regulated 5V DC supply

[Bas Horneman]

At the least you have gotten my expectations of the design where they belong........

Cheers,
Bas

 

[dhaen]

Oh dear, that's torn it

 

[Bas Horneman]

Don't worry..I forgot a smiley!

 

[Ralph]

Tomatito,

For what it's worth, this is the DC supply I use for my KR300BXLS's. Please take into account that although the tubes are specified as 1.9A filament, that's not true. It's around 1.4A. That's important for the 'range' on your pot when using a currect regulator.

Cheers, Ralph

 

[Tomatito]

Ralph,

The plus of the rectifier is not connected ?

cheers

Martin

 

[Ralph]

Martin,

Oeps, error in picture. + goes to the first cap, - to neg of first cap.

Ralph

 

[Bas Horneman]

Ralph,

What are the values for all the resistors in your psu?

Cheers,
Bas

PS..Tomatito how is your regulator coming?

 

[Ralph]

Bas,

The complete design:

http://www.homepages.hetnet.nl/~rjonkers/psu.gif

http://www.homepages.hetnet.nl/~rjonkers/amp.gif

Cheers, Ralph

If you use SPLAN:
http://www.homepages.hetnet.nl/~rjonkers/300B_V4.spl

 

[Bas Horneman]

Thanks Ralph..

Went to your website..had the values already in there...stom van me.

I thought you had mistakenly used 1/14w resistors. but they are 1R/14W.

Regards,
Bas

 

[Tomatito]

heya Bas,

PS..Tomatito how is your regulator coming?

I'm trying to find the time to work on my amps, but it's been rather hectic lately. Let you know when I do.

Ralph:

This should do nicely. What is the voltage of the transformer ? You don't want to dissipate too much power I guess ?


Martin

 

[Ralph]

Martin,

Trafos are 0-14V. I use two stages to get rid of the extra voltage and reduce the AC ripple. I measure approx 10.5V at Vin of the regulator and use quit a heavy heatsink.

Cheers, Ralph

 

[ClefChef]

Hello everyone,

I have read everything I could find on AC vs DC heaters, especially when it comes to 300b as these seem to suffer from AC induced hum the most.
I have a wonderful 300b amp built by one of "Triode Mafia" members, unique design, Tango OPT, etc. It was built using AC filaments throughout - signal tubes and DHT. Having suffered the hum and trying all kinds of solutions (different tubes, 10 turn pots, balanced isolation transformers) I decided to convert 300b filaments to DC, - I got a pair of Tent Labs boards.
DC filaments is a compromise, a worthy one for me. AC filaments definitely sound different, some argue it sounds better. AC heating introduces some artifacts to the sound that makes it "mellow", thanks to 60 & 120 Hz intermodulation; DC makes it more "clinical".
Another thing that DC exposes is power supply noise that is previously masked by AC hum, installing "Ultra Path" caps solved that as well.
I also wired DC filaments on opposite pins for left and right channel, so I could switch the tubes to avoid that theoretical filament burn.
My resume: AC sounds "juicy" but suffers from hum and noise problems, DC sounds "dry" and exposes other problems in the amp, but is ultimately the better solution to me.