The data I have compared until know indicates that the two is about similar. 24mW/C is the same and 10 ohm.
I think this is valid for my NTC:
How should I read this.......if ambient temp is less than 65C then Imax is 100A?
How should I read this.......if ambient temp is less than 65C then Imax is 100A?
compare Imax and steady I if original one and that one you have
still not dialysis; worst thing can happen is dead NTC and fuse
still not dialysis; worst thing can happen is dead NTC and fuse
10D20 only says that it is 10 ohm and 20mm in diameter. There is no brand name on it.
It seems that's how you compare NTC 🙂 ......ohm and diameter 🙂
I will try it.......
It seems that's how you compare NTC 🙂 ......ohm and diameter 🙂
I will try it.......
It works much better with new NTC. The delay from power-on to relay kicks in is longer and same as the SMPS in other amp.
I may be able to put in a smaller mains fuse than the 6.3A T I have in now. It was the bad SMPS that blew the 2A T. It "feels" like power-on is much softer now.
Here is the final proof that NTC was/is bad........
I may be able to put in a smaller mains fuse than the 6.3A T I have in now. It was the bad SMPS that blew the 2A T. It "feels" like power-on is much softer now.
Here is the final proof that NTC was/is bad........
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yeah
10D-20 is pretty generic drek, meaning no special characteristics
pretty much any 10R 20mm Dia is equally good
10D-20 is pretty generic drek, meaning no special characteristics
pretty much any 10R 20mm Dia is equally good
Yes, this delayed the project a bit but I never feel confident with this one SMPS of the two and happy that problem seems solved.
I will continue tomorrow. Maybe I will prepare the bleeder resistors and solder them across binder posts tonight.
Another task I did this evening was putting bottom cover on and screwed on some rubber feet. It will give better ventilation that the plastic 10mm feet applied with chassis kit. I think feet applied does not live up to the quality of the chassis.......but easy to put on other feet. 4mm screws fits in the ventilation cut outs. I could mount the rubber feet without any drilling......just screw them on.
I will continue tomorrow. Maybe I will prepare the bleeder resistors and solder them across binder posts tonight.
Another task I did this evening was putting bottom cover on and screwed on some rubber feet. It will give better ventilation that the plastic 10mm feet applied with chassis kit. I think feet applied does not live up to the quality of the chassis.......but easy to put on other feet. 4mm screws fits in the ventilation cut outs. I could mount the rubber feet without any drilling......just screw them on.
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I used Connex supplies for chip amps in the past and unfortunately they lived very short lives. The parts used are not name brand and do not give a feeling of “confidence”.
I hope these units live a long and fruitful life for you Meper! 😉
I hope these units live a long and fruitful life for you Meper! 😉
If not I will find another SMPS. Until know the SMPS for VFET amp have lived a year or so and run for many hours.
Now I use them with very little power compared to what they are specified to. I hope this helps a bit.
The SMPS for the VFET amp I got via Audiophonics in France. They sell a lot of them. I wrote to them before I ordered one and asked about the quality. They wrote back that they have had a long good relationship with Connex. After this I purchased one. But maybe I should have asked other than a dealer 🙂
The NTC I put in is a branded one......from RS Components. So at least one branded component now. The fuse Bussmann is also branded.......and works without sticky stuff on them. When I searched for the relay I found that Mouser had them.......but I agree that some components are unbranded like the 12V reg.
I will give feedback if something breaks in the SMPS's.......it seems they can be a bit "violent" during power on......
Now I use them with very little power compared to what they are specified to. I hope this helps a bit.
The SMPS for the VFET amp I got via Audiophonics in France. They sell a lot of them. I wrote to them before I ordered one and asked about the quality. They wrote back that they have had a long good relationship with Connex. After this I purchased one. But maybe I should have asked other than a dealer 🙂
The NTC I put in is a branded one......from RS Components. So at least one branded component now. The fuse Bussmann is also branded.......and works without sticky stuff on them. When I searched for the relay I found that Mouser had them.......but I agree that some components are unbranded like the 12V reg.
I will give feedback if something breaks in the SMPS's.......it seems they can be a bit "violent" during power on......
I just looked at the branded NTC I put in. It is also from China. But as a branded one the quality control might be better. It could be produced at the same factory?
Some of my Nikon lenses are also made in China and they are very good but also here I guess there are some quality control.
I hope the best with my Connex SMPSs.......at least they are very responsive when I write to them and I think basic design is ok.
Usually when electronics fails it is during the first period of time and then It will be stable for a long time......and then it starts failing.
The famous "bathtub curve" we learned about in school? 🙂
Some of my Nikon lenses are also made in China and they are very good but also here I guess there are some quality control.
I hope the best with my Connex SMPSs.......at least they are very responsive when I write to them and I think basic design is ok.
Usually when electronics fails it is during the first period of time and then It will be stable for a long time......and then it starts failing.
The famous "bathtub curve" we learned about in school? 🙂
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I am not at Facebook 🙂
How would an amp sound if it was made with only Swiss made components?
Maybe it would be a chassis only.......but a very nice and expensive chassis......
How would an amp sound if it was made with only Swiss made components?
Maybe it would be a chassis only.......but a very nice and expensive chassis......
Regarding connect to speakers......maybe tomorrow if everything goes smooth from here......
I play VFET in the moment which has some voltage gain so I go directly from DAC. Now with Lazy......it probably needs a bit more voltage swing than max 2.1 Vpp or so. So I need to find a preamp. It will be either Whammy or SSII.......probably SSII.....it has more gain. It will have very little distorsion driving 220k input resistor and 75 cm RCA cable.
I play VFET in the moment which has some voltage gain so I go directly from DAC. Now with Lazy......it probably needs a bit more voltage swing than max 2.1 Vpp or so. So I need to find a preamp. It will be either Whammy or SSII.......probably SSII.....it has more gain. It will have very little distorsion driving 220k input resistor and 75 cm RCA cable.
Will start "early" tomorrow with soldering but also need to watch Paris-Roubaix in TV. I could not participate this year 🙂
I can watch TV from where I solder amp.....so that is good.
I can watch TV from where I solder amp.....so that is good.
One channel is up and running with just DAC output which is max 2.1 Vpp. But it plays. It plays just below normal listening level at full output.
With no music I can hear just a slight trace of ripple noise if I put ear very close to tweeter. SMPS has about 130 mV ripple noise when I measure AC with DMM.
About Gnd to Chassis/Earth via 10 ohm NTC. If I remove this connection could it reduce noise?
Is a reference from Gnd to Chassis always necessary?
Could it float in this design?
Will see how the other channel behaves when finished.
With no music I can hear just a slight trace of ripple noise if I put ear very close to tweeter. SMPS has about 130 mV ripple noise when I measure AC with DMM.
About Gnd to Chassis/Earth via 10 ohm NTC. If I remove this connection could it reduce noise?
Is a reference from Gnd to Chassis always necessary?
Could it float in this design?
Will see how the other channel behaves when finished.
strong current path from amp PSU to chassis is matter of safety, not to play with
what you can try, in your setup, is to determine what's more effective in killing noises - direct connection to chassis or through NTC (or any other similar arrangement - NTC+cap+bridge, for example)
though, if you measured 130mV ripple, that's your culprit
either live with it or cure with additional filtering
what you can try, in your setup, is to determine what's more effective in killing noises - direct connection to chassis or through NTC (or any other similar arrangement - NTC+cap+bridge, for example)
though, if you measured 130mV ripple, that's your culprit
either live with it or cure with additional filtering
DMM just measure 0.0 mV at speaker out so less than 0.1 mV noise at speaker out. I guess that is acceptable. You can probably always hear a little bit of noise if ear is close enough to tweeter and I have to concentrate with ear 5 cm from tweeter to hear it. I have a waveguide attached to tweeter so difficult to get ear closer than 5 cm.
Amp itself has some suppression of the 130 mV ripple noise?
I think the 130 mV is what is specified for SMPS.
MJ has designed a SMPS filter rated 3A and max. 48V. I wonder if it can be tweaked to handle lets us say 75V and 4A to have a bit of margin?
Then this could be a future upgrade to implement such a filter.
Amp itself has some suppression of the 130 mV ripple noise?
I think the 130 mV is what is specified for SMPS.
MJ has designed a SMPS filter rated 3A and max. 48V. I wonder if it can be tweaked to handle lets us say 75V and 4A to have a bit of margin?
Then this could be a future upgrade to implement such a filter.
invest in fat EI choke and 22mF cap
you already did go wild, proceed in that manner
remove waveguide to get ear closer to tweet
you already did go wild, proceed in that manner
remove waveguide to get ear closer to tweet