It is not so much timing issues. But depending on cable L and C you can get additional phase shift in the feedback signal, and that may lead to instability.
Especially with boutique cables, that have been engineering with excessive L or C to make them sound different, this may be an issue.
Best results will be with short, Home Depot-type cabling.
Jan
Especially with boutique cables, that have been engineering with excessive L or C to make them sound different, this may be an issue.
Best results will be with short, Home Depot-type cabling.
Jan
I am glad NAD is offering the Purifi amp in the classic line. But I can't help noticing that its a de-tuned version. 227W in 8 ohm for the original module vs 185W in 8ohm for the C 298.
So I'll probably end up with a DIY version like the rest of you
Not necessarily detuned (?), it may be that they measure the power at clipping ar a lower distortion level. OTOH I do have a lower max power because I am giving it 55v instead of 65v - even if it is DIY
Or that it really matters at the end, in my case it will be something like a < 2 Db loss.
Has anybody here wired up the ET400 eval kit with the Hypex SMPS1200A400? I am a bit confused with the connections betwen the two.
The J1 power connector on the SMPS carries two bootstrap supplies, Vdr+ (pin J1.1) and Vdr- (pin J1.5).
On the ET400, the J1 power connector lists for pin J1.1 'gate drive referred to Vp-' . I assume that should be connected to the SMPS J1.1 Vdr+, but the 'referred to Vp-' confuses me.
Maybe SMPS J1.4 (Vdr-) should be connected to the ET400 J1.1 (Gate drive +, referred to Vp-) ?
At any rate, the ET400 J1.4 and J1.5 are interconnected and should be connected to SMPS J1.5, HV-, so one SMPS line (Vdr+ or Vdr-) does not need to be connected.
Who can clear this up from own experience having a non-exploded set working ? ;-)
Jan
The J1 power connector on the SMPS carries two bootstrap supplies, Vdr+ (pin J1.1) and Vdr- (pin J1.5).
On the ET400, the J1 power connector lists for pin J1.1 'gate drive referred to Vp-' . I assume that should be connected to the SMPS J1.1 Vdr+, but the 'referred to Vp-' confuses me.
Maybe SMPS J1.4 (Vdr-) should be connected to the ET400 J1.1 (Gate drive +, referred to Vp-) ?
At any rate, the ET400 J1.4 and J1.5 are interconnected and should be connected to SMPS J1.5, HV-, so one SMPS line (Vdr+ or Vdr-) does not need to be connected.
Who can clear this up from own experience having a non-exploded set working ? ;-)
Jan
Hi Ergo,
I think something clicked in my mind - you do that sometimes ;-)
Can you confirm: pin 4 of the SMPS J1 (Vdr-) does connect to pin 4 on the ET400. Since on the ET400 pin 4 and pin 5 are interconnected and connected to HV-, it seems that the SMPS Vdr- is connected to HV- and is the ref for the boost supply Vdr+ which is connected both sides to J1.1. ?
Jan
I think something clicked in my mind - you do that sometimes ;-)
Can you confirm: pin 4 of the SMPS J1 (Vdr-) does connect to pin 4 on the ET400. Since on the ET400 pin 4 and pin 5 are interconnected and connected to HV-, it seems that the SMPS Vdr- is connected to HV- and is the ref for the boost supply Vdr+ which is connected both sides to J1.1. ?
Jan
I know I had to put these pieces of pdf manuals side by side but can't find my paper copy to scan... anyhow I recreated it below and even though it was a while ago I'm pretty sure this is how it goes.
Not sure why Purifi keeps it this vague and documents it differently. As they do not offer PS I would expect majority of people are building it with Hypex SMPS.
Not sure why Purifi keeps it this vague and documents it differently. As they do not offer PS I would expect majority of people are building it with Hypex SMPS.
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Good - do confirm once you power it up successfully. Then I know if to keep that diagram for reference to others.
Btw, in the HTguide thread I documented my later upgrades too. Even just adding big 6800uF caps in between the SMPS and Purifi did result in a much bigger difference than I ever expected (I expected almost no change). In end I also ended up using WHAMMY as the gain/buffer stage for Purifi and that is what I'm running still and very happy with it. Anyhow - tweaking with buffers and bypassing the one on EVAL 1 is very beneficial in my opinion.
Btw, in the HTguide thread I documented my later upgrades too. Even just adding big 6800uF caps in between the SMPS and Purifi did result in a much bigger difference than I ever expected (I expected almost no change). In end I also ended up using WHAMMY as the gain/buffer stage for Purifi and that is what I'm running still and very happy with it. Anyhow - tweaking with buffers and bypassing the one on EVAL 1 is very beneficial in my opinion.
I use this a lot. Nowadays I only use this. They are 1,5 mm2 solid core installation cables. No way they would unwind themselves. After that you have wound them with the drilling machine they might do a short twirl back which you cant see on the finished cable and thats it - after that they stay.
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I made a few meters at once, tied both ends then with one end clamped used a drill to spin it. It did a little spin back but didn’t turn into a mess. A shame I only have red and black 22awg solid, I would like to use more colours. It is handy having it ready to go. I would like a purify amp too!
Someone, please help me.
Is it possible to connect a low power tube amp, say 2A3, to purifi module ? Or do we need some sort of buffer in between? The idea here is to create a hybrid amp with single Ended class A input stage ( yes to add some distortion !!! ) & class D output for a higher power. Technically feasible? What are the challenges?
Thanks...
Is it possible to connect a low power tube amp, say 2A3, to purifi module ? Or do we need some sort of buffer in between? The idea here is to create a hybrid amp with single Ended class A input stage ( yes to add some distortion !!! ) & class D output for a higher power. Technically feasible? What are the challenges?
Thanks...
Yes the wiring is correct, it worked first switch-on.
I will take a look at those other options. I plan to use it for my ESL63's, I wonder if there is an effect of the switching residual.
Jan
Well the Purifi wouldn't know that you use a tube. It expects a certain signal level with a low source impedance, a pre-amp type of thing. Could be a DAC, could be a tube stage. Important is the signal level, say up to a few volts, and a low output impedance, say less than a k, and Bob's your uncle.
Jan
Thanks. I don’t need to insert another tube stage in between. The unadulterated output signals from tube power amps should be fed directly to purifi module without any gain or whatsoever. Wish someone could design such a simple interface board just to accept power, input signal & speaker output. Is it that simple ??
Also not sure what’s the purpose of those pins for control signals in this context.
Also not sure what’s the purpose of those pins for control signals in this context.