[cobaltmute]

This has been strangely quiet from you all.
 
I know boards have been shipped to people.  Has anyone, beside me, built one? If so, any feedback?
 
Usually by this point there would have been some questions.

 

[cobaltmute]

Someone asked recently about using the r1 as a heater supply for 6.3V, 600ma - I would say it is definitely doable.
 
Bom parts would be as follows:
R3 - jumper
R6 - 649 Ohms (6.35V output) or 661 Ohms (6.26V output)
D1 -1N5230B
U2 - LM336BZ-2.5
R7 - CMF55274R00FHEB
C3 - EEU-FC1E562
R4 - 80 Ohms - CMF5578R700FHEB
Q1 needs to be mounted on a good heatsink.
Transformer - 9VAC output
 
Given the hfe of Q1, per datasheet minimum this config will deliver 900ma, but using the typical hfe graph on the OnSemi datasheet, it will be more like 1.5A.
 

 

[Blooze]

That'd be me Erik!!!  I'm looking at using it for a preamp that already has a LM317 implementation in it's schematic for the heaters (2 x 300mA), but I figure for a few more $$$ I can have super quiet DC on the heaters which would work great for a pre and something that looks better than a cobbled up perfboard.  I can think of several other projects where this would work well for the same job.
 
Thanks for figuring out the parts requirements for me.  The transformer has an 8V/1.5A secondary winding that I figure will run more like 9V anyway with my high mains voltage, so those numbers should be good.  Any recommendations for a heatsink?
 
Just checking.............Would R6 be 649 ohms or 3.8K?  If I use the calculator on the BOM sheet using a reference voltage of 5V and R5=1000, then 3.8K gives me 6.3V out.  649 ohms gives me 12.7V out.

 

[cobaltmute]

Well, the issue with R6, is that I would recommend the 2.5V reference, as I listed in the post above rather than the 5V reference.  The reason is that you'll get better start up performance out of the bootstrap on the regulator.  Using the 5V reference for 6.3V can be done, but the component choice for D1 becomes critical to ensure proper start up and I haven't had enough sleep lately to find a good part.
 
So R6 would be 649 Ohms for the 2.5V reference.  If you wanted to use 5V reference (LM336BZ-5 for U2), you can use the the 3.83K, but use something like a 5.7-5.9V zener for D1.
 
As for a heatsink, you'll be getting ~12V after the bridge.  5.7V drop in Q1 @ 600ma = ~3.4W of heat to be dissipated.  I might try something like this with the fins oriented off the board:
http://ca.mouser.com/ProductDetail/Aavid-Thermalloy/7023B-MTG/?qs=sGAEpiMZZMttgyDkZ5WiusUw%252bQXhbmeCbGT4Q7lNLYE%3d
 
 

 

[Blooze]

Duh.  Didn't see the 2.5 on U2.  Now it makes sense.  Thanks for all your help.  Plan on ordering later this week after the paycheck with expendable income arrives.  Gotta stick to the budget and all.

 

[cobaltmute]

Quote:

Someone asked recently about using the r1 as a heater supply for 6.3V, 600ma - I would say it is definitely doable.
 
Bom parts would be as follows:
R3 - jumper
R6 - 649 Ohms (6.35V output) or 661 Ohms (6.26V output)
D1 -1N5230B
U2 - LM336BZ-2.5
R7 - CMF55274R00FHEB
C3 - EEU-FC1E562
R4 - 80 Ohms - CMF5578R700FHEB
Q1 needs to be mounted on a good heatsink.
Transformer - 9VAC output
 
Given the hfe of Q1, per datasheet minimum this config will deliver 900ma, but using the typical hfe graph on the OnSemi datasheet, it will be more like 1.5A.
 

Ok, a note about R3.  A jumper is easy and you don't have to worry about dissipation.
 
That being said, you could put a power resistor in for R3, say something like this: http://ca.mouser.com/ProductDetail/Bourns/PWR221T-30-4R70J/?qs=sGAEpiMZZMsPqMdJzcrNwqJAQmshBUYlGg%252b3d6X9QRo%3d
 
You dissipate about 1.8W in that resistor, but you get some other benefits.  A really nice one is that R3/C3 would form a low pass filter with a corner of 6Hz, helping reduce noise.  That resistor is rated for 2.25W in free air, so you could likely use a small heatsink like this: http://ca.mouser.com/ProductDetail/Aavid-Thermalloy/577202B00000G/?qs=sGAEpiMZZMttgyDkZ5Wiut26jWwHqNF9cgDmGgnRNkQ%3d or the same one I suggested for Q1.
 
Edit:  And as a side effect, you split the heat dissipated total to both R3 and Q1.
 
 
 
 

 

[glt]

Very nice project.
What is the voltage headroom required to keep Q1 going? (the voltage headroom after R3)
Also what are the simulations results?
 
Thanks

 

[tomb]

OK guys - what gives?  I've sold all 29 prototypes that were available and no one who bought one has posted a dang thing.  Haven't any of you built one, yet?

 

[Blooze]

Quote:

OK guys - what gives?  I've sold all 29 prototypes that were available and no one who bought one has posted a dang thing.  Haven't any of you built one, yet?

Sorry about that Tom.  My amp and preamp projects got put on hold for a bit so I haven't populated the boards, but I see no reason why they wouldn't work very well for filament regulators, especially in my preamp project where quiet is better.  My preamp is awaiting the implementation of a friends remote control design into the existing schematic, but I'm hoping it will be ready to start in a month or so.

 

[tomb]

Quote:

Sorry about that Tom.  My amp and preamp projects got put on hold for a bit so I haven't populated the boards, but I see no reason why they wouldn't work very well for filament regulators, especially in my preamp project where quiet is better.  My preamp is awaiting the implementation of a friends remote control design into the existing schematic, but I'm hoping it will be ready to start in a month or so.

Well at least you posted, Blooze - even if you haven't built one, yet.  Thanks!!
 
I'm going to build one next weekend and let you all know how it turns out.

 
 

 

[cobaltmute]

Quote:

OK guys - what gives?  I've sold all 29 prototypes that were available and no one who bought one has posted a dang thing.  Haven't any of you built one, yet?

 
Maybe it is such a stunning design with such awesome docs and ease to build that no-one has to ever ask any question about it.  Ever.
 
And if you believe that I've got a small tropical island to sell you at a great price. 

 
 

 

[tcpoint]

Just started a board late last night.  Will probably finish either Tuesday or Wednesday (Got to take the kids trick or treatin' tonight).  Will let you know how it goes.  I expect it will just work.
 
I plan on making one 9V PS and a +/-15V (with the other two board).

 

[tomb]

Sounds great!  I'm delayed, as usual - hope to get to it this weekend.

 

[tcpoint]

Put together a 9 V board and it works great.  Thanks for putting together this project.

 

[tomb]

Quote:

Put together a 9 V board and it works great.  Thanks for putting together this project.

Excellent!