons of inputs/outputs.
(for those who don't know, Mola Mola is also a sister brand from Hypex for high end, while the brand DIY Class D is self explanatory)
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Sorry, but are you sure of this? I always tought that Bruno Putzeys founded Mola Mola and Purifi after leaving Hypex but I may be wrong. I also tought Putzeys used to be the head of engineering at Hypex, But essentially an employee.
Check their addresses, same building.
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