Switched DC/DCconverter for B+

revintage · 16th July 2007, 02:45 PM

Found these DC/DC converters for B+:

www.revintage.se/RecomDCDC.pdf

Recom have modules for 12V to up to 350V that also can be stacked.

Just an idea to have only a 12V transformer to get 12,6V DC for the preamp heaters and from there via the converters to anodevoltage.

Anyone who have tried?

Jeb-D. · 17th July 2007, 03:40 AM

Wow, that's a good find. Never tried one, but can think of plenty of uses for one. Perhaps in a hybrid automotive amplifier

r221b · 17th July 2007, 07:56 PM

For a start, you can't use a 12.6 volt transformer. Transformers only utilize AC. To get the DC input required, you'll need a rectifier and filter circuit. Another consideration is that these switchers run at 200 kHz according to the spec. sheet. That could produce switching noise in whatever you want to use them in. Third, the output is only 50 ma. If you stack them, only the voltage adds, the output current remains at 50 ma. If you can overcome these limitations, there's no reason they won't work.

sherlock

revintage · 17th July 2007, 09:19 PM

Quote:

Originally posted by r221b
For a start, you can't use a 12.6 volt transformer. Transformers only utilize AC. To get the DC input required, you'll need a rectifier and filter circuit. Another consideration is that these switchers run at 200 kHz according to the spec. sheet. That could produce switching noise in whatever you want to use them in. Third, the output is only 50 ma. If you stack them, only the voltage adds, the output current remains at 50 ma. If you can overcome these limitations, there's no reason they won't work.

sherlock

I asked if someone had tried them!

All you say is obvious: Of course you have to have a transformer to rectify from AC to DC! How should you otherwise do?

As I said preamp, 50mA should not be a problem.

And I wanted to know if someone had tested this IRL as swithcing noise probably is the issue that could be a problem.

So back to the question I wanted answer for: Have you or someone else tried them or any similar device.

Just found a test in Stereophile where Nagra uses this solution in their tube preamp so it must work! Will take a deeper look!

r221b · 18th July 2007, 01:13 PM

Just trying to help.... I haven't a clue as to your technical knowledge or lack thereof. From what I've seen on this forum, there are people that know virtually nothing about electronics all the way up to electrical engineers. What's "obvious" to you probably isn't to a lot of others. Since I took the time to reply, a simple "thanks" might have been in order. I hope you get your answers.

sherlock

revintage · 18th July 2007, 01:26 PM

Sherlock: Thank you for taking you time to answer. Sorry, did not mean to insult you

.
When I did not find the answers at Google, I asked here. Thought the knowledge level was higher. If you are still wondering about my level pls check my site www.revintage.se.

r221b · 18th July 2007, 03:20 PM

Quote:

Sherlock: Thank you for taking you time to answer. Sorry, did not mean to insult you .

Lars,

Apology accepted with no hard feelings. If you actually give these converters a try in your project, let us know how they work (or don't).

sherlock

tubelab.com · 20th July 2007, 02:21 AM

I looked up these converters since they would fit right in to an upcomming project (a battery powered tube guitar preamp). Unfortunately there is only one supplier in the US, and they only stock a few parts. No HV stuff, only 5 and 12 volt parts.

I have been experimenting with SMPS's and DC to DC converters for vacuum tube uses. The 200 KHz switching frequency is not a problem. The 30 to 50KHz converters can be a problem. As I am trying to mount the preamp inside the guitar, I have found that some designs can play havoc with a guitar pickup even at a distance of over 1 foot. Toroidal inductors are your friend. Unshielded ferrite bobbins are not.

revintage · 20th July 2007, 10:47 AM

Quote:

Originally posted by tubelab.com
I looked up these converters since they would fit right in to an upcomming project (a battery powered tube guitar preamp). Unfortunately there is only one supplier in the US, and they only stock a few parts. No HV stuff, only 5 and 12 volt parts.

Hi Guitar-buddy,

Can send you one when I get the R12-150As I will order. If you want a smaller one I can include it in the same order.

(About guitar-buddies: Check my bandsite: www.myspace.com/eflatjumptessandersson and also see a glimpse of my "reVintage Pro" guitar amp in between Tess and me)

Jeb-D. · 20th July 2007, 02:07 PM

What's the price range for those?

16th July 2007, 02:45 PM	#1
revintage diyAudio Member Join Date: May 2007	Switched DC/DCconverter for B+ Found these DC/DC converters for B+: www.revintage.se/RecomDCDC.pdf Recom have modules for 12V to up to 350V that also can be stacked. Just an idea to have only a 12V transformer to get 12,6V DC for the preamp heaters and from there via the converters to anodevoltage. Anyone who have tried?

20th July 2007, 02:21 AM	#8
tubelab.com diyAudio Member Join Date: Jul 2005 Location: South Florida	I looked up these converters since they would fit right in to an upcomming project (a battery powered tube guitar preamp). Unfortunately there is only one supplier in the US, and they only stock a few parts. No HV stuff, only 5 and 12 volt parts. I have been experimenting with SMPS's and DC to DC converters for vacuum tube uses. The 200 KHz switching frequency is not a problem. The 30 to 50KHz converters can be a problem. As I am trying to mount the preamp inside the guitar, I have found that some designs can play havoc with a guitar pickup even at a distance of over 1 foot. Toroidal inductors are your friend. Unshielded ferrite bobbins are not. __________________ Too much power is almost enough! Turn it up till it explodes - then back up just a little.

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17th July 2007, 03:40 AM	#2
Jeb-D. diyAudio Member Join Date: Nov 2005 Location: SoCal	Wow, that's a good find. Never tried one, but can think of plenty of uses for one. Perhaps in a hybrid automotive amplifier

17th July 2007, 07:56 PM	#3
r221b diyAudio Member Join Date: Jul 2007	For a start, you can't use a 12.6 volt transformer. Transformers only utilize AC. To get the DC input required, you'll need a rectifier and filter circuit. Another consideration is that these switchers run at 200 kHz according to the spec. sheet. That could produce switching noise in whatever you want to use them in. Third, the output is only 50 ma. If you stack them, only the voltage adds, the output current remains at 50 ma. If you can overcome these limitations, there's no reason they won't work. sherlock

18th July 2007, 01:13 PM	#5
r221b diyAudio Member Join Date: Jul 2007	Just trying to help.... I haven't a clue as to your technical knowledge or lack thereof. From what I've seen on this forum, there are people that know virtually nothing about electronics all the way up to electrical engineers. What's "obvious" to you probably isn't to a lot of others. Since I took the time to reply, a simple "thanks" might have been in order. I hope you get your answers. sherlock

18th July 2007, 01:26 PM	#6
revintage diyAudio Member Join Date: May 2007	Sherlock: Thank you for taking you time to answer. Sorry, did not mean to insult you . When I did not find the answers at Google, I asked here. Thought the knowledge level was higher. If you are still wondering about my level pls check my site www.revintage.se.

20th July 2007, 02:07 PM	#10
Jeb-D. diyAudio Member Join Date: Nov 2005 Location: SoCal	What's the price range for those?