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Old 27th December 2007, 10:15 PM   #11
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Location: South Florida
Here's the schematic, including the power supply.

How exactly did you configure the power supply?

-- josť k.
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Old 27th December 2007, 10:22 PM   #12
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Location: Maryland
Many folks have the board switchable between solid state and tube rectification with a switch so it shouldn't be a problem. By not shorting the terminals for choosing rectification the board should default to tube rectification.

I'm thinking I should pull the solid state diodes out, but they don't seem to be shorted according to my multimeter. I'll need to take a closer look.

Check out for more details.

I've also got a high-rez link to a photo that should make it easy to see the wiring.
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Old 27th December 2007, 10:29 PM   #13
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Location: West Virginia panhandle
Hi whitelabrat:

Remove the FRED diodes and try the amp again using the tube rectifier. There have been some issues with IXYS diodes blowing when the standby switch is flipped. They often test OK. The amp will work without them. They are only used in the SS rectifier mode, but when one dies it makes the transformer really unhappy. Unless you ran the transformer with a dead doide and no fuse for a long while it will be fine.

You should have a fuse in the circuit between the line input and the power transformer. 2 amp in 120 volt countries, 1 amp in 240 volt world.

I am 1200 miles from home, and missed the start of this thread. Just got DSL installed here, like 10 minutes ago.
Tubelab, it's 5 year mission. To explore strange new tubes, to seek out new circuits and topologies, to boldly go where no tube has gone before......
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Old 27th December 2007, 10:34 PM   #14
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Thanks George!!!

A personal thanks for the awesom board and instructions! For the 10 minutes I was up and runnging... It sounded fantastic!!!
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Old 28th December 2007, 01:32 AM   #15
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Ok. I yanked the Freds off the board. Rock and roll! Literally!

The solid state diodes shorted. All is well. Sounds great!
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Old 30th December 2007, 02:21 AM   #16
chrish is offline chrish  Australia
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I had a very similar problem with my SimpleSE. After removing the solid state diodes, I was still using the standby switch with a JJ 5AR4 and eventually fried the rectifier tube as well. My solution was to remove the solid state diodes and also remove the standby switch. No problems since. Here is a link to a very similar problem with an EL84 PP design. Similar standby switch implementation with similar failures.

Hope you don't have any more problems. Apart from this, my SimpleSE has been great!

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Old 2nd January 2008, 01:42 PM   #17
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I saw the same post for the Diytube ST35 board. I just got one recently and realized that the standby switch issue applies to the SimpleSE as well. I'll be using the ST35 board for a project to salvage an old PP EL84 amp.

I've done away with the switch and the diodes on the SimpleSE and I've had reliable operation for just about a week now.

Also another thing I've discovered. I've gone around and done a sampling of the resistance of the primary side of several power transformers. They all seem to be less than 2 ohms.
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