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Old 5th May 2011, 02:13 AM   #31
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Just turned it on again and here is the pic of voltage across R4. I kept it on for about a minute. I'm not feeling brave enough to keep it on for longer because of really loud hum and all. The C1 and C2 were not super hot.



Click the image to open in full size.

Last edited by imnewbie; 5th May 2011 at 02:18 AM.
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Old 5th May 2011, 10:14 AM   #32
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Quote:
Originally Posted by imnewbie View Post
Just turned it on again and here is the pic of voltage across R4.
Your meter is on AC volts. What you should have across R4 is pure rectified DC. Try it again with the meter on the high voltage (1000V) DC range.
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Old 5th May 2011, 10:36 PM   #33
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Oops...my mistake...now I see I'm getting 437V DC across R4. I'm using 33uF C1 and Triode C-14X choke(150 ohm), C17/27= 820 ohm. Then the blue glow must be normal characteristic with my 6L6GC as George has said. I'm using Ruby 6L6GCM-STR pair. Can OPT primary resistance of 8k cause this blue glow?

Played some Pink Floyd for 40 minutes without issues. Somehow this amp even in triode mode is louder than my 12WPC EL84 p-p amp.

BTW, my XPWR035 hums louder than the hum from speakers. It's like having a little battery powered fan on at all times...so annoying. Even without PCB connected to it's secondary, it hums quite loud, so It's going back to Edcor.

Last edited by imnewbie; 5th May 2011 at 10:38 PM.
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Old 6th May 2011, 12:14 AM   #34
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Quote:
Originally Posted by imnewbie View Post
...now I see I'm getting 437V DC across R4.

Then the blue glow must be normal characteristic with my 6L6GC as George has said. Can OPT primary resistance of 8k cause this blue glow?

Played some Pink Floyd for 40 minutes without issues. Somehow this amp even in triode mode is louder than my 12WPC EL84 p-p amp.

BTW, my XPWR035 hums louder than the hum from speakers. Even without PCB connected to it's secondary, it hums quite loud, so It's going back to Edcor.
Your voltage looks normal. The blue glow is fine, even in the 12AT7. I've had some tubes that get quite excited and glow a lot. There's nothing wrong with most types of blue glow. The blue glow is completely unrelated to the OPT primary load. It depends entirely on the materials used in the manufacture of the tube. I find the higher the plate voltage, the brighter it glows. As the tubes age, it wouldn't surprise me if the glow begins to fade. Here are some Chinese tubes in my SSE:

Click the image to open in full size.
http://i69.photobucket.com/albums/i4...es/Blue6L6.jpg

I always felt the SSE had a lot of gain, even in triode mode. Don't confuse gain for output power. High gain simply means you will likely need to keep the volume knob a little lower.

Sorry to hear your Edcor is a hummer. Some transformers hum because they don't know the words (sorry - bad joke). Just about every power transformer I own hums to some degree. Some are rather loud and annoying. The one Edcor (XPWR005) I have isn't too bad. Just make sure the four bolts in the corners are snug (but not overtight), and if that doesn't fix it there isn't much you can do. I wouldn't think it should hum at all if there is no load on any secondary. I think you are right to request an RMA.
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Old 6th May 2011, 02:07 AM   #35
rknize is offline rknize  United States
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I have two Edcors power transformers. They are both pretty quiet. The one in my SSE is dead quiet. The one in the TSE is dead quiet.

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Old 6th May 2011, 02:09 AM   #36
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My experience has been that the blue glow is a byproduct of a hot bias sounds good but short tube life 6l6/6v6 sound glorious EL34 can take the heat better with less distortion, share your circuitry and pin voltages with us that we may further evaluate. watch for hot spots on the plates as a tube failure can be painfull to your wallet .

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Old 6th May 2011, 11:00 PM   #37
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Originally Posted by rknize View Post
I have two Edcors power transformers. The one in my SSE is dead quiet
Not even a tiny bit hum/buzz from 7-8 inches away? Although, I don't have to go that close to my XPWR035 since it's buzz can be heard clearly from across the room.

Quote:
Originally Posted by Ty_Bower View Post
...because they don't know the words (sorry - bad joke).
lol..
BTW, my tubes have similar blue glow, and some little blunt blue spots on bottom plates. Most likely due to materials as you have pointed out.

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Share your circuitry and pin voltages with us that we may further evaluate. watch for hot spots on the plates...
There are no orange spots on the plates, its a blue glow as visible in my and Ty's pics. There are few blunt blue spots on the bottom plate. All the PCB parts are identical to parts list with an only exception of using a 33uF C1 and 820 ohm R17/27. The rest is 150 ohm C-14x choke and I'm not using any supplemental cap. Foe 12AT7 voltage across pin 9 and 4 or 5 is 6.1VAC while for 6L6s voltage across pins 2 and 7 is 6.2VAC. Not sure how to test the rest of the pins.

Last edited by imnewbie; 6th May 2011 at 11:15 PM.
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Old 8th May 2011, 02:22 AM   #38
rknize is offline rknize  United States
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Quote:
Originally Posted by imnewbie View Post
Not even a tiny bit hum/buzz from 7-8 inches away? Although, I don't have to go that close to my XPWR035 since it's buzz can be heard clearly from across the room.
Sorry...I missed-typed that. The one in the SSE is dead quiet for the most part. I have to put my ear few inches away to hear any buzz. It gets a bit louder if I push the amp hard with big power tubes and higher plate current. The one in the TSE was a bit more buzzy than the SSE.

Quote:
BTW, my tubes have similar blue glow, and some little blunt blue spots on bottom plates. Most likely due to materials as you have pointed out.
Some tubes do glow in operating. Sometimes there is discoloration of the internal materials from welds, etc. If the plates aren't glowing orange, I wouldn't worry about it.
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