Wanting to build a higher powered SE.

[nyazzip]

i just saved this thread to my faves...thanks guys(greg)! i may well refer to it down the road

[DeathRex]

A lot of schematics.
http://translate.google.com/translate?h ... 809-J.html

And some beautiful builds.

Warning NSFW, amplifier porn.

[Geek]

A lot of schematics.
http://translate.google.com/translate?h ... 809-J.html

And some beautiful builds.

Warning NSFW, amplifier porn.

Wow!

[DeathRex]

I missed posting the gallery.
http://translate.google.com/translate?h ... llery.html
Besure to click on Minute Production in 2007, 2006, 2005, and 2004 and before for more.
Click on the picture of each amp and he'll tell you about it and include a schematic of almost each one.

Check out the 1.6 million yen (about $15,000) amp with the 13 1/2" high STC4212. It makes the 845 look like a wee 6V6.

[kheper]

He uses the 5998a regulator tube (same as michimori) to drive the 100TH to a cool 23W audio output, but he does not use the same CF+CCS design. On some of his amps, he opts for pentode drive, c3g, ef86, etc.

[DeathRex]

These power SE amps are like stepping into a whole new world. Too many configurations and too many tube choices. I gotta build more than one.
I'm thinking of starting with a 811a driven by a 6L6. Then Gregg's 845, but with either a Chinese 845, GM-70, 813, or 838. Then maybe George's Tubelab SE. I gotta get a selection of tubes.
Are Edcor's CXSE OK with 1000 volts? What can they go up to?
What are some good 845s, GM70s or such?

[kheper]

These power SE amps are like stepping into a whole new world. Too many configurations and too many tube choices. I gotta build more than one.
I'm thinking of starting with a 811a driven by a 6L6. Then Gregg's 845, but with either a Chinese 845, GM-70, 813, or 838. Then maybe George's Tubelab SE. I gotta get a selection of tubes.
Are Edcor's CXSE OK with 1000 volts? What can they go up to?
What are some good 845s, GM70s or such?

Maybe someone here knows how much zap an Edcor can take before frying, but I would verify by sending Edcor an email, if I were to shoot more than 800V into their transformers.

Shuguang makes new production 845s. However, there are three different versions floating around: A, B and C. Before you buy, ask which one you are getting. Shuguang makes new production 813s. They were a decent price, until the price shot up recently to ~$70 a pop. GM70s come in two flavors: copper and graphite anode. The graphite anode is not recommended for high-end audio, so you pay through the nose for the copper.

From Michimori's website. He goes into detail on building the SE 811a:

http://www6.plala.or.jp/Michi/renewal81 ... l811A.html

[Geek]

Are Edcor's CXSE OK with 1000 volts? What can they go up to?

Not according to Brian. That's why they discontinued the XPWR169 as they found some long-term breakdown effects.

However, when I got my power transformer, I used lengths of heatshrink on each wire to protect them (it was a tight fit through the grommet) and after 1 year of service, there was no degredation or ozone damage. I think Edcor is just covering their butts

The OPT's are running at 900V, so they are fine and available.

Cheers!

[DeathRex]

From Michimori's website. He goes into detail on building the SE 811a:

http://www6.plala.or.jp/Michi/renewal81 ... l811A.html

I like Michimori's front end, but I don't like the driver, because it's more expensive than the 6AS7s I have now, I need a plus and minus 200 volt ps, and the 50 watt resistor under the chassis. Michimori also made a 4P1L driver with a choke load, like that one better, but I like this one best:

A simpler driver, but the EL34 anode voltage affects the bias voltage. I'm looking to increase B+ to about 550 - 600.

[DeathRex]

How big of a power transformer will I need? I'm thinking a 250-0-250 to 280-0-280 used as doubler, with the center voltage being used for the first AF amp and the driver, and in stereo.

[kheper]

How big of a power transformer will I need? I'm thinking a 250-0-250 to 280-0-280 used as doubler, with the center voltage being used for the first AF amp and the driver, and in stereo.

200Vac @ 1.1A (per channel) should be ok, which will yield 565Vdc @ 305madc (per channel) . To be sure, calculate the current draw for the 6l6s and the 717As in this circuit.

I am going by the 300ma x 2 in the schematic. 300madc per channel seems like overkill.

[DeathRex]

Yea, it says he only needs 132ma, maybe 300ma was the only size he could find. So if I need 160 ma @ 550 (80 ma X 550 + losses = ~42 watts), and 60ma @ 275VDC (center tap of doubler), could the minimum current of a 250-0-250 transformer be 380ma? (160ma X 2 + 60ma?)

[DeathRex]

Yea, it says he only needs 132ma, maybe 300ma was the only size he could find.

I found on number 221 he used a 150ma xformer for monoblocks, and he said 300ma was for stereo. Now I have to find one or 2.

[kheper]

Yea, it says he only needs 132ma, maybe 300ma was the only size he could find. So if I need 160 ma @ 550 (80 ma X 550 + losses = ~42 watts), and 60ma @ 275VDC (center tap of doubler), could the minimum current of a 250-0-250 transformer be 380ma? (160ma X 2 + 60ma?)

250-0-250 (with the center tap floating) will yield a voltage in the 845 (get zapped and go to the morgue) territory, ~1,414Vdc.

http://tubes.nekhbet.com/power.shtml#doub

I found on number 221 he used a 150ma xformer for monoblocks, and he said 300ma was for stereo. Now I have to find one or 2.

2 x Antek AS-1T200 (200Vac @ 1A) will produce 565Vdc @ 275madc. $34.50 a pop for the Antek is not a bad price. You can stack toroids without fear of EMI.

http://www.antekinc.com/details.php?p=669

Maybe, you could get a custom 200Vac @ 1.1A from Audio Vista, Piltron or elsewhere?

[DeathRex]

Yea I don't want to make 1400.
Here's a schematic of what I'm thinking about.
I can't make this in PSU designer II. But it should give me ~300 and ~600VDC from a 250-0-250.
It would almost be cheaper to use 2 Anteks, but then I have to enclose them into something.