Yep.
The regulator board will be all-DIY (it has seven components!) and all PTH/through-hole parts. It'll support the Hypex HPR and HNR, LM7812/LM7912, LM78L12/LM79L12, and other pin-compatible regulators. It'll be the most affordable board in my lineup.
Tom
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Thanks for information.
Do you know, how they (Purifi) have resolved the problem with their EVAL1 board (1 SMPS1200A400 supplying 2 modules) ?
The answer is in JimBl/Kim's reply that you quoted
The hypex PSU doesn't suffer from power supply pumping.
The hypex PSU removes the problem
Which means that the Audiophonics folks that use the Hypex supply and invert one channel to “mitigate supply pumping” do not really understand the matter. I might be excused, I do not sell audio stuff, but they should understand what they are doing. Makes me also not really trust their buffer...
In the specific case of the ET400A and the SMPS1200A400, we have the answer. But for some other combinations, it might matter. However, it doesn't hurt, for truly balanced source inputs. With single ended source input, I'm not so sure with the 1ET400A, because its input is DC coupled and its negative output connections are fixed at common ground (do not confuse this with the Purifi comment that the 1ET400A is single ended - I'm talking about the signal source). Others might know more. I'd judge their input buffer on its own merits (I have no knowledge about it).
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Or...
maybe they are just trying to be "safe". The thing which bothers me about this approach is that I like the "black, or white" speaker binding post to not be actively driven, as its color would indicate (for a single ended output stage). I run a subwoofer via high level inputs from the speaker binding posts. I got a little concerned about this because of the ET400A's data sheet saying to treat the output as if it was balanced, such that the feedback loop would work properly. I contacted Purifi about this, and they said it should be fine to connect a subwoofer to the speaker binding posts. I assume this is because the subwoofer input is relatively high impedance at over 4 kOhms.
My Hypex supply will be here tomorrow, looking forward to testing with it, but still with my custom linear supply for +/- 18 VDC.
maybe they are just trying to be "safe". The thing which bothers me about this approach is that I like the "black, or white" speaker binding post to not be actively driven, as its color would indicate (for a single ended output stage). I run a subwoofer via high level inputs from the speaker binding posts. I got a little concerned about this because of the ET400A's data sheet saying to treat the output as if it was balanced, such that the feedback loop would work properly. I contacted Purifi about this, and they said it should be fine to connect a subwoofer to the speaker binding posts. I assume this is because the subwoofer input is relatively high impedance at over 4 kOhms.
My Hypex supply will be here tomorrow, looking forward to testing with it, but still with my custom linear supply for +/- 18 VDC.
About Audiophonics I live next them and knew people that worked for them....
They are just a company buying stuff in china to sell it at gold price in europe. They are like any company of the kind, money before everything, including their own employee...
I won't have any problem buying their refurbish stuff as it is not much expensive if you buy it directly from china, and some services they offer is great, like their custom order toroidal transformer.
However i will never buy the very little they develop and manufacture them-self.
They are merchant that manage stocks, not audio engineer. I was even surprise they made their own buffer for the purifi... Generally the maximum they can do is rebuild components with new brand name, like their chinese R2R dac that seems mediocre.
They are just a company buying stuff in china to sell it at gold price in europe. They are like any company of the kind, money before everything, including their own employee...
I won't have any problem buying their refurbish stuff as it is not much expensive if you buy it directly from china, and some services they offer is great, like their custom order toroidal transformer.
However i will never buy the very little they develop and manufacture them-self.
They are merchant that manage stocks, not audio engineer. I was even surprise they made their own buffer for the purifi... Generally the maximum they can do is rebuild components with new brand name, like their chinese R2R dac that seems mediocre.
The (-)black output connections of the 1ET400A are connected to ground. They measure 0.0 ohms to the metal standoffs you connect to your metal chassis.
Yes...
I know that. But if you reverse polarity at the input and output on one channel to eliminate power supply pumping with a regulated SMPS such as is the discussion here, then one channel will have the "black or white" speaker post actively driven, and this is a bit confusing to users, that is my concern.
Also, if we are just talking about using the sub and not with the reverse polarity in one channel, section 4.3.2 of the 1ET400A data sheet is a bit concerning, and why I contacted Purifi to be certain.
I know that. But if you reverse polarity at the input and output on one channel to eliminate power supply pumping with a regulated SMPS such as is the discussion here, then one channel will have the "black or white" speaker post actively driven, and this is a bit confusing to users, that is my concern.
Also, if we are just talking about using the sub and not with the reverse polarity in one channel, section 4.3.2 of the 1ET400A data sheet is a bit concerning, and why I contacted Purifi to be certain.
Yes, they are just folks that buy stuff out of china to resell it. Sometimes the markup is, however, not as high as you may depict. Most PSUs cost as much as ordered from China, plus shipping, customs, maybe another 5% on top of it – of course since they buy in bulk, that's where their margins come from. if they have stuff in stock, they are very convenient. But I quickly got what they are and what they do, and am very satisfied with the speed of their deliveries and their customer service. I just do not expect them to be able to design circuitry.
Always okay to check with the authorities at Purifi while we are all working out the nuances of applications. I read that section to say that, while it is tied to ground, internally, you should not connect the -output connection itself to ground. This is to preserve the full benefit of sense feedback from the point in the output path that is closest to the load.
Yes.
I read it the same way, and connecting the sub ground to the black or white binding post directly violates that, hence why I contacted Purifi about it.
I read it the same way, and connecting the sub ground to the black or white binding post directly violates that, hence why I contacted Purifi about it.
Sorry. I think I am replying late on this. You have already heard back from them that your connection is okay, right?
How did it work? It might be tricky to assess, since, at most, it should have resulted in vanishingly small performance reduction.
Just started the vendor thread (and opened for pre-orders) of my Purifi 1ET400A / Hypex NC500 Input Buffer. You can find it here: https://www.diyaudio.com/forums/ven...00a-hypex-nc500-input-buffer.html#post6127335
Tom
Tom
Hi folks.
Just received a Purifi set. I plan to remove the banana jacks.
The sense input seems to play a somewhat important role.
I don't have a clue how much impact can be expected from toying around
with the sense input. Ok. I did understand that it has to be connected somewhere.
I'm wondering about the best spot where to put the/a sense wire/bridge !?!?
Wouldn't be a wire being attached (soldered) right to the speaker cable
to bypass all the connectors etc. the best option?
On the other hand.
If I'd solder my speaker cable right to the board a simple bridge
to the sense input would be required, wouldn't it.
Would be nice if somebody could post a picture showing how the sensing is
done without the bananas in a real-word setup.
THX
Just received a Purifi set. I plan to remove the banana jacks.
The sense input seems to play a somewhat important role.
I don't have a clue how much impact can be expected from toying around
with the sense input. Ok. I did understand that it has to be connected somewhere.
I'm wondering about the best spot where to put the/a sense wire/bridge !?!?
Wouldn't be a wire being attached (soldered) right to the speaker cable
to bypass all the connectors etc. the best option?
On the other hand.
If I'd solder my speaker cable right to the board a simple bridge
to the sense input would be required, wouldn't it.
Would be nice if somebody could post a picture showing how the sensing is
done without the bananas in a real-word setup.
THX
I just stepped over this @ASR.
Can somebody tell me why they use 2+1sense wires per leg on the shown image?
Is it just to cover for high current situations!?!?
When I was looking at some of the DIY build images I can't recall to see a sense wire
going to the outer binding posts. Obviously there are different ways to handle this.
Or perhaps the impact when choosing different positions can simply be neglected.
Can somebody tell me why they use 2+1sense wires per leg on the shown image?
Is it just to cover for high current situations!?!?
When I was looking at some of the DIY build images I can't recall to see a sense wire
going to the outer binding posts. Obviously there are different ways to handle this.
Or perhaps the impact when choosing different positions can simply be neglected.