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I was going to ask about the same behavior on start up. I am seeing -15v about 4 sec after power up. It declines rapidly and is at -5v by 15sec, and -180mV by 1 min. By 3 mins, it is at -25mV and steady state when warm is about -6mV. Both channels behave exactly the same way.
Guess it's not to worry about.
Guess it's not to worry about.
Folks:
Thanks for the support! Number 12 is up and running. This is a fun amplifier; it has much of the authority of my F5 Turbo mono blocks (more so than my F6) and it has a very good grip on my Elsinores. The soundstage is a little narrower than and not as deep as the F5T. The soundstage is more on a par with the F6 but there is precision here; neutral and well-balanced. It's doing a lovely job making my speakers fade into the background. Given the strengths of this little amp, Nelson's larger Sony VFET amplifier must be amazing.
As always, thanks to NP, diyAudio and the community. And HiFi2000 -- really cute chassis!
Regards,
Scott
Thanks for the support! Number 12 is up and running. This is a fun amplifier; it has much of the authority of my F5 Turbo mono blocks (more so than my F6) and it has a very good grip on my Elsinores. The soundstage is a little narrower than and not as deep as the F5T. The soundstage is more on a par with the F6 but there is precision here; neutral and well-balanced. It's doing a lovely job making my speakers fade into the background. Given the strengths of this little amp, Nelson's larger Sony VFET amplifier must be amazing.
As always, thanks to NP, diyAudio and the community. And HiFi2000 -- really cute chassis!
Regards,
Scott
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Pass DIY Addict
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Supplied speaker and ground wires are not long enough to reach the posts. I followed the instruction in the guide to the letter and they are incorrect.
Please make grey, orange and green wires 4 inch longer. I have plenty of signal wires left over.
The head of the bolts supplied to fasten the supply board to the bottom plate are barely wider than the plate slots. Consider using a bolt with wider head or a washer.
I had to use higher stands and lift the filter board up in order for the wires to reach their destination properly, I will have to replace the orange wires of the left channel. I m about to fire this up and adjust xfingers.
update: adjustment done...started at 18.75 V, brought up to 20...purring like a kitten! I m hooking it up to the altecs!
btw the sony gets hot QUICK!
Please make grey, orange and green wires 4 inch longer. I have plenty of signal wires left over.
The head of the bolts supplied to fasten the supply board to the bottom plate are barely wider than the plate slots. Consider using a bolt with wider head or a washer.
I had to use higher stands and lift the filter board up in order for the wires to reach their destination properly, I will have to replace the orange wires of the left channel. I m about to fire this up and adjust xfingers.
update: adjustment done...started at 18.75 V, brought up to 20...purring like a kitten! I m hooking it up to the altecs!
btw the sony gets hot QUICK!
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I am also confused by this. I am still waiting for my kit, but if the MeanWell brick is similar to all my other MeanWells, the DC output side is nicely isolated from the mains side. This means there cannot be any "mains earth" or "safety earth" in/at the amp. Also, the shield and the -Ve wire share the same connection inside the MeanWell brick, so the thermistor between the -Ve/GND and chassis is shorted and does not seem to have any function.
Can anyone shine some light on this?
The supplied meanwell is NOT isolated, i.e. Earth Ground (AC side) is connected to the DC negative output (AND the shield)
I you want to preserve the isolation from audio ground to earth through the thermistor on the power input board, you must NOT connect the shield of the power connector.
I you want to preserve the isolation from audio ground to earth through the thermistor on the power input board, you must NOT connect the shield of the power connector.
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Ok, in this case I can see how it makes sense to have the chassis connected to safety earth.
I don't understand this. The Ve- wire is connected to the shield inside the MeanWell, correct? Therefore, and because the MeanWell is not isolated to mains, the Ve- is also connected to the safety earth pin at the mains connector. And since Ve- is connected to audio GND, there is also a direct connection between audio GND and safety earth.
If this is correct, this is asking for ground loop problems. Also, the thermistor would not have any function to separate audio GND from safety earth.
I guess (hope) there's something flawed with my understanding how the grounding works here.
Can someone measure the following resistances with the MeanWell connected to the amp (but nothing else connected to the amp):
- From VFET amp chassis to safety earth pin at the mains connector of the MeanWell
- From VFET amp chassis to audio GND
The way I see it is like this:
Earth (AC side of the Meanwell) is somehow connected both to V- out and the shield.
What you are doing is connecting the V- (and the shield which is tied to V-) to the chassis via the thermistor on the power input board.
That means the chassis is connected to "earth" via the thermistor.
If you connect the shield wire to the chassis you short out that thermistor.
Both ways should work....
I wouldn't have a problem just leaving the whole thing floating in the chassis, that is NOT fitting the thermistor, and NOT fitting R7 on the input boards, but I am pretty sure this would be against rules/regulations in a couple of countries.
EDIT: I NEVER ever had an amp that silent... whatever overkill linear supply I was using....
Earth (AC side of the Meanwell) is somehow connected both to V- out and the shield.
What you are doing is connecting the V- (and the shield which is tied to V-) to the chassis via the thermistor on the power input board.
That means the chassis is connected to "earth" via the thermistor.
If you connect the shield wire to the chassis you short out that thermistor.
Both ways should work....
I wouldn't have a problem just leaving the whole thing floating in the chassis, that is NOT fitting the thermistor, and NOT fitting R7 on the input boards, but I am pretty sure this would be against rules/regulations in a couple of countries.
EDIT: I NEVER ever had an amp that silent... whatever overkill linear supply I was using....
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This thread moves crazy quickly.
Matthias / Coolnose -
Nelson was kind enough to explain earlier that the wiring diagram showing the additional run from the tabs to chassis ground was a redundancy put into place in the event an isolated supply was used. If you got a "full kit" then that run is not necessary.
The R7 position is also a belt and suspenders type of redundancy. I chose to install R7 b/c my boards had that provision. I have not checked the schematics for Mark's additional IPSs for similar provisions.
re: its silence. I've used SMPSs (clearly) in a bunch of "smaller" applications previously for audio, but this is my first power amp. All potential misgivings have been eliminated. It is dead silent in my system, and the amp is just amazing IMO.
Matthias / Coolnose -
Nelson was kind enough to explain earlier that the wiring diagram showing the additional run from the tabs to chassis ground was a redundancy put into place in the event an isolated supply was used. If you got a "full kit" then that run is not necessary.
The R7 position is also a belt and suspenders type of redundancy. I chose to install R7 b/c my boards had that provision. I have not checked the schematics for Mark's additional IPSs for similar provisions.
re: its silence. I've used SMPSs (clearly) in a bunch of "smaller" applications previously for audio, but this is my first power amp. All potential misgivings have been eliminated. It is dead silent in my system, and the amp is just amazing IMO.