50w Single-Ended BAF2015 Schade Enabled

[enochRoot]

Ah...thanks!

 

[enochRoot]

One more question, what voltage rating would be needed to use a rotary selector switch to change between the CCS taps? The highest rating I can find on Mouser w/ Grayhill switches is 28V DC. Would that be pushing it? Would that switch see the 28V DC before the output coupling cap?

 

[juanitox]

3.6Amp on a rotary switch don't know if it's a good thing

 

[enochRoot]

The current rating is actually 5A...just the voltage I'm concerned about.

 

[Soundhappy]

Or chose CCS connections points with a thick jumper on the amplifier boards

 

[enochRoot]

Yeah, that's my backup plan, but not as easy to use as a rotary switch.

 

[Zen Mod]

use some big hog switch , rated for 15 or 20A min.

voltage is not a problem , problem is contact impedance (resistance) ..... and higher rated are having smaller losses at contact

 

[Soundhappy]

My solution : 50w Single-Ended BAF2015 Schade Enabled

Point A and B have higher distortion numbers only C or D give better sound imho.
IXYS triode emulation distortion at the center tap C are very similar to 2SK77B

 

[enochRoot]

Thanks for the help guys!

I'm actually going to be using the 2SK77B circuit w/ either a 2SK182 or THF-51S and wanted to listen to all 4 positions to pick what I liked best. No offense on your opinions Soundhappy, but since the lower taps are hearing mainly just the SIT with no mosfet contribution...I wanted to at least give those a try. I had seen your implementation, and it is perfect for selecting one of 2 positions, but wouldn't help w/ the 4 unless I cascaded 3 switches which would start to look a bit off

And thanks ZM...I hadn't thought about the contact resistance issue. I found this badboy:

19001-04UL Grayhill | Mouser

I could give that a try, or else I guess go with the "not as easy to change" method, and use a short large-gauge wire jumper.

Not sure how I missed that switch in the first place while browsing Mouser. Spendy, but I would assume bulletproof!

 

[Zen Mod]

you're going to change taps only in first listening tests , and hopefully leave it later in one position

so , spend switch money on something else , do it any other way for testing

these things are sweet to have when you can buy them surplus

 

[enochRoot]

You're right...I guess I just like mechanical trinkets

Makes most sense to have a "jumperable" position on the board and then solder in the final position that I like.

 

[Soundhappy]

Thanks for the help guys!

I'm actually going to be using the 2SK77B circuit w/ either a 2SK182 or THF-51S
and wanted to listen to all 4 positions to pick what I liked best..

Ah OK You build with big Tokin's !
I understand better now , try all four CCS taps positions can be fascinating audio experiment
specially with the " Ninja Tune " record label music Have fun

 

[enochRoot]

Ah OK You build with big Tokin's !
I understand better now , try all four CCS taps positions can be fascinating audio experiment
specially with the " Ninja Tune " record label music Have fun

HAHA...yup! It was my favorite label through college 25 years ago. They still have some great releases, but when the owners sold the company I feel that it slipped a bit. Luckily I still have all my old records!

Thanks for the well wishes. Hopefully it doesn't generate too much heat here in the summer. Luckily I'm in Maine, so it's currently been nice and cool so far this year.

 

[Zen Mod]

every Home ought to have one 50W SE amp

 

[dantwomey]

Hi Pico,

I would not bias the bottom MOSFET in this way with these parts having such a great transconductance.
I did it only to show how smallest Vgs changes have big effects.
The only thing I would trust is Zen Mods servo solution!
He was so friendly to develop it for me, but I am afraid It will be autumn since I start the BAF2025 amp.

A couple things puzzling me are for one, why is a regulated supply so desirable? And two, later in the thread 1.2 was used to calculate the recommended transformer secondary voltage instead of 1.4. A minor point?

Anyways, I'm highly motivated to build the full 60V version!

Regards,
Dan

 

[Zen Mod]

Papa didn't said he used regulated supply , so why should you ?

1.2 for multiplicator is say thumb of rule - 1.41 being for unloaded rectifier+filter , 1.2something being for loaded rectifier+filter

when you are walking freely , you 're tall - how much?

when you're walking with cement bag on your shoulder(s) , you're tall how much minus 2 inches

 

[juanitox]

i have built mine with a 600VA 2X45V i gives me 60V B+ loaded and 64V unloaded 80V capacitor or more will suit well

 

[dantwomey]

i have built mine with a 600VA 2X45V i gives me 60V B+ loaded and 64V unloaded 80V capacitor or more will suit well

Perfect! Thanks for the info!

Regards,
Dan

 

[dantwomey]

I just ordered two of these AN-8445 - 800VA 45V Transformer - AnTek Products Corp. I'm very pleased that these include some low voltage secondaries for fans or other accessories.

Regards,
Dan

 

[dantwomey]

Papa didn't said he used regulated supply , so why should you ?

Starting around post #83 of this thread are conflicting opinions of what Pa is recommending. I hope my unregulated CLC will do.

Papa said it needs regulation to get the ripple down in the region of 1mV to 5mV.

Regards,
Dan