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DIY Purifi Amp builds
- Thread starter JimB
- Start date
It is not clear to which post you are replying. Which buffers?
The ones linked just above my post.
The ones on DIYaudio https://www.diyaudio.com/community/threads/universal-pcb-for-purifi-1et400a-amps.379211 . Yup, I have the same feeling that signal and power routing are bad, on a cursory look. In some places they seem inductively coupled, even.
I'm quite interested in doing something similar to what dudi has done on the first page of this thread - retrofit a purifi amp system into an existing amp (in my case Audiolab 6000A which is an integrated amp that i only use as a power amp). My reasoning is i quite like the simple aesthetics of the box, the front panel display, ability to control via remote and have multiple rca inputs. With this said, is it possible to fit a 1et400a amp plus any other necessary changes (e.g. power supply) given the capacity of the box and added complexity of needing to switch between inputs....etc and to do so preferably without electrocuting myself (noob who's never attempting anything like this before)
I have an EVAL1 built with the Ghent Case + SMPS1200A400. I'm wanting to expand to 3CH.
What would be the best course of action for that?
Also, I would like to add a 12v trigger to this setup as my current EVAL1 build does not have one at the moment. Would it be better if I just got a current sensing power strip instead of adding a 12v trigger?
If anyone can point me in the right direction that would be great, thanks!
What would be the best course of action for that?
Also, I would like to add a 12v trigger to this setup as my current EVAL1 build does not have one at the moment. Would it be better if I just got a current sensing power strip instead of adding a 12v trigger?
If anyone can point me in the right direction that would be great, thanks!
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OP
- Thread Starter
- #2,708
You could build an EVAL2 (Ghent has a matching case), or make another EVAL1. For 12V trigger, I settled on a triggered outlet box that switches two plugs. Just plug both amps into it and add trigger cable from your source to the switch box. Here is the one I used in my country:
https://dlidirect.com/products/iot-power-relay
FWIW, if pricing hasn't changed, the "value" of an EVAL2 is not so great compared to an EVAL1, so I ended up using an additional EVAL1 as my center channel amp (one channel idle). That gives me something more valuable/flexible in the future.
I was also thinking of just building an EVAL2 and also came to the same conclusion that another EVAL1 makes more sense.
I've thought about using the same SMPS1200 for the third channel with this splitter: https://neurochrome.com/collections/connectors-parts/products/hypex-smps-splitter
Only problem would be trying to find a case for all three channels.
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Hey Jim,
Thanks for all the help. That IOT switch looks like it'll fit the bill.
Question. Are there any concerns about mixing and matching with another build that's using a different input buffer? Asking because it looks like some of the pre-built options may be cheaper than building one yourself after shipping/taxes.
OP
- Thread Starter
- #2,712
Maybe. That would depend on the details of the amp you choose. One obvious difference could be the input sensitivity - the voltage required to get full power out. However, unless you are choosing something with significantly lower input sensitivity than your EVAL1, and have a source that cannot drive it, you might make it work. For example, using a common AVR, you can adjust the drive levels of each channel to match sound output for each speaker. You would just adjust that to get a match the same as any normal setup.
Long time lurker.....
Want to build my first amplifier, and the ABH2 benchmark caught my attention first: small footprint, low noise, and significant power. Purifi DIY amp kits seem to be a competitive solution. As that is I want to ask if any of you experienced diy'rs if anything about this build would raise any problems with heat?
The cassis is from DIYaudio store (Mini Dissipante 2U, internal size: WxDxH- 25x20x80)
Have a nice day! Thanks
Are there any rumors of new class-d modules that are even more efficient than this 1ET400A?
(The 1ET400A modules with Neurochrome buffer are mounted vertically to the mini dissipante heat sinks)
Want to build my first amplifier, and the ABH2 benchmark caught my attention first: small footprint, low noise, and significant power. Purifi DIY amp kits seem to be a competitive solution. As that is I want to ask if any of you experienced diy'rs if anything about this build would raise any problems with heat?
The cassis is from DIYaudio store (Mini Dissipante 2U, internal size: WxDxH- 25x20x80)
Have a nice day! Thanks
Are there any rumors of new class-d modules that are even more efficient than this 1ET400A?
(The 1ET400A modules with Neurochrome buffer are mounted vertically to the mini dissipante heat sinks)
The Purifi modules produce very little heat, just mounting them to the bottom plate of an aluminum chassis is enough to dissipate any heat produced, so no worries.
I do not think that it makes sense to wait for new modules with a higher efficiency. The given efficiency values are given at maximum power and for lower wattage the efficiency drops quite significantly, even into the single digits for very low output. The reason is that the power amplification itself is highly efficient, but there is a baseline fixed consumption for the control electronics, the modulators, and if available on the board, the input buffer which is usually in class A. Therefore if, say, an amp has an asymptotic efficiency of 95%, but a baseline consumption of 5W, at 1W output it will actually need about 6.05W to function. An efficiency of roughly 16.5%. And if your speakers are moderately sensitive, this may be your normal situation. A module that is 98% efficient at full power will not be as efficient at all output levels. Note that I am oversimplifying a bit, but only the model, not the basic principle and, qualitatively, the outcome.
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This is completely right. What makes the Purifi modules run cool is their idling consumption of 1W, not their efficiency at full power.
Yep; and a buffer is going to tilt the balance a bit further at low total outputs. My build, which you know, has an idle consumption of around 10W IIRC.
Hi NTK...
I have been sitting on my NC400 kits for a while, using Ghent Chassis.
Your write up is the most clear and succinct explanation I've seen. But this is also my first time and I'm not an electrician. *blushes
The case is fully anodized except for one spot where the AC GND connects.
I bring this up because you mention grounding the NC400 (and presumably the metal standoff for the SMPS600) modules. Do I need to get a tool to remove some of the finish from my chassis in order to properly ground these?
Or could I also connect a small spade or ring connector wired to that ground point from each module?
Also, I was curious about this nAMPON issue as well. I've seen some people solder it to a floating tab on the back of the XLR mount, or to the GND with the shield. According to your post, you recommend grounding to the chassis.
Is there a functional difference (asking because I am completely new to this!)?
And what is that extra tab on the back of the XLR, anyway?
I appreciate any info you, or anyone, may offer.
Many thanks!!!
OP
- Thread Starter
- #2,719
This is a Purifi amp thread. You are asking about a Hypex project. You might get better help in a different thread. Meanwhile, I believe Hypex uses Ghent cases in their kits (at least similar enough to learn from their instructions). Take a look at how they show their connections.
https://www.diyclassd.com/product/nc400-mono-kit/24
Also, in any case that you want an electrical connection to these types of aluminum cases, yes, you should remove the oxide coating of the case right where you need to make electrical contact. You could scrape or "sand" as needed to see bright metal.
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I well understand... and if you noticed I was replying to a very helpful post about the NC400 IN THIS THREAD... (which clearly didn't stay on topic over it's 136 pages). But it's HERE, and that's why I asked for clarification.
Thank you for your other input. I've gotten mixed input from other sources and queries. Always the most frustrating aspect of trying a new path. However, yours and a few others are clearly showing to be in the category of Best Practice. I appreciate your vote for that!
Cheers.
