4-channel Tube Pre Layout

[ruffrecords]

Please tell me more...

We have discussed using SmPS for heaters a couple of times in the past. I have now reached th point where I use them all the time heaters. The make I use is MeanWell. THey have a wide range of 12V PSUs from a few watts up to hundreds. Most of their range has what is called hiccup mode short circuit current limiting which is designed to power up into difficult capacative loads but also works well for cold heaters. Even so you I have found you need to rate the SPMS at twice the heater current to ensure it will always fire up. However, they are so small and cost effective this is not a disadvantage.  From the technical standpoint, I have found these supplies create much less interference than their linear equivalents.

Cheers

Ian

 

[BluegrassDan]

Something like this? http://www.meanwellusa.com/productSeries.aspx?i=18&c=6#tag-6-18

Any particular model you would use for a total 12v heater draw of 2A?

 

[BluegrassDan]

New layout with external PSU connection via Binder M23 connectors.

https://www.binder-usa.com/products/power-connectors/m23-power.html

Going with a 3U case by DIYAudioStore. Now...time to hurry up and wait for all the parts to arrive.

 

[ruffrecords]

Something like this? http://www.meanwellusa.com/productSeries.aspx?i=18&c=6#tag-6-18

Any particular model you would use for a total 12v heater draw of 2A?

I mostly use their LRS series so for 2A at 12V I would go for a LRS-50-12. 50 watts gives up to 4A which should be enough to cope with inrush.

http://www.meanwellusa.com/webapp/product/search.aspx?prod=LRS-50

Cheers

Ian

 

[BluegrassDan]

Very cool! And only $11 usd.

And would an SMPS supply work also for phantom power, or is there too much noise introduced into the signal?

The RS-15-48 perhaps? http://www.meanwellusa.com/webapp/product/search.aspx?prod=RS-15

 

[ruffrecords]

Very cool! And only $11 usd.

And would an SMPS supply work also for phantom power, or is there too much noise introduced into the signal?

The RS-15-48 perhaps? http://www.meanwellusa.com/webapp/product/search.aspx?prod=RS-15

I have been thinking about this. I purchased this little gem a while back;

https://uk.farnell.com/vigortronix/vtx-214-006-148/power-supply-ac-dc-48v-0-125a/dp/2464682?ost=vtx-214-006-148&ddkey=https%3Aen-GB%2FElement14_United_Kingdom%2Fsearch

Universal mains input, all the approvals and 48V and 100mA or so. Totally encapsulated and very small about 2in by 1in by 1in. Ripple is quoted at 50mV max but I have not measured it. As the ripple is high frequency, an external LC filter should be more than enough to drop it to audio levels. I might put it on the bench tonight and check it out.

I also bought it big 12V prother at the same time:

https://uk.farnell.com/vigortronix/vtx-214-006-148/power-supply-ac-dc-48v-0-125a/dp/2464682?ost=vtx-214-006-148&ddkey=https%3Aen-GB%2FElement14_United_Kingdom%2Fsearch

12V out at up to 1.6667 amps; should be good for half a dzoen 12V double triodes.

Cheers

Ian

 

[ruffrecords]

The Vigortronix SMPS tests I conducted last night were not very encouraging. I tried it will a 1K 5W resistor load which should sink 48mA (about half the rated current). I got lots of positive spikes a 1.5uS intervals several 100mV tall. A 4,7uF film cap knocked them down to about 100mV. I tried a 100 oh series R with a 47uF electrolytic cap to try to dampen things down. Unfortunately, the cap, although rated at 100V, started to smoke after about a minute. Also tried a series L paralle lC but nothing seems to stop these spikes.

So then I tried  MeanWell 48V supply (15W rated I think). Same 1K load and there was some high frequency ripple but not more than 100mV peak. Added a 4.7uF film cap which dropped it to 50mV peak. This supply looks much more amenable to external smoothing.

Cheers

Ian